Now, under federal investigation, both pills are being praised by doctors with infectious diseases not amenable to superlatives.
“This is really a game changer,” says Dr. Daniel Griffin, an infectious disease and immunology expert at Columbia University. “This is up there with vaccines. It’s not a replacement for vaccines; we still want to get people vaccinated. But, boy, this is just another great tool to have.”
The new regimens, which require taking 30 or 40 pills over five days, have been shown to dramatically reduce hospitalizations and prevent deaths in adults with mild to moderate covid, who are at risk for serious illness because of their age or underlying conditions. But experts say the success of the treatments depends on one uncertain factor: whether high-risk patients infected with Covid can be tested — and then treated — quickly enough to make a difference.
“Early, accessible testing and access to the results in a time frame that allows us to make a decision will really be key to these drugs,” said Dr. Erica Johnson, chair of the Infectious Disease Board of the American Board of Internal Medicine. “It puts the responsibility on our public health strategy to make it available.”
In clinical trials, molnupiravir, the antiviral drug developed by Merck & Co. and Ridgeback Biotherapeutics, administered to unhospitalized, unvaccinated, high-risk adult patients within five days of their first covid symptoms. Pfizer’s product, Paxlovid, was tested in similar patients as early as three days – just 72 hours – after the onset of symptoms.
“That’s just not human nature,” said Kelly Wroblewski, director of infectious disease programs for the Association of Public Health Laboratories. “If you have a sniff, you wait to see if it gets worse.”
Even as patients seek early care, access to covid testing has been wildly variable since the start of the pandemic. Testing capacity in the US continues to be plagued by a host of issues, including supply chain bottlenecks, staff shortages, periodic spikes in demand, and results that can take hours or much longer.
“Get ready,” Griffin said. “You don’t want to call someone four days later and say, ‘Ooh, you’re out the window now,’ and the efficacy of this oral medication has been lost due to difficulties on our side getting those results.”
Doses of the drugs distributed by the federal government would go to states and patients for free. But only a fraction of the planned inventory will be available to get started, said Dr. Lisa Piercey, the Tennessee health commissioner, who was part of a small group of state health officials working on the distribution plans.
In one scenario, in which 100,000 courses of the Merck drug will be available as early as Dec. 6, Piercey said Tennessee would receive only 2,000 patient courses, while the state averages more than 1,200 new cases per week. Deciding which sick patients get those scarce supplies will be “an educated stitch in the dark,” Piercey said.
The antivirals will be cheaper than the monoclonal antibody treatments, which can cost the government about $1,250 per dose and infusion costs that cost patients hundreds of dollars in copays. The pills are much easier to use and pharmacies will likely be able to order and dispense them for home use.
Still, the antiviral pills won’t replace antibody treatments, said Dr. Brandon Webb, an infectious disease specialist at Intermountain Healthcare in Salt Lake City.
Questions remain about the long-term safety of the drugs in some populations. Merck’s molnupiravir works by causing mutations that prevent the virus from reproducing. The Pfizer treatment, which includes Paxlovid and low-dose ritonavir, an HIV antiretroviral drug, can cause interactions with other drugs or even over-the-counter supplements, Webb said.
As a result, the antivirals are unlikely to be used in children, people with kidney or liver disease, or pregnant people. They should be given to patients who are able to take multiple pills at once, a few times a day, and those patients should be monitored to make sure they are completing the therapy.
“We are on an interesting tightrope where we will try to identify suitable patients at an early stage to treat them with antivirals,” Webb said. “We just have to be agile and ready to run.”
KHN (Kaiser Health News) is a national newsroom that produces in-depth journalism on health issues. Together with Policy Analysis and Polling, KHN is one of the three major operational programs of KFF (Kaiser Family Foundation). KFF is an endowed non-profit organization that provides information on health issues to the nation.