Long-term care facilities (LTCFs) remain highly vulnerable to COVID-19. Despite reduced virulence, Omicron's high transmissibility poses ongoing risks. The effect of infection under strict control measures and early antiviral treatment remains unclear.

We conducted a retrospective cohort study in a 450-bed LTCF, which implemented rigorous infection control and early antiviral use, evaluating survival outcomes during repeated Omicron outbreaks from January 2022 to December 2023 using Cox regression with time-dependent covariates, adjusted for age, sex, comorbidities, and vaccination status. Mortality trends were also compared across three periods: pre-COVID-19 (2018-2019), COVID-19 present in Japan but absent in our facility (2020-2021), and the Omicron outbreak period (2022-2023).

Among 623 residents, 253 were infected. Mortality was lower in the infected group than in the uninfected group (16% vs. 26%), and infection was not significantly associated with increased mortality (HR = 1.36; 95% CI: 0.91-2.04; p = 0.14). Although stratified analysis showed higher mortality among infected females, overall mortality during the outbreak period was unexpectedly lower than in prior periods.

In LTCFs with rigorous infection control and early antiviral use, Omicron infection did not raise mortality. Enhanced protocols may have improved survival, even among uninfected residents.

Based on a serosurvey conducted in March 2021, Barrie and colleagues published the first nationally representative SARS-CoV-2 serosurvey in Africa, estimating a SARS-CoV-2 seroprevalence of 2.6% in Sierra Leone, 43 times higher than the reported number of cases at that time. Over the following two years, increasingly transmissible variants-specifically Delta and Omicron-proliferated across the globe, and their impact in Africa is poorly understood. Additional nationally representative seroprevalence data are therefore necessary to understand the pandemic's progression on the continent and for evaluating containment measures and future preparedness. Our follow-up nationally representative survey was conducted in Sierra Leone from February to March 2023. We returned to the 120 Enumeration Areas throughout the country collecting blood samples from one or more individuals per household as well as information on sociodemographic characteristics, history of COVID-19 infection and immunization, and attitudes towards vaccination. The weighted overall seroprevalence (vaccinated and/or SARS-CoV-2 infection) for individuals >19 years of age was 33% (95% CI 29-37). Using the data and distributions from our previous serosurvey, the weighted predicted seroprevalence (any prior SARS-CoV-2 infection) for the general population was 28% (95% CI 15-41). The weighted predicted seroprevalence was ~11 times higher than the pre-Delta/Omicron prevalence. It was also over 300 times higher than the reported number of cases. Despite this, overall seroprevalence was low compared with countries in Europe and the Americas (pointing towards lower transmission in Sierra Leone). In addition, our results suggest the following regarding prevention campaigns claiming to have vaccinated 70% of adults in Sierra Leone as of December 2022: 1) they resulted in limited seroconversion; 2) there was significant waning of immunity; and/or 3) many less individuals were vaccinated than reported. Regardless of the cause, the utility of COVID-19 Vaccine Delivery Partnership (CoVDP) efforts three years into the pandemic is called into question.

ObjectiveTo examine the clinical outcomes of systemic lupus erythematosus (SLE) patients with COVID-19 during the Pre-Delta/Delta and Omicron periods.MethodsA retrospective study was conducted in a cohort of adult Puerto Ricans with SLE. Demographic parameters, SLE and COVID-19 manifestations, comorbidities, pharmacologic treatment, SLE exacerbations, hospitalizations, and mortality were determined. SARS CoV-2 infection was confirmed by polymerase chain reaction or antigen tests. Variables were compared between the Pre-delta/Delta and Omicron periods. Also, the proportion of COVID-19 cases and mortality of SLE patients was compared to the general population of Puerto Rico.ResultsOf the entire SLE cohort (n = 347), 169 patients (48.7%) had COVID-19. Twenty-two patients had COVID-19 during the Pre-delta/Delta period and 147 during the Omicron period. The proportion of COVID-19 cases in the SLE cohort was significantly higher when compared to the adult general population of Puerto Rico (25.7%), but no difference in mortality was found. Overall, the clinical outcomes of COVID-19 in the SLE cohort were favorable, with low rates of lupus flares (3.0%), hospitalizations (3.6%), and mortality (0.6%). Patients with COVID-19 during the Pre-delta/Delta period were more likely to have oral ulcers, anti-Smith antibodies, and chronic kidney disease, whereas those during the Omicron period were more likely to have COVID-19 symptoms (rhinorrhea, sore throat, and cough).ConclusionIn summary, is this group of Puerto Ricans with SLE, a high proportion had COVID-19, but disease exacerbation, hospitalization, and mortality rates were low. Few clinical differences were noted in SLE patients when comparing the Pre-delta/Delta and Omicron periods.

Post-exposure severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) testing following health facility outbreaks may control the spread of infection.

This study aimed to assess the impact of testing for SARS-CoV-2 infection on health outcomes during healthcare facility outbreaks.

This review included studies conducted at skilled nursing facilities, a cancer centre, and a geriatric psychiatric facility.

We followed the methods for conducting rapid systematic reviews, searched databases from December 2019 to August 2022, assessed the risk of bias using the modified Newcastle Ottawa scale, and graded the certainty of evidence using the Grading of Recommendations, Assessment, Development and Evaluations (GRADE) approach. We pooled the prevalence, mortality, and hospitalisation results as appropriate.

Of the 3055 articles from database search, no study was eligible for inclusion as outlined in the protocol. However, eight non-comparative reports (case series) in skilled nursing facilities were included. The pooled prevalence of SARS-CoV-2 infection among residents of care homes and patients were 38% (95% confidence interval [CI] = 25% - 51%; 5 studies, 2044 participants; I 2 = 94%, very low certainty evidence) and was 12% (95% CI = 6% - 19%; 5 studies, 2312 participants; I 2 = 94%, very low certainty evidence) for exposed healthcare workers. The pooled mortality estimate and hospitalisation rate were 17% and 24%, respectively, (very low certainty evidence).

There is no identified evidence for or against testing of people in healthcare facilities where there is ongoing transmission of SARS-CoV-2 infection.

The evaluation of the effectiveness of testing strategies during SARS-CoV-2 outbreaks need baseline and follow-up data from well-designed before and after studies appropriate for the setting.

