“Given the number of infections out there, it’s going to happen,” said a virologist. However, Pfizer believes its drug will prevent resistant mutations.
Doctors risk losing one of the most effective treatments against Covid-19, the new Pflovid antiviral drug from the American company Pfizer, express researchers.
Sales of Pfizer’s new antiviral drug have risen sharply in recent weeks, as the pill has been shown to reduce the chance of serious Covid-19 disease. But there is a more troubling aspect to the coin: The coronavirus can mutate in ways that make it less vulnerable to Paxlovid, according to new laboratory studies, according to the journal Science.
Researchers have found some of these mutations in new variants of the virus circulating in infected people, raising concerns that it is only a matter of time before one of the best anti-Covid-19 “weapons” disappears from the “quiver” of doctors. . As David Ho, a virologist at Columbia University in New York, put it, “When you put pressure on a virus, it escapes.”
Although these new escape mutations have not yet spread, Ho and many other scientists consider it a matter of time. “Given the number of out there, it’s going to happen, “ said Ho characteristically.
There have been previous reports that a small percentage of people with Covid-19 infection (almost 2%) have been found to feel better at first after five days of Paxlovid treatment, but then their symptoms flare up again. Questions have also been raised as to whether Paxlovid helps those who are not at high risk for serious coronavirus disease.
The US Food and Drug Administration (FDA) issued an emergency drug license in December 2021 and in the country Paxlovid – which consists of the combination of the active antiviral nirmatrelvir with ritonavir which slows down the breakdown of the former in the body – is given only in those who have risk factors for the possible occurrence of severe Covid-19. Today, more than 160,000 Paxlovid prescriptions are made in the United States each week, up from just 40,000 in mid-April, according to the Centers for Disease Control and Prevention (CDC).
This increasing use of Paxlovid favors the emergence of new, more resistant mutations in the coronavirus. As each infected human produces trillions of copies of the virus, he or she has ample opportunity to try different mutations when reproducing. So far, however, these mutations do not appear to have reduced the effectiveness of Paxlovid. However, recent studies, which have so far only been republished mainly in bioRxiv, provide evidence that the virus is gradually developing greater resistance, something that has been observed in other antiviral drugs in the past.
“It’s just a matter of time before resistance is seen,” said Jun Wang, an associate professor of medical chemistry at Rutgers University in New Jersey. However, Pfizer believes that its drug will prevent resistant mutations, as, among other things, patients take Paxlovid for only a few days.
Scientists believe that co-administration of many antiviral drugs may help prevent the development of resistance, which has been found in other viruses, such as HIV and hepatitis C. The other approved antiviral pill, molnupiravir (molnupiravir). ) has been shown to be less effective than Paxlovid and has raised safety concerns, as it could cause accidental genetic mutations in the coronavirus, which could potentially lead to potentially dangerous new variants, as some scientists fear.
The third and oldest intravenous antidepressant drug remdesivir, which prevents the virus from copying its genome, has only been approved for hospitalized patients. A recent study in rodents states that the combination of molnupiravir and nirmatrelvir is more effective against coronavirus than if each antiviral drug is given separately, but this must be confirmed by clinical trial in humans.
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