This is one of the greatest unknowns. Dr Norman Swan takes a closer look with Epidemiologist Professor Greg Dore from the Kirby Institute about what’s known and unknown about Long COVID.
Greg Dore is Professor of Epidemiology at the Kirby Institute in Sydney, and one of the leaders of a study following Australians with extended post-COVID symptoms.
What’s happening in the immune system of people who are getting long-term symptoms?
It’s interesting. We’ve followed many people through this in our St Vincent’s, Sydney cohort and it’s not only the people who develop long COVID symptoms, but people generally following a COVID infection have an activated immune system. So, we’re seeing what you might call an immunological fingerprint following initial infection.
Does that mean you could suppress that immune response and then prevent problems?
Some of the aspects of the immune activation, suggest there’s an immune activation where some of the type one interferons are elevated which does open the door to potential therapeutic strategies. There may be some immune modulators that we could look at to address Long COVID. It’s always got to be balanced with the downside of using therapies that affect the immune system.
You’ve been following a group of people at the University of New South Wales and St Vincent’s in Sydney. What are the hallmark symptoms that are developing/clustering around long COVID?
There are two different types of syndromes. There is a neurological cluster where people will have ongoing and quite severe fatigue, and that could be associated with what many describe as a brain fog – so issues with attention, concentration and short-term memory. Then there’s more of a cardiorespiratory cluster. People can still have the fatigue, but often describe chest discomfort, palpitations and ongoing issues in terms of breathlessness.
There have been a couple of papers recently showing long term brain effects. A Chinese study from Wuhan suggests that there’s loss of cognitive function. And then with the heart 12 months’ increased risk of heart attack and stroke. Is that panning out in the Australian data?
I think the neurological stuff is interesting. We’ve been doing detailed evaluation of neurocognitive function and there’s a small minority, about 10% of people, who have significant neurocognitive impairment and that seems to be sustained for several months. We’re now following people into the second year and hopefully will see that neurological impairment improve. It’s not surprising following SARS 1 there were long term neurological effects out to two years. So, we’ve seen this before with coronavirus.
What proportion of people are getting long COVID in your study?
Somewhere between 20% and 30% of people would be described as having long COVID, defined as having symptoms out to three months following initial infection. Sometimes those symptoms are relatively mild, and obviously that there’s a spectrum in terms of disability and symptoms.