On July 27, 2021, the Center for Disease Control (CDC) updated its mask-wearing guidelines as follows:

• If you are fully vaccinated, you can participate in many of the activities that you did before the pandemic.
• To maximize protection from the Delta variant and prevent possibly spreading it to others, wear a mask indoors in public if you are in an area of substantial or high transmission.
• Wearing a mask is most important if you have a weakened immune system or if, because of your age or an underlying medical condition, you are at increased risk for severe disease, or if someone in your household has a weakened immune system, is at increased risk for severe disease, or is unvaccinated. If this applies to you or your household, you might choose to wear a mask regardless of the level of transmission in your area.
• You should continue to wear a mask where required by law, rules, regulations, or local guidance.

The CDC has the level of Community Transmission in Warren County as high.

The Virginia Department of Health reports the following:

Dr. Rochelle Walensky and CDC officials held a briefing on July 27, 2021, to provide updated guidance on mask-wearing for vaccinated and unvaccinated people.

“In areas with substantial and high transmission, CDC recommends fully vaccinated people wear masks in public indoor settings to help prevent the spread of the Delta variant,”  Said Dr. Walensky.

Here is the transcript from that meeting:

Dr. Rochelle Walensky: As you have heard from me previously, this pandemic continues to pose a serious threat to the health of all Americans. I have said, throughout my tenure at CDC, that our guidance and recommendations will follow the science in our efforts to protect the health of as many Americans as possible. And today we have new science related to the Delta variant that requires us to update the guidance regarding what you can do when you are fully vaccinated. The Delta variant is showing every day its willingness to outsmart us and to be an opportunist in areas where we have not shown a fortified response against it.

This week, our data showed that Delta remains the predominant variant circulating in the United States. Eight in 10 sequence samples contain the Delta variant. In recent days, I have seen new scientific data from recent outbreak investigations showing that the Delta variant behaves uniquely differently from past strains of the virus that cause COVID-19. Information on the Delta variant from several states and other countries indicates that on rare occasions, some vaccinated people infected with the Delta variant after vaccination may be contagious and spread the virus to others. This new science is worrisome and unfortunately warrants an update to our recommendations.

First, we continue to strongly encourage everyone to get vaccinated. Getting vaccinated continues to prevent severe illness, hospitalization, and death, even with Delta. It also helps reduce the spread of the virus in our communities. Vaccinated individuals continue to represent a very small amount of transmission occurring around the country. We continue to estimate that the risk of a breakthrough infection with symptoms upon exposure to the Delta variant is reduced by seven-fold. The reduction is 20-fold for hospitalizations and deaths. As CDC has recommended for months, unvaccinated individuals should get vaccinated and continue masking until they are fully vaccinated.

In areas with substantial and high transmission, CDC recommends that fully vaccinated people wear masks in public indoor settings to help prevent the spread of the Delta variant and protect others. This includes schools. CDC recommends that everyone in K-12 schools wear a mask indoors, including teachers, staff, students, and visitors, regardless of vaccination status. Children should return to full-time in-person learning in the fall with proper prevention strategies in place. Finally, CDC recommends community leaders encourage vaccination and universal masking to prevent further outbreaks in areas of substantial and high transmission.

With the Delta variant, vaccinating more Americans now is more urgent than ever. The highest spread of cases and severe outcomes are happening in places with low vaccination rates and among unvaccinated people. This moment and most importantly, the associated illness, suffering, and death could have been avoided with higher vaccination coverage in this country. COVID-19 continues to present many challenges and has exacted a tremendous toll on our nation. We continue to follow the science closely and update the guidance should the science shift again. We must take every step we can to stop the Delta variant and end this pandemic. Now I’m happy to take your questions. Thank you.

What does this mean for vaccinated Americans? Who are these guidelines trying to protect if vaccinated Americans are not commonly hospitalized or dying from COVID and transmission is not as common? Are these guidelines mostly trying to protect them or the unvaccinated? And if it’s the latter, then how do these guidelines protect vaccinated and if this is the latter, then how do these guidelines protect the unvaccinated? 

