Expert explains how masking can reduce transmission of Delta variant

US travelers who have been fully vaccinated against COVID-19 may be able to travel to Europe this summer without restrictions. Liderina/iStock/Getty Images

As the U.S. faces a surge of new COVID-19 cases due to the Delta variant, health officials are now recommending that Americans mask up again.

On Tuesday, the Centers for Disease Control reversed an earlier guidance that said that fully vaccinated people no longer have to wear masks in some indoor situations.

“In areas with substantial and high transmission, CDC recommends fully vaccinated people wear masks in public indoor settings to help prevent the spread of the Delta variant and protect others,” CDC Director Rochelle Walensky said on Tuesday in a press briefing.

Visitors to the Grand Central Market
Visitors to L.A.’s Grand Central Market are mostly masked. (Brian van der Brug/Los Angeles Times via Getty Images)

This does not mean that vaccinations are less effective than predicted.

“If people think that this [new guideline] is undermining the effectiveness of vaccines, it’s not. All you have to do is look at the stark difference between death rates, hospitalization rates of people who are vaccinated and unvaccinated,” Yahoo News Medical Contributor Dr. Kavita Patel told Yahoo News.

Currently, 97 percent of people entering hospitals for COVID-19 are unvaccinated and 99.5 percent of all deaths from COVID-19 in the U.S. are among unvaccinated people. Those who are vaccinated can still sometimes become infected with the virus, but face far milder symptoms if they do. Vaccinated people also greatly reduce their chances of being hospitalized or dying of the disease, according to health experts.

For vaccinated people, masks can serve as an extra barrier against the virus and help lower transmission rates.

“The real reason to add that layer of protection with masks has a lot more to do with concerns about you being vaccinated and infected, not even knowing it, and potentially passing it on to half the country, which is not vaccinated for a variety of different reasons,” said Patel.

A sign encouraging mask
A supermarket in Indian Valley, Calif., encourages mask wearing. (Robyn Beck/AFP)

The new CDC guidance encourages vaccinated people to wear masks “in areas with substantial and high transmission.” These areas can be found on the CDC’s website, which showcases the level of community transmission by county. Any county displayed as orange or red is considered an area with substantial or high transmission.