The emergence of SARS-CoV-2 variants has significantly impacted the global response to the COVID-19 pandemic. This review examines the genetic diversity of SARS-CoV-2 variants, their roles in epidemiological tracking, and their influence on viral fitness. Variants of concern (VOCs) such as Alpha, Beta, Gamma, Delta, and Omicron have demonstrated increased transmissibility, altered pathogenicity, and potential resistance to neutralizing antibodies. Epidemiological tracking of these variants is crucial for understanding their spread, informing public health interventions, and guiding vaccine development. The review also explores how specific mutations in the spike protein and other genomic regions contribute to viral fitness, affecting replication efficiency, immune escape, and transmission dynamics. By integrating genomic surveillance data with epidemiological and clinical findings, this review provides a comprehensive overview of the ongoing evolution of SARS-CoV-2 and its implications for public health strategies and new vaccine development.

The global spread of the novel coronavirus disease 2019, caused by SARS-CoV-2 virus, impacts individuals of all age groups, including lactating women and children. Concerns have been raised regarding the potential transmission of SARS-CoV-2 from mother to child, following the discovery of SARS-CoV-2 RNA in human milk. Therefore, this study aims to investigate whether the Omicron novel coronavirus variants are transmitted through human milk. This study was conducted between March and May 2022 at Children's Medical Center, the First Hospital of Jilin University, Lequn Branch. Fourteen lactating mothers and their breastfed children hospitalized with COVID-19 (Omicron variant) formed mother-child pairs, which constituted the test group. Additional 11 non-breastfed children of the same age hospitalized with COVID-19 (Omicron variant) participated in the study as the control group. Their clinical manifestations were observed, and the milk of lactating mothers with COVID-19 was collected for SARS-CoV-2 RNA detection. Milk samples from each lactating mother were collected consecutively for 2-18 days and subjected to polymerase chain reaction (PCR) testing forSARS-CoV-2 RNA detection. The time span for sample collection ranged from admission to discharged. The symptoms observed in mothers and children infected with the Omicron variant of COVID-19 were primary upper respiratory tract infection, with fever and cough being the main clinical manifestations. In total, 104 breast milk samples were collected from 14 lactating mothers with COVID-19, and all samples were negative for SARS-CoV-2 RNA. This study found no evidence of Omicron variants transmission through breast milk and accepts the safety of breastfeeding for novel coronavirus-positive mothers when contact precautions are taken. Our findings provide additional support for recommendations that lactating women with COVID-19 continue to breastfeed while taking precautions.

The ongoing global health crisis caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) necessitates the continuous development of innovative vaccine strategies, especially in light of emerging viral variants that could undermine the effectiveness of existing vaccines. In this study, we developed a recombinant virus-like particle (VLP) vaccine based on the Newcastle Disease Virus (NDV) platform, displaying a stabilized prefusion form of the SARS-CoV-2 spike (S) protein. This engineered S protein includes two proline substitutions (K986P, V987P) and a mutation at the cleavage site (RRAR to QQAQ), aimed at enhancing both its stability and immunogenicity. Using a prime-boost regimen, we administered NDV-VLP-S-3Q2P intramuscularly at different doses (2, 10, and 20 µg) to BALB/c mice. Robust humoral responses were observed, with high titers of S-protein-specific IgG and neutralizing antibodies against SARS-CoV-2 pseudovirus, reaching titers of 1:2200-1:2560 post-boost. The vaccine also induced balanced Th1/Th2 immune responses, evidenced by significant upregulation of cytokines (IFN-γ, IL-2, and IL-4) and S-protein-specific IgG1 and IgG2a. Furthermore, strong activation of CD4+ and CD8+ T cells in the spleen and lungs confirmed the vaccine's ability to promote cellular immunity. These findings demonstrate that NDV-S3Q2P-VLP is a potent immunogen capable of eliciting robust humoral and cellular immune responses, highlighting its potential as a promising candidate for further clinical development in combating COVID-19.

The literature associating the spread of SARS-CoV-2 with the healthcare-related, geographical, and demographic characteristics of the territory is inconclusive and contrasting. We studied these relationships during winter 2021/2022 in South Tyrol, a multicultural Italian alpine province, performing an ecological study based on the 20 districts of the area. Data about incidence, hospitalization, and death between November 2021 and February 2022 were collected and associated to territorial variables via bivariate analyses and multivariate regressions. Both exposure variables and outcomes varied widely among districts. Incidence was found to be mainly predicted by vaccination coverage (negative correlation). Mortality and ICU admission rates partially followed this distribution, while the case fatality rate was inversely correlated to average salary, and hospital admission rates increased where hospitals capacity was higher, and from the southern to the northern border of the province. These findings, besides confirming the efficacy of vaccination in preventing both new and severe SARS-CoV-2 cases, highlight that several geographical and socio-demographic variables can be related to disease epidemiology. Remote areas with wage gaps and lower access to care suffered most from the pandemic. Our findings, therefore, underly the existence of health inequity issues that need to be targeted by implementing specifically tailored public health interventions.

The COVID-19 pandemic caused by the SARS-CoV-2 virus continues to circulate worldwide, causing the deaths of millions of people. The continuous circulation of the virus, its genetic diversity, the emergence of new variants with increased transmissibility, and/or the capacity of the virus to escape from the immune system constitute a major public health concern. In our study, we aimed to characterize SARS-CoV-2 strains in Iraq from the first introduction until the end of 2023, and to identify their variants, lineages, clades, and mutation patterns. All published Iraqi full genome sequences (2020-2023) were obtained from Global Initiative on Sharing All Influenza Data (GISAID) and subjected to molecular characterization along with 19 samples of full genome sequences that were collected during the fifth and sixth waves of the SARS-CoV-2 pandemic in this study. Next-generation sequencing was performed using an Illumina MiSeq system, and phylogenetic analysis was performed for all the Iraqi sequences. Three established global platforms, GISAID, Nextstrain, and PANGO, were used for the classification of isolates into distinct clades, variants, and lineages. Six wave peaks of COVID-19 cases have been identified in Iraq, resulting in approximately 2,400,000 cumulative confirmed cases and more than 25,000 deaths. Our study revealed patterns of circulation and dominance of SARS-CoV-2 clades and their lineages in the pandemic waves in the country.

