And new data suggests it protects against long-term symptoms if taken within five days of a positive test.
Paxlovid will be available on the PBS from 1 April for anyone aged 60 to 69 with mild to moderate covid and one risk factor for developing severe disease.
Previously, government funding was only available if patients were 70 or over, or 50 or over with two risk factors, 30 or over and identify as Aboriginal and Torres Strait Islander and have one risk factor, people 18 years of age or older who are moderately to severely immunocompromised and people 18 or over older who have been previously hospitalised with covid.
The government’s announcement comes as new data shows people at high risk of severe covid had fewer long covid symptoms if they took nirmatrelvir (Paxlovid, Pfizer) within five days of a positive covid test.
The antiviral reduced the risk of common post-covid conditions in people who were unvaccinated, vaccinated and boosted, and in those with first-time covid infection and those who were re-infected.
Those 13 sequelae included dysrhythmia, ischemic heart disease, pulmonary embolism, deep vein thrombosis, fatigue and malaise, acute kidney disease, muscle pain, neurocognitive impairment, dysautonomia and shortness of breath.
According to a study in JAMA Internal Medicine, nirmatrelvir was associated with a 26% lower risk of these post-covid conditions, 47% lower risk of post-acute death and 24% lower risk of post-acute hospitalisation.
This was equivalent to 4.51 fewer post-covid conditions, 0.65 fewer post-acute deaths and 1.72 fewer cases of post–acute hospitalisation for every 100 people in the six months after infection.
The US study used healthcare data from the US Department of Veterans Affairs and included more than 35,000 older white men who had at least one risk factor for developing severe covid.
Those risk factors included being older than 60, having a BMI greater than 25, currently smoking, or having cancer, cardiovascular disease, kidney disease, chronic lung disease, diabetes, immune dysfunction and hypertension.
The nirmatrelvir group had a lower risk of developing 10 out of 13 sequelae of long covid compared to a control group of 246,000 people with risk factors who were not prescribed nirmatrelvir within five days of covid diagnosis.
It did not appear to protect against the development of liver disease, diabetes and cough.
Surgeon and public health researcher Professor Nancy Baxter, from the University of Melbourne, said it was an important study that appeared to support the common belief that nirmatrelvir could reduce the risk of long covid.
“What they showed was that if you took Paxlovid, your risk of having these sequelae was lower for 10 of 13 of them,” said Professor Baxter.
“That’s a pretty strong signal that Paxlovid improved something, and that it seemed to improve it in everyone: those that had been vaccinated, those that hadn’t, those who were boosted and those who either had their first covid infection or were re-infected.
“It seems to say that if you have Paxlovid, not just your short-term risks of hospitalisation and death from the initial event, but your long-term risks are going to be lower over time.”
Nevertheless, the researchers didn’t actually assess “long covid”, and its reliance on mostly older men meant that randomised trials were needed in broader populations, Professor Baxter said.
But the study did show that nirmatrelvir had benefits beyond only preventing hospitalisation and death, she said.
“It does indicate that agencies that are making decisions about who does and doesn’t get Paxlovid need to start thinking beyond just who gets admitted to hospital and who dies. Those are obviously extremely important things, but there are other benefits to Paxlovid that really need to start to be considered.”
Professor Baxter said people over 70 with pre-existing conditions were at higher risk and the cost-benefit of nirmatrelvir was clear.
“But we do need to have more data and start considering who else benefits from Paxlovid. Who else should have access to that drug and not have to pay $1000 for it?”
Professor Baxter said the criteria to access nirmatrelvir in Australia were more stringent than in the UK, US and Canada.
“It’s a really high-risk cohort and that’s because they’re basing their cost-effectiveness analysis on hospitalisation and death. They’re not considering other things such as going back to work or long covid.”
Preventing long covid in younger people with nirmatrelvir would be cost-effective because it would prevent medical conditions and enable people to go back to work, she said.
Professor Baxter said long covid could develop in any age, but the highest risk group for long covid was middle-age women.
