• Varicella vaccine
• adolescents
• adults
• immunogenicity
• phase III
• safety

• Humans
• Double-Blind Method
• Adult
• Male
• Adolescent
• Female
• China
• Chickenpox Vaccine/adverse effects
• Chickenpox Vaccine/administration & dosage
• Chickenpox Vaccine/immunology
• Vaccines, Attenuated/immunology
• Vaccines, Attenuated/administration & dosage
• Vaccines, Attenuated/adverse effects
• Young Adult
• Antibodies, Viral/blood
• Middle Aged
• Chickenpox/prevention & control
• Immunogenicity, Vaccine
• Vaccination/methods
• Healthy Volunteers
• Herpesvirus 3, Human/immunology

• Adaptive immunity
• COVID-19
• Immunology
• Paediatrics
• T cell
• Vaccination

• Humans
• COVID-19/immunology
• COVID-19/prevention & control
• COVID-19/virology
• SARS-CoV-2/immunology
• Child
• Longitudinal Studies
• Male
• Female
• Child, Preschool
• Cytokines/metabolism
• Spike Glycoprotein, Coronavirus/immunology
• COVID-19 Vaccines/immunology
• COVID-19 Vaccines/administration & dosage
• Prospective Studies
• Vaccination
• mRNA Vaccines/immunology
• T-Lymphocytes/immunology
• Th1 Cells/immunology

• herpesvirus
• varicella vaccine
• varicella-zoster virus
• varicella-zoster virus pathogenesis

• Cellular immune response
• MAV/06 vaccine
• Serological cross-reactivity
• Varicella zoster virus

• Animals
• Antibodies, Viral
• Chickenpox/prevention & control
• Chickenpox Vaccine
• Disease Models, Animal
• Herpes Zoster Vaccine
• Herpesvirus 3, Human
• Vaccination
• Vaccines, Attenuated
• Viral Vaccines

• Green cross

With the rapid rise in COVID 19 cases incomparable to the number of vaccinations available, there has been a demand to prioritize the older age groups receiving the vaccine as they have more risk of morbidity and mortality and thus better outcome from vaccination.

Some studies showed a lower seroconversion rate in older group patients; thus, we discuss the necessity to reprioritize vaccinations to younger age groups who have better seroconversion rates, but we may face some ethical dilemma that could hinder our hypothesis. Decreased seroconversion rates in adults are attributable to immuno-senescence which involves a decrease in humoral and cellular-mediated immunity with age. Despite this fact, there remains some ethical dilemma that can hinder widespread vaccination of younger generations, the most important of which is the unknown long-term effects of COVID-19 vaccines due their fast-tracking under the pressure of the pandemic.

Prioritizing children vaccination against COVID-19 seems an interesting strategy that can help in containing the pandemic. Resolving some ethical dilemma needs to be done before implementing such strategy.

In view of new developments in vaccinology and the availability of new vaccines, there is a need to revise/review the existing immunization recommendations.

Advisory Committee on Vaccines and Immunization Practices (ACVIP) of Indian Academy of Pediatrics (IAP) had a physical meeting in March, 2020 followed by online meetings (September-October, 2020), to discuss the updates and new recommendations. Opinion of each member was sought on the various recommendations and updates, following which an evidence-based consensus was reached.

To review and revise the IAP recommendations for 2020–21 and issue recommendations on existing and new vaccines.

The major changes include recommendation of a booster dose of injectable polio vaccine (IPV) at 4–6 years for children who have received the initial IPV doses as per the ACVIP/IAP schedule, re-emphasis on the importance of IPV in the primary immunization schedule, preferred timing of second dose of varicella vaccine at 3–6 months after the first dose, and uniform dosing recommendation of 0.5 mL (15 µg HA) for inactivated influenza vaccines.

