The Global Prevalence of HTLV-1 and HTLV-2 Infections among Immigrants and Refugees-A Systematic Review and Meta-Analysis

Abstract

This is the first systematic review and meta-analysis to estimate the prevalence of human T-lymphotropic virus 1 and 2 (HTLV-1 and 2) infections among immigrants and refugees worldwide. PubMed/MEDLINE, Scopus, EMBASE, Web of Science, and Virtual Health Library (VHL) databases were searched for studies published from their inception to 6 January 2023. A meta-analysis using a generalized linear mixed model with a random effect was performed for HTLV-1 and HTLV-2. Subgroup analyses were performed based on the decade of study, sample size, confirmatory methods, region of study, risk group, and region of origin. Of the 381 studies initially identified, 21 were included. The pooled prevalence of HTLV-1 and HTLV-2 was 1.28% (95% CI: 0.58, 2.81) and 0.11% (95% CI: 0.04, 0.33), respectively. HTLV-1 prevalence differed significantly by region of origin, with the highest prevalence among those from the Western Pacific Region (7.27%; 95% CI: 2.94, 16.83). The subgroup analysis also showed significant differences between the estimates of HTLV-1 considering the decade of study, sample size, and region of study. For HTLV-2, significant differences were shown in relation to sample size, confirmatory methods, and risk group. The higher HTLV-1 prevalence found deserves public health attention in immigrant and refugee-receiving non-endemic countries.

Keywords: HTLV-1; HTLV-2; immigrant; meta-analysis; prevalence; refugee; systematic review.

Figure 1

PRISMA flow diagram.

Figure 2

Forest plot of the prevalence of HTLV-1 infection among immigrants and refugees [46,47,48,49,50,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67].

Figure 3

Forest plot of the prevalence of HTLV-2 infection among immigrants and refugees [46,47,48,49,50,52,53,54,55,56,62,63,64].