The different strains of SARS-CoV-2 were detected and labeled in 2021. Each strain differs in both clinical symptoms and severity. Previous studies found different clinical symptoms and treatment outcomes between outbreak waves; however, data in Southeast Asia were limited. This study collected data of hospitalized COVID-19 patients from a Tertiary hospital in Thailand between January 2020 and December 2023 and analyzed patients' data in each outbreak wave using Pearson's chi-square. A total of 1084 inpatients were included for analysis. The median age was 64 (IQR, 0.4-100) years. The patients were hospitalized in predominantly Alpha (22.78%), Delta (21.68%), and Omicron (5.07%) periods of the virus outbreak. The largest age group was elderly (over 65 years old) in all three variant of concern (VOC) periods; 82.65% of the patients had comorbidities, including 58.5% hypertension, 46.5% dyslipidemia, and 42.0% diabetes mellitus (DM). The study found pneumonia at 67.53%, septic shock at 4.61%, acute respiratory distress syndrome (ARDS) at 2.86%, and congestive heart failure at 0.83% in all age groups with no significant difference between outbreak periods. The overall mortality rate was 16.14%. A total of 75% of deaths occurred in patients over 65 years old. The mortality rates in each VOC period were 20.0% Delta, 19.83% Alpha, and 13.23% Omicron. In the elderly group, the mortality rates were Delta 15.32%, Alpha 11.75%, and Omicron 10.88%. The Omicron VOC was less severe than other variants, particularly in the elderly (≥65 years). There were no significant differences in the younger (<65 years) age group. The elderly still had more severe symptoms and the highest mortality rates in every wave of outbreak.

The COVID-19 pandemic has caused overwhelming morbidity, mortality, and hospitalization worldwide, including in the state of California. Vaccination efforts have been an important measure in curtailing the adverse outcomes of COVID-19.

To quantify the effectiveness of COVID-19 vaccinations in California, we conducted a retrospective cohort study investigating how vaccination has impacted the extent of COVID-19 contraction, hospitalizations, and death totals. We compared outcomes of the Delta Wave, Omicron Wave, and Pre-Delta Period.

Vaccinated individuals have far-lower incidence risk ratio (IRR) of and odds of contracting a COVID-19 case (Delta IRR: 0.197) being hospitalized from COVID-19 (Delta IRR: 0.105), and dying from COVID-19 compared with an unvaccinated individual (Delta IRR: 0.0941). The preventive fraction of the unexposed and population-preventive fractions for cases, deaths, and hospitalizations also showed significant proportions. All tests showed P < .001.

Vaccination was most effective in the Delta Wave, then in the Omicron Wave, and least effective in the Pre-Delta Period. Deaths were the most prevented outcome, followed by hospitalizations, then cases.

This study exposes the massive impact of vaccinations in California in reducing COVID-19 outcomes and the potential for fewer adverse outcomes had there been greater vaccination compliance, demonstrating the need to increase vaccination efforts.

Global investment in developing COVID-19 vaccines has been substantial, but vaccine hesitancy has emerged due to misinformation. Concerns about adverse events, vaccine shortages, dosing confusion, mixing vaccines, and access issues contribute to hesitancy. Initially, the WHO recommended homologous vaccination (same vaccine for both doses), but evolving factors led to consideration of heterologous vaccination (different vaccines). The study compared reactogenicity and antibody response for both viral protein spike (S) and nucleocapsid (N) in 205 participants who received three vaccination regimens: same vaccine for all doses (Pfizer), two initial doses of the same vaccine (CoronaVac or AstraZeneca), and a Pfizer booster. ChAdOx1 and BNT162b2 vaccines were the most reactogenic vaccines, while CoronaVac vaccine was the least. ChAdOx1 and BNT162b2 achieved 100% of S-IgG seropositivity with one dose, while CoronaVac required two doses, emphasizing the importance of the second dose in achieving complete immunization across the population with different vaccine regimes. Pfizer recipients showed the highest S-IgG antibody titers, followed by AstraZeneca recipients, both after the first and second doses. A third vaccine dose was essential to boost the S-IgG antibodies and equalize the antibody levels among the different vaccine schedules. CoronaVac induced N-IgG antibodies, while in the Pfizer and AstraZeneca groups, they were induced by a natural infection, reinforcing the role of N protein as a biomarker of infection.

The first case of COVID-19 was detected in Dec 2019, in China. The disease shortly evolved into a pandemic and imposed an unparalleled health and social burden on mankind. Severe forms of COVID-19 mainly affect adults, especially the elderly and those with comorbidities. We report a severe case of COVID-19 in a previously healthy 12-year-old female who was admitted to the emergency room on May 26, 2020, with fever, abdominal pain, vomiting, and diarrhea. During the hospital stay, she tested positive for SARS-CoV-2 and developed multiple organ failure and catastrophic thrombotic events resulting in bilateral amputation of legs and fingers. She was discharged from the hospital for outpatient follow-up after 107 days. By the time this report was written, the patient was undergoing prosthesis prescription and training and regaining her independence to walk.

This study aimed to evaluate the cost-effectiveness of nirmatrelvir/ritonavir (Nir/Rit) for adult outpatients with COVID-19 from the perspective of a Japanese public healthcare payer.

A cost-effectiveness simulation was conducted comparing Nir/Rit for the outpatient treatment of high-risk COVID-19 patients to best supportive care (BSC) without antiviral or antibody drugs. The analytical model was divided into two phases: the treatment phase, lasting 35 days from the start of COVID-19 treatment, and the post-treatment phase. Patients who survived the treatment phase were assumed to follow a general population survival curve. Expected costs and expected quality-adjusted life years (QALYs) for both BSC and Nir/Rit were calculated for ages 40 to 80 to obtain the incremental cost-effectiveness ratio (ICER). The robustness of the results was evaluated through deterministic and probabilistic sensitivity analysis (PSA).

The ICERs for patients aged 40, 50, 60, 70, and 80 were 18,854,276 Japanese Yen (JPY)/QALY, 8,482,034 JPY/QALY, 4,976,612 JPY/QALY, 2,636,096 JPY/QALY, and 1,597,783 JPY/QALY, respectively. In the deterministic sensitivity analysis, both the mortality risk during the treatment phase and the relative mortality risk with Nir/Rit had a high impact on ICER across all ages. In the PSA, when the willingness-to-pay (WTP) threshold was set at 5 million JPY/QALY, the probability of the ICER being below the WTP threshold was 0%, 0.2%, 45.4%, 99.9%, and 100% at ages 40, 50, 60, 70, and 80, respectively.

Nir/Rit is cost-effective for older individuals aged 60 and over but not for younger age groups.

