LA County advised people to wear masks indoors even if vaccinated

The Los Angeles County Department of Public Health is recommending that all residents, regardless of vaccination status, wear masks indoors “as a precaution” due to the highly transmissible delta variant.

Context: The recommendation that even fully vaccinated people wear masks indoors differs from the national guidance from the Centers for Disease Control and Prevention (CDC) issued in May, that outside of a few settings like public transit, the vaccines offer such strong protection that fully vaccinated people do not need to wear them.

The CDC has given no indication that it plans to change its recommendation because of the delta variant, and many other experts and jurisdictions in the U.S. have not followed Los Angeles’s recommendation.

Experts say that the delta variant is mainly a threat to unvaccinated people. The Pfizer and Moderna vaccines have been found to be highly effective against it. A British study last month found the Pfizer vaccine was 88 percent effective against the delta variant after two doses, for example.

But without proof of vaccination or vaccine “passports,” an idea that has been politically controversial, it is impossible to know who is vaccinated and who isn’t, and therefore how to apply blanket mask recommendations.