20 August 2020
Release date 14 August 2020
Just published in the Australian Financial Review, Health Editor Jill Margo spoke with three leading scientists about the crucial questions we need answered about COVID-19 including Burnet’s Director and CEO, Professor Brendan Crabb AC.
Since Australia’s first case of COVID-19 was confirmed just over 200 days ago, we have accumulated a phenomenal amount of knowledge about this disease but fundamental questions remain unanswered.
On the clinical front, we don’t know why many healthy people don’t get symptoms and some get them so badly they can be fatal.
We also don’t know how to nip this disease in the bud and treat mild cases to prevent them from becoming serious.
When they are serious, we only have two drugs that can help a little. Remdesivir can shorten the duration of the disease in people who are hospitalised and the steroid dexamethasone can reduce mortality a bit in seriously ill patients who are unable to breathe unassisted.
Although there have been some tweaks, such as turning patients face down to assist.
Because the disease is so young, there is much apprehension about what comes after it.
“We just don’t know what the long-term non-death consequences of COVID 19 might be,“ Professor Crabb said.
“Are those who get sick in their 30s going to have major problems their 60s?”
As the virus is not limited to the lungs but affects other tissues such as those in the vascular system, the brain and the kidneys, this issue needs close examination.
Professor Crabb expects that this pandemic will end and the virus will stay.
“This is a new virus with a completely new syndrome associated with it and as it’s affecting unexpected tissues and organs, there is every reason to think it may have an impact. Will the kidneys give up earlier or will it not matter?”
Coronaviruses are not like measles, which people have once and are protected for life. — Professor Brendan Crabb
It is very likely there is good immunity in those who have been infected but its potential durability and strength are unknown, Professor Crabb said.
“I say ‘very likely’ because that is the case for almost every other virus and because, among the millions being infected with it, there are very few reports of people known to have been infected before.
“But then, coronaviruses are not like measles, which people have once and are protected for life.”
He says the big question is whether a vaccine for COVID-19 can mimic that natural immunity and outlast it, or whether people will need to be vaccinated every year.
If this proves to be the case, it uncovers big holes in the prospect of creating and maintaining herd immunity.
‘‘It will make it much tougher to achieve,’’ Professor Crabb said.
‘If a vaccine lasted for life, then 60 or 70 per cent of the population might need to be immune to achieve herd immunity. But if immunity lasts six months, how will we get so many revaccinated to protect the herd? Vaccine immunity is likely to be circulating with some people getting COVID-19.’’
Buried in the optimism about vaccines is a deep scientific worry about whether what looks like a prize vaccine will backfire and cause more harm than good. This is known as “immune enhancement” and can cause the immune system to malfunction.
While there is a low likelihood of this occurring, Professor Crabb said this is a challenge and could be the biggest barrier for a COVID-19 vaccine ever making it to the market place.
And there is much uncertainty on the genetic front too. This virus is constantly mutating, causing small changes that appear to make no difference to its infectivity, but which signal where it has been. This helps with contact tracing.
But less often and more slowly, bigger mutations occur. These have been documented although it’s not known if they will alter transmissibility or severity for the worse or the better.
The mother of all questions, however, is about the endgame.
If we manage it well, what will we do with so much virus outside our borders? How will we interact with the world?
Even if excellent vaccines are produced, it will take a long time to vaccinate 7 billion people and while rich countries will easily afford it, and poor countries will get aid, many middle-income countries will struggle.
Professor Crabb expects this pandemic will end and the virus will stay.
“Although it is closely related to the coronaviruses SARS and MERS, I believe it will be much more like HIV, in the sense that it will be around for a long time,“ he said.
“SARS AND MERS have gone but HIV has been with us for 40 years and we can live with it. There’s no vaccine for it, but we have good tools.
“My institute still spends a large proportion of its budget on HIV.”