COVID rebound after Pfizer treatment likely due to robust immune response, study finds

Oct. 6 (Reuters) – Recovery of COVID-19 symptoms in some patients after taking Pfizer’s antiviral drug Paxlovid may be related to strong, not weak, immune responses U.S. government researchers reported Thursday.

They recommended 5 days to reduce the risk of recurrence of symptoms, as suggested by some, based on an intensive study of rebound in eight patients at the National Institutes of Health. concluded that there was no need to take the drug for a longer period beyond clinical center.

All patients in the study had strong immune responses, but researchers found higher levels of antibodies in those who experienced a rebound.

The team said their data refutes the hypothesis that an impaired immune response is the reason symptoms recur in some patients.

“Our findings suggest that stronger immune responses, rather than uncontrolled viral replication, characterize these clinical rebounds,” the team wrote.

the studyPublished in the journal Clinical Infectious Diseases.

President Joe Biden and Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, experienced a COVID rebound after taking the drug.

These cases have raised concerns that Pfizer’s dual antiviral therapy may interfere with the development of long-term immune responses.

The study involved 6 people who had recurrence of COVID symptoms after taking paxlovid and 2 people who had rebound symptoms after apparent recovery who did not take the pill. Their responses were compared to her group of six people who had COVID but did not experience rebound. All volunteers had been vaccinated and boosted, and all were infected with some version of the Omicron subspecies of the virus.

Blood from study volunteers underwent intensive investigation to assess immune responses during the acute infection and rebound phases.

All rebounding patients experienced significant improvement in symptoms prior to rebounding. Of those who rebounded after paxlovid, four reported milder symptoms than during their initial infection, one with the same level of severity, and one with worse symptoms.

Patients who rebounded did not require additional treatment or hospitalization.

Some of the rebound symptoms may be caused by a strong immune response to viruses that persist in the respiratory tract, the study authors suggest. We concluded that this drug does not inhibit the immune response in some individuals.

Larger and more detailed studies are needed to further understand the rebound of COVID symptoms, the research team said, adding that current data support the need for isolation of such patients.

The researchers also suggest that long-term administration of paxlovid in immunocompromised patients, whose immune responses may be ineffective, should be evaluated.

Reporting by Leroy Leo, Bangalore and Julie Steenhuysen, Chicago.Editing by Bill Barclot

Our criteria: Thomson Reuters Trust Principles.