Pfizer claims its antiviral pill 89% effective in high-risk COVID-19 cases - Know how it works

US pharmaceuticals company Pfizer has come out with an antiviral COVID-19 pill Paxlovid that cuts the risk of hospitalisation or death by 89% in vulnerable adults, clinical trial results suggest. The drug is intended for use soon after COVID-19 symptoms develop in people at high risk of severe disease.

Pfizer's Paxlovid pill could get approval from the US regulator by the end of the year. The company says it plans to submit interim trial results to the Food and Drug Administration (FDA) before November 25. Pfizer released preliminary results of its study on 775 adults on Friday.

This comes a day after the UK's Medicines and Healthcare products Regulatory Agency (MHRA) approved a similar treatment from Merck Sharp and Dohme (MSD) named Molnupiravir. The United Kingdom has already ordered 250,000 courses of the new Pfizer treatment along with another 480,000 courses of Merck's Molnupiravir antiviral pill.

Pfizer said the patients taking the company's drug along with another antiviral had an 89% reduction in their combined rate of hospitalisation or death after a month in comparison to patients taking a dummy pill. Fewer than 1% of patients taking the drug needed to be hospitalised and no one died.

In the comparison group, 7% were hospitalised and there were seven deaths among those who were given a placebo or dummy pill.

How the Pfizer antiviral pill works
The Pfizer drug, known as a protease inhibitor, is designed to block an enzyme the virus needs in order to multiply.

When taken alongside a low dose of another antiviral pill called Ritonavir, it stays in the body for longer.

In this process of treatment, three pills are taken by COVID-19 positive patients twice a day for five days.

This treatment works slightly differently from the Merck pill which introduces errors into the genetic code of the virus.

It has the potential to save patients' lives, reduce the severity of the infection and eliminate up to nine out of 10 hospitalisations.

Source : DNA India