In late July, the US Centers for Disease Control and Prevention reversed its earlier mask-wearing guidance for people vaccinated against Covid-19 by recommending that even those who are fully vaccinated resume masking indoors, in public, if they live in areas with “substantial or high transmission” of the virus. The update was a jarring 180 from the previous CDC mask guidance issued in May, which gave fully vaccinated individuals the green light to remove face coverings and resume activities without social distancing.
Confusing? Maybe just a bit. But there’s a logic to the CDC’s about-face.
In this new phase of the pandemic, there are two major variables to consider: the workings of the highly contagious Delta variant of the coronavirus, and the significant proportion of the US population that remains unvaccinated.
Vaccinated people are far less likely to contract Covid-19 than those who haven’t gotten their jabs. New research from the UK estimates that the unvaccinated are three times likelier to become infected with the Delta variant.
The vaccines work. But it is simply par for the course of any vaccination rollout that a small percentage of breakthrough infections do happen. And in the event of a breakthrough infection, vaccinated and unvaccinated people infected with the highly contagious Delta variant appear equally likely to transmit the virus to others.
Faced with the threat of yet more contagious variants, like Delta Plus, it’s imperative to limit opportunities for the virus to spread. That means, among other things, playing by the new rules of masking.
Should I wear a mask outdoors?
Saskia Popescu: Outdoors is lower risk, but it doesn’t eliminate it, so when we see large gatherings like packed outdoor concerts and people are face-to-face for hours and shouting or singing, I do worry that it diminishes the protective aspect of being outdoors.
Elaine O Nsoesie: If you are outdoors by yourself or with members of your household, then you do not need to wear a mask.
Should I wear a mask at the gym?
Popescu: If you’re in an area where Covid is being spread at a higher rate, I would definitely suggest it – even if you’re vaccinated. Indoor gyms are higher risk for transmission due to the number of people, variable ventilation, physical activity and increased work of breathing. If Covid is increasing in your community, wear a mask. Moreover, I encourage people to consider their own risk tolerance and potential vulnerable people at home.
Elaine O. Nsoesie: Cities and counties across the country are reporting high levels of transmission. So I would recommend that we wear masks indoors in places like gyms.
Should children under 12 wear masks at school?
Nsoesie: Children can get Covid, and we want to protect them, so they should wear masks. However, it may be challenging for younger children to wear masks for long periods of time. Our focus should be on lowering community transmission and increasing vaccination rates. If community transmission is low and vaccination rates are high, then it is less likely to have infected children and teachers and staff at school.
Popescu: Yes. Absolutely.
Do reusable cloth masks offer adequate protection for the Delta variant?
Popescu: They definitely can. Make sure to follow CDC guidance on what is considered a quality mask to ensure you’re getting the proper protection, as mask efficacy is about fit and filtration. The Delta variant is more transmissible, which means our interventions are that much more important, so it’s important people are mindful of not only wearing their mask, but also the quality of their mask.
Is it still safe for groups of vaccinated adults to congregate indoors, without masks?
Nsoesie: The decision on whether to wear a mask in this situation depends on many factors, including whether there is high community transmission, whether some of the individuals are immunocompromised, what mask mandates are in effect, etc. My sister is a frontline worker, and she is worried about the number of new Covid cases they are seeing at the hospital. Her advice is that people should wear masks and practice social distancing, irrespective of their vaccination status.
Popescu: Vaccines reduce your risk for infection and disease, but they’re not perfect, meaning that they reduce risk but don’t eliminate it. We’ve seen clusters of breakthrough infections in vaccinated folks who have congregated indoors together without masks, so I really encourage people to be mindful of community transmission rates and those they have at home who may be susceptible or vulnerable. Outdoors is always a nice option!
Saskia Popescu is an infectious disease epidemiologist and assistant professor at the George Mason University Schar School of Policy and Government
Elaine O Nsoesieis a computational epidemiologist and assistant professor at the Boston University School of Public Health