SARS-CoV-2 has triggered an international outbreak of the highly contagious acute respiratory disease known as COVID-19. Identifying key targets in the virus infection lifecycle is crucial for developing effective prevention and therapeutic strategies against it. Furin is a serine endoprotease that belongs to the family of proprotein convertases and plays a critical role in the entry of host cells by SARS-CoV-2. Furin can cleave a specific S1/S2 site, PRRAR, on the spike protein of SARS-CoV-2, which promotes viral transmission by facilitating membrane fusion. Hence, targeting furin could hold clinical implications for the prevention and treatment of COVID-19. This review offers an overview of furin's structure, substrates, function, and inhibitors, with a focus on its potential role in SARS-CoV-2 infection.

SARS-CoV-2 virus emerged as a new threat to humans and spread around the world, leaving a large death toll. As of January 2023, Brazil is among the countries with the highest number of registered deaths. Nonpharmacological and pharmacological interventions have been heterogeneously implemented in the country, which, associated with large socioeconomic differences between the country regions, has led to distinct virus spread dynamics. Here, we investigate the spatiotemporal dispersion of SARS-CoV-2 lineages in the Pernambuco state (Northeast Brazil) throughout the distinct epidemiological scenarios that unfolded in the first 2 years of the pandemic. We generated a total of 1,389 new SARS-CoV-2 genomes from June 2020 to August 2021. This sampling captured the arrival, communitary transmission, and the circulation of the B1.1, B.1.1.28, and B.1.1.33 lineages; the emergence of the former variant of interest P.2; and the emergence and fast replacement of all previous variants by the more transmissible variant of concern P.1 (Gamma). Based on the incidence and lineage spread pattern, we observed an East-to-West to inner state pattern of transmission, which is in agreement with the transmission of more populous metropolitan areas to medium- and small-size country-side cities in the state. Such transmission patterns may be partially explained by the main routes of traffic across municipalities in the state. Our results highlight that the fine-grained intrastate analysis of lineages and incidence spread can provide actionable insights for planning future nonpharmacological intervention for air-borne transmissible human pathogens.IMPORTANCEDuring the COVID-19 pandemic, Brazil was one of the most affected countries, mainly due its continental-size, socioeconomic differences among regions, and heterogeneous implementation of intervention methods. In order to investigate SARS-CoV-2 dynamics in the state of Pernambuco, we conducted a spatiotemporal dispersion study, covering the period from June 2020 to August 2021, to comprehend the dynamics of viral transmission during the first 2 years of the pandemic. Throughout this study, we were able to track three significant epidemiological waves of transmission caused by B1.1, B.1.1.28, B.1.1.33, P.2, and P.1 lineages. These analyses provided valuable insights into the evolution of the epidemiological landscape, contributing to a deeper understanding of the dynamics of virus transmission during the early years of the pandemic in the state of Pernambuco.

The coronavirus disease 2019 (COVID-19) has left a devasting effect on various regions globally. Africa has exceptionally high rates of other infectious diseases, such as tuberculosis (TB), human immunodeficiency virus (HIV), and malaria, and was not impacted by COVID-19 to the extent of other continents Globally, COVID-19 has caused approximately 7 million deaths and 700 million infections thus far. COVID-19 disease severity and susceptibility vary among individuals and populations, which could be attributed to various factors, including the viral strain, host genetics, environment, lifespan, and co-existing conditions. Host genetics play a substantial part in COVID-19 disease severity among individuals. Human leukocyte antigen (HLA) was previously been shown to be very important across host immune responses against viruses. HLA has been a widely studied gene region for various disease associations that have been identified. HLA proteins present peptides to the cytotoxic lymphocytes, which causes an immune response to kill infected cells. The HLA molecule serves as the central region for infectious disease association; therefore, we expect HLA disease association with COVID-19. Therefore, in this narrative review, we look at the HLA gene region, particularly, HLA class I, to understand its role in COVID-19 disease.

The Australian Government implemented a national vaccination campaign against COVID-19 beginning February 22, 2021. The roll-out was criticised for being delayed relative to many high-income countries, but high levels of vaccination coverage were belatedly achieved. The large-scale Omicron outbreak in January 2022 resulted in a massive number of cases and deaths, although mortality would have been far higher if not for vigorous efforts to rapidly vaccinate the entire population. The impact of the vaccination coverage was assessed over this extended period.

We considered NSW, as the Australian jurisdiction with the highest quality data for our purposes and which still reflected the national experience. Weekly death rates were derived among individuals aged 50+ with respect to vaccine status between August 8, 2021 and July 9, 2022. We evaluated deaths averted by the vaccination campaign by modelling alternative counterfactual scenarios based on a simple data-driven modelling methodology presented by Jia et al. (2023).

Unvaccinated individuals had a 7.7-fold greater mortality rate than those who were fully vaccinated among people aged 50+, which rose to 11.2-fold in those who had received a booster dose. If NSW had fully vaccinated its ~2.9 million 50+ residents earlier (by July 28, 2021), only 440 of the total 3,495 observed 50+ deaths would have been averted. Up to July 9, 2022, the booster campaign prevented 1,860 deaths. In the absence of a vaccination campaign, ~21,250 COVID-19 50+ deaths (conservative estimate) could have been expected in NSW i.e., some 6 times the actual total. We also find the methodology of Jia et al. (2023) can sometimes significantly underestimate that actual number.

The Australian vaccination campaign was successful in reducing mortality over 2022, relative to alternative hypothetical vaccination scenarios. The success was attributable to the Australian public's high levels of engagement with vaccination in the face of new SARS-COV-2 variants, and because high levels of vaccination coverage (full and booster) were achieved in the period shortly before the major Omicron outbreak of 2022.

Background and Objectives: Coronavirus disease 2019 (COVID-19) caused several cardiovascular complications, including acute myocardial infarction (AMI), in infected patients. This study aims to understand the overall trends of AMI among COVID-19 patients during the first two years of the pandemic and the disparities and outcomes between the first and second years. Materials and Methods: The retrospective analysis was conducted via the 2020 and 2021 National Inpatient Sample (NIS) database for hospitalizations between April 2020 and December 2021 being analyzed for adults with a primary diagnosis of COVID-19 who experienced events of AMI. A comparison of month-to-month events of AMI and mortality of AMI patients with concomitant COVID-19 was made alongside their respective patient characteristics. Results: Out of 2,541,992 COVID-19 hospitalized patients, 3.55% experienced AMI. The highest rate of AMI was in December 2021 (4.35%). No statistical differences in trends of AMI mortality were noted over the 21 months. AMI cases in 2021 had higher odds of undergoing PCI (aOR 1.627, p < 0.01). They experienced higher risks of acute kidney injury (aOR 1.078, p < 0.01), acute ischemic stroke (aOR 1.215, p < 0.01), cardiac arrest (aOR 1.106, p < 0.01), need for mechanical ventilation (aOR 1.133, p < 0.01), and all-cause mortality (aOR 1.032, 95% CI 1.001-1.064, p = 0.043). Conclusions: The incidence of AMI among COVID-19 patients fluctuated over the 21 months of this study, with a peak in December 2021. COVID-19 patients reporting AMI in 2021 experienced higher overall odds of multiple complications, which could relate to the exhaustive burden of the pandemic in 2021 on healthcare, the changing impact of the virus variants, and the hesitancy of infected patients to seek care.

