Success of Covid-antiviral pills depends on access to fast, accurate tests

Promising antiviral medication Covid can stop hospitalization and death, but only if given to patients within three to five days of their first symptoms.


In just a few weeks, perhaps before most Americans finish their holiday decorations, the US could get a new antiviral pill from Merck that is expected to reverse the deadly covid-19 epidemic - with a second option from Pfizer to be followed soon. of that. .

Now under state review, both pills are recommended by infectious disease doctors who do not tend to be too strong.

"This is a real change," said Drs. Daniel Griffin, specialist in infectious diseases and immunology at Columbia University. “This is high with vaccines. It does not replace goals; we still want to vaccinate people. But, boy, this is just another good tool you can have. ”

The new drugs, which require 30 or 40 pills to be taken within five days, have been shown to significantly reduce hospitalization and prevent the deaths of adults with mild to moderate Covid who are at high risk for serious illness or age. But experts say the success of treatment will depend on one thing: the high risk of Covid-infected patients being able to get tested - and treated - quickly enough to make a difference.

"Early, easily accessible and achievable testing time that allows us to make a decision will be key to these medications," said Drs. Erica Johnson, chairman of the Infectious Disease Board of the American Board of Internal. The tree. "It puts pressure on our public health strategy to make this a reality."

In clinical trials, molnupiravir, an antiviral drug developed by Merck & Co. and Ridgeback Biotherapeutics, were given to adult patients who could be hospitalized, vaccinated, and at high risk within five days of their first covid symptoms. Pfizer's product, Paxlovid, was tested on the same patients three days - just 72 hours - after symptoms appeared.

The results of a Merck study, released last month, showed that the drug reduced the risk of hospitalization by as much as 50 percent and even prevented complete death. It will be considered by an advisory panel to the Federal Food and Drug Administration on November 30. Pfizer officials, who requested immediate FDA approval for their drug on November 16, said Paxlovid had reduced the risk of hospitalization and death by 89 percent. Both of these drugs work by affecting the reproductive system of the Covid virus, although they do so at different stages of the process.

But those promising results suggest that medications can be given in less time spent on tests, a proven challenge when accessing medical care for real patients. The same medications can prevent the side effects of the flu if given early, but studies show that only about 40 percent of high-risk patients during the last five flu season seek medical attention within three days of illness.

"That's not just human nature," said Kelly Wroblewski, director of the Infectious Diseases Program of the Association of Public Health Laboratories. "If you have a sniffle, you wait to see if it gets worse."

Although patients require early care, access to Covid testing has varied greatly since the onset of the epidemic. U.S. testing capacity continues to suffer from a host of problems, including supply chain blockade, staff shortages, spikes at demand times and results that can take hours - or even more.

PCR, or polymerase chain reaction tests, the gold standard for SARS-CoV-2, may require scheduled scheduled times at medical offices or emergency care centers, and patients often wait days to study the results. Rapid antigen testing is fast but slightly accurate, and some medical providers are hesitant to rely on it. Home-based testing that can be used at home gives instant but hard-to-find results and is always expensive. And it is not yet clear how those results will be confirmed and whether they will be accepted as a reason for treatment.

"Be prepared," said Griffin. "You don't want to call someone after four days and say, 'Ooh, now you're out the window,' and the effectiveness of this drug is lost because of the problems we face in getting those results."