What does the new CDC guidance tell us about the COVID-19 pandemic?

The U.S. Centers for Disease Control and Prevention issued new guidance Thursday that rolls back recommendations for social distancing and quarantine after exposure to COVID-19, bringing the agency in line with how most Americans are already dealing with the ongoing coronavirus pandemic.

"If the guidelines were to recommend quarantine for everyone with an exposure, and to think about how many people in the U.S. have been exposed to COVID in the past two or three months with the high levels of transmission that we're having, we would be quarantining 10 to 15% of our population at any given time," says Johns Hopkins epidemiologist David Dowdy. "That's just not consistent, I think, with the risk of serious disease that we're seeing at this time."

Of the changes the CDC issued Thursday, the quarantine recommendations have made the most waves. The CDC no longer recommends those who have been exposed to COVID-19 to quarantine for 10 days; instead, they are recommended to mask for 10 days, get tested five days after exposure, and to monitor for symptoms of infection such as fever, cough, shortness of breath, or other COVID-19 symptoms. If symptoms develop, they are recommended to get tested as soon as possible and to isolate for at least five days beginning immediately.

The U.S. is seeing, on average, about 100,000 new cases of COVID-19 and 400–500 deaths from the disease each day, according to data from the New York Times. While these numbers still appear high, Dowdy notes that they are somewhat comparable to the number of deaths seen during peak flu season each year.

The rollback, Dowdy says, is "an acknowledgement that we should not be allowing COVID-19 to completely disrupt our society."

For more insights into the CDC decision to walk back some of its recommendations, the Hub reached out to Dowdy, who, in addition to serving as vice dean for education at the Bloomberg School of Public Health, is also a professor of epidemiology with a joint appointment in the Johns Hopkins School of Medicine.

Why is the CDC rolling back some of its COVID-19 guidance?

I think that this is mostly a move by the CDC to catch up with what people are already doing. The primary recommendations for people with COVID-19 haven't changed, but it's more about people who have been exposed. I think that the CDC wanted to make sure that they weren't putting out guidance that is broadly not being followed.

But it still speaks to the importance of vaccination, of wearing masks when transmission is high, of isolating if you've been diagnosed with COVID-19, and wearing masks if you've been exposed. But it takes that requirement of quarantine if you've been exposed—which again, I think is consistent with what most people in the country have already been doing—and acknowledges that we don't have to let this virus run our lives and run our society at this time. We want the level of our response to match the level of risk.

I also think that that the oncoming school year was a big driver in this. And that's because if you were to think of how many kids are likely to have a COVID exposure within the first month of the school year, and if you were to require all of those kids to undergo a week of quarantine, that would be a tremendous loss in terms of the educational experience of our nation's children. And I think it would be problematic to have guidance suggesting that every time a kid in school is exposed to COVID-19—not has COVID-19, but is exposed to COVID-19, right?—that they would need to be out for a week or 10 days, that, to me, would be problematic.

Are these guidance rollbacks signifying a change the phase of the pandemic we are in?

I think that we are in a new phase of the pandemic. I don't think that this particular piece of guidance is necessarily the signpost for that, but the number of deaths that we've been seeing in the U.S. has been stable for the last four months, and we have not seen that level of stability without a major wave of deaths since the beginning of the pandemic. So I do think that we are in a different phase right now. Whether that phase will continue forever, or whether we will see another wave, I think still remains to be seen.

For many people, the decision to take part in an activity like shopping or attending a gathering required a calculation of risk—risk of exposure to COVID-19 through the activity, plus risk of passing along the virus to others. How should people think about their risk potential now that people who have known exposures to COVID-19 no longer have to quarantine?

I think that that approach that you're describing—that individual risk calculation of, "how likely am I to be exposed and how likely am I to expose others who may be at risk?"—is exactly what we should be doing, and I don't think that this guidance changes that at all. I think that the guidance for people, as far as wearing masks and taking other protective measures, still benchmarks to community transmission levels, which are high in probably half the U.S. population.

Could these rollbacks undercut the CDC's authority later on, if, say, we do experience a wave of infections or there's a new variant that causes severe illness?

I don't think so. If anything, I think it gives the CDC room to move to strengthen their guidance if necessary. If you have guidelines that aren't being followed, it's better to bring those guidelines in line with what is going to be perceived as reasonable practice so that when we have more illness or reason to make things more stringent, it appears to the average person that that's a reasonable move to make.

What else should people bear in mind about the CDC's guidance and the state of the pandemic?

We are at a place where it's challenging to track case numbers anymore, because reporting practices and testing practices are so variable. So many people are testing at home and not reporting positive tests that it's hard to follow case numbers as a reliable indicator. But we do have other sources of information—including hospitalizations and deaths (if we're looking at metrics of more serious illness) but also things like test positivity, waste water surveillance, and the fraction of Emergency Department visits that carry a COVID-19 diagnosis—and by tracking trends in these things, we can get a sense of where things are.

For some perspective—the number of people who are dying of COVID every day right now is similar to the number of people who die of the flu at the peak of flu season. We have transmission levels that are as high now as they they've been at any point in time in the pandemic except during last winter, yet over the past four months there have been the fewest number of deaths since the start of the pandemic. So the average case is becoming milder.

It's absolutely possible that we see another wave of illness and death. It's also absolutely possible that we see the same sort of stability that we've seen for the past few months carrying forward for the next few months as well.