Developed by UK biotech company Synairgen, it uses a protein called interferon beta, which our bodies produce when we get a viral infection.

Initial results from the trial are expected by the end of June.

There are currently few effective treatments for coronavirus with doctors relying on patients’ immune systems.

What is the new drug?

Interferon beta is part of the body’s first line of defense against viruses, warning it to expect a viral attack, explains Richard Marsden, chief executive of Southampton-based Synairgen.

He says the coronavirus seems to suppress its production as part of its strategy to evade our immune systems.

The drug is a special formulation of interferon beta delivered directly to the airways when the virus is there, with the hope that a direct dose of the protein will trigger a stronger anti-viral response even in patients whose immune systems are already weak.

Interferon beta is commonly used in the treatment of multiple sclerosis.

Synairgen has already shown its preparation can stimulate the immune response in the lungs of patients with asthma and other chronic lung conditions.

But we can only know whether it works for Covid-19 patients after it has been through a rigorous clinical trial.

The patient

Kaye Flitney is one of 75 people who have been enrolled in the clinical trial, filmed exclusively by BBC Panorama. It requires Covid-19 patients, like her, to inhale the drug via a nebuliser to bring it deep into the lungs.

Kaye, 67, struggles to sit up in her hospital bed and coughs as she puts the dispenser to her lips. She says when she first found out she had coronavirus her first thought was not for her own health.

“I was frightened because my husband has heart failure. It would kill him.”

The 67-year-old, who was taken to hospital due to difficulty with her breathing, said taking the drug hasn’t caused her much discomfort.

“You don’t notice you’re taking it ’til you’re finished. It’s not so bad. I could see myself taking it at home.”