How quickly can people recover from COVID-19?

Medical staff wearing protective suits take a sample to test a possible patient infected with Coronavirus at a mobile testing center at the Na Bulovce hospital on March 13, 2020 in Prague, Czech Republic. (Credit: Gabriel Kuchta/Getty Images)

Researchers have mapped immune responses from one of Australia’s first COVID-19 patients, showing the body’s ability to fight the virus and the timing of recovery from the infection.

Researchers were able to test blood samples at four different time points in an otherwise healthy woman in her 40s, who presented with COVID-19 and had mild-to-moderate symptoms requiring hospital admission.

A report on the work in in Nature Medicine outlines how the patient’s immune system responded to the virus. One of the authors on the paper, Oanh Nguyen, a research fellow at the Peter Doherty Institute for Infection and Immunity (Doherty Institute), a joint venture between the University of Melbourne and the Royal Melbourne hospital, says this marks the first report of broad immune responses to COVID-19.

“We hope to now expand our work nationally and internationally to understand why some people die from COVID-19…”

“We looked at the whole breadth of the immune response in this patient using the knowledge we have built over many years of looking at immune responses in patients hospitalized with influenza,” says Nguyen.

“Three days after the patient was admitted, we saw large populations of several immune cells, which are often a tell-tale sign of recovery during seasonal influenza infection, so we predicted that the patient would recover in three days, which is what happened.”

The research team was able to do this research so rapidly thanks to SETREP-ID (Sentinel Travellers and Research Preparedness for Emerging Infectious Disease), led by Royal Melbourne Hospital infectious diseases physician Irani Thevarajan.

SETREP-ID is a platform that enables a broad range of biological sampling to take place in returned travelers in the event of a new and unexpected infectious disease outbreak, which is exactly how COVID-19 started in Australia.

“When COVID-19 emerged, we already had ethics and protocols in place so we could rapidly start looking at the virus and immune system in great detail,” Thevarajan says. “Already established at a number of Melbourne hospitals, we now plan to roll out SETREP-ID as a national study.”

Working together with Katherine Kedzierska, a laboratory head at the Doherty Institute, the team was able to dissect the immune response leading to successful recovery from COVID-19, which might be the secret to finding an effective vaccine.

“We showed that even though COVID-19 is caused by a new virus, in an otherwise healthy person, a robust immune response across different cell types was associated with clinical recovery, similar to what we see in influenza,” Kedzierska says.

“This is an incredible step forward in understanding what drives recovery of COVID-19. People can use our methods to understand the immune responses in larger COVID-19 cohorts, and also understand what’s lacking in those who have fatal outcomes.”

Thevarajan says that current estimates show more than 80% of COVID-19 cases are mild-to-moderate, and understanding the immune response in these mild cases is very important research.

“We hope to now expand our work nationally and internationally to understand why some people die from COVID-19, and build further knowledge to assist in the rapid response of COVID-19 and future emerging viruses,” she says.

Source: University of Melbourne