Dengue seroprevalence and transfusion risk in three regions of viral circulation in Argentina: a cross-sectional study.

Flichman, Diego Martín; Lema, José Martín; Pereson, Matías Javier; Espíndola, Sonia Lorena; Agote, Felicitas; Albrecht, Andrés; Alter, Adriana; Anhel, Susana et al. · Lancet Reg Health Am · 2026

cross_sectional · Level IV

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Abstract

Historically, multiple dengue virus (DENV) outbreaks have been recorded in Argentina. Although some regional studies exist, information remains fragmented and predates the two largest epidemics, underscoring the need for updated estimates. This study aimed to determine anti-DENV IgG seroprevalence among blood donors and evaluate the risk of transfusion-transmitted infection. Two blood donor surveys in three regions of Argentina were conducted in 2023 (N = 3000) and 2025 (N = 2443). Anti-DENV IgG antibodies were detected using a commercial ELISA. In 2023, DENV-RNA was additionally assessed by RT-PCR. A total of 5443 adult donors were included (median age 37 years (IQR 29-46); 44% women). In 2023, IgG seroprevalence was 693/3000 (23·1%; 95% CI 21·6-24·7), with regional heterogeneity (13·8-42·0%). Donors >56 years had the highest prevalence (31·8%; p = 0·010). Sex differences were significant: 19·7% in women versus 25·9% in men (p < 0·0001). By 2025, seroprevalence reached 516/2443 (50·6%; 95% CI 48·6-52·6), corresponding to ∼10·2 million new infections compared with 575,000 officially reported cases (∼5·6% ascertainment). Estimates varied substantially across provinces, ranging from 24·2% to 78·8%, with the Northwestern region most affected. Age and sex differences were no longer significant. Nucleic acid testing in 2023 identified DENV-RNA in five donors (0·17%), all from Tucumán, where prevalence reached 2·52% (5/198). Rising seroprevalence among blood donors from urban and peri-urban areas of central, northwest, and northeast Argentina suggests expansion of DENV in these regions. Strengthened surveillance, vector control, vaccination strategies, and targeted donor screening are critical to mitigate epidemic impact and transfusion-related complications. This research received financial support from TAKEDA Argentina S.A. as part of an Investigator-Initiated Study (code: IISR-2024-200504), with Federico Alejandro Di Lello as the grant recipient. Additional support was provided by grant UBACyT N°20020220100115BA from the Universidad de Buenos Aires (UBA), Buenos Aires, Argentina, and by Fundación René Barón. Some reagents for nucleic acid detection were kindly provided by altona Diagnostics.