Pfizer’s Paxlovid has a success rate of nearly 90% as a prophylaxis treatment against severe COVID-19 when administered shortly after the patient has been infected with the virus.

The Medicines and Healthcare Products Regulatory Agency (MHRA) has approved the use of a second oral antiviral pill for COVID-19 to be taken at home.

Pfizer’s Paxlovid can be given to those aged 18 years and older with mild-to-moderate symptoms of COVID-19, who are also at risk of developing severe disease. High-risk categories include those with diabetes, heart disease, obesity, and those over the age of 60.

Paxlovid boasts a nearly 90% success rate in preventing severe illness among those who fall into these categories, when taken soon after becoming infected with COVID-19. The agency recommended taking the pill within five days of a patient’s first symptoms.

The pill is to be taken orally twice a day for five days. Paxlovid is a mixture of two active ingredients, PF-07321332 and ritonavir, which acts by hindering a protease needed for the virus to replicate. These inhibitors are similar to those used to treat HIV, making the treatment beneficial for patients with weakened immune systems.

“We now have a further antiviral medicine for the treatment of COVID-19 that can be taken by mouth rather than administered intravenously. This means it can be administered outside a hospital setting, before COVID-19 has progressed to a severe stage,” shared Dr June Raine, the MHRA’s chief executive. “I hope the announcement gives reassurance to those particularly vulnerable to COVID-19, for whom this treatment has been approved. For these individuals, this treatment could be life-saving.”

In a clinical trial of the approved patient group, a five-day regimen of Paxlovid taken within three days of symptom development reduced the risk of hospitalisation by 89% compared with those given a placebo treatment. The number of hospitalisations and deaths were observed to be 0.8% for those patients given Paxlovid, compared to a rate of 7% among the placebo group.

The MHRA has emphasised that Paxlovid is ‘not a substitute for vaccination’.