Seroprevalence and trends in transfusion transmissible infections among voluntary non-remunerated blood donors at the Malawi Blood Transfusion Service-a time trend study

Introduction
Collecting blood from voluntary non-remunerated blood donors from low risk populations is a key strategy for blood safety. Identifying such populations involves analysis of population and blood donor data to identify risk factors for transfusion transmissible infections (TTIs). There are no recent seroprevalence statistics for blood donors in Malawi. This study fills this gap by describing characteristics of blood donors, trend of annual prevalence of HIV, HBV, HCV and syphilis and factors associated with each TTI.
Methods
Retrospective analysis of blood donors’ records in the MBTS database from 2011 to 2015 was undertaken. Summary statistics were performed to describe characteristics of the blood donors. Univariable and multivariable logistic regression analyses were performed to determine association between prevalence of infections and socio-demographic factors. Time trend analysis was done to assess changes in prevalence. P-value <0.05 was considered statistically significant.
Results
The number of blood donors screened over the 5 year period was 125,893. The mean number of donors donating blood per year was 39, 289; median age was 19 years; 82% were male, 87% single and 72% students and56% were repeat blood donors. Overall prevalence of each TTI decreased. The 2015 prevalence was: 3.6% for HBV; 1.9% for HIV; 2.6% for Syphilis and 1.0% for HCV while the 2011 prevalence was 4.7% for HBV; 3.5% for HIV 3.2% for syphilis and 2.4% for HCV.
Repeat blood donors had significantly lower prevalence of TTIs than first time donors. Females were associated with lower risk for HBV, HCV and syphilis. Age ≥25 years and being out of school were associated with HIV. Age ≥25 years was associated with reduced risk for HCV and being self-employed and married were each associated with syphilis.
Conclusion
The typical blood donor is a young single male student. Repeat blood donation improves safety of the blood supply. .

Keywords
Transfusion transmissible infections (TTIS); voluntary non remunerated blood donors (VNRBDs); HIV; Hepatitis B (HBV); Hepatitis C (HCV); Syphilis; family replacement blood donors (FRBDs)