evaluating individual stories. If someone receives a vaccine and later develops COVID-19, it is tempting to conclude that the vaccine did nothing. But that conclusion cannot be drawn from one case alone.
To assess vaccine effectiveness, researchers compare outcomes across groups of people while accounting for factors that may influence the results. They examine questions such as how frequently vaccinated and unvaccinated people become infected, how often they require hospital care, and how frequently they experience severe complications.
The results can differ depending on the vaccine formulation, the variant circulating
There’s more to discover. Continue to the next page for the rest of this article.