I think the most important thing to understand is the vaccines continued to do an exceptional job in protecting the individual who is vaccinated from severe illness, hospitalization, and death, and even, I guess, mild illness as they have indicated.

But your point is well taken and what is different with the Delta variant than what the Alpha variant is that in those cases, those rare cases that we have breakthrough infections, we felt it important for people to understand that they have the potential to transmit the virus to others.

Now, importantly, to convey in all of this is that of the transmission that is happening in the country right now, the vast majority of transmission occurring is occurring through unvaccinated individuals. But on that exception that there might have a vaccine breakthrough, we thought it was important for people to understand that they could pass the disease onto someone else. And that is important in the case, for example, of a vaccinated individual who might be going to visit an immunocompromised family member. We wanted to make sure that they took the precautions necessary to not pass the virus to them.

Is there a better way to think about the situation with Delta now? What are you telling your vaccinated friends and family when they go out for dinner, for example?

I think we still largely are in a pandemic of the unvaccinated. The vast majority of transmission, the vast majority of severe disease, hospitalization, and death, is almost exclusively happening among unvaccinated people which is why we so very much want to double down on making sure people continue to get vaccinated.

That said if you have vaccinated individuals who are in a place that with substantial or high transmission, there are contacting a lot of people, one in 21 in 10 of those contacts, could potentially lead to a breakthrough infection if you have an effectiveness of 90 to 95%. And so that’s why we’re saying in areas of substantial or high transmission, even if you are vaccinated, that we believe it’s important to wear a mask in those settings.

One, you said that you are seeing some who are fully vaccinated contribute to the spread. Can you say exactly how many people you have seen from this data that are vaccinated that are spreading this?

And secondly, when it comes to having everyone, regardless of vaccination status wear a mask in school, can you explain the thinking behind that? And are you worried that it will take away the incentive for some parents to get their children who are eligible to be vaccinated, vaccinated?

First, with regard to your first question, we are now actively conducting outbreak investigations of what is occurring in places that are having clusters and many of you have heard of many of those clusters.

 What we’ve learned in that context is that when we examine the rarer breakthrough infections, and we look at the amount of virus in those people, it is pretty similar to the amount of viruses in unvaccinated people. We are now continuing to follow those clusters to understand the impact of forward transmission of those vaccinated people. But again, I want to reiterate, 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 your rare breakthrough infection that you can transmit further, which is the reason for the change.

With regard to school, when we released our school guidance on July 9th, we had less Delta variants in this country. We had fewer cases in this country. And importantly, we were really hopeful that we would have more people vaccinated, especially in the demographic between 12 and 17 years old.

Next week, we have many school systems that are starting around the country and I think we all agree that children 11 and less are not going to be able to be vaccinated and with only 30% of our kids between 12 and 17 fully vaccinated now, more cases in this country and a real effort to try and make sure that our kids can safely get back to full in-person learning in the fall, we’re recommending that everybody wear masks right now.

Some people have asked me, why change math guidance to protect people who decide not to get vaccinated, even though they can. Can you say something about the role, the unvaccinated person who gets infected, even if they have mild or no illness, can play in the development of the next variant of concern, with that variant potentially going on to have a higher chance of potentially infecting those of us who are vaccinated.

The first thing I think we all need to acknowledge is there are some people who are not able to be fully vaccinated, like children, and some people who are not able to be fully protected even though they are vaccinated like immuno-compromised people.

So part of the reason for this guidance is to make sure that we can protect those and that people who are seeing immuno-compromised people, for example, know how to protect them, even though they themselves may be fully vaccinated.

But your point is well taken about those who have made the choice to not get vaccinated and the amount of virus that is circulating in this country right now. So for the amount of viruses circulating in this country, largely among unvaccinated people, the largest concern that I think we in public health and science are worried about is that virus and the potential mutations away we are from a very transmissible virus that has the potential to evade our vaccine, in terms of how it protects us from severe disease and deaths.

