““The vaccines were not tested on their ability to prevent infection,” said Susan Hassig, an epidemiologist at Tulane University. “What they are tested for — and are really good at — is greatly reducing the likelihood of becoming ill and requiring hospitalization and potentially dying.”

https://www.nola.com/news/coronavirus/article_6583709e-ea58-11eb-8c5e-fb0435c8d948.html