• Phase 3
• Russia
• VARIVAX™
• Varicella vaccine
• adults
• chickenpox
• immunogenicity
• safety

• guidelines
• inactivated polio vaccine
• pneumococcal vaccine
• rabies vaccine
• varicella vaccine

• Advisory Committees
• Chickenpox Vaccine
• Child
• Humans
• Immunization
• Immunization Schedule
• Infant
• Influenza Vaccines
• Pediatrics

• herpes zoster
• herpesvirus
• simian varicella virus
• varicella
• varicella zoster virus
• viral latency

In India, where varicella outbreaks are reported at a younger age, a two-dose vaccine schedule administered at an early age could be highly efficacious in preventing varicella infection. The aim of this study was to evaluate the immunogenicity and safety of live attenuated varicella vaccine (VR 795 Oka strain) in a two-dose, 3 months apart regimen.

Healthy children (⩾ 12 months and ⩽12 years; mean age: 4.4 years) of either sex were included. Geometric mean titers (GMT) were measured at baseline and 28 days post first- and second-dose, and seroprotection rates were measured 28 days post first and second dose. The incidence of breakthrough (BT) infections post vaccination was determined from 42 days post first and second dose of vaccine up to 12 months. Adverse events (AEs) were monitored and recorded throughout the study period.

Of 305 subjects enrolled, 217 were seronegative. The seroconversion rate (a change from a seronegative to a seropositive condition) was 93.3% post first-dose and 100% post two-doses. High levels (9 times) of GMT were reported since post first-dose to post second-dose in children aged 12–18 months, 18–60 months (99.43%); and in and above 60 months (99.02%). The extent of rise of anti-VZV IgG antibody titer post 28 days of first-dose at two-fold, three-fold and four-fold rise was 93.39%, 90.56% and 80.66%, respectively and 100% 4-fold rise post second-dose. A single case, a day after the first-dose of vaccination of mild BT infection, was observed after close contact with a severe case. AEs were mild and none of the serious AEs were related to the study drug.

The two-dose schedule of varicella vaccine was safe and immunogenic when given 3 months apart. However, further comparative studies and follow up for both dosing schedules are needed to validate the advantage of early dosing.

• antibody titer
• breakthrough
• seroprotection
• vaccine
• varicella

• CD4 T cells
• adaptive immunity
• bone marrow
• immune memory
• plasma cells
• varicella vaccines
• varicella-zoster virus

• Adaptive dynamics
• age‐structured population
• life‐history evolution
• parasite virulence
• senescence

Varicella zoster virus (VZV) is a neurotropic alphaherpesvirus and the causative agent of varicella (chickenpox) in humans. Following primary infection, VZV establishes latency in the sensory ganglia and can reactivate to cause herpes zoster, more commonly known as shingles, which causes significant morbidity, and on rare occasions mortality, in the elderly. Because VZV infection is highly restricted to humans, the development of a reliable animal model has been challenging, and our understanding of VZV pathogenesis remains incomplete. As an alternative, infection of rhesus macaques with the homologous simian varicella virus (SVV) recapitulates the hallmarks of VZV infection and thus constitutes a robust animal model to provide critical insights into VZV pathogenesis and the host antiviral response. In this model, SVV infection results in the development of varicella during primary infection, generation of an adaptive immune response, establishment of latency in the sensory ganglia, and viral reactivation upon immune suppression. In this review, we discuss our current knowledge about host and viral factors involved in the establishment of SVV latency and reactivation as well as the important role played by T cells in SVV pathogenesis and antiviral immunity.

• herpesvirus
• non-human primates
• shingles
• simian varicella virus
• varicella zoster virus
• viral latency
• viral reactivation

• Bacteria
• Fungal
• Infections
• Viral

• Anti-Infective Agents/therapeutic use
• Bacterial Infections/etiology
• Bacterial Infections/prevention & control
• Germany
• Hematology/organization & administration
• Hematopoietic Stem Cell Transplantation/adverse effects
• Hematopoietic Stem Cell Transplantation/methods
• Humans
• Medical Oncology/organization & administration
• Mycoses/etiology
• Mycoses/prevention & control
• Parasitic Diseases/etiology
• Parasitic Diseases/prevention & control
• Practice Guidelines as Topic
• Societies, Medical
• Transplantation, Homologous
• Vaccination/methods
• Virus Diseases/etiology
• Virus Diseases/prevention & control

