Israeli scientists have found that people who received childhood BCG and non-vaccinated with the same frequency are infected with the novel coronavirus. The study is published in the journal JAMA.
BCG — vaccine against tuberculosis based on attenuated strain of living bovine tubercle Bacillus Mycobacterium bovis. In some countries this inoculation do all children immediately after birth and persists throughout life.
In connection with the pandemic COVID-19 it has been suggested that in countries where there were mass BCG vaccination, the incidence of new coronavirus infection and mortality is significantly lower due to a nonspecific protective effect of this anti-TB vaccination. Recall that in Russia the BCG vaccination compulsory.
Researchers from tel Aviv University conducted a direct comparison of the incidence of COVID-19 among the Israelites, vaccinated and non-vaccinated BCG.
In Israel in the framework of the national immunization program, the vaccine BCG was administered to all newborns in the period from 1955 to 1982. The authors compared people of about the same age — someone who is 39-41 year and who were born within three years before the abolition of compulsory BCG vaccination, and those born in the next three years and I now have the age of 35-37 years. According to the researchers, the difference in age between the two groups insignificant, and the result can be considered quite informative.
To estimate incidence, the authors used data on the number of positive tests on a hundred thousand people, driven by the Ministry of health of Israel. Rates were stratified by year of birth and grouped into two age groups in accordance with the objectives of the study.
The basis was taken the results of PCR testing for SARS-CoV-2, which was conducted in the period from 1 March to 5 April for all patients with symptoms indicating COVID-19 — cough, shortness of breath, fever.
The sample included 72 060 tests, including those 3064 patients born between 1979 and 1981, the and 2869 — from born between 1983 and 1985, which most likely has not received the childhood BCG vaccine.
The results showed that those born before the abolition of BCG vaccination in the country after becoming infected with a coronavirus at about the same frequency. The proportion of positive test results of the total number of tested among the vaccinated was 11.7 percent, and among non-vaccinated — 10.4 percent.
In this second group, obviously, were still a small percentage of people who came to Israel from other countries where children are vaccinated with BCG. And this only reinforces the conclusion of the authors that the BCG vaccine has non-specific protective effect against SARS-CoV-2.
The authors understand that their study has several limitations. For example, in the sample did not get asymptomatic carriers, because they did not do PCR tests. Also failed to compare the morbidity and mortality among vaccinated and unvaccinated as among the studied patients there was not a single fatality.
In any case, scientists believe that the results of this work refute the idea that BCG vaccination in childhood protects against COVID-19. Much more, from their point of view, the statistics of disease in a particular country is influenced by such factors as the presence of the country at the beginning of the flash or on the decline, the average age of the population, measures to control the spread of infection, the number of tests conducted and the criteria for counting.