Clarifying the presence of viable severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) rather than SARS-CoV-2 viral RNA in inpatient rooms is important for infection control of coronavirus disease 2019 (COVID-19). In this study, we investigated levels of viral RNA and viable virus on environmental surfaces and in patient saliva.

Environmental samples from 23 sites in hospital rooms were collected every other day until patient discharge. Saliva specimens and samples from the inner surface of patient masks were also collected. Additionally, environmental samples were collected from 46 sites in hospital rooms on discharge day. The samples were examined using quantitative reverse transcription polymerase chain reaction (RT-qPCR) and plaque assays.

The 10 enrolled cases were classified as mild COVID-19, and patients were discharged after 6-9 days. The viral RNA was detected in 12.4% (105/849) of serially collected environmental samples during hospitalization, whereas viable virus was detected only in 0.47% (4/849), which were from sinks and tap levers. Although all patients recovered, three cases retained viable virus in the last saliva specimen collected. In the 15 discharged rooms, viral RNA was detected in 6.6% (45/682) of the samples, and viable virus was detected in only one sample from the sink.

Although environmental surfaces surrounding patients with COVID-19 were frequently contaminated with viral RNA, the presence of viable virus was rare and limited only to areas around sinks. These results suggest that contact infection risk via fomites in hospital rooms is extremely rare.

COVID-19 is a respiratory disease triggered by an RNA virus inclined to mutations. Since December 2020, variants of COVID-19 (especially Delta and Omicron) continuously appeared with different characteristics that influenced death and transmissibility emerged around the world. To address the novel dynamics of the disease, we propose and analyze a dynamical model of two strains, namely native and mutant, transmission dynamics with mutation and imperfect vaccination. It is also assumed that the recuperated individuals from the native strain can be infected with mutant strain through the direct contact with individual or contaminated surfaces or aerosols. We compute the basic reproduction number, R 0 , which is the maximum of the basic reproduction numbers of native and mutant strains. We prove the nonexistence of backward bifurcation using the center manifold theory, and global stability of disease-free equilibrium whenR 0 < 1 , that is, vaccine is effective enough to eliminate the native and mutant strains even if it cannot provide full protection. Hopf bifurcation appears when the endemic equilibrium loses its stability. An intermediate mutation rate ν 1 leads to oscillations. When ν 1 increases over a threshold, the system regains its stability and exhibits an interesting dynamics called endemic bubble. An analytical expression for vaccine-induced herd immunity is derived. The epidemiological implication of the herd immunity threshold is that the disease may effectively be eradicated if the minimum herd immunity threshold is attained in the community. Furthermore, the model is parameterized using the Indian data of the cumulative number of confirmed cases and deaths of COVID-19 from March 1 to September 27 in 2021, using MCMC method. The cumulative cases and deaths can be reduced by increasing the vaccine efficacies to both native and mutant strains. We observe that by considering the vaccine efficacy against native strain as 90%, both cumulative cases and deaths would be reduced by 0.40%. It is concluded that increasing immunity against mutant strain is more influential than the vaccine efficacy against it in controlling the total cases. Our study demonstrates that the COVID-19 pandemic may be worse due to the occurrence of oscillations for certain mutation rates (i.e., outbreaks will occur repeatedly) but better due to stability at a lower infection level with a larger mutation rate. We perform sensitivity analysis using the Latin Hypercube Sampling methodology and partial rank correlation coefficients to illustrate the impact of parameters on the basic reproduction number, the number of cumulative cases and deaths, which ultimately sheds light on disease mitigation.

of our study was to identify and characterize the SARS-CoV-2 variants in COVID-19 patients' samples collected from different regions of Ukraine to determine the relationship between SARS-CoV-2 phylogenetics and COVID-19 epidemiology.

Samples were collected from COVID-19 patients during 2021 and the beginning of 2022 (401 patients). The SARS-CoV-2 genotyping was performed by parallel whole genome sequencing.

The obtained SARS-CoV-2 genotypes showed that three waves of the COVID-19 pandemic in Ukraine were represented by three main variants of concern (VOC), named Alpha, Delta and Omicron; each VOC successfully replaced the earlier variant. The VOC Alpha strain was presented by one B.1.1.7 lineage, while VOC Delta showed a spectrum of 25 lineages that had different prevalence in 19 investigated regions of Ukraine. The VOC Omicron in the first half of the pandemic was represented by 13 lines that belonged to two different clades representing B.1 and B.2 Omicron strains. Each of the three epidemic waves (VOC Alpha, Delta, and Omicron) demonstrated their own course of disease, associated with genetic changes in the SARS-CoV-2 genome. The observed epidemiological features are associated with the genetic characteristics of the different VOCs, such as point mutations, deletions and insertions in the viral genome. A phylogenetic and transmission analysis showed the different mutation rates; there were multiple virus sources with a limited distribution between regions.

The evolution of SARS-CoV-2 virus and high levels of morbidity due to COVID-19 are still registered in the world. Observed multiple virus sourses with the limited distribution between regions indicates the high efficiency of the anti-epidemic policy pursued by the Ministry of Health of Ukraine to prevent the spread of the epidemic, despite the low level of vaccination of the Ukrainian population.

This study aimed to investigate the antibodies against SARS-CoV-2 in children hospitalized due to COVID-19 during the era of pre-Omicron and Omicron variants.

This was a retrospective observational study conducted at a tertiary academic medical center in Thailand between June 2021 and August 2022. We collected the data of children aged under 18-year who were hospitalized from SARS-CoV-2 infection. After hospital discharge, we scheduled clinical follow-up 60 to 90 days post-infection clinical follow-up. We measured antibodies against SARS-CoV-2 anti-spike protein receptor-binding domain in the serum during a follow-up visit and compared the mean difference of antibody levels between children infected with COVID-19 during the pre-Omicron and Omicron eras.

