The Morrison government has finally unveiled a four-phase plan to reopen Australia, 17 months after the pandemic first hit. The plan lacks data on vaccination rates, goals or dates — the government is waiting for modelling from the Doherty Institute.
But experts warn Australia may have to look abroad for guidance as the more infectious Delta variant spreads among populations, with herd immunity potentially off the table — even with high vaccination rates.
Let other countries be our guide
The UK has hit vaccination rates of 70%. Today it’s expected COVID-19 restrictions will be eased. Vaccinated adults will be able to return from certain countries without having to self-isolate; face masks will be voluntary outside healthcare settings, as will scanning QR codes to enter hospitality venues.
But experts warn this may be premature and could speed up the development of variants.
Associate professor James Trauer, head of the epidemiological modelling unit at Monash University, tells Crikey Australia will probably have to look at the impact that relaxing restrictions has abroad before clear targets can be set.
“It’s hard to really put concrete numbers on what level of vaccination coverage would be required before we could start reopening,” he said.
The four-phase plan ranges from the current suppression phase to post-vaccination, where restrictions will be eased and lockdowns used sparsely, to managing COVID with booster vaccinations, to the final phase with uncapped arrivals for all vaccinated travellers.
A population is generally considered to have herd immunity when 70% to 80% of the population is vaccinated — but Trauer warns against having this as a goal.
“We have to move away from thinking of herd immunity as all or nothing — herd immunity means the point at which transmission is just totally controlled without doing anything else,” he said.
Instead, herd protection should be Australia’s goal, which is when there’s enough immunity to prevent explosive outbreaks: “We do have to just learn to live with this virus and accept some transmission at some point and Australia has become extremely risk-averse.”
Herd immunity may be off the table
Herd immunity may never be possible. Adrian Esterman, professor of biostatistics at the University of South Australia, says herd immunity is 80% possible only if the vaccine is 100% effective. Pfizer has 95% efficacy in preventing infection, while AstraZeneca has an efficacy of between 60% and 73%.
“We’re going to have to keep social distancing, hand hygiene and contact tracing even once we hit phase four,” he said.
This puts Prime Minister Scott Morrison’s messaging that COVID during phase three will be treated like any other infectious disease, including the flu.
“COVID-19 certainly can’t be handled as it was ebola or the flu, for example, but could eventually end up like a flu-like illness,” Esterman said. “I think we’ll end up with a COVID-19 normal rather than pre-pandemic normal.”
When should we stop looking at infection rates?
Key to the vaccine’s success is not reduced infection rates but reduced serious illness — meaning eventually Australia will have to look at the rate of hospitalisation as a metric for success.
Esterman says this could happen when about 50% of Australia’s population is vaccinated.
“There’ll be far fewer chances of outbreaks and far fewer chances of having to get locked down,” he said.
Trauer said Australia’s focus on elimination — he disagrees with the government’s labelling of our approach as “suppression” — will have to change drastically. Success will be when every adult who wants to get vaccinated has had that opportunity: “Suppression means allowing some transmission, but keeping it manageable.”
Everytime I see Amber Shultz mis-state vaccine efficacy numbers, I am reminded that while it’s very easy to understand how drug trials work, so few people have bothered. It’s been one of the major communications screw-ups of the pandemic. So, for the umteenth time, it goes like this: A drug trial is composed of multiple arms, one with the new drug, others with the existing drug or a placebo etc. The trial arms are chosen to be statistically similar population samples – age, access to medical care, background disease prevalence. The results come in, and depending on trial size, positive and negative results, when the results are deemed very unlikely to be chance (mildly complex statistics but not necessary to understand for the purposes of this comment), the trial is halted and results declared. Because of the sample similarity requirement, it’s very unlikely the results from one trial can be compared to another. That is, the trial results are not absolute scores, the same for all time and places. They are unique to that trial. A 65% in one trial, and a 95% in a completely different trial are not scores than can be meaningfully compared. Now, until recently, no two Covid vaccines have been trialed as different ams in the same trial, so no two sets of results can be compared. The exception is the Valneva trial nearing completion, where one arm is Valneva snd the other AstraZeneca. Then we should get a meaningful comparison. The original trials for the mRNA vaccines and for AZ were done in utterly different populations, with different variants, prevalence, and care options available. They can’t be compared. Hopefully all future trials will be conducted as vaccine versus vaccine. One other note: now that 10s of millions of people have been vaccinated, we can conduct a sort of trial by looking at the medical outcomes of randomly selected people and seeing how they went. In the UK, the outcomes of AZ of Pfizer vaccinated people look very similar.
