With the BA.5 omicron subvariant causing an increase in reinfections, even for those who may have had omicron before, and with rare cases of rebound being reported with a popular COVID treatment drug, how do you know which one you are have ?
Questions about rebound infections have intensified after President Joe Biden tested positive for the second time in what appears to be a rare case of ‘rebound’ after treatment with an antiviral drug.
After initially testing positive on July 21, Biden, 79, was treated with the antiviral drug Paxlovid. He tested negative for the virus last Tuesday and Wednesday, clearing him to leave solitary confinement while wearing a mask indoors.
Research suggests that a minority of those who have been prescribed Paxlovid experience a rebound case of the virus.
So what’s the difference between a rebound case and a reinfection?
White House COVID-19 coordinator Dr. Ashish Jha told reporters on Monday that the data “suggests between 5 and 8 percent of people have rebounded” after treatment with Paxlovid.
“Recognizing the potential for so-called ‘rebound’ COVID positivity seen in a small percentage of patients treated with Paxlovid, the President has increased his testing cadence, to protect those around him and ensure early detection of any replication returns viral,” O’ Connor wrote in his letter.
O’Connor cited negative tests for Biden from Tuesday evening, Wednesday morning, Thursday morning and Friday morning, before Saturday morning’s positive result by antigen test. “It actually represents ‘rebound’ positivity,” he wrote.
According to the CDC, people with rebound COVID should self-isolate for at least five days, which ends if the fever has resolved for 24 hours without medication and symptoms have improved. The patient “should wear a mask for a total of 10 days after the onset of rebound symptoms. Some people continue to test positive after day 10, but are considerably less likely to shed infectious virus.
The Food and Drug Administration and Pfizer point out that 1-2% of people in Pfizer’s original Paxlovid study saw their virus levels rebound after 10 days. The rate was about the same in people taking the drug or the dummy pills, “so it’s not clear at this point whether it’s related to the drug treatment,” according to the FDA.
Paxlovid has been shown to significantly reduce serious illness and death in those most vulnerable to COVID-19. US health officials have encouraged people who test positive to see their doctor or pharmacist to see if treatment should be prescribed, despite the risk of rebound.
While many experts say the exact timing of potential reinfection remains uncertain, cases are being reported as early as a month.
“We don’t know exactly how long, but people have been recorded to get the infection as early as four weeks after having had a previous infection,” said Dr Sharon Welbel, director of hospital epidemiology and infection control. at Cook County Health.
Welbel said current reinfections could be linked to either decreased immunity from a previous infection or vaccinations, depending on whether and when a person received a booster. Because of this, Welbel said it was possible for some to contract the virus again even before a month after infection.
“It might even be sooner,” she said. “I would think, you know, based on his immune system, his level of antibodies – either to the vaccine or to a previous infection – but because, you know, we don’t become immune to that because of our vaccine or a prior infection to one of the variants we’ve experienced before… I don’t see why anyone couldn’t even get it as early as two weeks later. . Have I seen this being talked about? No . But I’ve definitely seen people in a month.”
Chicago Department of Public Health Commissioner Dr. Allison Arwady said while reinfection within weeks isn’t likely, it is possible.
Chicago’s Top Physician noted that while the omicron variant itself marked a distinct shift in reinfections, eschewing natural immunity against infection by previous strains, BA.5 also evaded immunity against even other omicron infections.
“All the variants before that, we weren’t seeing a lot of reinfection with the current variant,” Arwady said. “So we’ve seen people who had alpha or delta in the past being relatively protected, but potentially infected with omicron. Everything has been omicron since January, to be clear – all of these subvariants are different versions of omicron. BA. 4, BA .5 is the first where we see re-infection even of people who had an earlier version of omicron, so it’s different.
Arwady said while it’s still unlikely someone will get re-infected if you’ve recently had COVID, “we’re seeing more of these infections.”
“Especially if you’re counting on an omicron infection from six months ago, don’t count on it,” she said.
While patients who recovered from previous variants of COVID-19 tended to have high levels of immunity against future reinfection for 90 days, Jha said the BA.5 subvariant that infected Biden s proved to be more “immuno-evasive”.
“We have seen many people become reinfected in 90 days,” he said, adding that authorities do not yet have data on how long those who have recovered from the BA.5 strain are protected against it. reinfection.
In addition to being even more contagious than previous variants, scientists have tracked a mutation in BA.4 and BA.5 that may help it evade some immunity and cause reinfections.
A genetic trait reminiscent of the pandemic past, similar to the so-called “delta mutation”, appears to allow subvariants “to escape pre-existing immunity from vaccination and prior infection, especially if you’ve been infected with the omicron wave,” said Dr. Wesley Long, pathologist at Houston Methodist in Texas. This is because the original strain of omicron that swept the world didn’t have the mutation.
This genetic change is bad news for people who caught the original omicron and thought it made them unlikely to get COVID-19 again soon. Although most people aren’t sure which variant caused their disease, the original omicron caused a giant surge of cases late last year and early this year.
Long lab data suggests that prior infection with the original omicron is not very protective against reinfection with the new mutants, although the true risk of being reinfected, regardless of variant, is unique to each person and each situation.
However, vaccinations against COVID-19 continued to prevent serious hospitalizations and deaths, experts said.
Two new omicron subvariants known as BA.4 and BA.5 are gaining traction in the United States, but how transmissible are they and what do we know about them?