A total of 119 children enrolled into the study. There were 58 and 61 children hospitalized due to COVID-19 during pre-Omicron and Omicron era, respectively. The median (interquartile range, IQR) of SARS-CoV-2 antibodies in all cases was 206.1 (87.9-424.1) U/mL at follow-up. Children infected during pre-Omicron had SARS-CoV-2 antibody levels at follow-up higher than children infected during Omicron era [mean difference 292.57 U/mL, 95% CI 53.85-531.28, p = 0.017). There was no difference in SARS-CoV-2 antibody levels between the children based on gender, age, co-morbidities, chest radiograph classification, or diagnosis.

The antibodies response to SARS-CoV-2 infection was weaker during the Omicron era than previous variant of concern. Immunization strategies and policies should be implemented in children even if they had been previously infected.

The aim of the rapid introduction of vaccines during the COVID-19 pandemic was a reduction in SARS-CoV-2 transmission and a less frequent occurrence of severe COVID-19 courses. Thus, we evaluated COVID-19 severity in vaccinated individuals to examine variant-specific symptom characteristics and their clinical impact on the serological immune response.

A total of 185 individuals previously vaccinated against and infected with the SARS-CoV-2 Delta (B.1.617.2) or Omicron (BA.4 and BA.5) variant, were enrolled for anti-SARS-CoV-2 anti-N- and anti-RBD/S1-Ig level detection. A structured survey regarding medical history was conducted.

In 99.5 percent of cases, outpatient treatment was satisfactory. Specific symptoms associated with variants included ageusia and anosmia in patients with Delta infections and throat pain in Omicron infections. Among Delta-infected individuals with specific symptoms, significantly higher levels of anti-N antibodies were observed.

Our study identified variant-specific differences in the amount of SARS-CoV-2 antibody production and COVID-19 symptoms. Despite this, vaccinated individuals with Omicron or Delta infections generally experienced mild disease courses. Additionally, asymptomatic individuals exhibit lower anti-SARS-CoV-2 antibody levels, indicating a clinical correlation between disease-specific antibodies and distinct symptoms, particularly in the case of the Delta variant. In follow-up studies, exploring post-COVID syndrome and focusing on cognitive symptoms in the acute phase of Omicron infections is crucial as it has the potential to longitudinally impact the lives of those affected.

Since the COVID-19 outbreak, the severe acute respiratory syndrome coronavirus 2 (SARS-COV-2) virus has evolved into variants with varied infectivity. Vaccines developed against COVID-19 infection have boosted immunity, but there is still uncertainty on how long the immunity from natural infection or vaccination will last. The present study attempts to outline the present level of information about the contagiousness and spread of SARS-CoV-2 variants of interest and variants of concern (VOCs). The keywords like COVID-19 vaccine types, VOCs, universal vaccines, bivalent, and other relevant terms were searched in NCBI, Science Direct, and WHO databases to review the published literature. The review provides an integrative discussion on the current state of knowledge on the type of vaccines developed against SARS-CoV-2, the safety and efficacy of COVID-19 vaccines concerning the VOCs, and prospects of novel universal, chimeric, and bivalent mRNA vaccines efficacy to fend off existing variants and other emerging coronaviruses. Genomic variation can be quite significant, as seen by the notable differences in impact, transmission rate, morbidity, and death during several human coronavirus outbreaks. Therefore, understanding the amount and characteristics of coronavirus genetic diversity in historical and contemporary strains can help researchers get an edge over upcoming variants.

The aim of this work is to analyze the viral titers of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and respiratory syncytial virus (RSV) at the anterior nasal site (ANS) and nasopharyngeal site (NS), evaluate their virological dynamics, and validate the usefulness of a newly developed two-antigen-detecting rapid antigen diagnostic test (Ag-RDT) that simultaneously detects SARS-CoV-2 and RSV using clinical specimens. This study included 195 asymptomatic to severely ill patients. Overall, 668 specimens were collected simultaneously from the ANS and NS. The cycle threshold (Ct) values calculated from real-time polymerase chain reaction were used to analyze temporal changes in viral load and evaluate the sensitivity and specificity of the Ag-RDT. The mean Ct values for SARS-CoV-2-positive, ANS, and NS specimens were 28.8, 28.9, and 28.7, respectively. The mean Ct values for RSV-positive, ANS, and NS specimens were 28.7, 28.8, and 28.6, respectively. SARS-CoV-2 and RSV showed the same trend in viral load, although the viral load of NS was higher than that of ANS. The sensitivity and specificity of the newly developed Ag-RDT were excellent in specimens collected up to 10 days after the onset of SARS-CoV-2 infection and up to 6 days after the onset of RSV infection.

Severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) caused the outbreak of coronavirus disease 2019 (COVID-19) in late 2019 in Wuhan, China. In early 2020, the disease spread rapidly around the world. Since the pandemic, SARS-CoV-2 has evolved dramatically into a wide variety of variants endowed with devastating properties. As of March 6, 2022, five SARS-CoV-2 variants of concern, including Alpha, Beta, Gamma, Delta, and Omicron strains have been identified. Due to the crucial importance of understanding the differences between the Omicron and Delta variants, this systematic review was conducted.

This systematic review investigated new variants of Omicron SARS-CoV-2 based on current studies. Online databases were searched for English articles as of January 03, 2023. Selection of publications was a two-step process of title/abstract and full-text assessment against eligibility criteria. The relevant data from the included articles were systematically collected and organized in a designed table for analysis. To ensure the quality of the review, the PRISMA checklist and Newcastle- Ottawa Scale (NOS) of quality assessment were utilized.

The data extracted from 58 articles were analyzed, including 10003 pieces of evidence. Lower risk of hospitalization, ICU admission, and mortality after vaccination were reported in the Omicron variant compared to the Delta variant. Additionally, the Delta variant led to more severe clinical symptoms in comparison to the Omicron variant.

The Omicron variant of SARS-CoV-2 results in less severe disease outcomes as compared to Delta. Nevertheless, it remains crucial to maintain ongoing monitoring, implement containment measures, and adapt vaccination protocols to effectively address the evolving variants.

