COVID-19 Antivirals Are in High Demand and Short Supply

The FDA-authorized COVID-19 antiviral pills were hailed for their potential to save lives and ease the burden on U.S. health systems from soaring hospital admissions and staffing shortages.

But some experts worry that the initial supply of these drugs is too sparse to provide significant support during the Omicron surge.

For people at risk of severe COVID, the treatments can reduce the risk of hospitalization when taken early enough in the course of the illness. Unlike other COVID-19 treatments that must be given intravenously, patients can take the antiviral pills at home to avoid serious illness.

“The use of these antivirals can really, hopefully, help reduce severity of illness, hospitalizations, deaths, and sort of change the general tone of how we are feeling about COVID currently in this country,” Ronald Lubelchek, MD, an infectious disease physician at the John H. Stroger, Jr. Hospital of Cook County, told Verywell.

Oral Antivirals Could Be a “Game Changer”

The Food and Drug Administration (FDA) granted emergency use authorization for Pfizer’s Paxlovid and Merck's molnupiravir in late December.

The drugs are designed to slow disease progression and lessen the odds of hospitalization. Each treatment course includes 30 and 40 tablets, respectively, to be taken over five days.

Paxlovid reduced hospitalizations and deaths for people high-risk people with COVID-19 by nearly 90% in clinical trials, an outcome touted as a “game changer" by President Joe Biden.

Molunpiravir was about 30% effective at reducing COVID-19 hospitalizations and deaths in a final analysis. The FDA said molnupiravir could be used to treat mild-to-moderate cases when alternative treatment options are unavailable.

Doctors may prescribe one of the oral antiviral pills for patients who are at high risk of getting seriously ill from COVID-19.

The National Institute of Health outlines which patients are most at risk for hospitalization and death from COVID-19 in a guide for health systems to offer the limited supply of antivirals to those most vulnerable.

The first tier includes immunocompromised individuals, such as those who underwent solid organ transplants or chemotherapy. Unvaccinated people older than 75 years of age, or 65 years and older with an additional risk factor like diabetes, cardiovascular disease, hypertension, chronic lung diseases are also prioritized.

In some regions, states and local health systems can set their own guidelines. Lubelchek said his hospital follows a tiering system outlined by the Illinois Department of Public Health. Tier one under that system also includes people aged 12 and above with obesity and pregnant women.

“Given the current burden of COVID, we wouldn't be able to cover all the people who fit into tier one with those oral therapies,” Lubelchek said. “The providers who prescribe it first, and the patients who they serve, are going to be the ones who probably use it and get it."

The Antiviral Pills Are a 'Drop in the Bucket'

The federal government has purchased more than 3 million treatment courses of molnupiravir and distributed nearly 450,000 of those so far.

Earlier in January, the White House announced that it would purchase 20 million Paxlovid courses and said the first 10 million will be available by the end of June. About 117,000 courses have been delivered nationwide.

Rajesh Gandhi, MD, an infectious diseases physician at Massachusetts General Hospital and professor of medicine at Harvard University, told Verywell that the oral antivirals have just arrived in pharmacies across Massachusetts last week and that he hasn’t prescribed them to his patients yet.

“Hopefully the first shipment will be followed by many more shipments, but there's no doubt that in the very short term—the next week or two—there's going to be way more demand than there will be supply,” Gandhi said.

The White House is distributing the oral antivirals to states based on their populations, and the states will determine how to distribute the treatments to pharmacies and health systems. California, the most populous state, has received 45,750 courses of Paxlovid or molnupiravir as of Tuesday. Wyoming, with the smallest population, received 920, according to data from the Department of Health and Human Services.

Some leaders in hard-hit areas have raised concerns about this strategy, saying regions experiencing a surge in COVID-19 cases should be prioritized for drug deliveries.

“The federal government should not distribute them across the board. They should look at where is the greatest need,” Chuck Schumer, Senator from New York, said at a news conference last week.

New York state has so far received 33,620 courses. Meanwhile, the state is seeing a 7-day average of more than 62,000 cases per day.

More than 200 federally funded community health centers will also receive the antivirals and distribute them to vulnerable populations.  

“We want to make sure that people who are at the highest risk get access and also that we're equitable in the distribution of the medicine, so that people who have been disproportionately impacted and have traditionally had less access to care do get access to these meds,” Gandhi said.

Addressing the Supply Shortage

In a statement this month, President Biden acknowledged the scarcity of oral antivirals and said his administration is working to ramp up production. He said that it takes "months" to produce the Paxlovid pill due to its "complex chemistry."

Paxlovid consists of two components: nirmatrelvir and ritonavir. Nirmatrelvir is a protease inhibitor, which prevents the COVID-19 virus from multiplying by blocking a key enzyme in infected cells. Ritonavir supports that process by keeping other enzymes from destroying the nirmatrelvir. When the virus is prevented from replicating, it can lower the viral load and lessen the severity of the disease.

Ritonavir has been used to treat maladies like HIV for more than two decades. But nirmatrelvir is a new formulation and manufacturers may not be able to scale production as quickly.

Kris White, PhD, an assistant professor of microbiology at the Icahn School of Medicine at Mount Sinai, told Verywell that the complex chemistry of the nirmatrelvir contributes to how effective the drug is.

White, who worked with Pfizer on its Paxlovid clinical trials, said that while a future, simpler formulation may prove to be as effective as the current one, increasing supply in the short term will depend on manufacturers boosting production.

Both Paxlovid and molnupiravir are the most effective in the first five days after the onset of COVID-19 symptoms. In the first days after an infection, while the virus is replicating in the body, the drugs can slow its multiplication. After five days, symptoms are driven primarily by the body’s immune reaction to the infection and the treatment loses a majority of its efficacy.

“The earlier you can get them the better,” White said. “People should know that if they have risk factors, and they test positive, they should immediately start seeking out those drugs as soon as they can.”

“Right now, you might not be able to find them, but in the coming weeks and months you will and it can make a big difference,” he added.

Monoclonal Antibodies Continue to be Key for At-Risk Patients

In addition to the antiviral pills, there are a few treatments that are effective at preventing hospitalization from Omicron infection. The monoclonal antibody sotrovimab by GlaxoSmithKline is one of a few treatments shown to be effective against Omicron, according to a handful of recent preprint studies.

Sotrovimab, authorized by the FDA in December 2021, is 85% effective at preventing hospitalizations in clinical studies. GSK announced it will deliver 600,000 doses of the treatment in the coming few months.

Remdesivir is one of the earliest monoclonal antibodies approved to treat COVID-19 and clinicians are finding new infusion strategies using the drug to mitigate severe illness in patients now.

Given its relative abundance, Gandhi said clinicians may offer remdesivir to patients who test positive for COVID-19 while already hospitalized for a different condition.

Ghandi said oral antivirals are logistically preferable, as patients can self-administer the drug at home. But given the efficacy of sotrovimab and remdesivir at preventing severe outcomes, and the current shortage of oral options, intravenous options will continue to play a critical role for minimizing severe disease outcomes in the next few weeks.

“Even though we're excited to use the orals we're also in parallel going to use IV therapy,” Gandhi said.

In states where Delta is still responsible for a large portion of cases, the federal government is still shipping monoclonal antibodies from companies like Eli Lilly and Regeneron, which appear to be ineffective against Omicron.

“In this moment, we don't have any other choice,” White said. “[Monoclonal anitbodies] are the only treatment we have when nobody has access to Paxlovid until they can produce larger quantities of it.”

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