Unvaccinated people produce 2.58 to 4.5 times
more virus than vaccinated people do, researchers report March 29 in
Nature Medicine. Those data show vaccinated people have a lower “viral load” and are less likely to pass the coronavirus to others if they do become infected, but the effect is not as strong as might be hoped to truly limit transmission, Kilpatrick says. That reduction in viral load amounts to about an 11 percent decrease in infectiousness, he says. “That’s good … but you’d like to be half as infectious or three-quarters lower infectiousness.”