New Zealand has begun to roll out its Covid-19 vaccination programme, starting with those working at the border, including in the Managed Isolation and Quarantine (MIQ) facilities.

There have been calls for prioritising other groups such as those in South Auckland, meat industry workers, and the National Ethics Advisory Committee has released a final report on Resource Allocation and Covid-19 that includes a section on vaccine prioritisation. The Government has also developed a Covid-19 Vaccine Strategy but without any detailed prioritisation.

Broadly speaking, there are two benefits to vaccination: protection of the individual and protection of the community (by reducing the risk of transmission and of reducing the risk of outbreaks that overload the health system). It is important to keep in mind that the vaccine is less than 100 percent effective at preventing infection; we do not know what effect it has on asymptomatic transmission of the virus, and it is plausible that a new strain of the virus will develop which the current vaccines do not prevent.

Prioritisation for vaccination is not the same for all settings. The UK approached this with urgency and expedited the approval of vaccines because of the very high incidence of Covid-19 in the UK. Their priorities are as follows:

  1. Residents in care homes
  2. Everyone 80 and over and front-line health workers
  3. People aged 75 and over
  4. People aged 70 and over and clinically vulnerable
  5. People aged 65 and over
  6. People aged 16-64 with underlying health conditions
  7. People aged 60 and over
  8. People aged 55 and over
  9. People aged 50 and over.

They will then presumably offer vaccines to the rest of the UK population to reach “herd immunity” with the hope that the epidemic in the UK will be controlled.

In New Zealand, given we continue to be able to control cases at the border and do not end up with endemic disease, our priorities need to be different. We have started with vaccinating border workers in settings such as MIQ facilities, followed by vaccinating their whānau.

The argument for vaccinating the family of frontline workers is not that they are especially vulnerable, but that by doing this – given it is the border where the risk of disease importation exists – we lessen the likelihood of a community outbreak. As we have seen, the process of managed isolation and quarantine has worked well enough for us to have mostly been without restrictions, but it cannot be perfect.

However, any breach of the MIQ border is made less likely the more of the “bubble” of those exposed to the virus are covered. If all the people who come into contact with those infected by the pandemic virus are vaccinated, and their contacts and the people in their communities are vaccinated, then it is less and less likely that we will have community spread from a border control failure. Even though the vaccine is not perfect, this will be mitigated by immunising the bigger ‘bubble’. New Zealand priorities should therefore be:

  1. Any border or health worker likely to be exposed to cases of Covid-19, either already diagnosed or asymptomatic (including those doing testing)
  2. Family members of these workers
  3. The communities within which these workers live.

We should then vaccinate the rest of the community with the aim of reaching high enough numbers in New Zealand overall and in every community to mean that we could lift the requirement for quarantine on entry to New Zealand without there being a risk of community spread.

One risk of vaccinating is that those who have been vaccinated may believe they are immune when they are not and be less vigilant with PPE, distancing and QR scanning. This means that when we do start vaccinating, it is imperative we have as strong a border control as possible.

We should be looking at the vaccine as a tool to strengthen our already considerable ability to prevent community spread arising from border control failures. Whilst in other countries, vaccination is being used as a tool to provide protection to individuals, until herd immunity is achieved, by itself it cannot provide the level of protection we have achieved by border controls using a population approach.

Given the rationale and list above, the South Auckland community should be vaccinated as soon as the border workers and their families are vaccinated. However, the meat workers should be vaccinated along with the rest of the population unless they are in communities around the MIQ facilities or international airports or ports.

Dr Ben Gray is an Associate Professor in the Department of Primary Health Care and General Practice at the University of Otago, Wellington.

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