Influence of health-facility cold-chain storage logistics and staff capacity on thermo-stability of live-attenuated vaccines in Kisumu-county, Kenya

Abstract

Vaccines are integral in the control of infectious diseases globally. Successful immunization programs require robust cold-chain logistics and efficient service-delivery systems to ensure they remain within recommended temperature range to guarantee their stability and efficacy. In sub-Sahara Africa, approximately 15-20% of vaccine equipment are faulty while transport and electricity infrastructure pose additional challenges. Despite new technologies for tracking vaccine cold-chain performance, resurgences in live attenuated vaccine preventable childhood diseases are still common indicating potential multiplicity of factors. In Kenya, between 2014 and 2016, there were resurgences of measles, rota and, tuberculosis infections mostly in Kisumu County despite over 80% immunization-coverage and investment in new fridges, these implied potentially more complex unmet cold-chain challenges. Drivers of these outbreaks which are only associated with live-attenuated vaccines were still not clear. The current study assessed influence of health-facility cold-chain storage-logistics and staff-capacity on thermo-stability of live-attenuated vaccines. Specifically, it assessed association between: functionality of fridges, cold-boxes; vaccine-carriers and thermo-stability of vaccines; staff compliance with cold-chain guidelines and thermo-stability of vaccines; staff competency in cold-chain management and thermo-stability of vaccines; and staff cold-chain management perceptions and thermo-stability of vaccines. Analytical cross-sectional design with mixed methods techniques was adapted. Qualitative and quantitative site-level data were collected from 120 of 170 health-facilities using questionnaires. Stratified random sampling and convenient were applied through multistage approach. Variable characteristics were summarized descriptively; associations were tested using chi-square and binary logistic regression to identify predictors of vaccines thermostability. Qualitative information were coded, categorized and thematically analyzed to identify evolving perspectives through N-Vivo software. Overall fully-functional cold-chain storage logistic were 44.5% (95%C.I, 0.074-0.366; OR 0.165, p<0.001); functional-fridges, 64.2% (95%C.I, 1.332-6.370; OR, 2.913; p=0.007) and vaccine-carriers, 37.5% (95%C.I, 1.462 -6.884; OR 3.172; p=0.003), all associated and predicted thermo-stability of vaccines. Overallcompliance to Cold-chain guideline, 40% (95% C.I, 0.001-0.025; OR, 6.021; p<0.001); use of VVM to dispense vaccine, 42% (95%C.I, 0.645-6.787; OR, 2.085; p=0.022); monitored temperature twice daily, 69% (95%CI, 0.052-0.651; OR, 0.185; p=0.009), were all associated and predicted thermo-stability of vaccines; however, orderly arrangement of vaccines, 49%(95%C.I, 0.000-0.025; value,8.520;p=0.004) was only associated. Competency on vaccines-transfer when fridges were faulty, 53.3%(95%C.I, 0.955-7.397; OR, 2.658; p=0.031); and use of VVM stages to dispense vaccines, 55.8%(95%C.I, 0.127-0.988; OR, 3.540; p=0.047) were associated and predicted outcome of vaccines thermo-stability; conversely overall-competency 67% was not, similar to overall perception, 61.7%, except for perception on vaccines transfer,75%(95%C.I, 0.682-5.847; OR, 1.997; p=0.007); otherwise, perception on vaccines arrangement, 61.7%(95%C.I, 0.890-9.821; value, 7.023; p=0.030), was only associated. Vaccines at substantial private-facilities were at a higher-risk of thermo-instability due to marked lapses in compliance and in-adequate support supervision. Live-attenuated vaccines comparatively showed higher level of thermo-instability except for BCG hinting the notion that associates them with occasional outbreaks of vaccines preventable child-hood illnesses. There is need for KEPI managers to strengthen support supervision and extend provision of WHO recommended fridges to private facilities.