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Does BCG vaccine protect against Novel Coronavirus?

Does BCG vaccine protect against Novel Coronavirus?

Last Reviewed : 12/16/2020
Does BCG vaccine protect against Novel Coronavirus?

COVID-19 pandemic has spread all across the globe. The overall fatality rate and the impact of COVID-19 on each country are highly variable. The fatality rate or the death rate of COVID-19 in Italy is above 10%, in Spain, around 9%. In the rest of the world, the fatality rate is about 2%-5%. While it is attributed to the age of the population, it is not evident why it is highly variable from country to country.

According to a study that is not peer-reviewed yet, these national differences in COVID-19 impact could be partially explained by the different national policies with respect to BCG or TB vaccine. This study compared countries where BCG vaccination is universal to the countries where it is not offered to everyone. Countries like Japan adopted universal BCG vaccination policy in newborns due to high prevalence of Tuberculosis in these countries. Other countries like Spain, France, Italy, United States and Netherlands do not have universal TB vaccination policy.

As per the study, BCG vaccination produces immunity against several other non-TB organisms due to its non-specific immune effects. BCG vaccination significantly increases the secretion of pro-inflammatory substances which provide antiviral immunity. Apparently, BCG vaccination provides broader protection to respiratory infections.

This study aimed to identify the correlation between the number of COVID-19 cases and deaths and the existence of universal BCG vaccination policies. The study stated that the higher number of COVID-19 cases and deaths might be partially explained by a country’s BCG vaccination policy. Italy has one of the highest fatality rates and it never implemented universal BCG vaccination. On the other hand, Japan had early cases of COVID-19 but it maintained a low death rate. Japan has been implementing universal BCG vaccination since 1947. Iran has a higher COVID-19 case as it started implementing BCG vaccination only since 1984, leaving anyone above 36 years old unprotected. COVID-19 cases are high in the United States and Italy, where BCG vaccination is not required.

BCG vaccination is shown to produce broad protection against viral infections and sepsis. The study concluded that there is a correlation between BCG vaccination policies of a country and the number of COVID-19 cases seen in that country. It conferred that BCG vaccination may provide some protection against COVID-19.

This study is not peer-reviewed yet and the final conclusion is based on data correlation only. There is no direct evidence that BCG vaccination protects against COVID-19. Any individual, even with BCG vaccination, can contract COVID-19 if proper precautions are not taken. If BCG vaccination is truly protective, the severity of illness may be reduced but there is no strong evidence available yet. More research may be needed to get further clarification.

 

References:

  1. Miller et al. Correlation between universal BCG vaccination policy and reduced morbidity and mortality for COVID-19: an epidemiological study. medRxiv 2020.03.24.20042937; doi: https://doi.org/10.1101/2020.03.24.20042937
  1. https://www.worldometers.info/coronavirus/

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