Public Health

Mira Irons, MD, explains science behind CDC’s latest mask guidance

. 9 MIN READ

Watch the AMA's daily COVID-19 update, with insights from AMA leaders and experts about the pandemic.

 

 

In today’s COVID-19 Update, AMA's Chief Health and Science Officer Mira Irons, MD, reviews COVID-19 numbers and trending topics related to the pandemic over the past week. Dr. Irons also discusses the CDC's updated mask guidance, the science behind those changes, as well as the continued vaccinations efforts both here in the U.S. and abroad.

Learn more at the AMA COVID-19 resource center.

Speaker

  • Mira Irons, MD, chief health and science officer, AMA

AMA COVID-19 Daily Video Update

AMA’s video collection features experts and physician leaders discussing the latest on the pandemic.

Unger: Hello, this is the American Medical Association's COVID-19 Update. Today, we have our weekly look at the numbers, trends and latest news about COVID-19 with AMA's Chief Health and Science Officer Dr. Mira Irons in Chicago. I'm Todd Unger, AMA's chief experience officer in Chicago.

Dr. Irons, the big news this week is all about the new guidance from CDC about mask use and it's definitely created a bit of a stir and some confusion. Can you tell us about the guidance? How it's been received?

Dr. Irons: It certainly has. So, federal officials announced last Thursday that Americans who are fully vaccinated against the coronavirus could stop wearing masks or maintaining social distance in most settings. The new recommendations caught some state officials and businesses by surprise and raised a host of difficult questions about how the guidelines would be carried out.

But the advice does come as welcome news to many Americans who are weary of restrictions. Dr. Walensky, the director of the CDC, at a White House news conference on Thursday said, "We've all longed for this moment. If you're fully vaccinated, you can start doing the things you've stopped doing because of the pandemic. However, vaccinated Americans would have to continue to abide by existing state, local or tribal laws and regulations and follow local rules for businesses and workplaces." And at the time of the announcement about two dozen states mandated masking in public. So, people have had a lot of questions about this.

Unger: Yeah, it's one of those things where there's the science and then there's the practicality around implementation. There are a lot of people out there that still have not been vaccinated. So what is the implication there?

Dr. Irons: So, I think that the issue is that this guidance applies to fully vaccinated people. And we know that a large part of the population still has not been fully vaccinated. So it really relies on people to understand the guidance and to follow it. So the CDC's advice does come with some caveats. Even vaccinated individuals must cover their faces and physically distance when going to doctors, hospitals or long-term care facilities like nursing homes and homeless shelters. People must continue to mask up when traveling by bus, plane, train or other modes of public transportation or while in transportation hubs like airports and bus stations. And also, when in prisons and jails.

The agency wasn't specific about masking in some settings including schools. And Dr. Walensky said that those recommendations would be refined and coming out in the coming weeks.

Unger: It's interesting how things change so quickly. Only a few weeks ago, there was concern that the CDC was being too conservative in some of what they were talking about. And now, it feels or maybe some people are confused by what might seem abrupt in terms of the shift. Can you talk about the science behind the decision how physicians can help patients understand another change in the guidance?

Dr. Irons: You're absolutely right. For months we've been warning people that wearing masks and social distancing were necessary to control the pandemic. And now the question is, what's changed? And I think the landscape has changed and we're getting more information.

So, from the landscape issue, Dr. Walensky said the new recommendations have resulted from a steep drop in coronavirus cases. Infections have declined by about a third in the last two weeks and there is an increase in the availability of vaccines.

Second, we have updated science. The new guidance is based on two key scientific findings. Vaccinated people rarely transmit the virus and the shots are effective against variants. There's no doubt at this point that the vaccines are powerful.

On Friday, the CDC received results from another large study showing that the vaccines made by Pfizer and Moderna are 94% effective in preventing symptomatic illness in those who were fully vaccinated and 82% effective even in those partially vaccinated. Now those numbers aren't 100% and that's, I think, what people have to understand when they're in the presence of people who are at increased risk or who are unvaccinated but are certainly positive.

Unger: Yeah. But, nonetheless, I mean, I think the message here is that odds are they're very low for somebody who's fully vaccinated to get the virus and extremely unlikely from what the science is saying then to transmit the virus to others. Those are common misperceptions out there or even earlier guidance before the science was in. Any other data or information to provide around that?

