Pfizer’s second-generation COVID-19 vaccine, tailored to the Omicron variant as well as the initial Wuhan strain, has been approved for third and fourth doses for Australians 18 and over from mid-December. Moderna’s updated vaccine has been available since October 14.
But fifth doses are yet to be approved. With Australia in the grip of another wave, experts are turning their attention to direct treatments through antivirals as well as a new form of vaccines specifically designed to prevent transmission.
Here’s what we know.
To panic or not to panic?
First, while cases have been on the rise for the past fortnight, they haven’t been climbing anywhere near as high as previous waves. Last week, new cases rose to more than 60,000 compared with 41,000 the week before, partly thanks to yet another Omicron variant — the XBB.
While hospitalisations increased by 11%, putting pressure on Australia’s already strained healthcare system, chief medical officer Professor Paul Kelly said yesterday the wave is expected to peak soon and drop quickly.
So far, each emerging variant has been more transmissible but doesn’t pose a greater risk of severe illness and death.
A new generation of vaccines
The vaccines approved in Australia were designed to do one thing: reduce the severity of disease. While they also appear to reduce the amount of the virus circulating in the body — reducing transmissibility — they were not specifically designed to do so.
But Australian researchers are designing a vaccine specifically targeting transmissibility. Garvan Institute senior research officer Dr Deborah Burnett said these new vaccines could be variant-proof and won’t require updates.
Current vaccines have been tailored to produce antibodies to attack the spike protein of the COVID-19 virus. The new vaccines will target different regions, meaning antibodies produced will attack any SARS-CoV-2 virus, regardless of the variant.
“There are some regions of the virus that the virus can’t mutate, and that’s because they’re critical for the virus’ function,” Burnett said. “It’s going to be a real game-changer.”
Are antivirals the answer?
Two antiviral oral COVID-19 treatments, Lagevrio and Paxlovid, have been approved for use in Australia and added to the Pharmaceutical Benefits Scheme. So far, only the elderly, the immunocompromised and First Nations peoples with comorbidities or limited access to healthcare are eligible for them.
These have long been hailed as a solution to the COVID crisis. After registering an infection with the state government and having eligibility assessed, Australians can book a telehealth appointment with a GP, receive a prescription and have the drugs delivered, costing between $6.80 (for concession card holders) and $42.50 (for general patients). The drugs have been shown to reduce recovery time and may reduce the risk of hospitalisation by up to 66% (though other research has shown mixed results on hospitalisation).
Importantly, the antivirals have many drug interactions, meaning GPs have to carefully analyse a person’s medical history to decide whether they are appropriate, infectious diseases paediatrician Professor Robert Booy said.
“It needs a very wise approach from the GP to say which medication can be stopped, halved or be continuously taken with an antiviral,” he said.
Booy warned against relying on one treatment over another or waiting for a new vaccine instead of getting the current ones.
“While antivirals are critical for people who are already infected and aggressively vulnerable to multiple severe medical problems … booster vaccines can give improved protection within seven to 10 days,” he said. “We need a multi-pronged approach.”
