Recent public messaging harps on the idea that people can still become infected and transmit COVID-19 after they get vaccinated. While that is a risk, it’s an extremely low risk, and not worth the negative consequence: it’s stopping people from getting vaccinated.
People are using the idea that others can spread the virus after being vaccinated to claim that the vaccine does not work and therefore should not be taken. I have spoken with people who have done just that.
Vaccine trials measure how many people get infected after vaccination. Take for example the Moderna vaccine trial, published in the New England Journal of Medicine beginning in November with follow-up publications extending through February. In that trial they randomized 15,210 people to the vaccine and 15,210 people to placebo. Of those who got the placebo, 185 developed COVID-19. Therefore, 1.2% got COVID-19. Thirty of those became very ill. Of those who got the vaccine, 11 developed COVID-19. None of them got very ill. Therefore, 0.07% got COVID-19. So, the vaccine was effective: it prevented illness and it prevented serious illness.
The efficacy of the vaccine is quoted as 94%. That figure is arrived at by dividing 0.07 by 1.2, which equals 6%. Subtracting that from 100% equals 94%. This math can be worked in different ways but the bottom line is that 11 of 15,210 became mildly ill with COVID-19 after the vaccine. Those 11 could spread the illness. But 11 out of 15,210 is a very low number. But that is 22 out of about 30,000 and 44 out of about 60,000. So it is true that some might spread COVID-19 after the vaccination but it is also true that the risk of that is very low. . . .
Another way to approach this issue of whether the vaccine prevents spread is to consider what happens with other vaccines. When we give the flu vaccine do we find that those who get the vaccine contract the flu and pass it on to others at a clinically significant rate? The answer is no. Can it happen? The answer is yes. The flu vaccine, like the COVID-19 vaccine, is not perfect. But it is highly effective. The same holds for the smallpox vaccine (smallpox is now obliterated from the planet by vaccination), the polio vaccine, and others. Even when vaccines are not perfect they can be highly effective. Therefore, to harp on the rare possibility of spreading COVID-19 after vaccination is to focus on what is unlikely to happen rather than to focus on what is likely to happen — that it will work very well.
It’s enough to make you think they care more about fearmongering than about health.
Related: The growing evidence that the Covid-19 vaccines can reduce transmission, explained. “Some people may think, if I get vaccinated but I still have to continue masking and social distancing at all times, then why get vaccinated at all?”