Randomised Experimental Evaluation of a Social Media Campaign to Promote COVID-19 Vaccination in Nigeria

"Overall, these experiments provide further support for the social media campaign's effectiveness in promoting COVID-19 vaccination and the related psychosocial predictors of vaccination, with noted limitations."

Social and behavioural research has explored challenges in both the supply and demand for vaccination, including both COVID-19 and other routine vaccinations, in low- and middle-income countries (LMICs). One insight to emerge from that research is that demonstrating the benefits of vaccination and overcoming false and misleading information through influential messaging leveraging positive role models who promote a pro-vaccination norm via widely available and used channels such as social media are potentially powerful avenues to increase vaccine uptake. This paper reports on two randomised experimental evaluations of social media content designed to promote COVID-19 vaccination and to complement a previous quasi-experimental study on a nationwide vaccination promotion campaign in Nigeria run in 2022 (see Related Summaries, below).

Briefly, the social media campaign attempted to reach healthcare providers (HCPs) and their communities who were unsure or delaying getting vaccinated. It was designed and delivered by an independent team of creative designers and local organisations in Nigeria who curated social media content, customised it to specific geographical areas within the country, and delivered it on Facebook and Instagram. The campaign designers iterated a series of social media content focused on promoting pro-vaccination social norms and reducing vaccine hesitancy using social influencers (individuals such as local celebrities, other HCPs, religious and business leaders, and others who would be respected and trusted by the audience). Content consisted of graphics, videos, and other social media materials such as graphic interface format (GIF) images.

In this study, the researchers used two criteria to select social media content to use in the randomised experiments: (i) the posts with the highest Facebook/Instagram engagement statistics (greatest number of impressions and other activity such as likes and comments), where impressions were defined as the number of viewings of a social media post by a study participant, and (ii) the campaign design team's judgment as to which posts most closely aligned with the intended thematic content (the theory of change, or ToC) of the campaign. The campaign design team provided the data that the researchers used to select the posts with the highest engagement statistics. They used content specific to the first campaign that ran in January to February 2022 in the first randomised experiment, and content specific to the second campaign from May to September 2022 in the second randomised experiment.

The researchers conducted the two studies in March and August 2022 among Nigerians drawn from 31 states who had not been reached by the aforementioned nationwide campaign. They randomised the participants to either receive the pro-vaccination social media campaign or not and collected data at pre- and post-test time points to evaluate psychosocial predictors of vaccination and vaccination outcomes following the ToC, which was based on Diffusion of Innovations, Social Norms Theory, and the Motivation, Opportunity, Ability (MOA) framework. Data were collected through a novel intervention delivery and data collection platform through social media.

Overall, this study partially confirmed findings from the previous, nationwide quasi-experimental evaluation of the Nigerian COVID-19 vaccination social media campaign. The researchers found evidence that pro-vaccination social norms increased among the treatment group in study 1, confirming the hypothesis that the nationwide evaluation findings would be replicated in a randomised experiment. They also found evidence that vaccine hesitancy was reduced among the treatment group in study 1, which was not observed in the nationwide study. Finally, they found some directional evidence approaching, but not reaching statistical significance, for an increase in COVID-19 vaccination rates among the treatment group in study 2.

The finding that pro-vaccination social norms may be impacted by a COVID-19 vaccination social media campaign is noteworthy in terms of the mechanism of change. As discussed in the previous study (at Related Summaries, below), future research on social media vaccination campaigns should explore the mechanisms by which social norms are changed and how they influence vaccination outcomes. The reach and scale of social media may create a widespread sense that vaccination is what most of one's peers are doing and that it is widely socially accepted. The researchers argue that the mechanisms by which social media influences vaccination social norms also deserve further experimental research. In particular, HCPs served as pro-vaccination role models in the social media content, which should be further explored as a mechanism for reducing hesitancy and improving vaccination social norms.

Other recommendations for future research include employing RCT designs to evaluate social media health promotion in other settings and topics. Further development and evaluation of outcomes measures used here, including vaccine hesitancy and social norms, should also be done in the future. Finally, evaluation of the campaign ToC should be conducted through formal mediation analysis (structural equation modelling).

In conclusion: "Social media campaigns are a promising approach to increasing vaccination at scale in LMICs, while social norms are an important factor in promoting vaccination, which is consistent with the Social Norms Theory. This study demonstrates the capability and potential of new social media-based data collection techniques."