(Larson et al., 2014.) This underscores the importance of empirical evidence from a range of countries, and especially evidence that can illuminate pathways underlying these relationships.

The central findings of the representative phone survey in PNG illustrate the importance of trust in the COVID-19 vaccine and social norms in driving behavior. Less than one in five adults were planning to get the COVID-19 vaccine and the main reason people provided for not wanting to get vaccinated was concerns about side effects. Trusting the COVID-19 vaccine and believing it has important health benefits were positively correlated with people’s willingness to get vaccinated. Similarly, believing others will get vaccinated and encouraging others to get the vaccine were also positively associated with people wanting to get the COVID-19 vaccine. However, there was no clear relationship between other potential explanators of vaccine hesitancy, such as being concerned about COVID-19, people’s most trusted source of information about the COVID-19 vaccine, their history of receiving vaccines for other diseases (for example, measles or polio), and their willingness to be vaccinated. This survey also showed that overwhelmingly the most common way people say they would become more likely to get the COVID-19 vaccine is by hearing from health experts, particularly in the form of face-to-face communication.

The online randomized survey experiment builds on the results of the phone survey by showing that providing a short message about the relative safety of the COVID-19 vaccine (designed with the aim of building trust in the vaccine) substantially increased people’s willingness to get vaccinated. Only 19.3 percent of respondents in the control group (that is, where no intervention was provided) stated they would be willing to get the vaccine, whereas 30.6 percent of respondents that received the relative safety treatment said they would get vaccinated, representing an over 50 percent increase. The two other intervention arms that were provided (referring to expert advice and social norms) did not have a consistent impact on people’s willingness to get vaccinated. The main findings of the online randomized survey experiment did not vary substantially across the demographics of respondents, though female respondents and those in the Southern region were more likely to respond to the social norms treatment. These types of respondents were also less likely to participate in the online experiment relative to the general population. As a result, after population weights were applied (in terms of sex, age and location) the social norms treatment became statistically significant.

By considering the findings of the representative phone survey alongside the online randomized survey experiment, this study provides rich insights into key factors underpinning vaccine hesitancy. Drawing on the combination of the phone survey and the experiment also affords increased ability to assess the generalizability of our results. Both the phone survey and the experiment present very similar descriptive statistics that show there are high levels of COVID-19 vaccine hesitancy in PNG, primarily because of respondents being concerned about side effects from the vaccine, and that people claim health experts are the most likely to be able to change their mind. These patterns hold across the surveys, even though different platforms were used (that is, phone and online) at different points in time, and also hold across most demographic characteristics. As a result, the findings are robust to alternative approaches to weighting (or analyzing the data without survey weights). This suggests that the main findings are likely to hold across the general population in PNG and potentially in other countries facing similar challenges.

There are several implications that flow from our findings for policy makers as they work to address vaccine hesitancy. We provide comprehensive evidence that building greater trust in COVID-19 vaccines 3