A test for COVID-19 risk, infectivity and immunity

The Immunology/Allergy research team. L-R: Mrs Simone Reinwald, Ms Gemma Hartley, Dr Craig McKenzie, Professor Robyn O'Hehir AO, Associate Professor Menno van Zelm, Ms Pei Mun Aui, Dr Emily Edwards, Mrs Neeru Varese

by Tania Ewing

Monash scientists are repurposing technology they developed recently to make a rapid test to determine who:

• has immunity to coronavirus
• remains infectious
• is at risk of developing a severe form of the disease.

A team, led by Associate Professor Menno van Zelm from the Monash University’s Central Clinical School together with Professor Robyn O’Hehir from Central Clinical School and Alfred Health, is repurposing technology they recently developed to test for a patient’s immunity to allergens and to influenza – to make a rapid test to determine who has immunity to coronavirus, who remains infectious and who is at risk of developing a severe form of the disease.

The researchers will start receiving cell samples in early April from colleagues in Melbourne and three main hotspots: Italy, China and New York. There is a growing need to identify immune healthcare workers, minimise furloughing, and allow workers safely back into the frontline.

The test will also have the capacity to look for differences in the blood of patients with mild disease versus those with a severe infection, in the hope of finding biomarkers that can predict those who may need early medical intervention.

The test, similar to the recently developed test for influenza, looks at what are called “memory B lymphocytes”.  B lymphocytes are the cells of the immune system that make antibodies to invading pathogens such as viruses. They form memory cells that remember the same pathogen for faster antibody production in future infections – these are the cells formed after vaccination and that respond quickly when a pathogen is encountered, thereby preventing the disease (e.g. measles, tetanus).

If we have a population of memory B cells specific to a pathogen, then it is likely that we have been infected at some time in the past and remain immune to the disease.

A/Prof Menno van Zelm in the lab

The Monash team has developed markers for those memory B cells formed after coronavirus infection. By binding these markers to a fluorescent label they can use commonly available equipment called a Fluorescence Activated Cell Sorter to determine the number of memory B cells for coronavirus a patient has, thereby assessing their immune status.

They will be also looking at memory B cells taken at various stages, and severity, of coronavirus infection from patients in China, Italy, New York and Australia to look for different markers on these B cells that may become predictors of those who will get a mild version of the disease all the way to those who may need care in ICU.

“As we move from needing a test that simply tells whether someone is infected – which is the priority now – to needing a test that can determine who is infectious, who is immune, who is going to get a serious case of the disease and who will only develop a mild case of upper airway infection,” Associate Professor van Zelm said. “This and other tests like it will provide us with a more nuanced approach to managing the disease.”

6 April 2020 The Australian "How hard will coronavirus hit you? Scientists close to an answer": (Note - link is paywalled)

https://www.theaustralian.com.au/nation/test-will-drill-down-to-nittygritty-on-risk-and-recovery/news-story/cae534be2d97e082024552582e180766