As New Zealand inches up the mountain to vaccinate beyond the 80 per cent mark with at least one dose of the Covid-19 vaccine, we are more and more attempting to reach the unwilling.
It is worthwhile then considering who the reluctant are likely to be and what it is that's holding them back.
A study published in the Lancet in August, Covid-19 Vaccine Hesitancy and Acceptance in a Cohort of Diverse New Zealanders, identified key markers.
Kate Prickett and Hanna Habibi from Victoria University and Polly Atatoa Carr from Waikato University collected data in March this year via a web-based survey. The 1284 respondents were a diverse selection of New Zealanders from an earlier social research sampling initiative.
Seventy per cent stated they were likely to take the vaccine once it was available (very likely or somewhat likely). Being younger and less educated correlated with greater vaccine hesitancy risk, those who were very unlikely, somewhat likely, or unsure.
Women surveyed were more likely than men to be unsure and to cite concerns regarding personal health, such as potential side effects, as the obstacle. Men were concerned about trusting vaccines and what they perceived as an exaggerated risk of Covid-19 to them and the population.
Although most intended to take the Covid-19 vaccine once available, a sizeable minority - more likely to be young, female, and less educated - were unsure about or unlikely to get the vaccine, primarily because of worries around unknown future side effects.
The researchers from Victoria and Waikato concluded that about 30 per cent of the population in March were still unsure or unlikely to take the vaccine. They suggested targetted public health promotions should be aimed at increasing confidence in the vaccine for the younger and less educated.
Another interesting finding suggested a public health focus on perceived hesitancy in the Māori and Pacific populations - subgroups particularly at- isk of Covid-19 illness and death - may be misplaced.
"Instead, public health efforts should focus on combating the known inequities in health care access that may increase the risk that vaccine intention among these groups does not translate into uptake."
That is, simply make it easier for these people to get to a vaccination.
One of the many conundrums facing the vaccination push is that talking about hesitancy is also likely to entrench stasis. Jagadish Thaker from the Wellington School of Journalism and Marketing teamed with Arun Subramanian from the School of Computer Science in Hyderabad on a study that found talking about vaccine hesitancy has a similar dissuading effect as outright misinformation.
It's clear some conversations are needed if we are to overcome what might be readily mollified concerns and keeping it positive and focused on the benefits appear most effective.
Studies have also shown "ordinary people" talking about the personal risks of catching the virus and collective benefits of vaccination are comparatively more effective than medical experts communicating such messages.
We are now at Hillary's Step on our climb to safe levels of vaccination. Understanding and helping the hesitant will carry us all further.