BCG vaccine to prevent COVID-19? Top immunologist questions efficacy. (8)

How effective is BCG vaccine for COVID-19 prevention?

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There is a lot of discussion about the potential role against COVID-19 of readily available, a century-old vaccine against tuberculosis, BCG vaccine. This interest is based on two sets of data. First, when young children were vaccinated with the BCG vaccine against TB, it protected them from hospitalizations and deaths due to sepsis and unrelated, other respiratory infections. And the second set of data stems from the fact that the BCG vaccine decreased the amount of viremia after the yellow fever vaccine administration. But BCG vaccine did not prevent the formation of antibodies, and therefore, the effectiveness of the yellow fever vaccine. What is your take on the discussion around the BCG vaccine? We are aware that there is a clinical trial on the BCG vaccine in coronavirus in Australia in healthcare workers. Another BCG vaccine trial is going to be in Belgium, and, probably in the United States as well. So we will see that data. But what do you think, as a prominent immunologist, of the potential for BCG vaccine against COVID-19? Because the BCG vaccine is readily available in a lot of places. I would hazard a guess. And the guess is this. That if there is an effect that it will be modest. And so part of that guess is associated with the idea that many of the data described are associated with children. And the mechanisms that might work for amplifying immune responses, and in particular, innate immune responses in children, may not be the same or may not be as effective in later adults. And then I think this emphasis on the BCG vaccine reflects our need for something that can help and the absence of a more direct vaccine approach. So that’s very interesting. So how children, or young children especially, respond to a BCG vaccine, could protect them or protect them a little bit more than adults who are re-vaccinated. We don’t know that because, usually, it’s only the small children that get the BCG vaccine. I think there are way too many variables here to guess that the BCG vaccine is going to work. I will suggest that we will be lucky if the BCG vaccine gives anything than a very modest protection against COVID-19 coronavirus.