The UK has approved the world's first COVID antiviral pill that can be taken at home, in a landmark move that could significantly reduce deaths and hospitalisations from the disease.
Molnupiravir is produced by US pharmaceutical company Merck and Ridgeback Biotherapeutics and was approved by the Medicines and Healthcare products Regulatory Agency (MHRA) on Wednesday.
Merck has said the drug will remain royalty-free so long as the World Health Organization classifies the pandemic as a "Public Health Emergency of International Concern".
Here's what we know about the "game-changing" drug:
What is it?
Molnupiravir has been designed for people who have had a positive COVID test and are at risk from the disease.
It is the first anti-viral pill for COVID-19 that can be taken at home to be approved in the world.
All other drugs for COVID-19 can only be administered in hospitals and most are by injection or infusion.
Watch: Merck's COVID Pill Approved by UK Health Authority
It prevents the virus from multiplying, keeping levels low in the body and therefore reducing the severity of the disease.
The treatment involves taking two rounds of four pills twice a day for five days.
The aim is to get it prescribed to the at-risk person as soon as possible to prevent them from developing the severe disease and keep them out of hospital.
It will be branded as Lagevrio in the UK.
How effective is it?
Results from a study by Merck showed the drug reduced hospitalisations and deaths in a population of patients at risk of more severe outcomes by around 50% (from 14.1% to 7.3%).
No patient who took the drug died from the virus.
The results from the study haven’t yet been peer-reviewed or published in a scientific journal.
Who can take it?
Anyone over the age of 18 can take it but it is for people who are most. at risk from COVID such as those who suffer from obesity, diabetes, heart disease, or are over the age of 60.
When will it be available?
The Government announced last month that it had secured 480,000 courses of molnupiravir and will be rolled out within days.
Are there any side effects?
The final stage three trial of the drug found no serious side effects from the drug. No deaths were reported among molnupiravir recipients compared to 8 (2.1%) in placebo recipients
The most common minor side effects were headache and diarrhoea.
What has been the reaction?
Health and Social Care Secretary, Sajid Javid, said: “Today is a historic day for our country, as the UK is now the first country in the world to approve an anti-viral that can be taken at home for COVID-19.
“This will be a gamechanger for the most vulnerable and the immunosuppressed, who will soon be able to receive the ground-breaking treatment.
“We are working at pace across the Government and with the NHS to set out plans to deploy molnupiravir to patients through a national study as soon as possible."
Watch: How the world could be better after COVID
Professor Penny Ward, an independent pharmaceutical physician, welcomed the approval, but said the NHS needed to outline its plans for rollout and cautioned that supplies were likely to be tight given the strong global demand.
"Comments made by Mr Javid today suggest that it may be made available via a clinical trial, presumably to investigate its effectiveness in vaccinated patients with breakthrough infections, as the original study incorporated unvaccinated adults," she said.
If given to everyone becoming unwell, the nearly half a million courses would not last very long given the more than 40,000 current daily case rate, she said.
What do the experts say?
Dr June Raine, MHRA chief executive, said: “Following a rigorous review of the data by our expert scientists and clinicians, we are satisfied that Lagevrio (molnupiravir) is safe and effective for those at risk of developing severe COVID-19 disease and have granted its approval.
“Lagevrio is another therapeutic to add to our armoury against COVID-19.
“It is also the world’s first approved anti-viral for this disease that can be taken by mouth rather than administered intravenously.
She added: “With no compromises on quality, safety and effectiveness, the public can trust that the MHRA has conducted a robust and thorough assessment of the data.”
Robert Davis, chief executive officer of Merck Sharp & Dohme (MSD), said: “The first global authorisation of molnupiravir is a major achievement in MSD’s singular legacy of bringing forward breakthrough medicines and vaccines to address the world’s greatest health challenges.
“In pursuit of MSD’s unwavering mission to save and improve lives, we will continue to move with both rigor and urgency to bring molnupiravir to patients around the world as quickly as possible.”