Population‐based prevalence of human T‐lymphotropic virus type 1 in sub‐Saharan Africa: a systematic review and meta‐analysis

Background Human T-cell lymphotropic virus type 1 (HTLV-1), the causative agent of adult T-cell leukaemia/lymphoma (ATL) and HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP), is endemic in sub-Saharan Africa (SSA) and poses a high morbidity and mortality risk. Its prevalence in the general population is poorly understood. The potential for prevention motivated us to do a systematic review and meta-analysis of population-based studies to estimate the prevalence of HTLV-1 in SSA. Methods A comprehensive, no-limit search was conducted in EMBASE, PubMed, Web of Science and the Cochrane Library from their inception dates to March 2019. Population-based studies presenting data on HTLV-1 in sub-Saharan Africa were included. Pooled prevalence was estimated using a random-effects meta-analysis. Results A total of 21 studies were included, representing 42 297 participants. The pooled HTLV-1 seroprevalence was 3.19% (95% CI 2.36-4.12%) with variations across year of study. Prevalence of HTLV-1 positively correlated with year of study (beta = 0.0036, P = 0.007). Participants from Central, Western and Southern Africa had a seroprevalence of 4.16% (95% CI 2.43-6.31%), 2.66% (95% CI 1.80-3.68%) and 1.56% (95% CI 0.48-3.15%), respectively. Conclusions Our findings suggest that HTLV-1 infection is a public health concern in SSA and highlight the need to implement effective preventive programmes and interventions aimed at reducing the burden of this common yet neglected infection.