CDC updates isolation guidance

What to do when you're sick? The debate and my thoughts.

On Friday, CDC announced updated virus guidance for Covid-19 (and flu and RSV and any common respiratory illness). News leaked a few weeks ago, but now we have the whole story.

What does the updated guidance say?

The best thing you can do hasn’t changed: Prevent illness in the first place through vaccination, ventilation, and masking.

But, if you’re sick with any common respiratory illness (i.e., not measles), CDC says to approach it in two phases:

• Phase 1: Stay home when sick until your fever resolves for 24 hours and your symptoms improve.

  • This is when you’re most contagious (see figure below.)

  • Not all infections result in a fever, so paying attention to other symptoms (cough, muscle aches, etc.) is important. The severity of symptoms is loosely connected to contagiousness.

  • What does symptoms improving mean? CDC doesn’t define it, but some local health departments do: It’s when “a person no longer feels ill; they can do their daily routine just as they did before they were ill, and any remaining symptoms, such as a cough or runny nose, are very mild, or infrequent.”

• Phase 2: Use caution for five days after take additional precautions (e.g., wear a mask, use at-home Covid-19 tests before seeing grandma at the nursing home).

  • This is important because people remain contagious beyond the “stay-at-home” period.

This is what it could look like in different scenarios:

Top figure from Nature. Bottom figures from CDC. Annotations by YLE

The debate

The vast majority of the general public won’t bat an eye at this change. However, there’s a big debate within public health about whether this was the right call:

• On the one hand, people feel that revising the 5-day isolation guidance is a sign we are moving backward. We in public health know, far too well, the cycle of panic and neglect. Also, the burden is placed more on vulnerable groups, like those severely immunocompromised.

• On the other hand, things are different now; interventions appropriate earlier in the pandemic may no longer be necessary or effective, especially given other tradeoffs. And, as the Infectious Diseases Society of America says, harmonizing guidance for viruses is a “simpler way for everyone to stay healthy.”

My thoughts

I think this guidance update is reasonable. Some reasons why:

1. Updating isolation guidance will not increase community transmission. This sounds counterintuitive, but CDC did their homework. They triangulated three new pieces of data:

   1. Models: Using testing data from 600+ people, they compared the old guidance to the new. They found little difference in onward transmission. This is because more than half of Covid-19 transmission happens among asymptomatic or pre-symptomatic people. Among those with symptoms, most onward transmission happens in the first three days of symptoms.

   2. Real-world data from California, Oregon, and other countries already implementing similar guidance found no change in cases or hospitalizations.

   3. Surveys found most people stay home while sick with Covid-19 (about 27% don’t isolate if they are sick). What fascinates me is that many people stay home regardless of their virus.

      So, in the end, this update won’t greatly impact net community transmission. Some people that were doing nothing may now do something. And vice versa.

   

   Figure by YLE

2. I appreciate the 5-day cautionary period. There is no denying you can be contagious for 8-10 days, albeit at lower viral levels, especially for Covid-19. This 5-day cautionary period reflects tradeoffs, like not having sick time. It also integrates lessons learned from the pandemic.

   1. This cautionary period also elevates flu and RSV guidance. Less than half of people with flu have a fever. Yet, old flu guidance used “fever-free” as the guidepost for being in the clear. Now, the flu has a cautionary period. (I don’t think we even had guidance for RSV, so this is a step up too).

3. I agree that the type of virus doesn’t largely matter. No one knows what virus they have if they are sick. And, most of the time, it doesn’t change what you do: stay at home. We have Covid-19 tests, but they don’t turn positive until 3, 4, or 5 days after symptoms. These are most useful in the cautionary phase.

4. We made it through the first winter after ending the emergency. Things are (thankfully) very different now than at the height of the emergency. 98% of people have immunity from vaccines and/or infections. Covid-19 is now ranked the 10th leading cause of death (it was 3rd at the height of the pandemic). Long Covid prevalence has remained relatively stable, regardless of additional waves.

5. This won’t impact what must change the most: the number of hospitalizations, deaths, and treatments for long Covid. At this winter’s peak, Covid-19 resulted in 20,000 hospitalizations and 2,000 deaths per week. But, 95% of hospitalizations are among people who are not up-to-date on vaccines. 1 in 4 nursing home residents didn’t get Paxlovid. Long Covid-19 treatment is moving at a snail’s pace. We need to be laser-focused on what will move the needle. What are we doing here?

My concerns

I am most concerned about the implementation of guidance:

1. What will people hear? I worry the focus is on “fever” without paying attention to the next instructions: symptoms must also be improved. Also, there is a cautionary period after leaving home.

2. What will businesses do? I worry that employers will not provide flexibility. Although, I admit, most companies have returned to pre-pandemic policies a while ago. Regardless, the U.S.’s “work until you die” approach is unacceptable.

Other thoughts

1. We shouldn’t hold one policy hostage to advocate for another. Many dissenting voices say that since we are loosening the Covid-19 policy, we are giving up the fight on the need for paid sick leave. Congress doesn’t feel the pressure, regardless of what we do with isolation. Yes, this needs to change. No, CDC isolation is not the avenue to change it.

2. CDC did things differently this time. It’s refreshing to see a 25+ page document justifying the policy change with science, new data, and an acknowledgment of tradeoffs. This is exactly what CDC was missing throughout the pandemic, regardless of if you agree or disagree with the policy change.

3. I am very disappointed with some of my colleagues' commentary on social media. A constructive debate is helpful, healthy, and welcome. However, calling colleagues anti-public health, ableist, participating in eugenics, and, worst, calling for death because we come to a different conclusion is unacceptable. Hard stop. You know damn well that the type of people that get into public health have heart. They have to. We can disagree, but we are still on the same team. Act like it.

What will I do if I’m sick?

If I got sick tomorrow, I would stay home. I would test for Covid-19 (probably at the tail end of symptoms, given the high number of false negatives in the beginning of illness). I would stay home until I was negative. I have the job and financial privilege to take time off. I certainly do not fault people who cannot. I encourage those to wear masks and test before seeing high risk.

Bottom line

Guidance is now updated to largely answer one question: What to do if I’m sick? I think it’s very reasonable at this point. I also believe we can live in a world with two truths: Things have greatly improved, and Covid-19 (and flu and RSV) is still a problem.

Love, YLE

---

“Your Local Epidemiologist (YLE)” is written by Dr. Katelyn Jetelina, M.P.H. Ph.D.—an epidemiologist, wife, and mom of two little girls. During the day, she is a senior scientific consultant to several organizations, including CDC. At night, she writes this newsletter. Her main goal is to “translate” the ever-evolving public health world so that people will be well-equipped to make evidence-based decisions. This newsletter is free, thanks to the generous support of fellow YLE community members. To support this effort, subscribe below: