A new antibody treatment with the potential to give people immediate protection after being exposed to Covid-19 and prevent illness is being trialled in the UK.

The University College London Hospitals NHS Trust (UCLH) is looking into the use of an antibody which could offer long-term protection to patients when it would be too late to offer a vaccine, as part of a new trial called Storm Chaser.

Scientists have also begun a second clinical trial named Provent, to examine the use of the antibody for people who may not benefit from vaccinations, such as patients with a compromised immune system, or those at increased risk of Covid-19 infection due to factors such as age and existing conditions.

NHS England national medical director Professor Stephen Powis said: “The continuing contribution of the NHS to pioneering global efforts to fight Covid-19 is remarkable.

“These two clinical trials are an important addition to testing new therapeutic approaches, as antibody treatments may offer an alternative to patient groups who cannot benefit from a vaccine, such as immunocompromised patients.”

UCLH has so far injected 10 people as part of Storm Chaser at its new vaccine research centre after the study entered phase three trials on December 2, with an aim to trial the new treatment on 1,125 people globally.

Key groups of the trial include healthcare workers, students who live in shared accommodation and patients who have been recently exposed to anyone with Covid-19, as well as those in long-term care, the military and industry staff such as factory workers.

The antibody, known as AZD7442, has been developed by pharmaceutical company AstraZeneca, which has also created a vaccine with Oxford University that is awaiting approval for use by the Medicines and Healthcare products Regulatory Agency (MHRA).

UCLH virologist Dr Catherine Houlihan, who is leading the Storm Chaser trial, said: “We know that this antibody combination can neutralise the virus, so we hope to find that giving this treatment via injection can lead to immediate protection against the development of Covid-19 in people who have been exposed – when it would be too late to offer a vaccine.”

Meanwhile, older people and those in long-term care, as well as people with conditions such as cancer and HIV, will be recruited to take part in the Provent trial.

UCLH infectious diseases consultant Dr Nicky Longley, who is leading the university’s portion of Provent, said: “We want to reassure anyone for whom a vaccine may not work that we can offer an alternative which is just as protective.”