The CDC’s new, relaxed Covid isolation guidance makes perfect sense

What makes for good public health guidance? That’s the conversation I was having with a colleague in her 40s railing against the Centers for Disease Control and Prevention’s erstwhile guidance about alcohol consumption for women of “childbearing” years. The guidance, if followed closely, would mean that all women ages 15 to 49 should fully abstain from alcohol consumption unless they’re using birth control. That’s more than 77 million women in the U.S. alone. The CDC guidance was finally archived last year, along with a similar proposal from the World Health Organization. For good reason: It’s absurd.

In four years of the Covid pandemic, we have seen lots and lots of guidance change over time. Most recently, the CDC has relaxed its recommendations about isolating after testing positive for Covid.

People often ask: How much should guidance be based on evidence versus what the public is willing to do? But that’s the wrong way to think about it. Instead, those in charge of public health guidance should consider the burden it imposes on people to change their behavior, balanced against the health benefits the change can offer to them and those around them.

The CDC’s new guidance on what to do after a Covid infection has been controversial among some. It says that you should isolate when symptomatic but when the fever subsides and symptoms improve, you can end isolation. Using this lens of burdens and benefits, the new approach makes a lot of sense.

The abstention from alcohol for women between the ages of 15-49 (unless using birth control) is a great example of applying that framework. On the surface, it may make sense — fetal alcohol syndrome (FAS) is a serious issue. Many women don’t know that they’re pregnant for some period of time after conception. If the goal was to eradicate all instances of FAS, ensuring no women of childbearing age ever drank alcohol would indeed be a reasonable recommendation.

But most instances of FAS aren’t from having occasional alcohol early in pregnancy. They are largely driven by heavy, often binge drinking through much of pregnancy. So asking all women to stop drinking alcohol during their potential childbearing years? That is a very high burden. It would theoretically be beneficial. But the absurdly high cost for a small benefit means it makes no sense.

When we think about other public health guidance that does make sense — hand-washing after using the bathroom, wearing a seat belt in a car, getting the flu or Covid vaccine if you are older — these are all low-burden, high-benefit activities. Even when the burden is moderate or high, the benefits can be worth it: quitting cigarettes, losing weight if you have obesity, limiting the number of sexual partners and/or using condoms for sexual activity. None of these are easy. Many people are not willing to do them. But that doesn’t change the fact that the benefits of doing so far outweigh the burden — and thus, the public health recommendation makes sense.

So how does this framework apply to the new Covid-19 isolation guidelines? In 2020, without vaccines or widely available treatments, Covid-19 infections caused serious illness, hospitalizations, deaths, and, even for young healthy people, long Covid. Reducing the spread of infection was critically important, and the best way to do that was asking people who were infected to isolate for five to 10 days, with masking and multiple negative tests as potential ways to end the isolation a little earlier.

That imposed a substantial burden. People missed work — and for those who don’t have paid sick leave, that loss of income can be the difference between paying the rent and putting food on the table. Kids missed school. Parents who were isolating couldn’t take care of their children. These are indeed large burdens, but for years, the benefits were very large and worthwhile: keeping people alive, reducing hospitalizations, decreasing long Covid.

But that is no longer the consequence of Covid. With nearly everyone in the U.S. having some degree of immunity against the virus (CDC estimates 98% of Americans have been infected or vaccinated or both), the consequences of infection in 2024 are just very different for the majority. (The very highest-risk people still can get quite sick, especially if they haven’t kept up with their vaccines. But most high-risk people can remain safe.) The goal of isolation guidelines should be to weigh the burdens of individuals and their families against the benefits.

In that light, asking people to isolate while they are symptomatic — have a fever, symptoms getting worse — makes sense. They are likely to be quite contagious. But as symptoms wane, so too does contagiousness. So while someone a week after symptoms could still be contagious, they are much less so. And the risk of spreading the virus days after symptoms have abated is low. As is the consequence.

But the burden of isolating many days after symptoms have resolved is very high. In 2020, this recommendation made sense. In 2024? Not so much.

The explosion of public health science over the past 50 years has identified lots and lots of things that can potentially improve health. Some of these things have large benefits while others small. If we took an absolutist approach — in which public health officials issued guidance for everything that provided any benefit — we would end up recommending that people never eat bacon, likely avoid all meat, never drink alcohol (no amount is safe!), never drive above 30 miles per hour, and so forth. Sure, those things have benefits, but the benefits of avoiding bacon (technically a Group 1 carcinogen) are small — and for bacon lovers, the burden is high.

Public health guidance has been confusing during the pandemic. It feels like it keeps changing, leading people to ask: Is the science changing? Sometimes yes, our scientific understanding does change as we learn new things. But that’s not the only thing that should drive our guidance. As population immunity grows, the benefits of avoiding infection by taking on high burdens wanes. And as the pandemic progresses, our guidance should absolutely change to reflect not just new science, but the new realities of the burdens and benefits.

Ashish K. Jha is the dean of the Brown University School of Public Health and former White House Covid-19 response coordinator.