Systematic review with meta-analysis of the epidemiological evidence in Europe, Israel, America and Australasia on smoking and COVID-19

Figure 2 Forest plot of the relationship of the index “closest to current smoking” to positivity for coronavirus disease 2019 among those tested. The individual study effect estimates and random-effects combined effect estimates are shown, both as numbers and as horizontal lines with the weight of the estimate indicated by a box of proportional size. “Best estimates” are selected in the preference order (first to last) comorbidity-adjusted, demographic-adjusted and unadjusted. Estimates from ESSVRD, GDEM and HOPKIN are for current vs non-smokers, from FONTAN and OREILL for smokers (undefined) vs non-smokers, and from MUNOZP and ROZENF for ever vs never smokers, with estimates from the other eight studies being for current vs never smokers.