The Burden of Vaccine Hesitancy for Routine Immunization in Yaounde-Cameroon: A Cross-sectional Study

"If awareness is raised on the importance of immunization and finding a way to combat misinformation on media, it will go a long way to improve routine immunization uptake in Yaounde-Cameroon."

According to the results of the 2018 demographic and health survey in Cameroon, approximately 10% of children aged 12-23 months had not received any vaccine dose, and only 41.5% of them had received all the required vaccines. In general, vaccination uptake in a population is determined by vaccination service availability and the level of vaccine hesitancy. Concerning vaccination service availability in Cameroon, routine immunisation services are available free of charge at all public and private health facilities and at all the levels of the health pyramid. Thus, it is reasonable to believe that low coverage might be associated more with vaccine hesitancy than unavailability of vaccination services. The objective of this study was to estimate the burden of vaccine hesitancy associated with routine vaccines in Yaoundé, the administrative capital of Cameroon.

According to the Strategic Advisory Group of Experts (SAGE) Working Group on Vaccine Hesitancy, vaccine hesitancy is defined as the delay in acceptance or refusal of vaccination despite the availability of vaccination services. It is complex and context-specific, varying across time, place, and vaccines. There are 2 models of vaccine hesitancy determinants: The 3C model includes 3 determinants (Complacency, Confidence, and Convenience), while the 5C model adds 2 more factors to the 3C model (rational Calculation and Collective responsibility).

A 2-stage cross-sectional cluster survey was conducted in Yaoundé in November 2021, involving 529 parents/guardians of children 0-59 months. Vaccine hesitancy was analysed as proportions of the parent's/guardian's self-reported vaccine refusal or delay in vaccination with 95% confidence interval (CI). These data were stratified by household wealth level and tested using Chi-Square test to appreciate the effect of household wealth on vaccine hesitancy.

The study found that approximately 85% of parents believe that vaccination can protect their children from serious illness. However, vaccine hesitancy was reported in 137 (25.90% [22.35-29.80 CI] of respondents. Oral polio vaccine (OPV) was the most affected vaccine, representing 35.65% and 44.68% of delay and refusal cases, respectively. According to the researchers, the finding about this particular vaccine (OPV) could be explained by the Ministry of Health's recent organisation of many sessions of polio vaccination campaigns over the national territory. This intense effort might have raised questions and suspicion within the population. In Northern Nigeria, polio vaccine refusal was reported to be due to lack of confidence, especially because of "too frequent" campaigns and due to the the false belief that the OPV contains birth control ingredients.

Vaccine hesitancy prevalence did not vary significantly across different households' wealth levels (p-value = 0.3786). However, in wealthy households, refusal of vaccines (14%) was lower than in economically poorer households (20%).

According to the findings, causes of vaccine refusal or delay were numerous, but the most reported causes included the respondent's having heard or read negative information about vaccine on social media (over 40%), the respondent's believing that the vaccine was not needed (over 29%), bad experience with previous vaccination (over 13%), and bad experience with a vaccinator in the past (over 8%). Overall, the findings show that lack of trust and confidence, perceived complacency (e.g., people did not see the need to vaccine their children), and convenience (e.g., few people did not know where to get vaccine) are the leading causes of vaccine hesitancy in Yaoundé.

Framed another way: Of 43% of parents that had received negative information on vaccination, only 55% of them still proceeded to vaccinate their children after the information. On the other hand, only 10% reported that distance, timing of clinic, time needed to get to the clinic or wait at the clinic, and/or costs in getting to the clinic prevented them from getting their children immunised.

Notably, data collection was done in November 2021, approximately 22 months following the onset of COVID-19 in Cameroon and 2 years following the onset of the global pandemic. The ongoing pandemic might have increased vaccine hesitancy, as people were avoiding health facility due to fear of being contaminated, and the controversy about the COVID-19 vaccine might have indirectly affected routine vaccines.

In conclusion: "There is a need for the public health authorities in Yaounde and Cameroon as a whole to design interventions to minimize routine immunization hesitancy thereby improve immunization coverage for EPI. In particular, fighting rumors...and educating mothers on the importance of immunization might go a long way to reduce vaccine hesitancy in Yaounde." The researchers "recommend that the burden of vaccine hesitancy be assessed at national scale and the sources of misinformation causing vaccine hesitancy clearly identified and controlled. Having a clear notion of the effect of social media (Facebook, Instagram, WhatsApp, etc,), radio, TV, and other information sources can better guide interventions to combat their contribution to vaccine hesitancy."