'When you hear such rumours, you get scared': A comparison of vaccine-related concerns between the oral polio vaccine and Covid-19 vaccines among communities in Cameroon and Ethiopia.

Despite widespread acceptance of the oral polio vaccine (OPV), vaccine hesitancy towards OPV in some countries presents a barrier to global eradication efforts. Between 2021 and 2022, the Global Polio Eradication Initiative implemented OPV campaigns concurrently with the roll-out of Covid-19 vaccines, for which vaccine hesitancy is well-documented. We sought to understand stakeholder perceptions of OPV and Covid-19 vaccines in Cameroon and Ethiopia. We implemented 32 focus group discussions (16 per country) with n = 216 caregivers of children under 5 and polio frontline workers to understand reasons for hesitancy, which included: fear of side effects, fear of vaccine overdosing, religious leaders being against vaccines and a lack of confidence in health workers, among others. These concerns were especially prominent toward the introduction of Covid-19 vaccines, less so toward OPV. Hesitancy reasons were more often reported as a concern held by community members, rather than participants themselves. Despite concerns, 69% of Ethiopian and 57% of Cameroonian respondents had received a Covid-19 vaccine. Our findings suggest a need for continued efforts to listen to caregiver and health worker concerns and co-create local solutions to enhance vaccine acceptability. Building trust amongst populations and addressing commonly held misconceptions is integral to vaccine introduction plans.