Herd Immunity Cannot Be Delivered Threatening The NZ Covid-19 Elimination Strategy

The present Government vaccination plan and rollout plans will not deliver

population immunity – ‘aka’ herd immunity.

There are three factors that stand in the way of population immunity and any future relaxation of border controls. These are vaccine hesitancy & vaccine skepticism, children under 16 years old not being vaccinated, and to a lesser extent vaccine ineffectiveness. These factors effectively mean approximately half of our entire population will not be immune after the full rollout of the COVID-19 vaccination. This effectively will stop our borders from opening.

The end game of the NZ elimination strategy relies on effective treatments and/or a vaccine to support the strategy’s pillars; of border controls, detection/surveillance, contact tracing and quarantine. It inherently assumes that these controls cannot be relaxed until there is a majority of Kiwis who are immune through vaccination. The Government has publicly implied it has assumed this will happen by the end 2021.

Vaccine hesitancy & Vaccine skepticism - 30-36%

A number of New Zealand surveys show more than 1 in 3 Kiwi’s hesitant or skeptical about getting a Covid-19. At present our surveys are similar to those in Australia showing a figure of about 36% in these two categories. These NZ and Australian figures may now be higher with the recent high-profile news on the AstraZeneca’s vaccine and the reported rare adverse reaction of blood clots.

Children under 16 years old not being vaccinated - 20%

Presently the Government vaccine strategy has no plans to vaccinate children, one fifth or 20% of the population. To date there are no vaccines approved for children under 16-years-old. While trials are well underway their results and approvals in NZ are sometime away. Recently, AstraZeneca paused its trial on children while the blood clot issue is further researched in adults. At the time of writing Pfizer/BioNTech was applying to the Food and Drug Administration for emergency use to expand the existing authorisation to permit it's use in children ages 12 to 15.

If and when childhood COVID-19 vaccinations are approved in New Zealand there is undoubtedly going to be a greater degree of vaccine hesitancy and skepticism in this younger cohort. Parents may be less willing to consent to their children being vaccinated than themselves.

Vaccine ineffectiveness – 0.5% (Pfizer/BioNTech)

Trials have shown the Pfizer/bioNTech vaccine to be 95% effective leaving 0.5% with ineffective immunity after being vaccinated. While this is a highly effective vaccine against COVID-19, it still allows for a small proportion of the vaccinated population vulnerable to infection. For New Zealand this would mean a quarter of a million of our 5,000,000 million people (if they were all vaccinated) to remain susceptible after vaccination. It is important to note that other vaccines that NZ is considering generally have lower efficacy rates than Pfizer/BioNTech.

These three factors add up to large deductions to our goal of population immunity

These three factors create deductions against the population’s COVID-19 collective immunity. Thus, our path to herd immunity is not straight forward. We need to reach a population immunity of approximately 70-85% before this protective phenomenon will form a population defense. This figure is an approximation, the exact percentages are not known for the COVID-19 virus and it’s variants. Viruses have different population immunity percentages based on unique characteristics and behaviors of each virus. Based on the above assumptions we are already in deficit by a minimum of 50% of the population that could potentially have gained immunity from vaccination but did not or could not.

Nearly all of NZ’s population immunity will need to be generated from vaccinations. We will be very reliant on our vaccination programmes to create a herd immunity much more than other countries that have had much higher levels of ‘wild’ COVID-19 virus infections in both adults and children. In these jurisdictions a significant proportion of individual immunity was inferred from higher per capita community infections. This means we will need to vaccinate more Kiwis due to our very low community infection rates to reach population immunity. Paradoxically, due to NZ successful elimination strategy we will need to convince more vaccine hesitants & sceptics and children to get vaccinated than other countries whose hesitants & sceptics and children may have already been inadvertently inoculated in the community.

A likely scenario for the vaccination rollout would be 70% of the 5 million population receive the two jabs. This allows for 30% declining the vaccination leaving a remaining 3.5 million immunized. From this, a deduction for children (20%) and vaccine failures (0.05%) is required bringing down the total with immunity to 2.66 million which is 53% of the total population. This figure is well below what is required for population immunity.

Even if we assume that in the future, when childhood vaccinations are approved, if half of all children under 16 years-old are vaccinated then the percent immune in the total population improves to 60%, still barely adequate for population immunity. To get up to 77% immune, necessary for herd immunity, the country would need to vaccinate 90% of the entire population including 10% of children. To get anywhere near herd immunity, we would have to recruit as many hesitants & sceptics as possible to get the jabs, leaving those declining vaccination limited to about half a million people or 10% of the NZ population.

It seems the Director General of Health Dr Bloomfield has also done similar calculations as he recently said his‘personal goal is 90 per cent’ of the country vaccinated by the end of 2021. What is very clear is that for NZ to reach herd immunity a massive and sustained effort is required to convince the vast majority of people in our country to get vaccinated

The difficult path to population immunity

Getting to population immunity is the only way that NZ border controls can begin to be relaxed. Therefore, a robust and world class vaccination rollout plan and implementation is essential to the success of the New Zealand elimination strategy for COVID-19. This requires very high-quality plan that is benchmarked and tested, is nationally consistent and well communicated to health providers and the public.

By now all this should have already been in place or at least the bulk of the strategy firmed up. Unfortunately, this is not the case. For example, now a year into the pandemic, many DHBs are still doing their core planning, with 20 DHBs there are inconstancies between DHB plans and execution. The pace of vaccinations is slower than planned, in fact, NZ is one of the slowest vaccinators in the OECD. In the seven weeks since we began only around 20,000 individuals have received the full two-dose immunization. This equates to just 400 per day that have reached their full immune potential. While the rate will increase with time, it is a very slow start, putting NZ in catch-up mode at the start line.

Slow rollouts, mediocre communications, lack of data transparency allow misinformation and conspiracy theories to fill the vacuum. Critically, communications to hesitants & sceptics must be coordinated, targeted, and choreographed to local audiences. This is vital to the entire NZ COVID-19 response. If those who decline vaccinations get into the 30 - 35% range NZ will struggle to ever reach herd immunity especially if children or a significant proportion of them are excluded.

Leadership - up the tempo

It is time for our leaders; political, official, religious, unions, corporate and community to strongly lead with emphatic messages for all Kiwi’s to get vaccinated. Messages need to go beyond just moderate encouragement occasionally embellished with selfies posed with needle-in-arm jabs. The language needs to be clear, precise and motivating.

The leader’s statements need to sound more like this:

“to protect you, your family and our country, I as a leader, strongly urge you to get vaccinated. It is safe. It is highly effective. Please roll up your sleeves”

Our leaders need to put their own personal conviction into their messaging and make it a self-replicating meme. Like this one:

“But if there's one message to cut through to everyone in this country, it's this: the vaccines are safe. Please, for yourself, your family, your community, this country take, the vaccine when it's your turn and available…...it’s your patriotic duty.”

President Joe Biden February 2021

To reiterate, encouragement to get vaccinated, on its own, is not enough. Prime Minister Adern, COVID-19 Minister Hipkins, Minister of Health Little, Director General Bloomfield respectfully up the tempo. Next time you’re on camera lean in towards the lens and clearly tell us, truly urge us, strongly motivate us to get vaccinated for COVIS-19. The NZ elimination strategy depends on it.

Marcus Livingstone

Director of Reform Strategy

The Health Reformist

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