There is now published evidence that the Pfizer BioNTech COVID-19 vaccine not only prevents symptomatic infection, but also reduces the amount of virus produced during infections in vaccinated people. This data clearly demonstrates that vaccination should reduce the likelihood of passing infection even in the rare individuals who become infected after the vaccine.
This is exceptionally good news and was really the only question not resolved surrounding these vaccines. Not only do they reduce severe illness and death, but they also reduce the amount of virus produced in the individuals who get infected so they will be much less likely to infect anyone else.
This new information comes a week after a study showing the vaccine was shown to be 80% effective 14 days after just a single dose!
These findings should go a long way toward assuring people that they are safe to interact with others once they are vaccinated. This will be particularly important for families and loved ones who’ve been separated in nursing homes or in other situations where transmission of COVID-19 was feared.
The other remarkably good news is that this vaccine is highly effective in preventing disease in adolescents. The companies did a study in 2,260 adolescents, 12 to 15 years old, who were randomly assigned to receive two doses of the vaccine or placebo. There were no infections whatsoever in the actively immunized group. This was contrasted with 12 infections in the control group, showing a reduction of infections of 100%. The primary endpoint in this study was that the immune response to the virus was equivalent to or better than the response seen in adults.
They also reported that the vaccine was well-tolerated, with symptoms in the 12 to 15 year old age group similar to those observed in the 16 to 25 year old age group, where the vaccine was previously authorized.
Together, this suggests that the vaccine will be used in ages down to 12 providing assurance that secondary schools, colleges, and universities will be able to open and operate normally!