What to know about COVID-19 rebound
President Joe Biden speaks virtually during a meeting last week while recovering from COVID-19. Credit: AFP via Getty Images/Brendan Smialowski
"N95s," "PCR tests," "social distancing," "spike proteins," meet "COVID-19 rebound."
The term earned a prominent place in the pandemic lexicon when President Joe Biden announced Saturday on Twitter that he had rebounded and returned to isolation after testing positive once again for COVID-19, days after emerging from a bout with the disease.
The rebound is a phenomenon particular to those who are treated with the antiviral pill Paxlovid, which is for COVID patients who are at heightened risk due to factors like age and health.
Here's a primer on COVID-19 rebound.
What is Paxlovid?
Being treated with Paxlovid — which is sort of like Tamiflu, for the flu — has been shown to reduce serious illness, hospitalization and death by 89%, Dr. Ashish Jha, the White House COVID czar, said last month in Manhattan. The antiviral pill is recommended for older people, like Biden, who is 79, and those with preexisting conditions. The treatment is available from clinicians and free from certain local governments, including New York City.
What is COVID-19 rebound?
Although the Paxlovid treatment reduces serious or even deadly effects of COVID-19, the medication can lead a person to test positive for the virus once again, even days after a negative test. COVID-19 rebound can also include the reemergence of symptoms.
How long after the initial recovery does COVID-19 rebound occur?
Reports show that the rebound happens between two and eight days following the initial recovery, according to the Centers for Disease Control and Prevention.
How common is COVID-19 rebound?
About 10% of patients who are treated with Paxlovid experience a rebound, according to what Dr. Bruce Farber, chief of public health and epidemiology for Northwell Health, has seen in Northwell’s system.
Why does the virus rebound?
“When you treat very quickly” — treatment with Paxlovid, made by pharmaceutical giant Pfizer, is recommended to be started as soon as possible after diagnosis — “you may transiently blunt the immune response, and so the medication makes the antigen tests turn negative, but the virus comes back because the immune response hasn’t had a chance to take hold. And that’s the most likely explanation for why this rebound occurs,” Farber said.
Can I infect others if my COVID-19 rebounds?
Yes.
Should I isolate once again during a rebound episode?
Yes. “People with recurrence of COVID-19 symptoms or a new positive viral test after having tested negative should restart isolation and isolate again for at least 5 days. Per CDC guidance, they can end their re-isolation period after 5 full days if fever has resolved for 24 hours (without the use of fever reducing medication) and symptoms are improving,” the CDC recommends. Masking is recommended for a total of 10 days after rebound symptoms have started.
Can taking Paxlovid actually extend the time a person is infectious to others?
Yes, Farber said, but Paxlovid is still recommended for patients at risk for serious illness or death from COVID-19, because the medicine greatly improves the chances of staying out of the hospital and surviving. Still, he said, the potential for a longer period of infectiousness is a big reason the lowest-risk COVID-19 patients — such as young, healthy people who are vaccinated — considering Paxlovid “might want to pass.”
Does having been vaccinated — or not — make a person more or less likely to rebound?
No, Farber said: “as of now, no one can really state with any degree of confidence that that matters.”
What kind of test detects rebound?
Home tests, because PCR tests are more sensitive than home tests and can remain positive for weeks, even if a person is no longer contagious, Farber said.
Matthew Chayes, a Newsday reporter since 2007, covers New York City.