• AGIHO

Varicella-zoster virus, which is responsible for varicella (chickenpox) and herpes zoster (shingles), is ubiquitous and causes an acute infection among children, especially those aged less than six years. As 90% of adults have had varicella in childhood, it is unusual to encounter an infected pregnant woman but, if the disease does appear, it can lead to complications for both the mother and fetus or newborn. The major maternal complications include pneumonia, which can lead to death if not treated. If the virus passes to the fetus, congenital varicella syndrome, neonatal varicella (particularly serious if maternal rash appears in the days immediately before or after childbirth) or herpes zoster in the early years of life may occur depending on the time of infection. A Microbiology laboratory can help in the diagnosis and management of mother-child infection at four main times: (1) when a pregnant woman has been exposed to varicella or herpes zoster, a prompt search for specific antibodies can determine whether she is susceptible to, or protected against infection; (2) when a pregnant woman develops clinical symptoms consistent with varicella, the diagnosis is usually clinical, but a laboratory can be crucial if the symptoms are doubtful or otherwise unclear (atypical patterns in immunocompromised subjects, patients with post-vaccination varicella, or subjects who have received immunoglobulins), or if there is a need for a differential diagnosis between varicella and other types of dermatoses with vesicle formation; (3) when a prenatal diagnosis of uterine infection is required in order to detect cases of congenital varicella syndrome after the onset of varicella in the mother; and (4) when the baby is born and it is necessary to confirm a diagnosis of varicella (and its complications), make a differential diagnosis between varicella and other diseases with similar symptoms, or confirm a causal relationship between maternal varicella and malformations in a newborn.

• Mother-child infection
• Congenital varicella syndrome
• Varicella-zoster virus
• Neonatal varicella
• Microbiology laboratory

• Fluorescent-antibody-to-membrane-antigen-assay
• VZV glycoprotein EIA
• VZV immunoglobulin G
• VZV time-resolved fluorescence immunoassay
• healthcare workers
• vOka vaccine

• Adult
• Antibodies, Viral/blood
• Chickenpox Vaccine/immunology
• Fluorescent Antibody Technique
• Fluoroimmunoassay
• Health Personnel/statistics & numerical data
• Herpesvirus 3, Human/immunology
• Humans
• Immunoenzyme Techniques
• Immunoglobulin G/blood
• Middle Aged
• Young Adult

• Wellcome Trust
• G0700814 Medical Research Council
• R01 DK093094 NIDDK NIH HHS

• VZV-cellular immunity
• Varicella vaccination
• epidemiology
• herpes zoster incidence
• varicella zoster virus

• Adult
• Chickenpox/prevention & control
• Chickenpox/transmission
• Chickenpox Vaccine/administration & dosage
• Child
• Herpesvirus 3, Human
• Humans
• Post-Exposure Prophylaxis/methods
• Randomized Controlled Trials as Topic
• Vaccines, Attenuated/administration & dosage

Background: Pneumonia is the most common complication of varicella-zoster infection in adults and has potentially devastating effects when complicating pregnancy. Due to the significant morbidity and mortality associated with this complication during pregnancy and the small number of reported cases in the literature, we present this report to help educate physicians who care for pregnant women.

Cases: Seven patients are presented in this report. These patients presented at various stages in pregnancy, from 17 to 31 weeks of gestation. Three of the patients had unremarkable hospital courses. Three of the patients had hospital stays over 21 days in duration. One patient died from complications of varicella pneumonia after 31 days of hospitalization. The obstetric outcomes of the 7 patients described include 1 non-viable delivery at 20 weeks gestation, 3 term deliveries, 2 preterm deliveries, and 1 patient who has not yet delivered. All of the patients presented were treated with intravenous acyclovir therapy. Of the patients described, 3 required intubation and ventilatory support. Other complications encountered include disseminated intravascular coagulation (DIC), adult respiratory distress syndrome (ARDS), metabolic encephalopathy, pneumothorax, superimposed bacterial pneumonia, and sepsis.

