Editorial: Boosters are needed now - and study shows more are likely down the track

The Ministry of Health is urging people to get booster shots before the end of the month. Photo / Michael Craig

The old Nike slogan of "Just do it" could be applied to New Zealand's booster campaign and beyond.

It's looking more likely that people will have to get used to boosters until a second-generation vaccine that is better at preventing infection and maintaining protection is developed.

The original mRNA vaccines provide strong protection against severe Covid-19 outcomes and boosters work like a maintenance service, topping up people's immunity for several months.

But based on real-world data from the US, booster effectiveness wanes. Countries and their populations face the need to "just keep doing it" for the near future.

A study released on Saturday by the US Centres for Disease Control and Prevention on the Pfizer/BioNTech and Moderna mRNA vaccines found both good and not so good news.
Firstly, boosters were highly effective in keeping people out of hospitals during the Omicron surge in the US. They can work in the same way here.

Secondly, the study found that booster effectiveness declined after four months, which suggested the need for extra boosters.

At two months after a booster shot, the vaccine was still 91 per cent effective in preventing a vaccinated person from being hospitalised. After four months, that protection had fallen to 78 per cent — which is still high.

The US study found booster protection waned more in preventing the need for visits to urgent healthcare clinics. It fell from 87 per cent at two months to 66 per cent after four months. More data will come through as the six-month period after a booster nears.

Here, a major push is underway to get boosters into the arms of adults, and second doses for children aged five to 11, before the phased border reopening. More than a million people need a booster by the end of the month to reach the 90 per cent target.

It comes as a record 810 Covid cases were confirmed yesterday. The number of people in hospital has risen to 32.

Boosters for parents will also be important because there has been a delay for more data on shots for kids aged under 5.

Health authorities and governments will have to determine when the best time is for future boosters. In the northern hemisphere, booster campaigns will likely kick in around September to provide protection over winter. Here, current boosters will need to get people through the southern winter.

US Government medical adviser Dr Anthony Fauci said: "There may be the need for yet another boost — in this case, the fourth dose for an individual receiving the mRNA — that could be based on age, as well as underlying conditions."

With the world trying to find a stable and consistent footing in the pandemic, governments will likely take the wider view — that it's best for health systems and economies to have as many people as possible well protected.