Concerns of fecal-aerosol transmission of coronavirus disease 2019 (COVID-2019) coupled with increased transmissibility and disease severity of Delta and Omicron variants of concern (VOC) of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), suggest studies on survival of VOC in wastewater are warranted. To the best of our knowledge, this is the first study to investigate the survivability of Delta and Omicron VOC in filtered and unfiltered raw wastewater, and secondary effluent at room temperature (23 °C). The time required for 90 % inactivation (T90) of Delta and Omicron VOC in unfiltered raw wastewater was calculated as 17.7 and 15.3 h, respectively. Rapid inactivation of VOC in wastewater and inability to isolate SARS-CoV-2 in wastewater suggest risks from fecal-aerosol transmission are low. Nevertheless, high transmissibility of VOC cautions overruling fecal-aerosol transmission of COVID-19. Future studies on survival of SARS-CoV-2 in wastewater should attempt viral culture by spiking feces collected from COVID-19 infected patients into wastewater to match the real-world scenario.

The COVID-19 pandemic stressed public health systems worldwide due to emergence of several highly transmissible variants of concern. Diverse and complex intervention policies deployed over the last years have shown varied effectiveness in controlling the pandemic. However, a systematic analysis and modelling of the combined effects of different viral lineages and complex intervention policies remains a challenge due to the lack of suitable measures of pandemic inequality and nonlinear effects.

Using large-scale agent-based modelling and a high-resolution computational simulation matching census-based demographics of Australia, we carried out a systematic comparative analysis of several COVID-19 pandemic scenarios. The scenarios covered two most recent Australian census years (2016 and 2021), three variants of concern (ancestral, Delta and Omicron), and five representative intervention policies. We introduced pandemic Lorenz curves measuring an unequal distribution of the pandemic severity across local areas. We also quantified pandemic biomodality, distinguishing between urban and regional waves, and measured bifurcations in the effectiveness of interventions.

We quantified nonlinear effects of population heterogeneity on the pandemic severity, highlighting that (i) the population growth amplifies pandemic peaks, (ii) the changes in population size amplify the peak incidence more than the changes in density, and (iii) the pandemic severity is distributed unequally across local areas. We also examined and delineated the effects of urbanisation on the incidence bimodality, distinguishing between urban and regional pandemic waves. Finally, we quantified and examined the impact of school closures, complemented by partial interventions, and identified the conditions when inclusion of school closures may decisively control the transmission.

Public health response to long-lasting pandemics must be frequently reviewed and adapted to demographic changes. To control recurrent waves, mass-vaccination rollouts need to be complemented by partial NPIs. Healthcare and vaccination resources need to be prioritised towards the localities and regions with high population growth and/or high density.

Coronavirus disease 2019 (COVID-19) has caused more than 690 million deaths worldwide. Different results concerning the death rates of the Delta and Omicron variants have been recorded. We aimed to assess the secular trend of case fatality rate (CFR), identify risk factors associated with mortality following COVID-19 diagnosis, and investigate the risks of mortality and hospitalization during Delta and Omicron waves in the United States.

This study assessed 2,857,925 individuals diagnosed with COVID-19 in the United States from January 2020, to June 2022. The inclusion criterion was the presence of COVID-19 diagnostic codes in electronic medical record or a positive laboratory test of the SARS-CoV-2. Statistical analysis was bifurcated into two components, longitudinal analysis and comparative analysis. To assess the discrepancies in hospitalization and mortality rates for COVID-19, we identified the prevailing periods for the Delta and Omicron variants.

Longitudinal analysis demonstrated four sharp surges in the number of deaths and CFR. The CFR was persistently higher in males and older age. The CFR of Black and White remained higher than Asians since January 2022. In comparative analysis, the adjusted hazard ratios for all-cause mortality and hospitalization were higher in Delta wave compared to the Omicron wave. Risk of all-cause mortality was found to be greater 14-30 days after a COVID-19 diagnosis, while the likelihood of hospitalization was higher in the first 14 days following a COVID-19 diagnosis in Delta wave compared with Omicron wave. Kaplan-Meier analysis revealed the cumulative probability of mortality was approximately 2-fold on day 30 in Delta than in Omicron cases (log-rank p < 0.001). The mortality risk ratio between the Delta and Omicron variants was 1.671 (95% Cl 1.615-1.729, log-rank p < 0.001). Delta also had a significantly increased mortality risk over Omicron in all age groups. The CFR of people aged above 80 years was extremely high as 17.33%.

Male sex and age seemed to be strong and independent risk factors of mortality in COVID-19. The Delta variant appears to cause more hospitalization and death than the Omicron variant.

During replication, some mutations occur in SARS-CoV-2, the causal agent of COVID-19, leading to the emergence of different variants of the virus. The mutations that accrue in different variants of the virus, influence the virus' ability to bind to human cell receptors and ability to evade the human immune system, the rate of viral transmission, and effectiveness of vaccines. Some of these mutations occur in the receptor binding domain (RBD) of the spike protein that may change the affinity of the virus for the ACE2 receptor. In this study, several in silico techniques, such as MD and SMD simulations, were used to perform comparative studies to deeply understand the effect of mutation on structural and functional details of the interaction of the spike glycoprotein of SARS-CoV-2, with the ACE2 receptor. According to our results, the mutation in the RBD associated with the Omicron variant increase binding affinity of the virus to ACE2 when compared to wild type and Delta variants. We also observed that the flexibility of the spike protein of the Omicron variant was lower than in comparison to other variants. In summary, different mutations in variants of the virus can have an effect on the binding mechanism of the receptor binding domain of the virus with ACE2.

This study aimed to compare the clinical picture of COVID-19 in the initial and later period of Omicron dominance and to identify populations still at risk. A retrospective comparison of the clinical data of 965 patients hospitalized during the early period of Omicron's dominance (EO, January-June 2022) with 897 patients from a later period (LO, July 2022-April 2023) from the SARSTer database was performed. Patients hospitalized during LO, compared to EO, were older, had a better clinical condition on admission, had a lower need for oxygen and mechanical ventilation, had less frequent lung involvement in imaging, and showed much faster clinical improvement. Moreover, the overall mortality during EO was 14%, higher than that in LO-9%. Despite the milder course of the disease, mortality exceeding 15% was similar in both groups among patients with lung involvement. The accumulation of risk factors such as an age of 60+, comorbidities, lung involvement, and oxygen saturation <90% resulted in a constant need for oxygen in 98% of patients, an 8% risk of mechanical ventilation, and a 30% mortality rate in the LO period. Multiple logistic regression revealed lower odds of death during the LO phase. Despite the milder course of infections caused by the currently dominant subvariants, COVID-19 prophylaxis is necessary in people over 60 years of age, especially those with comorbidities, and in the case of pneumonia and respiratory failure.

