Media release

From: The Australian National University

A widely available and affordable drug has shown to be effective in treating seriously ill COVID-19 patients, according to a new study from The Australian National University (ANU).

The researchers believe the drug could also be useful in fighting other serious respiratory infections such as pneumonia.

Heparin has traditionally been injected and used to treat blood clots.

But lead author, ANU Professor Frank van Haren, said the new study confirms heparin's effectiveness in treating COVID-19 when it is inhaled, rather than injected.

“Our trial – conducted in the early stages of the pandemic – involved almost 500 patients from six different countries,” Professor van Haren, who is also the Director of the Intensive Care Unit at the St George Hospital in Sydney, said.

“All had been hospitalised with COVID-19 but were not yet sick enough to require a breathing machine. The heparin treatment halved their risk of being placed on a ventilator and significantly reduced their risk of dying.

"It follows our initial results which found breathing and oxygen levels improved in COVID-19 patients after they inhaled a course of heparin.”

Heparin is what’s known as a pathogen agnostic drug, meaning it could help treat patients with a whole range of respiratory infections, regardless of which viruses or bacteria are causing it.

“It doesn’t matter what kind of respiratory infection the patient is dealing with, when inhaled, the drug will stop it from infecting the patient and damaging the lungs,” Professor van Haren said.

“We’re aiming to conduct another trial in Europe to confirm its effectiveness in fighting other common respiratory infections such as influenza and RSV.

“And because it’s inexpensive, it’s much more accessible for those from low-income countries.”

According to Professor van Haren, the drug would also be helpful for those with a compromised immune system, such as cancer patients, who develop a respiratory infection.

“Inhaled heparin is anti-viral, anti-inflammatory and anti-coagulant. There’s no other drug that has that unique combination,” Professor Clive Page from King's College in London, who co-led the study, said.

“We know it’s only a matter of time until the next pandemic, and there are still COVID-19 patients who get very sick. This is a great weapon to have up our sleeve.”

The team is now working on an improved formulation of heparin specifically designed to be given by inhalation.

The study will be published in the Lancent Group journal eClinicalMedicine and simultaneously presented at the European Respiratory Society meeting in Amsterdam on 28 September 2025.