factually
Index/Topics/Vaccine Safety and Efficacy

Vaccine Safety and Efficacy

The balance between the benefits and risks of COVID vaccines, including the potential for rare adverse events.

Fact-Checks

2 results
Feb 1, 2026

How long does spike protein from mRNA or adenoviral COVID vaccines stay in the body?

The bulk of expert guidance and many clinical studies report that produced by or adenoviral COVID vaccines is present for a short period — typically days to a few weeks — as the injected mRNA or vecto...

Jan 10, 2026

What peer‑reviewed studies compare health outcomes of fully vaccinated and unvaccinated children?

A small number of peer‑reviewed and non‑mainstream studies have directly compared health outcomes in vaccinated and unvaccinated children; the most prominent are a U.S. pilot/home‑school survey and se...