With Covid-19 case numbers on the rise, should we be concerned that so many New Zealanders still aren’t eligible for a second vaccine booster? Charlotte Muru-Lanning asks the experts.

It’s easy to start feeling as though the Covid-19 pandemic should be discussed entirely in the past-tense. Over the last six months, the government has steadily rolled back almost all Covid-19 response measures that were once in place. The traffic light system is kaput. Managed isolation is gone. Scanning in and contact tracing is a thing of the past. Masks are encouraged, but no longer mandatory outside healthcare settings and as a result are scarcely seen anymore. 

The numbers

The numbers tell a different story though. There were 4,282 daily Covid-19 cases reported yesterday – a number 9.4% higher than the previous Tuesday. The last time cases were in the 4,000s was mid-August, as the country descended from a major winter wave. There were also 56 deaths over the last week attributed to Covid-19, 15 more than the week prior. The Ministry of Health has said it expected the current wave of infections to keep rising, with modelling showing cases over summer could peak up to over 11,000 cases a day and 100 hospital admissions a day.

Among these rising case numbers and with a large part of our response to Covid-19 now hinged on vaccine needles, some have begun questioning whether we need to expand our eligibility access to secondary boosters, along with accessing more up to date boosters. 

The current booster rules

Currently, only people the Ministry of Health describe as at risk of severe illness from Covid-19 are recommended to receive a second booster. That includes:

• People aged 65 and over 
• Residents of aged care and disability care facilities 
• Severely immunocompromised people who have already received four doses 
• People aged 16 and over with certain comorbidities, disabilities or medical conditions. 

The secondary booster is also available for anyone aged 50 and over, along with health, aged care and disability workers who are aged 30 and over. It was also announced yesterday at the first Covid-19 press briefing in two months that Māori and Pacific peoples 40 years and over are now eligible for the second booster.

The official recommendations

In August, the Ministry of Health’s vaccine technical advisory group recommended against allowing over-30s to get a second booster. At the time, it wrote that “the available data in this age group suggests that the impact of a second booster dose on infection, transmission and maintenance of healthcare capacity is likely to be limited”.

According to reporting by 1News, there remains no plan to launch an annual Covid-19 vaccine booster, but health officials are actively considering whether to expand access to second Covid-19 boosters. At yesterday’s press conference Ministry of Health chief science advisor Dr Ian Town said the focus of boosters had been on those at greater risk. 

Why do we need a second booster?

“Some viruses, we remember forever, and some viruses, we forget really quickly, whether it’s through vaccination or natural infection,” virologist Dr Natalie Netzler told The Spinoff. The reason boosters are useful is because “the Covid-19 virus is one of those viruses that our body would naturally forget quite quickly.” Infection offers some protection, but vaccination and boosters offer even better protection, Netzler explains. The main reason for this is that you don’t have to get sick, and expose yourself to the risks that infection comes with to gain protection. 

Second shots of the booster are more widely available overseas. In Australia, for example, over-30s have been eligible for a fourth dose since July. When expanding eligibility, Australian health officials said those in the younger age bracket can choose “to reduce their risk of infection” but added that it would likely only have a “limited” overall impact on population-wide transmission. 

At this stage, Netzler says the evidence shows that, “a full course of two shots and the booster for anyone under 50 or anyone that’s generally healthy, is actually the best protection”. For those who are young and healthy, “additional boosters don’t seem to be adding anything at this stage”. 

Many people outside the eligibility criteria will have had their booster near the start of the year. Within this group some of those will have been infected more than six months ago, or in some cases, not at all. “There is evidence that your immune system would have started to forget it,” says Netzler. “But it’s very unlikely that you would think that you would need hospital if you’re young and healthy and you’ve had that vaccine course”.

The case for more boosters

Cellular immunologist Anna Brooks says, “anyone under 50, who was boosted such a long time ago, and has not been infected, is absolutely a sitting duck right now if they get exposed, because their immune system hasn’t been revived since January.” A secondary booster “would absolutely help their immunity”. The booster isn’t a fix-all though, she explains. That’s because “immunity does not stop infection”. 

Brooks has concerns that there’s not enough awareness around the risk of long-term impacts of Covid-19 which include long-Covid, strokes, heart attacks and blood clots. “The vaccines do not prevent infection,” she says. “And every single person who gets infected, has a risk of long term impacts.” She points to the reintroduction of masking in Queensland and believes there’s a need for strengthening other public health measures like ventilation, masking and the bivalent vaccine on our shores. 

Where are bivalent vaccines?

Last month, Pfizer made an application to Medsafe for approval of its BA.4/BA.5 bivalent Covid-19 vaccine. However, Stuff reported at the time that clinical data to support the application is not expected to be available until “later this year at the earliest” and there was no update on the bivalent vaccine at yesterday’s press conference. Already, Australia, the UK and the US have approved the bivalent vaccines. “It does make total sense that any vaccine that we have against any virus would include the latest version of that virus or the latest variant,” says Netzler.

“The international data shows that it looks like those bivalent vaccines will make a difference and protect us well.”