Conclusion: The course and treatment of varicella pneumonia complicating pregnancy are discussed. Current recommendations regarding the use of varicella-zoster immune globulin (VZIG) are also reviewed.

Primary infection with varicella zoster virus (VZV) results in varicella (more commonly known as chickenpox) after which VZV establishes latency in sensory ganglia. VZV can reactivate to cause herpes zoster (shingles), a debilitating disease that affects one million individuals in the US alone annually. Current vaccines against varicella (Varivax) and herpes zoster (Zostavax) are not 100% efficacious. Specifically, studies have shown that 1 dose of varivax can lead to breakthrough varicella, albeit rarely, in children and a 2-dose regimen is now recommended. Similarly, although Zostavax results in a 50% reduction in HZ cases, a significant number of recipients remain at risk. To design more efficacious vaccines, we need a better understanding of the immune response to VZV. Clinical observations suggest that T cell immunity plays a more critical role in the protection against VZV primary infection and reactivation. However, no studies to date have directly tested this hypothesis due to the scarcity of animal models that recapitulate the immune response to VZV. We have recently shown that SVV infection of rhesus macaques models the hallmarks of primary VZV infection in children. In this study, we used this model to experimentally determine the role of CD4, CD8 and B cell responses in the resolution of primary SVV infection in unvaccinated animals. Data presented in this manuscript show that while CD20 depletion leads to a significant delay and decrease in the antibody response to SVV, loss of B cells does not alter the severity of varicella or the kinetics/magnitude of the T cell response. Loss of CD8 T cells resulted in slightly higher viral loads and prolonged viremia. In contrast, CD4 depletion led to higher viral loads, prolonged viremia and disseminated varicella. CD4 depleted animals also had delayed and reduced antibody and CD8 T cell responses. These results are similar to clinical observations that children with agammaglobulinemia have uncomplicated varicella whereas children with T cell deficiencies are at increased risk of progressive varicella with significant complications. Moreover, our studies indicate that CD4 T cell responses to SVV play a more critical role than antibody or CD8 T cell responses in the control of primary SVV infection and suggest that one potential mechanism for enhancing the efficacy of VZV vaccines is by eliciting robust CD4 T cell responses.

Varicella zoster virus (VZV) causes chickenpox and establishes a life-long latent infection in humans. VZV can reactivate years later to cause shingles, a debilitating and painful disease. Vaccines against both chickenpox and shingles are available but not 100% efficacious. Two doses of the chickenpox vaccine are required to provide adequate protection and the shingles vaccine reduces the incidence of this disease by 51%. To improve these vaccines, we must identify the components of the immune system that are important for the control of VZV replication. However, the contribution of T versus B cell responses is unknown. Infection of rhesus macaques with simian varicella virus is a robust model of VZV infection. Here, we used this unique animal model to show for the first time that the absence of B cells does not alter disease severity and that the loss of CD8 T cells only results in a mild increase in disease severity. In sharp contrast, the lack of CD4 T cells leads to disseminated varicella. These data highlight the importance of CD4 T cells and suggest that novel vaccines that focus on engendering a more robust CD4 T cell response against VZV might provide better protection from chickenpox and shingles.

