Going over the new CDC guidelines

This week, the U.S. Centers for Disease Control and Prevention recommended that vaccinated people should wear masks indoors in most parts of the country due to the swift spread of the delta variant of the coronavirus.

On Friday, it released a report that helped spur the change in guidance. The report looks at transmission and cases in a Massachusetts community that had high vaccination rates but nonetheless saw an uptick in cases following multiple densely packed events.

That led officials to conclude that vaccinated people may be able to spread the virus more readily than they previously thought, though not nearly as much as unvaccinated people, who also are getting hospitalized and dying at higher rates.

What does the report say?

Over July 2021, there was a sharp increase in cases of COVID19 among people who either lived in or recently visited Barnstable County, Mass., where there had been several summer gatherings. Of 469 cases, about three quarters of those were in vaccinated people. However, vaccination rates were relatively high: at the time, 69% of eligible Massachusetts residents were vaccinated, according to the report. People who got the virus reported attending densely packed indoor and outdoor events.

Of the 469 cases, five were hospitalized, about 1%. Four of the five hospital cases were also vaccinated. No deaths were reported. Almost 80% of the breakthrough infections were symptomatic, with the most common symptoms being a cough, headache, sore throat, muscle aches and fever.

What’s new about it?

The data in the report suggests that vaccinated people who get a coronavirus infection likely carry just as much of the virus as those who are not vaccinated — which could mean that vaccinated people who get an infection spread the virus as easily as unvaccinated people with an infection, though that is not yet known for certain. Previously, before the delta variant was so widespread, health experts thought that

vaccinated people with breakthrough infections were very unlikely to spread the disease.

But context is important: vaccinated people are eight times less likely to get a coronavirus infection in the first place, according to a separate set of internal CDC data, first reported Thursday by the Washington Post — so they are still far less likely to transmit infections, too.

The CDC data indicates the delta variant spreads as fast as chicken pox and faster than smallpox, Ebola, the 1918 flu, MERS and SARS and the common cold.

What does this mean for mask policies and other public health measures?

Authors of the report wrote that local governments should consider expanding prevention strategies like universal indoor mask mandates — even in areas that are not designated as “substantial” or “high” transmission as defined by the CDC.

San Francisco, where indoor mask use is currently recommended but not required for everyone, is very likely to see a mask mandate as early as next week, according to San Francisco health director Dr. Grant Colfax.

I’m vaccinated. What does this mean for my risk?

If you’re vaccinated, you are still much less likely to get the virus than if you weren’t vaccinated, experts stress — even though breakthroughs are more common than previously believed. You are also very unlikely to get a case of COVID that results in hospitalization or death.

How can I protect myself ?

The best way to protect yourself from COVID is to get vaccinated, officials said. If you’re already vaccinated, safe practices include wearing a mask indoors and avoiding large, unmasked gatherings.

What about unvaccinated children or the immunocompromised?

Both of these groups are more protected if more people around them get the vaccine, Colfax said. For now, masking is an important way to slow the spread to these individuals as well, he said.

Will the pandemic ever end?

The new report suggests that the end of the pandemic may be further than previously believed, experts said. Increasing the number of vaccinated people — even in areas with relatively high vaccination rates — is the best way to stop the pandemic, according to officials.