Israeli cohort shows no protection against COVID-19 from childhood BCG vaccination
A large observational analysis has reported no relationship between rates or severity of COVID-19 in adults and whether or not they received a BCG vaccination in childhood. 
These results, published in the Journal of American Medicine (JAMA) are disappointing as it was hoped this vaccine might have offered broad protection to respiratory infections. Several papers have also suggested that COVID-19 might have lower prevalence in countries with higher use of the vaccine.
Changes in vaccination policy in Israel meant that BCG was routinely given to newborn babies from 1955 to 1982 but only subsequently given to migrants from countries with a high prevalence of TB. This allowed researchers to compare two similar aged groups for any evidence of protection against COVID-19.
Of 72 060 test results reviewed, 3064 were from patients born between 1979 and 1981 (and 2869 were among likely unvaccinated people born between 1983 and 1985. Both groups were approximately 50% male with mean age 40 and 35 years respectively.
There was no significant difference in the proportion of positive test results in the BCG vs no-BCG group: 361 (11.7%) vs 299 (10.4%); difference, 1.3%; 95%CI: −0.3% to 2.9%; p=0.09). There was also no difference in positivity rates per 100 000: 121 vs 100; difference, 21 per 100 000; 95%CI: −10 to 50 per 100 000; p= 0.15).
One case of severe disease was reported in each group with no deaths.
The implications of these results are unclear for studies that have already been designed to look at prospective use of BCG vaccination.
At least ten ongoing studies are already either planned or ongoing that use BCG vaccinations as COVID-19 prophylaxis for adult health workers. [2, 3, 4]
Unless there is still a mechanism for plausibility of protection, health workers should be allowed to use more promising options. Those that continue for any reason should have a very tightly defined mandate to recognise early futility.
- Hamiel U et al. SARS-CoV-2 rates in BCG-vaccinated and unvaccinated young adults. JAMA, research letter. doi:10.1001/jama.2020.8189 (13 May 2020).
- clinicltrials.gov. BCG Vaccination to Protect Healthcare Workers Against COVID-19 (BRACE). (n=4170)
- clinicltrials.gov. BCG Vaccination for Healthcare Workers in COVID-19 Pandemic (n=500).
- Using BCG Vaccine to Protect Health Care Workers in the COVID-19 Pandemic. (n=1500).