From the Journal of the American Medical Association today. It is an interesting theory that those who received tuberculosis vaccine as young children may have better protection against COVID-19 than those who weren't vaccinated. This new study out of Israel does not support that:
Confirmed cases of coronavirus disease 2019 (COVID-19) and case-fatality rates vary among countries. One reason could be national policies regarding childhood BCG vaccination, with fewer confirmed cases and a lower death toll reported in countries with vs without universal BCG vaccine coverage. Comparing outbreak characteristics between countries is influenced by potential confounders such as different phases of outbreak, mean age of affected population, management of the pandemic, amount of tests being administered, definitions of COVID-19–related deaths, or underreporting.
The BCG vaccine was routinely administered to all newborns in Israel as part of the national immunization program between 1955 and 1982. Overall, the vaccine acceptance rate in Israel is high, with greater than 90% coverage. Since 1982, the vaccine has been administered only to immigrants from countries with high prevalence of tuberculosis. This change allowed comparison of infection rates and proportions with severe COVID-19 disease in 2 similar populations with differing BCG status: individuals born during the 3 years before and 3 years after cessation of the universal BCG vaccine program.
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Results
Of 72 060 test results reviewed, 3064 were from patients born between 1979 and 1981 (1.02% of birth cohort of that period; 49.2% male; mean age, 40 years) and 2869 were among likely unvaccinated people born between 1983 and 1985 (0.96% of total birth cohort; 50.8% male; mean age, 35 years). There was no statistically significant difference in the proportion of positive test results in the BCG-vaccinated group (361 [11.7%]) vs the unvaccinated group (299 [10.4%]; difference, 1.3%; 95% CI, −0.3% to 2.9%; P = .09) or in positivity rates per 100 000 (121 in vaccinated group vs 100 in unvaccinated group; difference, 21 per 100 000; 95% CI, −10 to 50 per 100 000; P = .15). There was 1 case of severe disease (mechanical ventilation or intensive care unit admission) in each group, and no deaths were reported (Table).
Discussion
In this cohort of Israeli adults aged 35 to 41 years, BCG vaccination in childhood was associated with a similar rate of positive test results for SARS-CoV-2 compared with no vaccination. Because of the small number of severe cases, no conclusion about the association between BCG status and severity of disease can be reached. Although the BCG vaccine is given to protect against tuberculosis, it has also been found to exert nonspecific beneficial effects such as protection against other infectious diseases3 and to enhance immunogenicity of certain vaccines, such as the influenza vaccine.
. . . .
In conclusion, this study does not support the idea that BCG vaccination in childhood has a protective effect against COVID-19 in adulthood.
The BCG vaccine was routinely administered to all newborns in Israel as part of the national immunization program between 1955 and 1982. Overall, the vaccine acceptance rate in Israel is high, with greater than 90% coverage. Since 1982, the vaccine has been administered only to immigrants from countries with high prevalence of tuberculosis. This change allowed comparison of infection rates and proportions with severe COVID-19 disease in 2 similar populations with differing BCG status: individuals born during the 3 years before and 3 years after cessation of the universal BCG vaccine program.
. . . .
Results
Of 72 060 test results reviewed, 3064 were from patients born between 1979 and 1981 (1.02% of birth cohort of that period; 49.2% male; mean age, 40 years) and 2869 were among likely unvaccinated people born between 1983 and 1985 (0.96% of total birth cohort; 50.8% male; mean age, 35 years). There was no statistically significant difference in the proportion of positive test results in the BCG-vaccinated group (361 [11.7%]) vs the unvaccinated group (299 [10.4%]; difference, 1.3%; 95% CI, −0.3% to 2.9%; P = .09) or in positivity rates per 100 000 (121 in vaccinated group vs 100 in unvaccinated group; difference, 21 per 100 000; 95% CI, −10 to 50 per 100 000; P = .15). There was 1 case of severe disease (mechanical ventilation or intensive care unit admission) in each group, and no deaths were reported (Table).
Discussion
In this cohort of Israeli adults aged 35 to 41 years, BCG vaccination in childhood was associated with a similar rate of positive test results for SARS-CoV-2 compared with no vaccination. Because of the small number of severe cases, no conclusion about the association between BCG status and severity of disease can be reached. Although the BCG vaccine is given to protect against tuberculosis, it has also been found to exert nonspecific beneficial effects such as protection against other infectious diseases3 and to enhance immunogenicity of certain vaccines, such as the influenza vaccine.
. . . .
In conclusion, this study does not support the idea that BCG vaccination in childhood has a protective effect against COVID-19 in adulthood.
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