The first at-home pill to treat COVID-19 has been approved by Britain’s medicines watchdog.

Antiviral molnupiravir was shown in clinical trials to slash the risk of hospitalisation by half in vulnerable and elderly patients.

The tablet, which will be sold under the brand name Lagevrio, will be given twice a day to people within a week of testing positive.

It will be targeted at those who are considered high risk, including Britons over the age of 60, or patients with heart disease, diabetes, obesity, or other comorbidities.

Health secretary Sajid Javid said the treatment was a ‘gamechanger’ for the most frail and immunosuppressed, who are vulnerable to Covid even when vaccinated.

The UK has bought 480,000 doses of molnupiravir at a cost thought to be in the region of £250million.

Announcing its approval today, the UK’s Medicines and Healthcare products Regulatory Agency said the drug was safe and effective

Molnupiravir, made by pharmaceutical giant Merck and its partner Ridgeback Biotherapeutics, works by blocking the virus from replicating in the body.

The MHRA said the drug should be taken as soon as possible following a positive Covid test and within the first five days.