Since early 2020, coronavirus variants have evolved that are better able to escape immunity from past infection or vaccination. This has prompted updates to the COVID-19 boosters that better match the components of the vaccine with the circulating omicron subvariants. Updated bivalent COVID-19 boosters are now available.
How well did the original vaccines work to protect against COVID-19?
The original Pfizer-BioNTech and Moderna mRNA vaccines targeted the spike protein from the ancestral strain of SARS-COV-2. Vaccine efficacy was 95% against the early variants that circulated in 2020 and early 2021. The effectiveness declined slightly with the emergence of the delta variant in the summer of 2021.
Continue Reading on Patch
