Researchers at UC San Francisco (UCSF) in the US have started a clinical trial to evaluate an antibiotic called azithromycin for the treatment of patients with Covid-19.

The team is enrolling more than 2,500 adults newly diagnosed with the disease. The trial is assessing if the drug can decrease hospitalisation stays and death from Covid-19.

Participants will be given a single oral dose of azithromycin or a placebo. The study drug will be sent to patients’ homes, while enrolment and follow-up visits will be performed remotely.

Named ACTION, the trial is being conducted in alliance with Pfizer, the Bill & Melinda Gates Foundation, and Stanford University.

UCSF Francis I Proctor Foundation assistant professor Catherine Oldenburg said: “Identifying early-stage therapeutics has the potential to limit disease progression, hospitalisations and deaths, so we are hoping to recruit patients early in their illness, before they require hospitalisation.

“Macrolides such as azithromycin have long been hypothesized to have therapeutic benefits on viral infections, either via their anti-inflammatory or off-target effects on viral replication.”

If the drug demonstrates effectiveness in patients with mild Covid-19, it is expected to improve patient outcomes and mitigate the strain on the healthcare system.

During a large, randomised study, researchers observed that children in communities receiving azithromycin for trachoma twice-a-year had lower non-SARS coronavirus levels in their throats compared to those on a placebo.

Commenting on the new trial, UCSF researchers said: “The trial is designed to be scalable to adapt to changes in the pandemic, probability of hospitalisation, and challenges with recruitment or enrollment.”

In March this year, Pfizer reported positive data for the use of its azithromycin (Zithromax) drug, along with hydroxychloroquine, in a Covid-19 trial performed in France.

Data showed that the rate of virologic cure was highest in people who received hydroxychloroquine plus azithromycin.