In the 13-country international study, health care workers and the local health system were consistently found to be the most trusted source of guidance about COVID-19 vaccination (Solís Arce et al., 2021, p. 1386). Although no equivalent question was asked in the Africa study, responses to a question about who should be responsible for approving the vaccine point to comparatively high levels of trust in health care workers (Africa CDC, 2021, p. 12). One further finding from the Africa study is particularly notable: social media was a common source of information on COVID-19 in many of the surveyed countries, and using social media as a source of information was associated with increased vaccine hesitancy and an increased likelihood of believing vaccine-related conspiracy theories (Africa CDC, 2021, p. 14).

# <u>2.2 Changing vaccine preferences</u>

Some approaches that have been shown to increase vaccine uptake, such as mandates and incentive schemes (Dubé et al., 2015; Eskola et al., 2014) are beyond the scope of this research. Other approaches, on the other hand, like campaigns designed to provide people with accurate information about COVID-19 vaccines are more feasible for PNG with the support of government and development partners. Moreover, existing studies of people’s knowledge of COVID-19 vaccines in PNG point to a clear knowledge deficit and a desire to learn more (Fox, 2021; Pogo et al., 2021).

Although complex schemas have been developed of the factors that may potentially influence people’s views of vaccines (Brewer et al., 2017), one clear division in potential approaches to changing views noted in the literature is between information on the safety of vaccines and the risks of illness, and information that emphasizes community norms favoring vaccine uptake (Palm et al., 2021).

Observational studies provide good grounds for anticipating information on vaccine safety and disease risk to be effective in reducing vaccine hesitancy. In line with the findings from developing countries on attitudes to COVID-19 vaccines outlined above, a common finding in much work on attitudes to vaccinations is that people’s reluctance to be vaccinated stems in part from fear of vaccines or their perceived side effects (Brewer et al., 2017; Kang et al., 2017; Karlsson et al., 2021). Similarly, a common finding in observational studies is that when people perceive an illness to be more threatening, and the vaccine efficacious in reducing that threat, they are more willing to be vaccinated (Karlsson et al., 2021; Palm et al., 2021).

Although observational studies provide evidence that information on the relative risk of vaccines and diseases will increase people’s willingness to be vaccinated, experimental studies have returned mixed results. Positive treatment effects have been found in some studies (for example, Palm et al., 2021), other experiments have failed to find clear evidence of the efficacy of information treatments (Brewer et al., 2017; Dubé et al., 2015), while some studies have found adverse effects, at least in certain groups (Nyhan and Reifler, 2015; Nyhan et al., 2014).

Broader non-vaccine-related work in social science suggests that beliefs about social norms, and in particular beliefs about what most other people are doing, will be an effective means of changing vaccine attitudes. Norms have been found to shape human actions and interactions in many ways (Tankard and Paluck, 2016). And there is some evidence from earlier vaccine work suggesting that norms are important in influencing views, although their potential use as a tool for increasing vaccine uptake remains a comparatively new research area (Brewer et al., 2017; Dubé et al., 2015). One of the few currently published experimental papers on attitudes to COVID-19 vaccines finds that in the United 6