4.3). The impact of the relative safety treatment remains of a similar magnitude as those presented in Section 5.3.2 as this treatment had similar effects across respondents with different demographic characteristics (see Figure A19 in Appendix A). In contrast, the impact of the social norms treatment becomes substantially larger and is now statistically significant. This is primarily because female respondents and those in the Southern region were under-sampled in the online experiment and the weights corrected for this. Similar results hold after controlling for the background characteristics of respondents (see Table A8 in Appendix A).

# **6. Discussion and conclusion**

In this section we first outline the areas that our findings suggest policy makers should and should not prioritize to address COVID-19 vaccine hesitancy. We follow this with a broader discussion on the generalizability of the results and areas for further research.

# <u>6.1 Issues to focus on to address vaccine hesitancy</u>

Our study highlights three key areas for policy makers to prioritize as they attempt to reduce vaccine hesitancy. Firstly, it provides comprehensive evidence that boosting people’s trust in COVID-19 vaccines appears to be a fundamental step in increasing people’s willingness to get vaccinated. The phone survey showed strong correlations between willingness to get vaccinated and trust in the vaccine as well as believing it has important health benefits. The online experiment illustrates that information about the relative safety of COVID-19 vaccines substantially increases willingness to get vaccinated and reduces opposition to receiving the vaccine. Collectively, these results suggest that many people make some form of basic “cost benefit analysis” about whether the consequences of COVID-19 justify the risk of being vaccinated. Further evidence that this is the case can be seen by the fact that respondents who believed many people had died from COVID-19 in PNG were much more likely to want to get the vaccine (see Figure A20 in Appendix A). The implication for policy makers from this is that they should prioritize efforts to inform the general population that COVID-19 vaccines can be effective at preventing severe illness, there are very low risks of developing negative side effects and becoming ill with COVID-19 results in a non-trivial chance of death for those who are unvaccinated.

Importantly, unlike much of the existing work based on other vaccines and coming from studies in highincome countries (for example, see Dai et al., 2021), the information treatment used in the relative safety treatment was clearly effective in reducing COVID-19 vaccine hesitancy. This is good news. It suggests that at least some of the apprehension about COVID-19 vaccines present in PNG stems simply from the fact that people do not feel they know enough about the new vaccine, as opposed to entrenched “anti-vaccination” positions of the sort found in other countries. As a result, it may prove feasible to shift people’s views on COVID-19 vaccines in Papua New Guinea.

Secondly, the importance of social norms in shaping people’s willingness to be vaccinated is reaffirmed by the findings of the phone survey. The phone survey illustrated that most people who were willing to be vaccinated believed their family and friends would also be vaccinated. People intending to be vaccinated were also likely to recommend vaccination to others. Those who were not willing to be vaccinated did not think their family and friends would either. At present it appears that PNG is in a lowlevel equilibrium whereby few people are willing to get vaccinated, partly because few people are willing to get vaccinated. Vaccine hesitancy and supply are interrelated through this mechanism, which highlights the need to pair communications with other policies that will encourage vaccine take-up, in 23