In historical accounts of the 1918 influenza pandemic, references can be found to people experiencing exhaustion, nervous complications, apathy and depression for weeks, even months, after they recovered from infection.
And reports of persistent, chronic fatigue-like symptoms have emerged following the major respiratory disease outbreaks of the past two decades: the first SARS epidemic in the early 2000s, MERS since 2012, and the H1N1 influenza – swine flu – pandemic of 2009. Those symptoms have been known to last months and even more than a year after infection.
There has been no shortage of warnings that viral infections have a sting in their tail: those who survive the acute infection are at elevated risk of long-term, chronic, debilitating illness. And yet in the federal government’s 2019 influenza pandemic management plan there is not one mention of post-viral illness, chronic fatigue or long-term illness resulting from infection. It’s a glaring omission, and one that left a gaping hole in Australia’s pandemic response.
At the heart of the problem is the lack of understanding of just how many people are affected by long Covid, and what impact it is having on their lives, their work, the healthcare system and the economy.
“What’s been very interesting to me in this country – and I’ve been banging this drum for a long time – is that we just still do not have proper surveillance of long Covid,” says health economist Professor Martin Hensher, the Henry Baldwin professorial research fellow in health system sustainability at the University of Tasmania.
What we do have are a few one-off surveys in Australia, as well as studies conducted in countries such as Britain and the United States, where the experience of the Covid pandemic has been vastly different.
What we don’t have is an understanding of who is affected by long Covid, how many people are affected so badly that it affects their ability to work, and what demands long Covid is placing on Australia’s already strained healthcare system.
The World Health Organization defines long Covid as new or ongoing symptoms three months after initial SARS-CoV-2 infection, and lasting at least two months and with no other possible medical explanation. The symptoms fit broadly – but not exclusively – into the categories of fatigue, shortness of breath and cognitive difficulties, or “brain fog”.
Based on that definition, the largest global analysis yet suggests about 6 per cent of people who have had symptomatic SARS-CoV-2 meet the criteria for long Covid, and 15 per cent of those – about 1 per cent overall – are still affected one year after infection. The duration of long Covid is greater in those who were hospitalised than those who were not, and women are at greater risk than men.
But a global estimate that includes data from countries that experienced major outbreaks of the earlier and more severe variants – before vaccines were available – may not represent the experience in Australia, where the bulk of infections has occurred with less severe variants such as Omicron and in a highly vaccinated population.
In Australia, a 2020 study of 2904 Covid cases found about 5 per cent of people had not fully recovered from their symptoms at three months. Another survey of 3510 Australians in August 2022 estimated 4.7 per cent of Australian adults who had had Covid-19 were still experiencing symptoms at three months, and about one quarter of these said they were less able to carry out their day-to-day activities than before Covid. The ongoing ADAPT study, based at St Vincent’s Hospital Sydney, has estimated 20 per cent of its relatively small study population – people testing positive for SARS-CoV-2 – meet the criteria for long Covid at eight months after infection. Modelling by Hensher and colleagues last year suggested that several hundred thousand people in Australia would be affected by long Covid in December 2022.
While these figures are consistent with the global estimate of 6 per cent, they are just a snapshot in time, says epidemiologist Dr Claudia Slimings, senior project manager at the Australian Institute of Health and Welfare. “We haven’t been tracking the prevalence of Covid-19 over time, unlike some other countries such as the UK, which makes it difficult to implement the types of support that may be needed,” she says.
What these studies also don’t reveal is how badly people are affected by their long Covid. “Because it was a very quick survey, we didn’t go into all those sorts of details like ‘is this cough stopping you from doing your normal daily activities’,” says medical epidemiologist and associate professor Bette Liu, from the UNSW Sydney Vaccine and Infection Research Lab and leader of the 2020 study.
That is a critical absence, because the data is crucial for understanding and responding to the impact of long Covid on the healthcare system, workforce and economy. “Our health system is not set up for managing between half a million and a million Australians with long Covid,” says epidemiologist Professor Mike Toole, associate principal research fellow at the Burnet Institute in Melbourne.
Australia does use an international disease classification code for long Covid – “U09.9 Post COVID-19 condition, unspecified” – which was added to the International Classification of Diseases in October 2021. This is used only for people admitted to hospital with severe long Covid, however.
In the outpatient setting, respiratory specialists such as Professor Peter Wark are seeing people with long Covid – some of whom had severe infection to begin with but also some who had only mild Covid – but even these more severe cases aren’t captured in any data. “Unfortunately they’re not showing up in Medicare or PBS [Pharmaceutical Benefits Scheme] data because there’s no way to identify them uniquely in that data, and then they get referred to services that don’t actually rely on PBS or MBS [Medicare Benefits Scheme] data,” says Wark, a senior staff specialist at John Hunter Hospital and the University of Newcastle.
And then there are people who are incapacitated enough by long Covid to reduce their work hours and cut back on other daily activities but who aren’t sick enough to get a specialist referral and so rely on the primary care system, which is already under enormous strain.
“The last thing we can deal with is even more increased demand for care,” says Hensher. “All the existing burden of disease is there, and then stuck on top now is an unknown level of additional disease burden affecting both people who already had chronic conditions and people who were previously otherwise healthy.”
Not only is primary care struggling in Australia, it also isn’t set up for the complex needs of patients with long Covid. Toole cites guidance from the highly respected Mayo Clinic in the US, which recommends that an initial consultation with a doctor about long Covid should be at least one hour long. “Under Medicare, that first consultation is limited to 20 minutes,” he says.
But without a Medicare item number for a long-Covid consultation, it’s impossible to know how much additional strain it is placing on healthcare. There are item numbers for managing chronic disease but these do not identify long Covid specifically and there is confusion and ambiguity about how they should be used for long-Covid patients. “We’re just groping in the dark, and therefore just ignoring it, because we just don’t have a solid database,” Toole says.
A better understanding of the prevalence and impact of long Covid would support a lot of important decision-making. At the personal level, it could give Australians a sense of their individual risk, Liu says. “We’re not able to say to people, ‘If you get Covid, your chances of getting symptoms that might go beyond three months is this much,’ ” she says. It might prompt more preventive behaviours and better vaccine uptake, Liu says.
At the state and federal levels, it could shape policy around how to better manage long Covid, Toole says. “The state-run long Covid clinics are overwhelmed,” he says, suggesting that governments need to look at general practitioner-led multidisciplinary clinics that include professionals such as physiotherapists, psychologists and social workers. He also argues that economists need to better understand the potential financial impact of long Covid, with data from the US suggesting four million people there are out of work because of the disease.
In an attempt to get to grips with the long-Covid data problem in Australia, the Australian Institute of Health and Welfare is now funded to sync Covid-19 infection notifications with national data sets from deaths, hospitals, aged care, immunisation, the MBS and the PBS. The aim is to enable research into hospitalisations and healthcare use after initial Covid-19 infection.
There’s one hitch: fewer people are testing for Covid or reporting the results of positive tests.
Slimings says the data set will still be extremely useful in helping to design more targeted models of care for people with long Covid. “There is still a rich amount of data collected prior to these changes, which will be valuable for research into risk factors for long Covid, the impact on patients and the Australian health system,” she says.
But it’s just a start, and it’s just one data set. Slimings says there is no single source of truth on long Covid. “We need data from a variety of sources, settings and population groups to build a comprehensive picture of the long-Covid burden in Australia, as we do for other health outcomes.”
This article was first published in the print edition of The Saturday Paper on February 18, 2023 as "The long and winding Covid".
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