• Animals
• Antigens, CD20/immunology
• B-Lymphocytes/immunology
• CD4 Antigens/immunology
• CD4-Positive T-Lymphocytes/immunology
• CD8-Positive T-Lymphocytes/immunology
• Chickenpox/immunology
• Chickenpox/prevention & control
• Chickenpox/virology
• Chickenpox Vaccine/immunology
• Disease Models, Animal
• Herpesviridae Infections/immunology
• Herpesviridae Infections/virology
• Herpesvirus 3, Human/immunology
• Macaca mulatta
• Varicellovirus/immunology
• Varicellovirus/physiology
• Viral Load
• Virus Replication

• P51 RR000163 NCRR NIH HHS
• R01 AG037042 NIA NIH HHS
• T32 AI078903 NIAID NIH HHS
• P51 RR00163-51 NCRR NIH HHS

• Antibodies, Viral/biosynthesis
• Chickenpox/immunology
• Chickenpox/prevention & control
• Chickenpox Vaccine/administration & dosage
• Chickenpox Vaccine/immunology
• Child
• Enzyme-Linked Immunosorbent Assay
• Female
• Fluorescent Antibody Technique
• Herpesvirus 3, Human/immunology
• Humans
• Immunization, Secondary
• Male
• Measles/immunology
• Measles/prevention & control
• Measles virus/immunology
• Measles-Mumps-Rubella Vaccine/administration & dosage
• Measles-Mumps-Rubella Vaccine/immunology
• Mumps/immunology
• Mumps/prevention & control
• Mumps virus/immunology
• Rubella/immunology
• Rubella/prevention & control
• Rubella virus/immunology
• Vaccines, Attenuated/immunology
• Vaccines, Combined/administration & dosage
• Vaccines, Combined/immunology

• Chickenpox/diagnosis
• Chickenpox/epidemiology
• Chickenpox/immunology
• Chickenpox/pathology
• Chickenpox Vaccine/immunology
• Clinical Laboratory Techniques/methods
• Disease Outbreaks
• Herpesvirus 3, Human/immunology
• Herpesvirus 3, Human/isolation & purification
• Humans
• United States/epidemiology

• Chickenpox/epidemiology
• Chickenpox/prevention & control
• Chickenpox Vaccine/administration & dosage
• Chickenpox Vaccine/immunology
• Europe/epidemiology
• Humans
• Vaccination/statistics & numerical data

• Adult
• Chickenpox/prevention & control
• Chickenpox/transmission
• Chickenpox Vaccine/administration & dosage
• Child
• Herpesvirus 3, Human
• Humans
• Randomized Controlled Trials as Topic
• Vaccines, Attenuated/administration & dosage

• Antibodies, Viral/blood
• Chickenpox/genetics
• Chickenpox/immunology
• Chickenpox/prevention & control
• Chickenpox Vaccine/administration & dosage
• Chickenpox Vaccine/immunology
• Child
• Child, Preschool
• Diseases in Twins/genetics
• Diseases in Twins/immunology
• Diseases in Twins/prevention & control
• Female
• Genetic Predisposition to Disease
• Herpesvirus 3, Human/immunology
• Humans
• Infant
• Male
• Siblings
• Twins
• Vaccination

• Adolescent
• Antibodies, Viral/immunology
• Chickenpox/prevention & control
• Chickenpox Vaccine/therapeutic use
• Child
• Child, Preschool
• Herpesvirus 3, Human/genetics
• Herpesvirus 3, Human/immunology
• Herpesvirus 3, Human/ultrastructure
• Humans
• Vaccination
• Vaccines, Attenuated/therapeutic use

• Adult
• Age Factors
• Asian People
• Black People
• Epidemiologic Factors
• Female
• Herpes Zoster/epidemiology
• Herpes Zoster/immunology
• Humans
• Male
• Middle Aged
• Tropical Climate
• White People

• Antiviral Agents/therapeutic use
• Chickenpox/diagnosis
• Chickenpox/prevention & control
• Chickenpox/therapy
• Chickenpox Vaccine
• Decision Trees
• Herpes Zoster/diagnosis
• Herpes Zoster/prevention & control
• Herpes Zoster/therapy
• Herpesvirus 3, Human
• Humans

