Seropositivity of Transfusion-Transmissible Infections Among Blood Donors in the Eastern Zone of Tanzania During the Early COVID-19 Period: A Cross-Sectional Analysis

Background Transfusion-transmissible infections (TTIs), such as human immunodeficiency virus (HIV), hepatitis B virus (HBV), hepatitis C virus (HCV) and syphilis, remain critical threats to blood safety in many low and middle-income countries. The COVID-19 pandemic has disrupted blood donation activities globally, raising concerns about its impact on donor screening outcomes. This study assessed TTI seropositivity among blood donors in the Eastern Zone of Tanzania during the early COVID-19 period. Methods A retrospective cross-sectional analysis was conducted using donor records collected between January and July 2020 at the Eastern Zone of the Blood Transfusion Centre. Screening adhered to the national and WHO-recommended algorithms using chemiluminescent immunoassays. Donor characteristics and TTI prevalence were summarized descriptively. Logistic regression was used to identify factors associated with HBV seropositivity, as hepatitis B had the highest prevalence and sufficient event counts to support stable multivariable analysis compared with other TTIs. Results Among 16,767 donors with complete records, 1,774 (10.7%) tested positive for at least one TTI. HBV was the most frequent infection (897, 5.4%), followed by syphilis (453, 2.7%), HIV (311, 1.9%), and HCV (207, 1.2%). Coinfections were rare: HBV-HIV (35, 0.21%), HBV-syphilis (27, 0.16%), and HBV-HCV (15, 0.09%). Blood collection volumes decreased sharply in April-May 2020 but recovered by July. Monthly HBV and TTI seroprevalence showed stable descriptive trends (4.1-6.1%), with no apparent increase during low-donation months. Independent predictors of HBV seropositivity included male sex (AOR 1.7, 95% CI 1.4-2.3) and age 30-39 years (AOR 3.2, 95% CI 2.1-4.8). Conclusion Despite disruptions in blood collection, TTI seroprevalence remained stable during the early COVID-19 period, suggesting resilience in donor selection and screening procedures. Strengthening donor recruitment and maintaining rigorous laboratory screening remain essential to safeguard the blood supply in Tanzania.