(2021-07-29) Cdc Reversal On Indoor Masking Prompts Experts To Ask Wheres The Data

CDC reversal on indoor masking prompts experts to ask, ‘Where’s the data?’

New recommendations from federal health officials this week on when vaccinated Americans should don face masks came with a startling bolt of news: People who have had their shots and become infected with the delta variant of the coronavirus can harbor large amounts of virus just like unvaccinated people.

“They’re making a claim that people with delta variant who are vaccinated and unvaccinated have similar levels of viral load, but nobody knows what that means,” said Gregg Gonsalves, an associate professor at the Yale School of Public Health. “It’s meaningless unless we see the data.”

Because tests showed similar levels of virus in the vaccinated and unvaccinated, the CDC inferred the delta variant can be transmitted by people with breakthrough infections.

But Fauci noted there is not yet clinical data on what the high viral loads mean in terms of disease transmission. “You can make a reasonable assumption that vaccinated people can transmit the virus just like unvaccinated people can,” Fauci said.

Several organizations and public health experts issued statements saying the CDC should have gone further and broadened the criteria for deciding which communities have transmission high enough to warrant universal masking indoors.

Although delta is more than twice as transmissible as earlier variants, it does not have some of the mutations seen in other variants that can help the virus evade antibodies. But the delta floods the zone. It grows so quickly in the nose that it may be overwhelming the body’s vaccine-enhanced defenses before the immune system can marshal a robust response, said William Hanage, an epidemiologist at the Harvard T.H. Chan School of Public Health.

Even if tests find lots of virus in vaccinated people, it is uncertain how contagious they are.

CDC document breakthrough infections (PDF).