Twitter and Reddit have been filled with patients and doctors sharing their experiences and hypotheses over the past few days, including John Donoghue, a 71-year-old emeritus physics professor at Amherst.
“We had three cases in the house with the same pattern,” Donoghue said in an interview.
Donoghue, his wife and her 95-year-old mother were all infected with COVID in the last month. All three received Paxlovid, felt better and tested negative on rapid tests for four or five days. Then their symptoms returned and each tested positive again.
“The symptoms a second time were milder,” Donoghue said. “In some ways, we feel like Paxlovid did his job. It removed the extreme symptoms from the first round and reduced them very quickly in all three cases.”
Paxlovid, granted an emergency use authorization from federal regulators in late December, is a home treatment prescribed at the first sign of infection for patients at high risk for severe COVID complications. The treatment consists of a series of three pills taken twice daily for five days.
In its clinical trial, Pfizer reported an 89 percent reduction in COVID-related hospitalization or death from any cause in patients receiving Paxlovid within three days of symptoms, compared with patients receiving placebo.
The pills had initially been shortage and hard to find for some, however, are more available now. Doctors have hailed the antiviral drug as an invaluable treatment that helps prevent vulnerable people from developing life-threatening complications.
However, some infectious disease specialists, while still praising the benefits of Paxlovid, have expressed concern that the setbacks they see and hear about may indicate that patients after treatment – and tested negative and then positive again – may still be contagious and transmit the virus to others.
“If you have a rebound after 12 days and are back at work and not wearing a mask, are you still contagious?” said Dr. Kathryn Stephenson, an assistant professor at Harvard Medical School, and an infectious disease physician at Beth Israel Deaconess Medical Center. “If you test positive on a quick antigen test, then you have a decent amount of virus and probably an infectious amount of virus,” she said.
Stephenson is Examine why some people in one household become infected with COVID while others do not. She is currently registration of volunteers in the study and said she also expects to investigate why some patients who have taken Paxlovid become ill again.
Stephenson said the project will often test volunteers using PCR nose tests, and researchers can examine these samples for genomic information to determine if the virus developed a resistance to Paxlovid, or perhaps patients quickly became infected with another variant of COVID. .
Pfizer, the pharmaceutical giant that makes Paxlovid, listed in the documents submitted last fall to federal regulators for their emergency use permit that “several subjects appeared to have a recovery in SARS-CoV-2 RNA levels around day 10 or day 14”, but said that “at present there are no clear signals” that the virus had developed a resistance to one of Paxlovid’s primary components. The documents said Pfizer would continue to analyze the data.
In a statement to Globe, the company said: “We continue to monitor data from our ongoing clinical trials and real-world evidence. We have not seen any resistance to Paxlovid and remain very confident in its clinical efficacy.”
Dr. Michael Charness, Chief of Staff at VA Boston Healthcare System, recently completed an in-depth study of a patient who experienced a recovery after taking Paxlovid.
He sequenced three nasal swabs from the patient and tested the patient for a number of other respiratory diseases. Charness concluded that the virus was not resistant to Paxlovid and that the patient had not been infected with other respiratory viruses or other variants of COVID. On the contrary, he concluded that some patients may need a longer course of treatment in order for their immune system to build a robust defense.
“It’s literally that Paxlovid is the cat, it suppresses the virus, and when the cat is gone, the mice come out to play,” Charness said.
“Paxlovid works really well while it is there, and for many people, they can remove the virus in a single phase of the infection,” he said. “But for some people, perhaps because it takes a little longer to boost immunity, they can not get rid of [all the virus] and Paxlovid is no longer there to help. ”
Charness said his study is being reviewed by a medical journal and has not yet been published.
Dr. Paul Sax, clinical director of the Department of Infectious Diseases at Brigham and Women’s Hospital, said he hears about the problem from patients.
“At the very least, people taking Paxlovid and clinically recovering should not ignore their symptoms if they come back,” Sax said. “They should think this is a repeat of COVID, and so on [test] himself again. “
There is little scientific data at present on the Paxlovid rebound phenomenon, which leads Sax and other infectious disease specialists to say that they are not sure of the best approach to dealing with such cases.
He noted that the problem is not addressed in any of Paxlovid’s clinical trials or its treatment guidelines.
But Sax said it makes “intuitive sense” to re-treat patients with a second course of Paxlovid if they rebound after the first course.
“That’s what I would recommend to anyone who had it,” he said.
Meanwhile, Donoghue, the Amherst professor who suffered a COVID rebound earlier this month with his wife and mother-in-law, was so concerned about their experiences – and worried about others – that he contacted Pfizer via its online site to report their cases.
“They sent me a questionnaire asking for more information,” he said.
He said family doctors did not recommend another round of Paxlovid, but he also believes he and his family have finally beaten the virus.
His mother-in-law is still very tired and his wife still suffers from cold-like symptoms even though all three have recently been tested negative.
“The second round was mild,” he said. “We’re pretty much okay.”