On July 21, 2022, U.S. President Joe Biden said he had tested positive for COVID-19 and was experiencing mild symptoms. In a letter to the public, Biden’s doctor explained that the president had a slight runny nose, some fatigue and the occasional dry cough, and that Biden had already begun taking the antiviral drug Paxlovid. Patrick Jackson, an assistant professor of infectious diseases at the University of Virginia, explains the risks that someone like Biden faces from a bout of COVID-19 and the treatments available.

1. What are the important risk factors for Biden?

The most important risk factor for developing severe COVID-19 is age. If you are 79 years old when you become infected with COVID-19, like President Biden, you are eight times more likely to become hospitalized and 140 times more likely to die compared with someone who gets COVID-19 at age 20. Preexisting health conditions – like obesity, cancer and chronic kidney or lung disease – also increase the risk of severe illness. But Biden is reported to be fairly healthy.

Fortunately, preexisting immunity from vaccination or from a previous episode of COVID-19 is highly protective against severe disease. Researchers only have limited data on the BA.5 variant that is responsible for most recent COVID-19 cases in the U.S. – and likely Biden’s, too – but the level of protection from vaccines is likely similar to that of the previous strains BA.1 and BA.2. While the BA.1 and BA.2 omicron variants of SARS-CoV-2 were very adept at infecting people who are vaccinated and boosted, the data shows that prior immunity from vaccines provides strong protection against severe or fatal disease. During the first omicron wave in California, COVID-19 patients who did not have immunity from vaccination or previous infection were much more likely to be hospitalized, be admitted into an intensive care unit or diecompared with people who were vaccinated and boosted.

2. What is the first line of treatment for someone like Biden, and why?

Current best medical practice is to give antiviral treatments to patients who have recently developed mild to moderate COVID-19 symptoms and are at higher risk of severe illness. The goal of antivirals is to stop the virus from replicating in the body in order to prevent hospitalization or death.

Currently there are four antiviral drugs available in the U.S. for the treatment of COVID-19 in outpatients: nirmatrelvir-ritonavir, better known by the brand name Paxlovid, remdesivir, bebtelovimaband molnupiravir. The best drug for a particular patient depends on preexisting health conditions, accessibility and drug interactions with other medications. Paxlovid is widely used because it was shown to be highly effective in a clinical trial and is available in pill form.

3. How does Paxlovid work, and what are its shortcomings?

Paxlovid is an oral antiviral drug that is used to treat some patients with mild to moderate COVID-19 who do not require hospitalization.