Some report COVID symptoms after taking Pfizer’s Paxlovid. Here’s what we know
Global News
As Paxlovid has become more widely used, some patients have reported that COVID-19 symptoms recurred after completing treatment and experiencing improvement.
More than 2.8 million courses of Pfizer Inc’s COVID-19 oral antiviral treatment Paxlovid have been made available at pharmacies around the United States, with the Biden administration working to improve access to the drug.
As Paxlovid has become more widely used, some patients have reported that COVID-19 symptoms recurred after completing treatment and experiencing improvement. Here is the latest information on these rebounds:
Dozens of individuals have reported rebounding COVID symptoms on social media or to the U.S. Food and Drug Administration after taking Paxlovid, but Pfizer suggests the experience is rare.
Pfizer has said that from more than 300,000 patients it is monitoring who received the five-day treatment, around 1-in-3,000, or about 0.03 per cent, reported a relapse after taking the pills.
That is a lower rate than Pfizer saw in its Paxlovid clinical trial, where about two per cent of participants experienced a rebound in viral levels after completing treatment.
The Pfizer trial suggested relapses may be a broader COVID trend as a similar number of those who had received a placebo also had a rebound in viral load levels.
The cause is not yet known. Some doctors have suggested that because the drug attacks the virus so quickly, some patients’ immune responses to COVID may be muted, allowing the virus to replicate again. Others have said there may be a not yet identified common characteristic among those who suffer a rebound.
Pfizer Chief Development Officer William Pao said it may be related to the virus itself, not Paxlovid, since the phenomenon was found among patients who got the drug and those who did not.