Right now, fortunately, we are not there. These vaccines operate really well in protecting us about severe forms of severe disease and deaths. But the big concern is that the next variant that might emerge, just a few mutations potentially away, could potentially invade our vaccine.

I was wondering if you could talk a little bit more about the data showing that some vaccinated individuals have similar viral loads to unvaccinated. And if you could talk about whether the CDC is looking at expanding the mask guidance to maybe require masking indoors, in public spaces, in all circumstances or other being indoors in public spaces, in all circumstances or other public health measures, given the spread of Delta?

So, as I mentioned, in these outbreak investigations, we are able to stratify the clusters that we are seeing. Unfortunately, because we have so much disease right now, some of these clusters are large, and we’re able to stratify them by a smaller proportion that is vaccinated and breakthrough infections, and a larger proportion that is unvaccinated. And so, when we look at their Ct values, or otherwise their viral load, and what we’re seeing is that they’re actually quite similar. That leads us to believe that the breakthrough infections, where they are, have the potential to [inaudible] transmit with the same capacity as an unvaccinated person. So the burden is less because there are fewer of them people-wise, but the amount of virus is the thing between those two strata.

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 something that is stigmatized or otherwise. But in terms of our guidance, if you have a vaccine that is 90 to 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. So the potential for this to be a problem is much, much lower in areas with low 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 the transmission right now, down to lower amounts of transmission, to protect the unvaccinated and get them vaccinated, and also to protect the vaccinated.

Dr. Walensky, can you tell me whether or not you are intending to start collecting and releasing data on the breakthrough cases? I mean, a while back, the CDC announced that they were not going to be reporting on this data, but it looks like the Delta VarianT is changing the equation in a lot of ways. When will we start to see those data? 

I would like to correct a misperception that is out there. The first thing I want to say is we are collecting passive reporting data on people who are hospitalized and who have died, but we recognize that epidemiologically, that is not going to give us the best information with regard to rates of breakthrough infection because passive data collection is generally underreported. In order to counter that. We have been collecting data through more than 20 cohorts of people. These include tens of thousands of people who we are following nationwide, and they include healthcare workers, essential workers, long-term care facilities, and in some of these cohorts, we’re collecting PCR data from every person in them weekly. So we are absolutely studying and evaluating breakthrough infections in many different sites, many different people across the country. We are looking at those data on a weekly to bi-weekly basis, and we will be reporting on those soon.

Can you just sort of define how you assess substantial and high transmission? If someone reading, one of our stories wants to know if this applies to them, how are they supposed to know what their community level of transmission is, and in turn when they should be wearing a mask, and then maybe if rates fall, when they can kind put them back away?

So the CDC COVID Data Tracker tracks the amount of community transmission by county and is updated daily. It’s color-coded, so substantial is orange and high is red, and in fact, most departments of public health and local jurisdictions track this pretty carefully as well. We can get you the link, of course, to find the data. But the important thing I want to continue is what it means. Substantial transmission in areas that have 50 to 100 cases per a hundred thousand over a seven-day period, and substantial are places that have more than a hundred cases in a seven-day period per hundred thousand. So I do want to sort of articulate that we have places in counties and states here that are now reporting over 300 cases per hundred thousand over a seven-day period, so really an extraordinary amount of viral transmission, which is what we’re concerned about.

I am wondering if given what you now know about the Delta variant and the transmissibility if the CDC is giving any thought to recommending vaccine mandates, for instance, of the federal workforce or the military, which President Biden could impose, or mandates perhaps for schools or employers?

So that is not something that the CDC has jurisdiction over. We certainly will be technical advisors to the government as they’re making these decisions. What I will say is that we are recommending that communities look to their community levels and really look to what would motivate their communities to help get vaccinated. If businesses believe that it would be a mandate, then we encourage them to do so. We’re encouraging really any activities that would motivate further vaccination. Not all communities are going to be responsive to a mandate, in the same way, so we’re really encouraging communities to look to their own areas and see what would be most motivational to get vaccinated.

