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Molnupiravir: The Game-Changing Antiviral Pill for COVID-19?


Pharmaceutical company Merck applied on October 11 for FDA emergency use authorization for its oral antiviral COVID-19 drug, molnupiravir. In this Q&A, Carl Dieffenbach, PhD, director of the Division of AIDS at the National Institute of Allergy and Infectious Diseases, and Joshua Sharfstein, MD, talk about the development of the medication, how soon could it be approved, and how it might change the trajectory of the pandemic. 

Portions of this Q&A are adapted from the October 13 episode of Public Health On Call.

Can you tell us a bit about molnupiravir and how it works?

With COVID, we’ve seen the pattern where some people convalesce very easily, while others get sick and the disease progresses rapidly. The goal of oral antivirals is to prevent people from getting sicker so they can rehabilitate faster. The idea is like with any other drug: You get an infection, you take the drug, you get better, you move on. 

People who are newly infected with the coronavirus or are newly symptomatic begin taking the drugs within three to five days of symptoms starting. The treatment consists of eight pills a day for five days. With the flu, we know that people have to take the drug (the oral antiviral Tamiflu) quickly after becoming infected. It’s the same principle with molnupiravir.

Other drugs are still in development that targets the virus in different places, but molnupiravir is the first one to progress to the point of EUA application.

How soon could we see molnuparavir approved?

It will probably be approved by the end of the year. Like the COVID-19 vaccines, we will probably see an emergency use authorization process first, where the drugs will be approved for a certain population.

 Will this drug be free? 

It will be free. The United States government will make this drug—like the monoclonal antibodies—available at no cost as part of our pandemic response.

Will molnupiravir be available to anyone exposed to COVID or only specific groups?  

It's likely that the recommended population will include those represented in the clinical trial: nonhospitalized adults with mild to moderate COVID-19, who are within five days of symptom onset and have at least one risk factor for severe disease. It's possible that FDA may permit broader use beyond this group.

Will kids be able to take it?

The initial studies were conducted in adults. It's likely that pediatric studies will not be far behind.

Can vaccinated people take this medication?


Is there any concern that having an effective treatment would prevent people from getting vaccinated?

There is a concern there. We already have governors in certain red states that are promoting antibodies instead of vaccination.

But from a public health perspective, we need to have different tools in our toolbox so we can deal with whatever comes at us. With a vaccine, we can prevent infection and disease. With monoclonal antibodies and with pills now, we can prevent disease progression. Hopefully over the next year or so, we will have even more choices.

Will this drug help prevent long COVID? 

This is a long-term question, and people have been taking these pills for a relatively short period of time. We won’t know for a while whether the use of medications and antibodies prevent long COVID. But if the pills help people convalesce quicker and also prevent long COVID—that is a game-changer. 

What do you think we will see next?

There's another antiviral, a protease inhibitor from Pfizer, in clinical trials, that should be complete late this year or early next. There are also other drugs further back in the pipeline that are at different stages. But between now and June or July 2022, we may have three or four oral antivirals either at the EUA stage or that have at least reported data. 

We could eventually have medicines to use prophylactically if people think they’ve been exposed. In fact, Merck is testing molnupiravir in a post-exposure model. I think that's the vision everybody has, because we know how wonderful it is to have something simple, like a Z-Pack of pills that you can take quickly should you get exposed or start showing symptoms.

Are you surprised that these kinds of drugs have been developed as quickly as they have been? 

No, not at all. Molnupiravir has been in development as a broad-spectrum antiviral for approximately 10 years. It was first tested as an Ebola drug in Liberia’s 2016–2017 outbreak.  The other drugs in development are more coronavirus-specific and have progressed a little quicker. 

How will having medications to treat COVID-19 affect the trajectory of the pandemic?

The goal is to keep people from progressing into the hospital and dying. Merck reported in their press release that molnupiravir reduced the risk of hospitalization or death by 50%. The advantage of pills is they're a lot easier to access and you can treat more people quicker than you can with monoclonal antibodies. Having a sufficient supply of molnupiravir could make a huge impact on hospitalizations and deaths.




Public Health On Call

Portions of this Q&A are adapted from the October 13 episode of Public Health On Call.

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