Dr. Irons: Yeah. Mounting evidence indicates that people who are vaccinated are highly unlikely to catch or transmit the virus. The risk is definitely not zero, but it's clear that it's very low. One of the lingering concerns amongst scientists has been that even a vaccinated person might carry the virus, perhaps briefly without symptoms and spread it to others.

However, CDC research, including the new study I mentioned, has consistently found few infections among those who received the Pfizer and Moderna vaccines. This study added to the many studies that preceded it; was pivotal to the CDC changing its recommendations. Other recent studies confirm that people who are infected after vaccination carry too little virus to infect others.

We should mention most of the data have been gathered on the Pfizer and Moderna vaccines. Because the Johnson & Johnson vaccine was authorized later, there are fewer studies assessing its effectiveness. It's a very good vaccine and will likely save many lives. We just need more data.

Unger: Well, speaking of the data, vaccinations, as we've passed through, I guess, the enthusiasts, we call that the first group to get through. We're now into a somewhat more reluctant population or people experiencing access issues. Where are we with vaccination numbers and what's going on there?

Dr. Irons: Yeah. So last week, as expected, the CDC recommended use of Pfizer vaccine for children ages 12 to 15 opening eligibility to a whole new age group. And we're hoping to see an uptick because millions more Americans are now eligible. The CDC said on Sunday, about 157.1 million people have received at least one dose of the COVID-19 vaccine including about 123 million people who have been fully vaccinated by either the Johnson & Johnson single dose vaccine or the two-dose series made by Pfizer and Moderna.

So, that translates to more than 59% of adults have received at least one shot. When factoring in the age group under 18, slightly more than 47% of our total population has received at least one shot. And about 37% of the total population is fully vaccinated. President Biden set a goal on May 4 of reaching 70% of adults by July 4. And providers are now administering about 1.89 million doses per day on average. That is a decrease from a peak of 3.38 million on April 13. But some of the numbers are trending higher as we bring in the 12 to 15 age group.

Unger: That's good news. You mentioned the cases are dropping. What do the numbers look like this week?

Dr. Irons: So the numbers this week, 32,994,769 cases and 586,470 deaths. Cases, hospitalizations and deaths have been trending downward in the United States for weeks. About 37,000 cases are being identified each day, the fewest since September. And about 630 deaths are being announced daily, the lowest average since July. Some of the states with the worst early spring outbreaks have seen the most significant progress. It's good to see that cases are down about 70% in the last two weeks in New Jersey and down about 40% in Michigan and New York. So, things are trending positive.

Unger: It's funny because I check every day the little case statistics here in our local area of Chicago and it still says it's very high. So, I'm hoping I'll see that tick down sometime soon as well. What are we seeing globally? Obviously, big news continues with terrible situations in countries like India. How are you viewing the global situation at this point?

Dr. Irons: Well, you're absolutely right. I mean, it's tragic. The pandemic is quickly splitting into the haves and have nots. Many wealthy cities are making dramatic progress slowing COVID-19. As they vaccinate more people, cases have started to drop.

However, outbreaks are devastating India and much of South America. And there aren't nearly enough vaccines available to them. The Biden administration announced on Monday that the United States will send at least 20 million coronavirus vaccine doses in June to countries struggling against the pandemic. Now those 20 million doses of Pfizer and Moderna and Johnson & Johnson vaccines would be in addition to the 60 million doses of the AstraZeneca vaccine which the U.S. plans to donate once the vaccine is cleared for use by the Food and Drug Administration.

It's not exactly clear how long it will take the FDA to authorize the AstraZeneca vaccine. During a White House press conference on Monday, President Biden said, "We know America will never be fully safe until the pandemic that's raging globally is under control. No ocean is wide enough, no wall is high enough to keep us safe. And so we really have to look at this as a global pandemic."

Unger: Indeed. Well, thanks so much, Dr. Irons, for being here today and sharing your perspectives. We'll see you next week for another update. In the meantime, for additional resources on COVID-19, visit ama-assn.org/COVID-19. Thanks for joining us today. Please take care.


Disclaimer: The viewpoints expressed in this video are those of the participants and/or do not necessarily reflect the views and policies of the AMA.

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