Coronavirus: Australian scientists map how immune system fights virus

Scientists in Australia say they have identified how the body's immune system fights the Covid-19 virus.

Their research, published in Nature Medicine journal on Tuesday, shows people are recovering from the new virus like they would from the flu.

Determining which immune cells are appearing should also help with vaccine development, experts say.

Globally, authorities have confirmed more than 160,000 cases of the coronavirus and about 6,500 deaths.

"This [discovery] is important because it is the first time where we are really understanding how our immune system fights novel coronavirus," said study co-author Prof Katherine Kedzierska.

The research by Melbourne's Peter Doherty Institute for Infection and Immunity has been praised by other experts, with one calling it "a breakthrough".

Many people have recovered from Covid-19, meaning it was already known that the immune system can successfully fight the virus.

But for the first time, the research identified four types of immune cells which presented to fight Covid-19.

They were observed by tracking a patient who had a mild-to-moderate case of the virus and no previous health issues.

The 47-year-old woman from Wuhan, China, had presented to hospital in Australia. She recovered within 14 days.

Prof Kedzierska told the BBC her team had examined the "whole breadth of the immune response" in this patient.

Three days before the woman began to improve, specific cells were spotted in her bloodstream. In influenza patients, these same cells also appear around this time before recovery, Prof Kedzierska said.

"We were very excited about our results - and the fact that we could actually capture the emergence of immune cells in the infected patient prior to clinical improvement," she told the BBC.

More than a dozen scientists worked around the clock for four weeks to deliver the analysis, she added.

Identifying when the immune cells kick in can help "predict the course of the virus", said Prof Bruce Thompson, dean of health sciences at Swinburne University of Technology.

"When you know when the various responses take place you can predict where you are in the recovery of the virus," Prof Thompson told the BBC.

Australia's Health Minister Greg Hunt said the finding could also help "fast-track" a vaccine and potential treatments for infected patients.

Prof Kedzierska said the next step for scientists was to determine why the immune response was weaker in worse cases.

"It is really key now to understand what is lacking or different in patients who have died or who have really severe disease - so we can understand how to protect them," she said.

In January, the institute became the first in the world to recreate the virus outside of China.

The centre has since received additional funding from the Australian government as well as donations from businesses and Chinese billionaire Jack Ma.