Severe Stage COVID-19

A step closer to knowing who can or cannot fight severe COVID-19

Earlier last year, as COVID-19 restrictions set in throughout Australia, bringing with them many unknowns, QIMR Berghofer researchers put out an urgent call for Queenslanders who had recovered from the virus to participate in an important immunity study. Months later, we are now excited to share the initial findings.

The hope was that we could identify early on which patients’ immune systems are not responding appropriately to the virus, and who might therefore be at higher risk of becoming seriously unwell.

Study leader and head of QIMR Berghofer’s Translational and Human Immunology Group, Associate Professor Corey Smith, said the researchers examined blood donated by 44 Queenslanders who had recovered from COVID-19. Their goal was to find a way of testing whether
or not COVID-19 patients’ immune systems are gearing up to fight the SARS-CoV-2 virus.

The prototype test detects high levels of 2 key chemical signals that are produced by T cells when they recognise SARS-CoV-2-infected cells and start to fight the infection.

T cells are the immune cells that recognise and destroy cells infected with viruses such as SARS-CoV-2. They typically mount an early response, even before the body starts to produce antibodies. Most importantly, T cells develop a lasting memory of viral infections, which enables the immune system to respond rapidly in the event of reinfection.

‘T cells produce a range of signalling molecules when they fight viruses,’ Associate Professor Smith said.

‘These signalling molecules are basically indicators of whether T cells are responding to the SARS-CoV-2 virus and are mobilising the immune army to launch an attack.

‘If we can find a way to detect whether or not they are present, then we can find out whether or not a patient’s immune system is responding as it should.

‘We found that T cells from people who had recovered from COVID-19 produced larger amounts of the signalling molecules interferon gamma and interleukin-2, which are involved in killing virus-infected cells and encouraging other T cells to come to the infected area,’ he said.
At time of writing, almost 100 million cases of COVID-19 have been reported worldwide and the disease has caused more than 2 million deaths, according to Johns Hopkins University data.

In Australia 909 people have died from the disease, and there have been more than 28,000 reported infections. As the Northern Hemisphere settles into the winter season, this research into immunity is more important than ever.

QIMR Berghofer researcher Dr Katie Lineburg said while Australia had been largely successful in controlling infection rates, a blood test for early immune responses to the virus could particularly help other countries experiencing second and third waves.

A blood test could help doctors identify patients who are not fighting the virus and are at higher risk of becoming seriously unwell. A screening test could therefore enable early identification of people who are most at risk of serious illness, so clinical management could start sooner.

‘While the world waits for a vaccine to be fully rolled out, it’s clear the virus will continue to spread and people will continue to get sick, placing more pressure on health systems. A blood test that could detect whether a patient is developing an effective immune response would be another important tool in managing how countries deal with the pandemic.

‘These are the first results from this COVID-19 study, and we will follow up with as many participants as possible in future, to improve our understanding of long-term immunity to the virus.’

The research was made possible by the generous actions of Queenslanders who donated blood samples for this study, and funded by philanthropic donations, including from Mr Clive Berghofer AM and the Brazil Family Foundation. It is also one of the COVID-19 research projects that will benefit from a recent injection of funding from the Queensland Government for QIMR Berghofer’s COVID-19 research projects.

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