factually
Index/Topics/Effectiveness of COVID-19 vaccines

Effectiveness of COVID-19 vaccines

The effectiveness of COVID-19 vaccines, particularly variant-adapted vaccines, in reducing symptomatic infection and severe outcomes

Fact-Checks

2 results
Jan 31, 2026
Most Viewed

How do risks of COVID-19 vaccination compare to risks from COVID-19 infection?

, mostly short-lived risks—most notably rare cases of after mRNA shots—while SARS‑CoV‑2 infection carries substantially higher and broader risks, including greater odds of myocarditis, hospitalization...

Jan 22, 2026

How do SARS-CoV-2 variants like Omicron specifically reduce vaccine effectiveness and what lab and epidemiologic evidence supports immune escape?

Variants such as reduce vaccine effectiveness primarily by accumulating mutations in the Spike protein that change antibody binding sites, producing antigenic mismatch to vaccine-elicited antibodies a...