Those vaccinated against Covid-19 may still need to wear masks: Here's why

If vaccinated people are silent spreaders of the virus, they may keep it circulating in their communities, putting unvaccinated people at risk

The new Covid-19 vaccines from Pfizer and Moderna seem to be remarkably good at preventing serious illness. But it’s unclear how well they will curb the spread of the coronavirus.

That’s because the Pfizer and Moderna trials tracked only how many vaccinated people became sick with Covid-19. That leaves open the possibility that some vaccinated people get infected without developing symptoms, and could then silently transmit the virus — especially if they come in close contact with others or stop wearing masks.

If vaccinated people are silent spreaders of the virus, they may keep it circulating in their communities, putting unvaccinated people