A retrospective review of vaccine wastage and associated risk factors in the Littoral Region of Cameroon during 2016-2017

Abstract Background Immunization is an effective preventive health intervention. In Cameroon, the Expanded Program on Immunization (EPI) aims to vaccinate children under five years of age for free, but vaccination coverage has consistently remained below the national target. Vaccines are distributed based on the target population size, factoring in wastage norms. However, vaccine wastage rates (VWR) may differ among various settings. Our study aimed to assess vaccine wastage for different site settings, seasonality, and vaccine types in comparison to vaccination coverage in order to provide comprehensive insights on vaccine wastage. Methods A retrospective data collection and analysis was conducted on the immunization and vaccine wastage data in the Littoral Region of Cameroon during the period of 2016 and 2017. Health districts were classified as urban or rural, seasonality was categorized as rainy or dry season, and vaccine types were grouped into liquid, lyophilized, oral, and injectable vaccines. The VWR and vaccination coverage rates (VCR) were calculated, and the vaccine waste factor was investigated. Results The VWR of Bacillus Calmette-Guérin (32.19%) was the highest, followed by measles and rubella (19.05%) and yellow fever (18.34%) among all EPI vaccines in the Littoral Region of Cameroon during 2016 and 2017. Single-dose vaccine vials exhibited lower VWR than multi-dose vials. Dry season was associated with higher VWR for most vaccines though more lyophilized vaccines (BCG, MR, YF vaccines) were wasted in rainy season in 2016. VWR was persistently higher in rural than urban health districts. The months of February and November saw a decrease in VCR. The study found an overall negative correlation between VCR and VWR. Conclusions Multiple factors may cause wastage of EPI vaccines in Cameroon. Vaccination area characteristics, seasonality, types of vaccines such as multi- or single-dose, lyophilized or injectable vaccines are related to VWR in Littoral Region. Further research on vaccine wastage and vaccination coverage across Cameroon is needed to better understand the socio-behavioural aspect of vaccine in-take that may affect the level of vaccination and vaccine wastage. Public health system strengthening is warranted to adapt more real-time monitoring of VWR and VCR for each vaccine in the government’s immunization programs.