COVID-19: Antiviral pills 'look good' but may come too late for outbreak's next peak - expert

Antivirals pills could help combat the symptoms of COVID-19 but may arrive here too late for the next Delta peak.
Antivirals pills could help combat the symptoms of COVID-19 but may arrive here too late for the next Delta peak. Photo credit: Getty Images

Charlie Dreaver, Russell Palmer RNZ

Covid-19 antiviral pills show promise, but experts warn they are unlikely to be available to help as the virus spreads through traffic-light New Zealand.

The traffic light system - officially dubbed the Covid Protection Framework - is a shift in strategy from elimination to suppression of Covid-19.

It will mean tolerating some community spread of the virus throughout New Zealand and relying on vaccines and public health measures to manage the spread and keep New Zealand's health system from being overwhelmed.

Worst-case scenarios predict up to 16,000 new cases per week in January, and as DHBs brace for an influx of cases beyond Auckland, Health Minister Andrew Little says oral anti-viral medicines will play a critical role in the response.

"We know that a lot of the treatments at the moment require an injection, but actually new treatments that are emerging - molnupiravir and the new Pfizer therapeutic treatment - are taken orally, so people can actually get a prescription and administer it themselves," Little says.

"That will take a lot of pressure off the hospital system as well."

Infectious Disease physician and professor of biochemistry at Otago University Kurt Krause says early data for these pills are promising.

"The data that they've released look quite good where they're seeing some very significant reductions in hospitalisations and very significant reductions in mortality if these medications are used early during a Covid infection," he says.

However, he says the process for getting such drugs approved for safety in New Zealand through Medsafe, and supplied through Pharmac, can take several months.

"Even in a favourable case it's looking more likely that it will be early in next year before we're able to roll these medicines out even if everything goes smoothly. If there are any hiccups it can take even longer," he said.

"It means during the initial period where things open up, and the number of cases rise we might not have those treatments available."

Medsafe says it is awaiting an application with supporting data for molnupiravir, and while there is a Pharmac deal to supply some 60,000 courses of it, that deal is conditional on Medsafe's approval.

Paxlovid, Pfizer's new oral drug, has performed even better in early trials, but having been developed later is even further behind in the approvals process.

Pharmac chief executive Sarah Fitt said paxlovid was among treatments being assessed by its Covid-19 expert clinical advisory group. Medsafe is yet to make any announcements about the drug.

Another treatment closer to being approved for Covid use is ronapreve, which has been under consideration by Medsafe since September. Medsafe says it is being treated as a priority, but is waiting on additional information it has requested from the manufacturer.

National Party health spokesperson Shane Reti, a former GP, warns even if the treatments get Medsafe approval, there might not be enough to go around.

"I think we've been late-ish to actually get these into New Zealand. Once they get here it's not clear to me there is urgency from Medsafe in getting these approved, and also not clear we've got numbers that if we get a really severe progression of our current outbreak that we're going to manage well.

"Molnupiravir, 60,000 doses, that's twice a day, so that's 30,000 days, ronapreve is 5300 infusions, only 500 of the baricitinab, so we're kind of thin for these frontline treatments for coronavirus.

"I don't have confidence that we'll have them by the end of this year but nor do I have any projected timeframe as to when we might expect them. All I would say is that we need to indicate urgency."

However, Prof Krause cautions against rushing into approvals without having done the scientific groundwork.

"It's hard to tell people that they need to wait and go through the process but it's actually really really important ... I can remember that everybody was very excited about a combination of two drugs in HIV and everybody said 'oh don't worry about the publications'.

"When the papers came out it turned out that those two medicines used together interfered with one another ... if we hadn't done the science we would have made a mistake."

He says vaccines and public health measures remain the best protection for now.

"Certainly in general throughout this entire Covid period, vaccination is the number one way to prevent Covid - vaccination, and following public health measures and then add on to that the idea of getting a booster."

This was a point brought home by Medsafe group manager Chris James.

"It ought to be noted, the Covid-19 vaccine remains our number one protection against the virus. The vaccine is safe, it will help to stop you and your loved ones getting seriously ill, and it could save your life and theirs."


These drugs are to be taken early in the infection. They are not thought to be effective for patients who have already gone into hospital.

They would be more useful if there is widespread access to Covid-19 tests which can catch the virus early, so the drugs can stop it in its tracks before it leads to hospitalisation.

However, rapid antigen tests - which could prove useful in widespread surveillance monitoring - would likely be less effective for this, because they are less effective at detecting the virus early in the infectious period.

Oral versions would increase availability and accessibility, allowing people to get a prescription as soon as they started feeling ill, to reduce the risk of severe disease.

The US has already purchased millions of doses of two such pills - molnupiravir and paxlovid - in anticipation of their authorisation. Both showed a lot of promise in early trials, which were stopped early because it would be unethical to continue giving placebo to the control group.

Both are most beneficial when taken within five days off symptom onset.

Crucially, no patients who took either drug died in the studies.