Understanding the human body is a team effort. That's where the Yachtel group comes in.

Researchers at Yachtolt have been delving into the secrets of probiotics for 90 years.

Yachtold also partners with nature portfolio to advance gut microbiome science through the global grants for gut health, an investigator-led research program.

To learn more about Yachtolt, visit yawcult.co.com.j, that's Y-A-K-U-L-T.

C-O-J-P. When it comes to a guide for your gut, count on Yacolt.

Hi, and Hi and welcome to COVID quickly, a scientific American podcast series. This is your fast track update on the COVID pandemic. We bring you up to speed on the science

behind the most urgent questions about the virus and the disease. We demystify the research and help you understand what it really means.

I'm Tanya Lewis.

I'm Josh Fishman.

And we're Scientific Americans' senior health editors.

Today we'll explain why the CDC now wants vaccinated people to wear masks indoors again.

And we'll discuss one big reason why some people still refuse

to get vaccinated. Just a few months ago, the CDC said vaccinated people didn't have to wear

masks in most settings, but this week the agency reversed course, saying vaccinated people

should wear masks at times. What do the

recommendations actually say, Tanya, and why this sudden shift in position? So in its latest

guidance, the CDC says that vaccinated people should once again wear masks in public indoor

settings under certain circumstances. For example, if you live in an area with high levels of

COVID transmission, which includes

people who live in places with more than 50 cases per 100,000 people in the last week.

The agency also recommended universal masking in all K-12 schools, including all students, teachers,

and staff. The CDC says the reason for the shift is new data about the Delta

...