Infection with one of four related dengue virus serotypes (DENV-1-4) is thought to result in life-long immunity to re-infection with the same serotype (homotypic DENV re-infection). Archived serum samples, collected as part of an ongoing pediatric dengue cohort study in Nicaragua, were tested for DENV by real-time RT-PCR. Samples were collected from 2,892 children who presented with an acute febrile illness clinically attributed to a non-dengue cause ("C" cases). Test results were added to a database of previously-identified symptomatic dengue cases in the cohort to identify repeat infections. Four patients with homotypic DENV re-infections were identified and confirmed among 29 repeat DENV infections with serotype confirmation (13.8% of repeat symptomatic infections). Homotypic re-infections with DENV-1, -2, and -3 occurred 325-621 days after the initial infection. Each patient experienced one symptomatic dengue case and one DENV-positive C case, and two patients presented with symptomatic dengue during their second infection. These DENV-positive C cases did not elicit long-lived humoral immune responses, despite viremia up to 6.44 log10 copies/mL of serum. We describe the first set of virologically confirmed homotypic DENV re-infections. Such cases challenge the current understanding of DENV immunity and have important implications for modeling DENV transmission.
View details for DOI 10.1093/infdis/jiw099
View details for PubMedID 26984144