• Amino Acid Sequence
• Animals
• Antibodies, Viral/biosynthesis
• Base Sequence
• CHO Cells
• Chickenpox/immunology
• Chickenpox/prevention & control
• Cloning, Molecular
• Cricetinae
• DNA, Recombinant/genetics
• Female
• Guinea Pigs
• Herpes Zoster/immunology
• Herpes Zoster/prevention & control
• Herpesvirus 3, Human/genetics
• Herpesvirus 3, Human/immunology
• Immediate-Early Proteins/genetics
• Immediate-Early Proteins/immunology
• Mice
• Mice, Inbred BALB C
• Recombinant Fusion Proteins/genetics
• Recombinant Fusion Proteins/immunology
• T-Lymphocytes/immunology
• Vaccines, Synthetic/genetics
• Vaccines, Synthetic/immunology
• Vaccines, Synthetic/pharmacology
• Viral Envelope Proteins/genetics
• Viral Envelope Proteins/immunology
• Viral Vaccines/genetics
• Viral Vaccines/immunology
• Viral Vaccines/pharmacology

• Antibodies, Monoclonal/metabolism
• Antigens, Viral/immunology
• Cell Aggregation/drug effects
• Cryopreservation/methods
• Cryoprotective Agents/adverse effects
• Endonucleases/pharmacology
• Enzyme-Linked Immunosorbent Assay/methods
• Enzyme-Linked Immunosorbent Assay/standards
• Herpesvirus 3, Human/immunology
• Humans
• Interferon-gamma/analysis
• Interferon-gamma/biosynthesis
• Leukocytes, Mononuclear/cytology
• Leukocytes, Mononuclear/immunology
• Leukocytes, Mononuclear/virology
• Lymphocyte Activation/immunology
• Recombinant Proteins
• T-Lymphocytes/immunology
• T-Lymphocytes/metabolism
• T-Lymphocytes/virology
• Titrimetry

• Adult
• Chickenpox/prevention & control
• Chickenpox/transmission
• Chickenpox/virology
• Chickenpox Vaccine/administration & dosage
• Child
• Clinical Trials as Topic
• Herpes Zoster/immunology
• Herpes Zoster/prevention & control
• Humans
• Safety
• United States
• Vaccination
• Vaccines, Attenuated/administration & dosage

• Animals
• Antibodies, Viral/immunology
• CHO Cells
• Cricetinae
• Disease Models, Animal
• Gene Expression
• Genetic Engineering
• Herpesvirus 3, Human/immunology
• Immunoglobulin G/immunology
• Mice
• Mice, Inbred BALB C
• Neutralization Tests
• Plasmids
• Vaccination
• Vaccines, DNA/immunology
• Viral Envelope Proteins/genetics
• Viral Envelope Proteins/immunology
• Viral Vaccines/immunology

• Adult
• Chickenpox/immunology
• Chickenpox/prevention & control
• Chickenpox/transmission
• Chickenpox Vaccine
• Child, Preschool
• Disease Transmission, Infectious
• Female
• Health Personnel
• Herpesvirus 3, Human/pathogenicity
• Humans
• Male

• Adult
• Antibodies, Viral/blood
• Chickenpox Vaccine/administration & dosage
• Enzyme-Linked Immunosorbent Assay
• Female
• Fluorescent Antibody Technique
• Glycoproteins
• Herpesvirus 3, Human/immunology
• Humans
• Immunization
• Lymphocyte Activation
• Skin Tests

• Antibodies, Viral/blood
• Chickenpox Vaccine/immunology
• Chickenpox Vaccine/therapeutic use
• Child, Preschool
• Diphtheria-Tetanus-Pertussis Vaccine/immunology
• Diphtheria-Tetanus-Pertussis Vaccine/therapeutic use
• Female
• Herpesvirus 3, Human/immunology
• Humans
• Immunity, Cellular/immunology
• Immunization Schedule
• Immunization, Secondary
• Immunoglobulin G/blood
• Infant
• Interferon-gamma/biosynthesis
• Interleukin-10/biosynthesis
• Lymphocyte Activation/immunology
• Male
• T-Lymphocytes/immunology
• T-Lymphocytes/metabolism