Vaccines effective even without post-shot symptoms or prior infection

Vaccination with the two messenger RNA (mRNA) vaccines for SARS-CoV-2, the virus that causes COVID-19, yields a robust antibody response, even if a person did not develop significant symptoms following vaccination or did not have a prior SARS-CoV-2 infection. That's the key finding from a recent study of nearly 1,000 health care workers in the Johns Hopkins Health System who received two doses of either the vaccine manufactured by Pfizer/BioNTech or the one produced by Moderna.

source https://medicalxpress.com/news/2021-08-vaccines-effective-post-shot-symptoms-prior.html