CDC director’s COVID returns as study shows such rebounds are shockingly common

Rochelle Walensky, director of the Centers for Disease Control and Prevention, experienced a COVID-19 rebound — the return of mild symptoms and positive tests after completing a course of the antiviral drug Paxlovid and testing negative — the CDC announced today.

Valensky tested positive for the first time on October 21 and had mild symptoms. She took a five-day course of Paxlovid, got better and tested negative. But on Sunday, Oct. 30, her mild symptoms returned and she tested positive again, the agency said.

Walensky now joins the ever-growing ranks of people reporting post-Pakslav pick-ups, including notable picks like President Biden and Chief Infectious Disease Specialist Anthony Fauci. But according to a small study published in JAMA Network Open last week, rebounds can be surprisingly common in all cases of COVID-19 — even in those not treated with Paxlovid.

The study looked more closely at the daily symptom data of 158 untreated people with COVID-19 who served as a placebo group in a drug trial. They were followed for 28 days after they developed cases of COVID-19. During that time, 108 of the 158 people — 68 percent — reported recovery, in which their symptoms disappeared completely for at least two days. But of those 108 people, 48 people — 44 percent — reported a return of symptoms before the end of the 28-day observation period.

Frequent relapse

The tackles were generally weak. Of the 48 rebounders, 41 reported only mild symptoms while rebounding, seven reported moderate symptoms, and none reported severe outcomes. The most common rebound symptoms were cough, fatigue, and headache.

Overall, the authors, led by researchers from the University of California, San Diego, concluded that “the natural history of untreated COVID-19 was variable and wave-like,” which “may explain some of the recovery symptoms after treatment of COVID-19, as in cases of which has been described as a Paxlovid rebound.”

The study had limitations, as all do. It did not confirm the rebounds with the results of the express test. This also happened when alpha was the dominant variant of SARS-CoV-2, so it is unclear whether the rebound rates are the same now, as the omicron subvariants are dominant and people generally have higher levels of immunity from vaccination and previous infections.

But it adds more information to the mysterious phenomenon. Scientists still don’t understand why rebounds occur, who is at risk, or how common it is. Some speculate that this may have been due to viral replication or an erratic immune response. Some preliminary data from the National Institutes of Health, however, suggested that the rebound may be related to an immune response that flares up as the body clears the debris from the destroyed infection.

During clinical trials of Paxlovid, Pfizer researchers noted that about 1 to 2 percent of both the treatment and placebo groups had a relapse, suggesting that it was equally likely to occur with or without treatment. But as the use of Paxlovid became more widespread, anecdotal reports of relapses after a course of treatment accumulated, giving the impression that the percentage of people affected was much higher than just 1 or 2 percent. A new study supports this anecdotal finding, but not just for those taking antiviral drugs.