Deals have been agreed for two new treatments which could be used for some of those most vulnerable to the effects of Covid-19.

Thousands of courses of the antivirals have been secured by the Government to be ready for use this winter, subject to approval by the UK medicines regulator.

The treatments, from pharmaceutical companies Merck Sharp and Dohme (MSD), and Pfizer, would be aimed at those most at risk from the virus, including the elderly and those with weakened immune systems.

Antivirals are used to either treat people infected with a virus or to protect exposed individuals from becoming infected.

The data currently available for the new antivirals is for their use as treatment for people who have Covid-19, while studies on using them in a preventive way have only just begun.

The Department of Health and Social Care said 480,000 courses of Molnupiravir, made by MSD, have been secured, as well as 250,000 courses of Pfizer’s PF-07321332/ritonavir.

Molnupiravir has been shown in clinical trials to reduce the risk of hospital admission or death for at-risk adults with mild to moderate Covid-19 by 50%, the department said.

Pfizer’s antiviral is at the beginning of its phase three trials.

Both are awaiting approval by the the Medicines and Healthcare products Regulatory Agency (MHRA).

It is understood that, if approved, Molnupiravir could be available by the middle of November, and Pfizer’s treatment by the middle of January 2022.

Health Secretary Sajid Javid said: “I am delighted to confirm we may soon have a new defence in our arsenal with two new antiviral drugs that we have secured.

“Our work is far from done though – and we’ll continue our tireless work to secure more innovative treatments so we can protect as many people as possible from the virus, its variants and future diseases.”

Both treatments, taken as oral medicines, “have the potential to speed up recovery time and to stop infections from progressing”, Mr Javid told a Downing Street press conference.

Work is under way to look at how to deploy the treatments, with making them available from pharmacies understood to be one option under consideration.

Eddie Gray, chairman of the Government’s Antivirals Taskforce, said the deals are a “very important development in our mission to find antivirals for those exposed to Covid-19, supporting the renowned vaccination programme and the NHS over the coming months”.

England’s deputy chief medical officer Professor Jonathan Van-Tam said antivirals “bring another key intervention to the table”.

He said: “They will be particularly vital in protecting those who may not get the same antibody response to the vaccines as the majority of the population.

“We will now work quickly to ensure the right cohorts of people receive these treatments as soon as possible, should they be approved by the MHRA.”

Professor Stephen Powis, national medical director for NHS England, said the new treatments “will add to the health service’s armoury in giving the most vulnerable people the best chance of recovery from this deadly virus, and with cases rising, it is still very much a threat to public health”

Costs of the deals have not been given due to commercial sensitivities.

Ben Osborn, country manager at Pfizer UK, said: “If successful, oral antiviral therapies, such as protease inhibitors, may help to reduce the severity or onset of illness in adults who contract, or have been exposed to, Covid-19.

“An oral treatment option may therefore be an important tool to help address the ongoing impact of the Covid-19 pandemic.”

Dr Ruth McKernan, chair at the BioIndustry Association, said: “Prevention is still better than cure but for vulnerable patients who can’t be vaccinated or don’t respond well, post-infection treatment with an oral drug is important.

“These are the strongest candidates currently available for this winter.”