The other factor to consider is the trial length and its influence on outcome measurements. AZ consistently takes longer to achieve maximum protection, longer than trial study duration, so we really need to look at real-world experience with various vaccines where protection from severe illness to most variants is pretty similar
I’d be clarifying in your moniker that you were not ‘that Peter Evans’. Your points are all valid and attempts are being made to assess real world efficacy rates, but in real world populations that is tricky. It appears that AZ has a much higher efficacy than in the trial. The other factor which nobody knows is the duration of effectiveness, and as AZ takes longer to provide full effects and is delivered with a 12 wheel break, there is reason to believe it may produce a longer lasting protection.
Having said that, the mRNA technology is completely new, so there’s that.
I would be aiming for the highest possible number of the whole population including kids, down to whatever age has been shown to be safe (which is likely to be quite young given kids immune systems).
And in putting a figure out in public I would go for a very high number, 90% plus, to help get the message out there that the ‘free rider’ option isn’t viable.
I’m resigned to the ‘living with it’ part, the anti-vaxxers can get what is coming to them, but I’d still insist on quarantine for anyone coming back into the country who isn’t fully vaccinated. The vaccine-hesitant can either eschew overseas travel or pay the price via two weeks in quarantine.
I’m heartily sick of the ‘me-me’ population though.
Key to the vaccine’s success is not reduced infection rates but reduced serious illness — meaning eventually Australia will have to look at the rate of hospitalisation as a metric for success.
Nothing Morrison or Berjiklian does inspires confidence that any metric for success will be fair dinkum, especially give Michael West’s article here:
Who to believe on Bondi Cluster: Limousine Man or NSW Government?https://www.michaelwest.com.au/who-to-believe-on-bondi-cluster-limousine-man-or-nsw-government/
NSW Coalition’s figures have never stacked up.
Interesting numbers from Michael West’s team. Gladys reluctance to go to full lockdown made no sense even at the time. The inclusion of the Randwick LGA in the first lockdown group could also not be justified on what was being published, there were no sites of concern in the entire Randwick LGA.
The strange reluctance to lockdown the Hills district in particular was unfathomable. I hope it is not related to the fact that the Hills district is ‘Pentecostal central’.
Gladys reluctance to lock Sydney down earlier means we will be in lockdown for much longer than necessary, I suspect they will be extending the lockdown for another week or fortnight (and that’s the best case scenario).
Where is the media and social media outcry over Gladys using Sydney, and ultimately the rest of Australia, as her social and political experiment that went wrong.
Oh the media is in full cry alright, but it’s directed at Qld Labor ; whereas NSW is the state of disaster AGAIN, another Ruby Princess moment which also has links to them thar hills.
NSW shouldn’t leave COVID-19 lockdown until infectious cases in community are down to ‘zero’, expert sayshttps://www.abc.net.au/news/2021-07-06/too-early-for-nsw-to-lift-covid-lockdown-says-epidemiologist/100268710
The strange reluctance to lockdown the Hills district in particular was unfathomable. I hope it is not related to the fact that the Hills district is ‘Pentecostal central’.
You called that one correctly, same as the delay last March til after their conference was over.
The Hills district being Pentecostal country could well explain that reluctance. Has anyone done any studies on vaccine hesitancy in this group? I suspect this group harbours many Qs & anti vaxers. Morrison’s mob.
I have no objection to the ‘insightful’ statement today from #joshfromaccounts that we have to manage living with COVID-19. What he omitted was that is an option only after the great majority is vaccinated. Wonder why he left that link out.
I suspect the so-called ‘magic’ number exists in the range whereby if an outbreak of Covid spreads in the community the hospitals can keep functioning. It does not mean people won’t die, some will. But, it does mean hospitals are not completely overwhelmed (stretched is fine – it happens now with influenza) and can still treat both Covid and other patients. However, as mentioned already, influenza stretches our hospitals now in winter, what will happen if Covid and influenza align? I trust such risks are part of the modelling.