Public Perceptions of Ebola Vaccines and Confidence in Health Services to Treat Ebola, Malaria, and Tuberculosis: Findings from a Cross-sectional Household Survey in Uganda, 2020

"Understanding vaccine confidence and trust in health services is...a key part of building successful community engagement strategies aimed at strengthening Ebola preparedness."

Ebola vaccines are a pillar of Ebola virus disease (EVD) prevention and response, but the limited supply of vaccines - and, therefore, access to vaccines - precludes their widespread use. Community engagement strategies must therefore build trust in vaccines despite the ineligibility of most individuals for vaccination during an outbreak. Uganda used Ebola vaccines as part of its preparedness and response during the 2018-2020 tenth EVD outbreak in neighboring Democratic Republic of the Congo (DRC). To guide future risk communication and community engagement (RCCE) strategies in EVD outbreak preparedness and response in Uganda, this study evaluated the public's perceptions of Ebola vaccines and compared their confidence in health services to treat Ebola versus malaria and tuberculosis.

Vaccine confidence is defined here as trust in (i) the effectiveness and safety of vaccines, (ii) the system that delivers them, including the reliability and competence of the health services and health professionals, and (iii) the motivations of policymakers who decide on the need of vaccines. In addition to vaccine confidence, vaccine perceptions and uptake are associated with risk perception of disease, structural and psychological constraints (e.g., vaccine access and convenience), individual cost-benefit calculations, social norms, and collective responsibility to protect others. Confidence in health systems and the services they offer also influence perceptions about vaccines, and vaccine confidence is correlated with confidence in the health system. Research shows that interventions that leverage trust in healthcare systems (e.g., vaccination recommendations from trusted providers) are among the most effective ways to increase vaccine uptake.

Carried out as part of a March 2020 survey on Ebola knowledge, attitudes, and practices (KAP), this cross-sectional household survey was implemented in six districts in Uganda that were classified by the government as at high or low risk for an EVD outbreak. (Notably, most existing evidence on the public perception of Ebola vaccines has been collected in countries involved in the West African Ebola virus epidemic. Perceptions about Ebola vaccines may differ in settings such as Uganda, where outbreaks have historically been less widespread and a smaller proportion of the population may have personal experiences related to EVD.)

Among 3,485 respondents, 18% were aware of Ebola vaccines. Of those, 92% agreed that the vaccines were needed to prevent Ebola. Participants aged 15-24 years were 4% more likely to perceive such need compared to those 60 years and older (adjusted prevalence ratio [aPR] 1.04, 95% confidence interval [CI] 1.0-1.08). The perceived need was 5% lower among participants with at least some secondary education compared to uneducated participants (aPR 0.95; 0.92-0.99).

In terms of awareness, the researchers point out that risk communication materials for the public in Uganda included only basic information about the availability of vaccines to prevent EVD transmission. More detailed information about the importance, efficacy, and safety of vaccines was geared towards healthcare and frontline workers who were eligible for vaccination and was not widespread in communities.

Overall, 81% of those aware of the vaccines believed that everyone or most people in their community would get vaccinated if offered, and 94% said they would likely get vaccinated if offered. Over 75% of participants stated they had no concerns about the Ebola vaccine. Among those who expressed a concern, fear of vaccine side effects was most frequently reported (9%; 95% CI: 7, 11).

Confidence in health services to treat Ebola was lower compared to treating malaria or tuberculosis (55% versus 93% and 77%, respectively). This finding may be reflective of the higher current and historical prevalence of malaria and tuberculosis in Uganda and participants' more recent experiences with health systems for these conditions. However, participants from the EVD high-risk districts were 22% more likely to be confident in health services to treat Ebola compared to those in low-risk districts (aPR: 1.22; 95% CI: 1.08, 1.38). Greater confidence in health services to treat EVD in the high-risk districts may have been influenced by the increased investments in the overall health systems in these high-risk districts as part of outbreak preparedness and response.

Thus, if an Ebola outbreak originates or spills into low-risk districts, RCCE to strengthen public confidence in Ebola treatment services needs to be rapidly scaled up given the current lower baseline confidence compared to the high-risk districts. RCCE messages should describe Ebola Treatment Units (ETUs) and the specific treatment services they provide, emphasising how available services can significantly improve chances of survival if given early.

In conclusion, the findings suggest that public confidence in Ebola vaccines was strong once people had received information about them, which may yield high vaccination uptake in the event of an EVD outbreak. Thus, more work needs to be done to increase public awareness of these vaccines. The public's high confidence in health services to treat other health threats, such as malaria and tuberculosis, offers a building block for strengthening their confidence in health services to treat - and in bolstering trust in vaccines and vaccinators to prevent - EVD in the event of an outbreak.

Full list of authors, with institutional affiliations: Aybüke Koyuncu, CDC; Rosalind J. Carter, CDC; Joseph Musaazi, Makerere University; Apophia Namageyo-Funa, CDC; Victoria M. Carter, CDC; Mohammed Lamorde, Makerere University; Dimitri Prybylski, CDC; Rose Apondi, CDC; Tabley Bakyaita, Uganda Ministry of Health; Amy L. Boore, CDC; Jaco Homsy, CDC and University of California San Francisco; Vance R. Brown, CDC; Joanita Kigozi, Makerere University; Maria Sarah Nabaggala, Makerere University; Vivian Nakate, Makerere University; Emmanuel Nkurunziza, Makerere University; Daniel F. Stowell, CDC; Richard Walwema, Makerere University; Apollo Olowo, Makerere University; Mohamed F. Jalloh, CDC