Vaccinated people less likely to spread COVID – HotAir

British scientists at the University of Oxford examined national records of nearly 150,000 contacts that were traced from around 100,000 original cases. The samples included people fully or partially vaccinated with Pfizer-BioNTech or AstraZeneca vaccines, as well as unvaccinated people. The researchers then looked at how vaccines affected the spread of the virus if a person had a breakthrough infection with the highly contagious alpha variant or delta variant.

Both vaccines reduced transmission, although they were more effective against the alpha variant compared to the delta variant. When infected with the delta variant, a given contact was 65% less likely to be positive if the person to whom the exposure had occurred was fully vaccinated with two doses of Pfizer vaccine. With AstraZeneca, a given contact was 36% less likely to be positive if the person to whom the exposure had occurred was fully vaccinated.