High caliber masks, because in areas where there are low vaccination rates, one would expect that mask adoption would also be low. In order to sort of maximum personal protection, are you emphasizing N95 masks over cloth and surgical? 

Right now, often surgical.

Right now, we’re really motivated to get people masked to prevent transmission. If people have a personal choice as to whether they have access to and want to wear an N95, we leave that to their personal decision, the CDC does have guidance as to what are the best masks to wear, a multi-layer cloth mask, a surgical mask. So we’re leaving that to the CDC guidance on masking

Doctor, given the definitions that you’ve had here of the high and substantial transmission, and I understand that you’re doing it county by county, will you consider much of the state of Missouri now as in high or substantial transmission and subject to the recommendations that the CDC is making this afternoon? And are some of the clusters that you are investigating also in the state of Missouri?

The state of Missouri, I’m actually just even looking, but my understanding is the state of Missouri is largely classified as higher substantial. It’s not entirely, but it’s largely classified as substantial or high with a few exceptions in the county. And we are collaborating with the state when they ask for our assistance related to outbreak investigation

One of the big outstanding questions here is how much compliance we might expect to get in terms of folks masking up indoors. Have you done any type of modeling work to get a sense of if you get certain percent compliance, whether that would be sufficient in helping to drive down cases at this time?

We work together. We worked together with numerous modeling groups. I don’t specifically know which ones might have examined that. So I think I should probably refrain from answering that right now, but I suspect that one of the modeling groups has examined the question. I really do believe that masking right now, especially for those unvaccinated, is a temporary measure. What we really need to do to drive down these transmissions in areas of high transmission is to get more and more people vaccinated and in the meantime to use masks.

I just have one sort of closing remark.

So I just want to indicate that this is not a decision that we or CDC has made lightly. This weighs heavily on me. I know at 18 months through this pandemic, not only are people tired, they’re frustrated. We have mental health challenges in this country. We have a lot of continued sickness and death in this country. Our health systems are, in some places, being overrun for what is preventable. And I know in the context of all of that, it is not a welcomed piece of news that masking is going to be a part of people’s lives who have already been vaccinated.

So this new data weighs heavily on me. This new guidance weighs heavily on me, and I just wanted to convey that this was not a decision that was taken lightly. Public health experts, scientific experts, medical experts, when we have shown them these data have universally said that this required action. I thought and I felt that when I saw the data myself. So I just wanted to perhaps close and say that this was not something that we took lightly and something that I know weighs heavily with me and with all of America.

Rochelle P. Walensky, MD, MPH

Rochelle P. Walensky, MD, MPH, is the 19^th Director of the Centers for Disease Control and Prevention and the ninth Administrator of the Agency for Toxic Substances and Disease Registry. She is an influential scholar whose pioneering research has helped advance the national and global response to HIV/AIDS. Dr. Walensky is also a well-respected expert on the value of testing and treatment of deadly viruses.

Dr. Walensky served as Chief of the Division of Infectious Diseases at Massachusetts General Hospital from 2017-2020 and Professor of Medicine at Harvard Medical School from 2012-2020. She served on the frontline of the COVID-19 pandemic and conducted research on vaccine delivery and strategies to reach underserved communities.

Dr. Walensky is recognized internationally for her work to improve HIV screening and care in South Africa and is nationally recognized for motivating health policy and informing clinical trial design and evaluation in a variety of settings.

She is a past Chair of the Office of AIDS Research Advisory Council at the National Institutes of Health, Chair-elect of the HIV Medical Association, and previously served as an advisor to both the World Health Organization and the Joint United Nations Programme on HIV/AIDS.

Originally from Maryland, Dr. Walensky received her Bachelor of Arts from Washington University in St. Louis, her Doctor of Medicine from the Johns Hopkins School of Medicine, and her Masters in Public Health from the Harvard School of Public Health.