SARS-CoV-2 has been highly susceptible to mutations since its emergence in Wuhan, China, and its subsequent propagation due to containing an RNA as its genome. The emergence of variants with improved transmissibility still poses a grave threat to global health. The spike protein mutation is mainly responsible for higher transmissibility and risk severity. This study retrieved SARS-CoV-2 variants structural and nonstructural proteins (NSPs) sequences from several geographic locations, including Africa, Asia, Europe, Oceania, and North and South America. First, multiple sequence alignments with BioEdit and protein homology modeling were performed using the SWISS Model. Then the structure visualization and structural analysis were performed by superimposing against the Wuhan sequence by Pymol to retrieve the RMSD values. Sequence alignment revealed familiar, uncommon regional among variants and, interestingly, a few unique mutations in Beta, Delta, and Omicron. Structural analysis of such unique mutations revealed that they caused structural deviations in Beta, Delta, and Omicron spike proteins. In addition, these variants were more severe in terms of hospitalization, sickness, and higher mortality, which have a substantial relationship with the structural deviations because of those unique mutations. Such evidence provides insight into the SARS-CoV-2 spike protein vulnerability toward mutation and their structural and functional deviations, particularly in Beta, Delta, and Omicron, which might be the cause of their broader coverage. This knowledge can help us with regional vaccine strain selection, virus pathogenicity testing, diagnosis, and treatment with more specific vaccines.

Aprotinin (APR) was discovered in 1930. APR is an effective pan-protease inhibitor, a typical "magic shotgun". Until 2007, APR was widely used as an antithrombotic and anti-inflammatory drug in cardiac and noncardiac surgeries for reduction of bleeding and thus limiting the need for blood transfusion. The ability of APR to inhibit proteolytic activation of some viruses leads to its use as an antiviral drug for the prevention and treatment of acute respiratory virus infections. However, due to incompetent interpretation of several clinical trials followed by incredible controversy in the literature, the usage of APR was nearly stopped for a decade worldwide. In 2015-2020, after re-analysis of these clinical trials' data the restrictions in APR usage were lifted worldwide. This review discusses antiviral mechanisms of APR action and summarizes current knowledge and prospective regarding the use of APR treatment for diseases caused by RNA-containing viruses, including influenza and SARS-CoV-2 viruses, or as a part of combination antiviral treatment.

This study aimed to spatiotemporally analyze the profile of influenza-like illness (ILI) outbreaks in the state of São Paulo, Brazil, between 2020 and 2022.

This was a cross-sectional retrospective study.

Outbreaks of ILI with final diagnoses of COVID-19, influenza, or other respiratory viruses (ORVs) recorded between January 2020 and November 2022, obtained from the Notifiable Diseases Information System (SINAN NET) Outbreak module, were analyzed. Kernel density estimates and Getis-Ord Gi∗ statistics were performed to identify spatial clusters.

A total of 13,314 ILI outbreaks were identified, involving 130,568 cases and 2649 deaths. Of these, 104,399 (80%) were confirmed as COVID-19, 15,861 (12%) were confirmed as ORV, and 10,308 (8%) were confirmed as influenza. The year 2021 had the highest number of outbreaks and cases. Schools recorded the most outbreaks and cases, followed by long-term care facilities for older adults (LTCs). The highest average number of cases per outbreak and the highest attack rates occurred at social gatherings and prisons. Prisoners were three times more likely to contract COVID-19 during outbreaks than people in other institutions. The highest hospitalization and mortality rates for all virus types occurred in the LTC group. The occurrence and intensity of outbreaks were highly heterogeneous among the different institutions after the introduction of new SARS-CoV-2 variants in the state.

ILI outbreaks were not randomly distributed; they clustered in specific areas. Transmissibility varied among different institutions with different responses to the COVID-19 pandemic. These results can be used as a basis for prioritizing actions and allocating resources during future pandemics.

As of 31 December 2022, there were over 6.6 million coronavirus disease 2019 (COVID-19) deaths and over 651 million cases across 200 countries worldwide. Despite the increase in vaccinations and booster shots, COVID-19 cases and deaths continue to remain high. While the effectiveness of these vaccines has already been established by different manufacturers, the fact remains that these vaccines were created quickly for global emergency use, tested under controlled clinical conditions from voluntary subjects and age groups whose general characteristics may differ from the actual general population.

To conduct a systematic review to determine the real-world effectiveness of mRNA COVID-19 vaccines in the elderly during the predominance of Delta and Omicron variants in preventing COVID-19 related infection, hospital, intensive care unit (ICU) admission and intubation, and death.

A combination of Medical Subject Headings and non-Medical Subject Headings was carried out to identify all relevant research articles that meets the inclusion and exclusion criteria from PubMed, Cochrane, CINAHL, Scopus, ProQuest, Embase, Web of Science, and Google Scholar databases, as well as qualified research studies from pre-print servers using medRxiv and Research Square, published from January 1, 2021 - December 31, 2022.

As per the inclusion and exclusion criteria, the effectiveness of Pfizer-BioNTech and Moderna vaccines were evaluated from an estimated total study population of 26,535,692 using infection, hospital, ICU admission and intubation, and death as outcome measures from studies published between 2021 and 2022, conducted in New York, Finland, Canada, Costa Rica, Qatar, Greece, and Brazil. The risk of bias was evaluated using risk of bias in nonrandomized studies of interventions (ROBINS-I) tool for cohort, case-control, and cross-sectional studies. While clinical trial data on Pfizer-BioNTech and Moderna vaccines demonstrated 94% vaccine effectiveness in the elderly, the results in this study showed that vaccine effectiveness in real-world settings is marginally lower against infection (40%-89%), hospitalization (92%), ICU admission and intubation (98%-85%), and death (77%-87%) with an indication of diminished effectiveness of vaccine over time. Furthermore, 2 doses of mRNA vaccines are inadequate and only provides interim protection.

Because of the natural diminishing effectiveness of the vaccine, the need for booster dose to restore its efficacy is vital. From a research perspective, the use of highly heterogeneous outcome measures inhibits the comparison, contrast, and integration of the results which makes data pooling across different studies problematic. While pharmaceutical intervention like vaccination is important to fight an epidemic, utilizing common outcome measurements or carrying out studies with minimal heterogeneity in outcome measurements, is equally crucial to better understand and respond to an international health crisis.