> Unvaccinated, infected inmates had an estimated 36% risk of spreading the virus, compared with 28% among infected vaccinees. After adjustment, any vaccination, previous infection alone, and both vaccination and previous infection cut the risk of SARS-CoV-2 transmission by 22%, 23%, and 40%, respectively.
> Booster doses and more recent vaccination further lowered infectiousness among vaccinated inmates, with each dose conferring an 11% risk reduction; the risk of transmission rose 6% for every 5 weeks that had elapsed since the last shot.