What you need to know about the new COVID-19 antiviral pills


COVID-19 vaccines have been the key weapon in managing the spread of the coronavirus and fending off its most dangerous strains, but pills to treat the virus are on the horizon. So far, pharmaceutical giants Pfizer and Merck have developed experimental antiviral pills – called Paxlovid and molnupiravir, respectively – that have shown promising efficacy in clinical trials in adults with COVID-19. Below is what we know about these new COVID-19 antiviral drugs, and when they might be available.

The two antiviral pills – which, unlike other therapeutic treatments for COVID, might be available by prescription to be taken orally at home – bolster the global therapeutic arsenal against the virus by reducing its ability to replicate. Both treatments are intended to be taken orally for five days when the first symptoms of COVID-19 appear. Pfizer’s medicine, Paxlovid, also includes a low dose of ritonavir – a medicine that is also used to treat HIV – to make the medicine work longer in the body. It’s important to note that antiviral pills are not meant to replace highly protective vaccines, but could work in tandem with them to tame the pandemic.

The most significant difference between COVID antiviral pills and monoclonal antibody treatments for COVID that are already available is how much easier the pills would be to administer. Monoclonal antibody treatments are given intravenously in a medical facility in a process that takes about an hour. Both oral medicine treatments are also expected to be less expensive than monoclonal antibody treatments.

Neither Merck nor Pfizer have published detailed data on their clinical trials for their respective antiviral treatments, but the early results shared by the companies look promising.

Molnupiravir (from Merck and Ridgeback Therapeutics)
Merck said that, according to test data released last week, its antiviral pill – a type of drug called a polymerase inhibitor – was much less efficient than previously thought, reducing hospitalizations and deaths by about 30% in its clinical trial in high-risk people within five days of developing their COVID-19 symptoms.

Paxlovid (from Pfizer)
Pfizer said its drug – which is a combination of two components, an investigational molecule called PF-07321332 and a drug called ritonavir – reduced the risk of hospitalization or death by 89% when given to patients within three days of developing their COVID-19 symptoms, and by 85 percent when given to patients within five days.

It is not yet known whether or not the drugs affect the transmission of the coronavirus.

a FDA Advisory Group narrowly voted (13 to 10) to recommend that the agency approve Merck’s antiviral drug, molnupiravir. (Emergency use authorization would likely be limited to patients at high risk of developing serious illness, although the exact population is defined by the agency.) He recently got a clearance in the UK after health authorities have declared their review concluded that the drug was “safe and effective for those at risk of developing severe COVID-19 disease.” According to NPR, the federal government has already purchased 3.1 million courses of molnupiravir, which it will acquire between the date of FDA clearance and early next year.

Meanwhile, Pfizer’s antiviral pill will be reviewed by the panel in the coming months, but the drug company has said it will submit its recent test data to be considered for emergency clearance.

“COVID-19 is still an emergency,” said committee member Dr David Hardy, who voted yes. “There is a need for something like this. This is the first time that an oral ambulatory drug for people with mild to moderately symptomatic has been made available, although I have questions about its overall long-term effectiveness.

Probably. Carlos del Rio, Executive Associate Dean and Infectious Disease Specialist at the Emory School of Medicine, told Politico that drugs “Should work” against other variants because of the way they prevent the virus from replicating. However, more data needs to be collected.

The potential FDA clearance of these antiviral drugs matters, as the Omicron variant increases the number of cases and, potentially, the demand for simple treatment. “With omicron [variant] we breathe, we need drugs, we need really effective antivirals and we need more ”, noted Carl Dieffenbach, director of the AIDS Division at the National Institute of Allergy and Infectious Diseases, which leads the development of antivirals.

Both companies said their antiviral drugs were well tolerated by patients and claimed the side effects would be minor, but neither have released detailed data to confirm this. Pfizer did not detail the side effects of her pill, but said adverse events, including nausea and diarrhea, occurred in about 20% of patients. Meanwhile, Merck said diarrhea, nausea, dizziness, and headaches have been listed among the common side effects of the drug which “may affect up to one in ten people”.

This post has been updated.