Higher vaccination rates may reduce need for hard lockdowns, Covid-19 modeller says

A Covid-19 modeller would like vaccination rates "into the high 90s" by March when the border is potentially partially opened, but acknowledges that may not be realistic.

The government yesterday revealed its plan to open the borders from early 2022 on a risk-based approach, and also announced it was accelerating the vaccine rollout, including for the 16 and over bracket as soon as 1 September.

University of Auckland Covid-19 modeller and professor of physics Shaun Hendy told Morning Report he would like vaccination rates including children, not just 16-year-olds and over - "into the into the high 90s" by March.

"That would be great. It's probably not realistic, so maybe we're looking at something like 70 to 80 percent."

"You know, once we get start to get to say 60 to 70 percent coverage across the [entire] population then our options start to open up in terms of maybe not having to use a very hard lockdown."

"At the moment to control the Delta variant, we'd have to go to something like a level 4 lockdown.

"Once we get to 60 to 70 percent coverage, maybe we can be looking at a level 3 lock down if there's an outbreak and once we get higher - 80 to 90 percent - it's possible that we won't need lockdowns to control outbreaks."

Another part of the government plan is a trial later this year of home isolation for travellers returning from overseas.

Hendy said that 60 to 70 percent vaccination rate would also be needed to ensure the risks of any home self isolation plans were managed.

"It's going to very much depend on the size of that trial and what kind of vaccination rates we've actually reached by the time we're rolling out that trial... I think you know as we get further through that vaccination program, trials like the [home isolation] that's being proposed become more feasible...

"Home isolation [in the past] it did actually have an effect. It wasn't perfect, but if you combine that with rapid tests, some of which can be done at home, but perhaps have a PCR test at the end of that period, then actually you can manage the risks."

Secondary Principals' Association of New Zealand president Vaughan Couillault told Morning Report it was encouraging that 16-year-olds and over would be able to access the vaccine from 1 September.

"You know the greater the number of our population that can get access to the vaccine as soon as possible the better we will all be.

The idea for using schools as a platform for delivering vaccines has been floated, and Couillault said there was precedent for vaccinations being delivered at schools.

"In the past ... we've supported the measles immunisation programme, TB immunisation programme, going back in time a bit more, the polio vaccination programme.

"So schools in the past have been used as vaccination centres and if the call came out I don't see any reason why we wouldn't be able to help with the logistics of doing it again."

Asked at what point of vaccination rate he would be happy with pupils going to school with the border open, Couillault said "that's an interesting conversation that is yet to be had, [we have] been sort of dipping our toes in that water with the measles outbreak that we had recently in New Zealand where individual centres or schools were making decisions around whether or not it was safe to attend based on your immunisation status, so we do have precedent for that as well, but that conversation in New Zealand schools has not occurred yet.

"In my personal view, the greater number of our population that is vaccinated the better and the faster the better, but that discussion about whether it is safe or not to go to school, and an unvaccinated state, we'd have to have that debate as a society and decide whether human rights are being impinged or whether there was health orders and all of that stuff so that is a complicated tale."