Evaluation of a new point-of-care test to determine prior dengue infection for potential use in pre-vaccination screening.

OBJECTIVE:Vaccination with the first licensed dengue vaccine is recommended only for those who have had previous infection with dengue virus (DENV). A point-of-care test with the desired sensitivity of 95% and specificity of 98% could facilitate pre-vaccination screening. We evaluated a newly developed, automated dengue immunoglobulin fluorescence immunoassay for determining dengue serostatus. METHODS:We used serum samples collected just prior to a mass dengue vaccination in Cebu, Philippines. Healthy children residing in Bogo and Balamban who would be 9-14 years old at the time of the mass dengue vaccination were eligible to participate. We evaluated the ichroma™ II dengue fluorescence immunoassay (Boditech Med Incorporated, Gang-won-do, Republic of Korea) using a neutralization test (NT) as the reference assay. RESULTS:We enrolled 2996 children (mean age 10.39 years, 51.7% female) in the cohort and included a subsample of 1000 (mean age 10.56 years, 54.4% female) in this study. Of the 1000 children, 86/1000 (8.6%) tested seronegative and 914/1000 (91.4%) seropositive for DENV antibodies by neutralization testing. Compared with the NT, the dengue IgG fluorescence immunoassay had an overall specificity of 90.7% (95%CI: 82.5-95.9%) and a sensitivity of 91.8% (95%CI: 89.8-93.5%) for determining dengue seropositivity. The sensitivity declined to 51.2% (42.3-61.0%) for the detection of the subset with a monotypic dengue profile. CONCLUSION:The insufficient specificity and sensitivity (particularly in the detection of a previous monotypic dengue infection) would render the test, in its current state, inadequate for pre-vaccination screening. Considering its user-friendly interphase and possibility of point-of-care use, the test could be further developed and validated to improve its performance characteristics.