Americans who have been fully vaccinated against COVID-19 should continue wearing masks in indoor public settings when in areas of high COVID-19 transmission, the Centers for Disease Control and Prevention (CDC) recommended on Tuesday.
The guidelines apply to areas designated as having “substantial” or “high transmission.” The CDC defines substantial transmission as counties with more than 50 new cases per 100,000 residents over a seven-day period; high transmission is defined as counties with more than 100 new cases per 100,000 residents over a seven-day period. (High test positivity rates can also land a county in a substantial- or high-transmission category.)
Just over 60% of counties in the U.S. are classified as having high or substantial spread, according to CDC data.
“In terms of otherwise updating our guidance, we’re not looking at that right now. What I will say is, if you are in a place that doesn’t have very much disease out there – obviously, I should mention, it’s always a personal choice as to whether someone chooses to wear a mask or not, and that should not be something that is stigmatized or otherwise,” CDC Director Dr. Rochelle Walensky said in a phone call with reporters Tuesday afternoon, responding to a question about whether the agency would expand guidance to require masking in indoor public spaces in all circumstances.
“But in terms of our guidance, if you have a vaccine that is 90-95% effective, and you don’t have very much disease around, the chance of you getting infected should you meet somebody is already pretty low, but then the chance that you’re going to meet somebody who is infected is also pretty low,” she added. “So the potential for this to be a problem is much much lower in areas with lower amounts of disease, which is why we really need to work hard to get these areas in the country that have substantial and high amounts of transmission right now, down to lower amounts of transmission to protect the unvaccinated and get them vaccinated, and also to protect the vaccinated.”
The CDC has also encouraged mask-wearing in schools, even among the vaccinated. Walensky said the decision to change the masking guidelines was not made lightly, and “weighed heavily” on her.
The new guidelines come amidst spread of the Delta variant, which only ten weeks ago accounted for roughly 1% of sequenced COVID-19 cases. “Most of what we’re sequencing now is Delta variant, and Delta is just a different kind of beast,” CDC Director Dr. Rochelle Walensky told CBS “This Morning” host Gayle King in a Wednesday interview.
Walensky said that the CDC’s guidance change was based on new data, from the last several days and “corroborated several times,” that vaccinated individuals who manage to contract COVID-19 — breakthrough cases — can still spread the virus to others.
She said Tuesday, during the call with reporters, that breakthrough cases seem to have similar amounts of virus as unvaccinated cases. “We believe the vast majority of transmission is occurring in unvaccinated people and through unvaccinated people, but unlike the Alpha variant that we had back in May — where we didn’t believe that if you were vaccinated you could transmit further — this is different now, with the Delta variant, and we’re seeing now that it’s actually possible if you are a rare breakthrough infection that you can transmit further, which is the reason for the change,” she said.
The CDC director has previously said that 97% of hospitalized COVID-19 patients are not vaccinated, and 99.5% of people who die from COVID-19 have not been vaccinated.
Walensky also pointed to worries among public health officials and scientists that, with significant spread among unvaccinated people, the virus could mutate in such a way that makes it even more transmissible and also capable of evading existing vaccines.
“Fortunately, we are not there. These vaccines operate really well in protecting us…for severe disease and death, but the big concern, that the next variant that might emerge, just a few mutations potentially away, could potentially evade our vaccine,” she added.
The new CDC guidelines read in part:
Wear a mask in public indoor settings if they are in an area of substantial or high transmission,
- Fully vaccinated people might choose to mask regardless of the level of transmission, particularly if they or someone in their household is immunocompromised or at increased risk for severe disease, or if someone in their household is unvaccinated. People who are at increased risk for severe disease include older adults and those who have certain medical conditions, such as diabetes, overweight or obesity, and heart conditions.
Get tested if experiencing COVID-19 symptoms.
Get tested 3-5 days following a known exposure to someone with suspected or confirmed COVID-19 and wear a mask in public indoor settings for 14 days after exposure or until a negative test result.
Isolate if they have tested positive for COVID-19 in the prior 10 days or are experiencing COVID-19 symptoms.
Follow any applicable federal, state, local, tribal, or territorial laws, rules, and regulations.