As COVID-19 continues to grip the nation, eyes are turning to drugs that are being tested to treat COVID-19 and could soon be administered in Australia.
It comes as Pfizer announced on Tuesday its antiviral drug named paxlovid is 89 per cent effective in protecting people who have tested positive to COVID-19 from serious illness or death.
"This [result] underscores the treatment candidate’s potential to save the lives of patients around the world,” Pfizer's CEO and chairman, Albert Bourla, said.
Australia's medicines watchdog, The Therapeutic Goods Administration (TGA) currently has paxlovid — and its Merck & Co competing drug, molnupiravir - under provisional determination.
While Australia's COVID-19 infections rise with little information known about the emerging variant of concern Omicron, experts say the antiviral drugs could be an effective additional tool in protecting the world from the pandemic's wrath.
What are these drugs?
Associate professor at University of Sydney's pharmacy school, Nial Wheate, explained there are two categories of drugs that relate to COVID.
The first are those designed to treat symptoms of COVID-19, and are traditionally used for patients who were admitted to the hospital.
It's the second kind of drug that experts say will change the scope of how the world grapples with the global pandemic: treatment that directly treats COVID-19.
This is where Pfizer's paxlovid and Merck & Co's molnupiravir come in.
Professor Wheate said both of these drugs are promising because of their efforts to "keep people out of hospital".
"If we've got medicines that people can just take home, which stops them from getting seriously sick and suffering from going to hospital that is a game changer," he said.
Why are they so important?
COVID-19 treatments are critical because they provide "another tool" to combat hospitalisations and deaths due to the virus, professor of chemistry at the University of New South Wales, Pall Thordarson, said.
"We shouldn't rely on just one layer of protection, we should use several ... the ones we have available are good, but they're not perfect," he said.
He added that while scientists work to create vaccines that provide long-term protection against COVID-19, having a plethora of options to prevent the seriousness of the virus is necessary for Australians to lead normal lives.
Pall Thordarson is a chemistry professor at the University of New South Wales. Source: Supplied/Pall Thordarson
"Whether you use masks, use social distancing, use vaccines, use antiviral [drugs], they all give you some protection but not 100 per cent.
"If you only trust the one, if you only trust the masks, or you only trust the vaccine, or you only trust the antiviral [drugs], you're not as well protected as using several layers."
What about Omicron?
Professor Wheate said that antiviral drugs like molnupiravir and paxlovid are designed to tackle the virus, rather than only one specific variant. This means that they should be "efficacious" to use against Omicron too.
The World Health Organization (WHO) is still undertaking tests to determine whether the recognised COVID-19 vaccines are effective in protecting people from Omicron.
"If we find out [Omicron] is able to get around our vaccinations, then these drugs provide us with a really great back-up for treating people so they don't get seriously sick," Professor Wheate said.
He also said getting a booster vaccine shouldn't prevent anyone from using antiviral drugs.
"I don't see any reason why getting a booster vaccination would preclude someone from taking an at-home treatment for COVID," Professor Wheate said.
'Is it safe and does it work?'
The TGA has not yet provisionally approved either of the two oral treatments.
Professor Wheate said the TGA will ask two questions to determine whether the drugs can be used in Australia in their evaluation.
"They're concerned with two things: is it safe and does it work?"
The TGA has not provided an estimated time that Australians can expect to get their hands on the drugs, and it's unlikely they will disclose a date to the general public in advance.
"Given the nature of COVID and the situation we're in, I think it's likely that they would expedite their evaluation process, but they will never commit to a timeline."
What we don't know, Professor Wheate said, is what kinds of criteria the TGA will place on the administration of the drugs, if they are approved.
These conditions can include, but are not limited to, whether a person needs to test positive to COVID-19 before receiving the drug and which doctors have the power to prescribe the drug.
But Professor Thordarson said that traditionally antiviral drugs are not effective until a person is confirmed to be infectious, so the drug is likely only to be administered to confirmed COVID-19 cases.
Australia stocks up
Despite TGA having not approved the oral treatments yet, the federal government has pre-emptively bought 300,000 doses of molnupiravir in October.
Professor Thordarson said the government has taken "a sensible approach" to ensure Australia has enough stock available in the event the TGA announces its provisional approval.
"People will say, 'this is very expensive', well actually it isn't compared to loss of life, which is incalculable."
And Professor Wheate agrees, warning these drugs could be highly sought after if approved by the various medical authorities around the world.
"What we don't want is to get approval from the TGA and then have to wait two or three months for the first drugs to arrive," he said.
"What [the government] is doing is helping to reduce the risk to the country and the risk to patients by having [the drugs] available when we're ready to use them."
