Joe Biden, the oldest person ever to serve as president of the United States, has tested positive for COVID-19.
The White House says the 79-year-old is experiencing mild symptoms and had begun taking the antiviral treatment Paxlovid, which has proven effective in reducing the risk of hospitalisation or death.
The drug was authorised in the United States last year and was added to the Pharmaceutical Benefits Scheme in Australia in May.
Here's what you need to know.
What is Paxlovid and how is it administered?
Paxlovid is an oral antiviral medicine for patients with mild to moderate COVID-19, who have a high risk of developing severe disease.
In a letter detailing the US President's diagnosis and symptoms, his physician Kevin O'Connor wrote that Mr Biden met the emergency use authorisation (EUA) criteria for the drug, and initiating treatment was recommended.
"The President is fully vaccinated and twice-boosted, so I anticipate that he will respond favorably, as most maximally protected patients do," Dr O'Connor wrote.
The five-day course of tablets have two active ingredients, nirmatrelvir and ritonavir, which reduce the ability of the virus that causes COVID-19 to multiply.
According to the Australian Department of Health, treatment with Paxlovid "should be commenced as soon as possible after a diagnosis of COVID-19 and within five days of symptom onset".
How effective is Paxlovid?
A phase-three clinical trial found Paxlovid reduced the risk of hospitalisation and death significantly when unvaccinated COVID-19 patients were treated within five days of the onset of symptoms.
The trial of 2,246 unvaccinated adults (who had mild to moderate COVID-19) found that the treatment "resulted in a risk of progression to COVID-19 that was 89 per cent lower than the risk with placebo, without evident safety concerns".
However, Paxlovid has also been linked to a so-called "COVID-19 rebound", which prompted the US Centers for Disease Control and Prevention (CDC) to issue a health advisory back in May.
"COVID-19 rebound has been reported to occur between 2 and 8 days after initial recovery and is characterized by a recurrence of COVID-19 symptoms or a new positive viral test after having tested negative," the CDC wrote.
"A brief return of symptoms may be part of the natural history of SARS-CoV-2 (the virus that causes COVID-19) infection in some persons, independent of treatment with Paxlovid and regardless of vaccination status.
"Limited information currently available from case reports suggests that persons treated with Paxlovid who experience COVID-19 rebound have had mild illness; there are no reports of severe disease."
Does Paxlovid have any side effects?
In a small percentage of people, Paxlovid can cause diarrhoea and a condition called dysgeusia, where all food tastes sour, sweet, bitter, or metallic.
The antiviral can also interact with many different medicines, which this may result in "clinically significant adverse reactions, potentially leading to severe, life-threatening or fatal events", the Department of Health notes.
After Mr Biden's diagnosis was confirmed, White House COVID-19 coordinator Ashish Jha told reporters the President would stop taking two drugs — Eliquis and the statin Crestor — while he underwent treatment to avoid a negative interaction.
After Mr Biden's last physical in November 2021, doctors reported that the President had atrial fibrillation, a common irregular heartbeat for which he takes Eliquis, a drug designed to prevent blood clots and reduce the risk of heart attacks and stroke.
Who is eligible to receive Paxlovid in Australia?
Paxlovid is a prescription-only medicine for adults who meet the PBS criteria.
You can find the full list of eligible people here, but they include:
- Adults 70 years of age or older, with mild to moderate COVID-19 confirmed by a PCR or medically verified RAT
- People 50 years of age or older, with two additional risk factors for developing severe disease
- People 30 years of age or older, identifying as Aboriginal or Torres Strait Islander, with two additional risk factors for developing severe disease
- People 18 years of age or older, who are moderately to severely immunocompromised
ABC/wires
