When President Joe Biden tested positive for COVID-19 on July 21, his doctor recommended that he take the antiviral drug Paxlovid, which significantly reduces the chance of hospitalization or death for someone at high risk of developing severe COVID.
Biden began the five-day course immediately and, the White House reported, within six days he tested negative for the virus and was cleared to leave isolation.
Since Paxlovid became available seven months ago, it has overshadowed other therapies available to prevent severe Covid symptoms in high-risk patients. Some doctors are quick to prescribe it, but as with so much about the covid pandemic, there is controversy.
Some patients are worried about a possible rebound of the disease, while others have difficulty convincing their doctors that they are good candidates for the drug.
“Paxlovid is still the gold standard,” although it may not be appropriate for everyone, said Dr. Priya Nori, an infectious disease physician at Montefiore Health System.
In a clinical trial, people who had mild to moderate covid and a high risk of severe illness reduced their risk of being hospitalized or dying from the illness by 88% if they took Paxlovid within five days of onset of the symptoms.
But even as infectious disease specialists praise the treatment’s effectiveness, many doctors want better data. Here are answers to some common questions about Paxlovid.
What is Paxlovid and how does it work?
Paxlovid is an antiviral drug made up of two drugs: one blocks a key enzyme that the coronavirus needs to replicate, and the second blocks the metabolism of the first drug in the liver so it doesn’t leave the body as quickly. Patients take three pills twice a day for five days.
Who should take Paxlovid?
When the Food and Drug Administration (FDA) authorized the emergency use of Paxlovid, it specified that the drug be prescribed for people at high risk of severe illness. This list is long and includes those over the age of 65 and those with chronic or serious illnesses such as cancer, obesity, diabetes and heart disease.
However, seven months after its approval, some patients have the protection of two booster doses against covid, and many were previously infected with the omicron variant. So doctors must assess how much a patient’s history raises or lowers a patient’s risk of serious infection, weighing it against the usefulness of prescribing a drug that also has drawbacks.
Some people who are in a high-risk category may not be able to take Paxlovid if they take any of a long list of drugs that could interact with the antiviral.
Temporarily pausing some medications on the list, such as those that treat high cholesterol or high blood pressure, until a cycle of Paxlovid is finished may not cause problems. But others, such as heartbeat or transplant drugs, “could cause catastrophic complications” if taken with Paxlovid, said Dr. Scott Roberts, an assistant professor of infectious diseases at Yale School of Medicine.
Paxlovid is not recommended for people who are not at risk of severe covid. In June, Pfizer, the drug’s maker, announced it was halting a clinical trial for standard-risk people because Paxlovid did not significantly reduce hospitalization and death in that group.
What are the options for someone who cannot take Paxlovid?
Other antiviral drugs (Veklury and Lagevrio) and a monoclonal antibody drug (Bebtelovimab) also reduce the risk of hospitalization and death from covid. But they are less convenient than Paxlovid, require injections or infusions, or are not as effective.
How often do people experience rebound infections after taking Paxlovid?
A small percentage of people show symptoms of covid and test positive for coronavirus again after completing a five-day course of Paxlovid. But how many patients are affected, and why rebounds occur, is up for debate.
In the Pfizer clinical trial, between 1% and 2% of participants retested positive for covid after completing a course of Paxlovid. Because rebound occurred in people who received the drug and those who received a placebo, the FDA concluded that “at this time it is unclear whether this is related to drug treatment.”
“I’m still confused about it, and most people I talk to are still confused, because we don’t know exactly why it happens,” said Dr. Robert Wachter, professor and chair of the Department of Medicine at the University of California-San Francisco. Francisco. In May, Wachter tweeted about the recovery experience of his wife, writer Katie Hafner. “Public data on frequency is not in sync with everyone’s experience.”
There are several theories as to why bounces occur. Some experts suspect the drug doesn’t completely clear the virus in some people who have a high viral load, leading to a resurgence after five days of treatment. Or it could be that some people clear the antiviral drug from their bodies faster than others.
Given the rebound effect, is it necessary to revise the prescribing guidelines?
Some experts question whether adjusting the timing or length of a Paxlovid cycle could eliminate the rebound effect that some patients experience. If people started taking Paxlovid on day 3 of symptoms, instead of right away, for example, their body’s defenses could kick in, boosted by previous vaccinations or infections, Nori said.
Many believe a five-day course is too short, said Wachter, who wants more data. “You would think it wouldn’t be that hard to do a five-day versus seven-day versus 10-day study,” he added.
According to Pfizer, “there may be some patient populations that may benefit from longer duration or recurring treatments, and we are considering additional studies to evaluate this in some populations.”
Are people contagious if they have a rebound? Should they isolate themselves?
If people test positive again after Paxlovid treatment, they are assumed to be contagious and should be isolated from others, the experts explained.
Will Paxlovid become resistant to the coronavirus?
It’s a concern, experts say, but there’s no evidence yet that it has happened.
“The virus is mutating in all regions of its genome at all times, so at some point Paxlovid will probably become less effective than it was when the study was done a year ago,” Roberts said.
KHN (Kaiser Health News) is the newsroom of KFF (Kaiser Family Foundation), which produces in-depth health journalism. It is one of three major programs of KFF, a nonprofit organization that analyzes the nation’s health and public health issues.