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expert reaction to study looking at BCG vaccination programmes and COVID-19 deaths in different countries

A study, published in PNAS, looked at BCG vaccination programmes and COVID-19 deaths in different countries.


Prof Ben Neuman, Chair of Biological Sciences at Texas A&M University-Texarkana, and Visiting Associate Professor at the University of Reading, said:

“This study sums up the worldwide COVID-19 picture as of a few months ago, when the bulk of the infection and the highest death rates per capita were clustered in Europe and the United States, and presumably when this paper was written.  However, since that time, COVID-19 has spread widely with very high death rates in parts of the world that already had a higher uptake of the BCG tuberculosis vaccine, particularly in South America and the Middle East.

“There is still a direct potential benefit in vaccinating with BCG against tuberculosis, but it is questionable whether a tuberculosis vaccine would be seen as a viable form of long-term immune system modification for use against COVID-19 if this project were being developed now, with the benefit of the latest data.”


Prof Keith Neal, Emeritus Professor of the Epidemiology of Infectious Diseases, University of Nottingham, said:

“This is an ecological study where data in one area (country) is correlated with another set of data (COVID-19 deaths).  They are particularly useful in hypothesis generation.

“These are often problematical, including one study around 120 years ago in the USA which showed schools were INVERSELY correlated with literacy in English.  This was because newly arrived immigrants to the USA went to the major cities where there were schools but they still spoke the language of their home country.  Rural areas in the USA where there were no schools there was home schooling in English.

“Within the UK, most people over 30 and under 80 will have had BCG in the schools programme.  Many children in the BAME groups will have continued to be vaccinated at birth although people born outside the UK may not have been vaccinated.

“Previous work on BCG suggests the age it is given affects the affects BCG has on the immune system.  The age of vaccination was not assessed in the paper.  There also many different BCGs around the world.  BCG has been shown to have a long duration of protective effect against TB.

“Any BCG effect should be assessed in case control studies where mild, moderate and severe cases are included.

“Further work is needed to assess the effect of BCG.  There have been shortages of BCG vaccine so if confirmed this one for the planning of the next pandemic.”



All our previous output on this subject can be seen at this weblink:


‘BCG vaccine protection from severe coronavirus disease 2019 (COVID-19)’ by Luis E. Escobar et al. was published in PNAS on Thursday 9 July 2020.

DOI: 10.1073/pnas.2008410117


Declared interests

None received.

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