A trial of coronavirus drugs aimed at over-50s, who are vulnerable to developing serious symptoms, is being rolled out across the UK.

Led by an Oxford University team, the Platform Randomised trial of Interventions against Covid-19 in older People (Principle) is testing pre-existing drugs for older patients in the community who show signs of the disease.

It aims to slow or halt the progression of the virus and prevent the need for hospital admission.

The treatment trial is the first to take place in primary care, and one of the Government’s four national priority platform trials on the disease.

More than 500 GP practices across the country are already recruiting people aged 50 and over with underlying health conditions, or people aged over 65 regardless of underlying health conditions, into the trial.

This week, the trial will start to screen participants online, meaning that regardless of what surgery they are registered with, older people with symptoms can fill out a questionnaire to see whether they can be included in the trial.

Principle is trialling a number of low-risk treatments recommended by an expert panel advising the chief medical officer for England.

In the first phase, it is evaluating whether a seven-day course of hydroxychloroquine, a well-known drug used for acute malaria and certain types of arthritis, can reduce the severity of symptoms in vulnerable groups and help avoid hospital admission.

The antibiotic azithromycin will soon be added to the trial.

Chris Butler, professor of primary care in the Nuffield Department of Primary Care Health Sciences, is a part-time GP for the Cwm Taf Morgannwg University Health Board, Fellow of Trinity College, and chief investigator of the trial.

He said: “The Principle trial platform is enabling us to rapidly evaluate potential treatments for Covid-19 in older people who are most at risk of serious complications from the illness.

“With enough people recruited, this trial will give us the vital information we need to understand whether existing drugs can help people recover sooner and at home, without needing to be admitted to hospital – a significant milestone in the course of this pandemic.

“As soon as we find that any one of the drugs in our trial is making a critical difference to people’s health, we want it to be part of clinical practice as soon as it can be introduced.”

Chief medical officer Professor Chris Whitty said: “The Government is working with researchers to find proven, effective treatments for Covid-19.

“This Principle trial is a vital part of this research effort and it’s being scaled up by GP surgeries across the country.

“I would urge anyone who is contacted to take part in this trial to do so and contribute to helping our world-class scientists find a treatment that will save lives.”

Participants will be closely monitored for the first 28 days of the trial, with a health record notes review taking place for up to three months.

This will allow researchers to understand the longer-term effects of the illness on participants’ health.

People are eligible to join the trial if they have had symptoms – a continuous new or worsening cough, or a high temperature – for fewer than 15 days.

Other criteria is that they are aged 50-64 with a pre-existing illness such as high blood pressure and/or heart disease, asthma or lung disease, a weakened immune system, diabetes not treated with insulin, stroke or neurological problems, or liver disease.

They may also be eligible if they are aged 65 and above.