If enough people are vaccinated, we reach herd immunity, or population immunity. At that point, any Covid outbreaks will naturally die out. But even if we don’t reach population immunity, every jab counts.
New Zealand’s next Covid hurdle could be a year of outbreaks as border restrictions ease.
That’s what medical minds at a vaccine forum at the University of Waikato thought when asked about the scenario given that vaccination rates are unlikely to reach herd or population immunity levels.
Broadly speaking, 2020 was the year of Covid and 2021 is the year of vaccination, said Waikato DHB medical officer of health Richard Hoskins, who was in the audience.
“These are gross oversimplifications, but I believe 2022 onwards is going to be the year of outbreaks in Aotearoa,” he said.
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“We’re going to be deploying our traditional tools and new ones to keep those outbreaks as small as possible and protect as many people as possible.”
Recent data suggests New Zealand won’t be able to vaccinate enough people to achieve herd immunity – a point at which enough people are immune to the virus to stop it circulating.
The vaccine forum on Monday night was organised by the University of Waikato Student Health Service: Hauora Ākonga and the Waikato University Chaplaincy, to answer people’s questions as the vaccine rollout continues.
Political pressure to reopen the border will mount, University of Waikato population health professor Ross Lawrenson said, but vaccination levels will play into the decision.
Even if everyone’s had the chance for vaccination, it won’t reach 95 per cent, Lawrenson said.
“So the reality is, Covid is going to come into the country. People will be infected and some will die from Covid.”
The Government hasn’t yet decided how to manage Covid after the vaccine, but Covid-19 Response Minister Chris Hipkins said the UK decision to end legal requirements for masks and social distancing and reconcile itself to more deaths would be unacceptable here.
Hipkins favoured incremental change, he said.
About 444,500 people in New Zealand have had two doses of the Covid vaccine, according to Ministry of Health data, and another 705,000 have had the first.
But we’re unlikely to get 97 per cent of New Zealanders vaccinated and reach herd immunity for the newer, more easily spread Covid variants, recent modelling from Te Pūnaha Matatini suggests.
The maximum possible is about 85 per cent – that’s excluding children 12 and under, for whom the Pfizer vaccine isn’t approved, but not taking into account people who can’t or won’t have vaccination.
Still, hospitalisations and deaths will “massively reduce” at 75 per cent vaccination, Te Pūnaha Matatini principal investigator professor Michael Plank has previously told Stuff.
“There will still be potential for outbreaks and significant demand on the health system, but it would be more likely to be manageable.”
The “awful reality” is that people who can’t get or choose not to get the vaccine will be vulnerable when international travellers can enter freely, Waikato University student health GP Dr Steven Lillis said.
“We’re going to have a pretty substantial bit of our health system, into the future, dealing with Covid.”
It wouldn’t be ethical to open the border before everyone who wants a vaccine has had one, said Dr John Kleinsman from the Nathaniel Centre for Bioethics.
“It doesn’t give us total immunity from catching the virus but it does lessen the health consequences. So, for me, that would be an important marker from an ethical perspective.
“I think there will be some consequences for people who decide not to have [the vaccine] … I’m not quite sure what that looks like.”
And borders won’t be shut one day and open to the world the next, Waikato DHB’s Hoskins said.
Instead, it’s more likely to be progressive – for example, with isolation requirements for countries with lots of Covid cases and poor control, but open travel for countries that have control of the virus.
Vaccine passports – such as for yellow fever – are likely, Lawrenson said.
“They’re going to say not only have you had your vaccine, but which one did you have.”
The Ministry of Health responded to queries with a statement, saying changes to border restrictions would happen in stages, when it is safe.
“Towards the end of the year, when the science is clearer and the vaccination rollout has reached all groups, things will be much clearer on the way forward.
“It’s important to stress also that as well as getting as many people as possible vaccinated, we’ll keep using standard public health controls to stamp out outbreaks as long as Covid-19 remains a global threat,” the statement said.
Controlled opening of the borders has already started, with quarantine-free travel with Australia, Cook Islands and Niue.
“Professor Sir David Skegg’s group is working on options to advise the Government on the safest way to open up to other countries.”