A new drug which could offer instant immunity against Covid-19 is being trialled by British scientists, it has been reported.

The antibody therapy has been developed by University College London Hospitals (UCLH) and AstraZeneca - the pharmaceutical company that has, along with Oxford University, created a vaccine that is expected to be approved for use next week.

But unlike a vaccine, the new drug would be given to someone who has been exposed to the virus, preventing them from going on to develop it.

It could be given as an emergency treatment to hospital inpatients and care home residents to help contain outbreaks.

People living with someone who has caught Covid-19 could also be injected with the drug to stop them becoming infected, and it could be used in areas at risk of rapid transmission, such as in Kent's universities.

Dr Catherine Houlihan, a virologist at UCLH who is leading the study, called Storm Chaser, told The Guardian: “If we can prove that this treatment works and prevent people who are exposed to the virus going on to develop Covid-19, it would be an exciting addition to the arsenal of weapons being developed to fight this dreadful virus.”

This month University College hospital became the first site in the world to recruit patients into the randomised control trial and give them the jab or a placebo.

The drug involves a long-acting antibody combination known as AZD7442, which has been developed by AstraZeneca.

Rather than antibodies produced by the body to help fight an infection, AZD7442 uses monoclonal antibodies, which have been created in a laboratory.

So far 10 people who have been exposed to the the virus at home, in a healthcare setting or in student halls have been injected.

But the trial also involves several other British hospitals and a network of 100 sites globally.

Dr Houlihan and colleagues will now monitor those given the drug to see if any of them develops Covid-19.

It is hoped the drug could offer protection for between six and 12 months, playing a vital role in reducing the impact of the virus until everyone has been immunised.

It could be available as soon as March or April if it is approved by the Medicines and Healthcare products Regulatory Agency after it has reviewed evidence from the study.

Paul Hunter, a professor of medicine at the University of East Anglia who specialises in infectious diseases, says the new treatment could significantly reduce the death toll from Covid.

He told The Guardian: "If you are dealing with outbreaks in settings such as care homes, or if you have got patients who are particularly at risk of getting severe Covid, such as the elderly, then this could well save a lot of lives. Providing it’s borne out in phase 3 trials, it could play a big role in keeping alive people who would otherwise die. So it should be a big thing.

“If you had an outbreak in a care home, you might want to use these sorts of cocktails of antibodies to bring the outbreak under control as soon as possible by giving the drug to everybody in the care home – residents and staff – who hasn’t been vaccinated. Similarly, if you live with your elderly grandmother and you or someone else in the house gets infected, then you could give her this to protect her.”

The trial - along with another into a drug to protect people with compromised immune systems - is being undertaken at UCLH’s new vaccine research centre.

Dr Richard Jarvis, a co-chair of the British Medical Association’s public health medicine committee, the the Guardian: “For the vast majority of the population, vaccination offers the best protection against Covid-19, and NHS staff are working around the clock to administer this to as many vulnerable patients as possible in this first rollout wave.

“It’ll certainly be interesting to see if these trials are effective. But it’s important that any new treatments are thoroughly researched, scrutinised and, most importantly, safe before we consider introducing them.”

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