Vaccination driving down long COVID risk, but numbers still high

One in 20 Australians infected with COVID-19 during the Omicron wave is expected to still have symptoms three months later, but as vaccination rates rise the prevalence of long COVID among those infected is declining, an infectious diseases expert says.

Kirby Institute Scientia Professor Gregory Dore said widespread vaccination was driving down the risk of long COVID among the tens of thousands infected every day, but said the theory that the Omicron variant carried a lower risk of long COVID was less likely.

Kaillee Dyke, with her husband Chris Lassig and their twins. Kaillee is still experiencing long COVID symptoms two years after she was put on a ventilator at 25 weeks pregnant.Credit: Darrian Traynor

“Most of the impact on prevalence [of long COVID] seems to come from vaccination rather than different strains,” he said before a COVID conference in Sydney on Thursday. “It’s more about the immunity you have when you become infected.”

“It’s the people who haven’t been infected yet and are not up-to-date with vaccination that are the greatest concern,” said the infectious disease physician who treats patients at St Vincent Hospital’s long COVID outpatient clinic in Darlinghurst.

Dore is among the top Australian and international experts attending the Australasian COVID-19 Conference to discuss the latest in COVID prevention, treatment and management.

He said the prevalence of long COVID among cases has shrunk by more than half since the first year of the pandemic, when an estimated 10 to 30 per cent of unvaccinated COVID patients developed the protracted illness.

“For people infected now, the risk that they will still have symptoms in three months’ time is around 5 per cent,” he said. “But 5 per cent is still a lot of people given our current rate of infection.”

With national daily case numbers rising above 53,000 people, this equates to an additional 2700 long COVID cases per day by mid-October.

“A lot of these people will be on the milder end, with some having ongoing fatigue and will improve,” he said. “My sense, clinically, is that for the long COVID we will see from this, the recovery trajectory will be more rapid.”

“What is clearly worrying is that a significant proportion of long COVID patients who were infected in the unvaccinated era still have debilitating symptoms two years on.”

Kaillee Dyke was among the first wave of long COVID patients, before vaccinations were available. She contracted COVID in July 2020 when she was 25 weeks pregnant with twins and was admitted to intensive care, with her oxygen levels plummeting. She had 20 minutes to call her loved ones before she was sedated.

“I didn’t think I was going to make it, so I tried to say goodbye to my babies as meaningfully as I could,” she said.

But 10 days later she woke up.

Two years on, Dyke is still feeling the effects of long COVID.

“I still have breathlessness … my lungs aren’t working as well as they used to, and I still have brain fog. My symptoms have decreased all the time but they’re still quite prominent,” she said.

Dore said he hoped cases of long COVID patients with debilitating symptoms two years after infection would be “very, very rare” among vaccinated people. But he said too many patients have been dismissed by doctors who don’t understand long COVID, don’t believe it exists, or think the illness is “just psychological”.

“We need to gain the trust of patients and really reinforce that we are taking their symptoms seriously, that we are going to do a thorough investigation and consider other causes, then do a more detailed investigation and refer when appropriate,” he said.

The lack of diagnostic tools or proven effective treatments made for tough conversations, he said.

“We have to be upfront about this with patients,” he said.

However, there are multiple trials underway overseas exploring potential therapies for long COVID, including anticoagulants, an anti-inflammatory drug traditionally used to treat gout, and antihistamines.

Multidisciplinary long COVID clinics offer patients support, including access to respiratory physicians, physiotherapists and psychologists, but have long waiting lists, Dore said.

The two-day conference on COVID-19 is run by the Australasian Society for HIV, Viral Hepatitis and Sexual Health Medicine.

Vaccination versus long COVID

A UK study compared self-reported symptoms among people who had been vaccinated two or three times and infected with either the Delta or Omicron variants. 

Roughly 9.5 per cent of people likely infected with Delta who were double-vaccinated reported having long COVID symptoms compared to 4.5 per cent among triple-vaccinated people. 

For the Omicron-infected, 6.2 per cent of double-vaccinated reported long COVID symptoms compared to 5.3 per cent of the triple vaccinated group. 

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