Determining Dengue Serostatus by Indirect IgG ELISA Compared to Virus Neutralization Test in a Cohort of Children in Cebu (Philippines) Prior to a Mass Dengue Vaccination

Abstract

Background: Detection of dengue virus (DENV) antibodies is important for understanding future dengue risk and for pre-vaccination screening. We assessed dengue seroprevalence in a cohort of Filipino children and compared a dengue immunoglobulin G indirect enzyme-linked immunosorbent assay (ELISA) with focus reduction neutralization test (FRNT). Methods: We collected 2,996 serum samples from 9 to 14 year old children, just prior to a mass dengue vaccination. Sera were batch tested by ELISA and FRNT. Findings: By FRNT, 320 (10.7%) of the 2,996 were dengue naive, 292 (9.7%) had past primary dengue infection and 2,384 (79.6%) had 2 or more (multitypic) infections. Compared with an FRNT seronegative or seropositive outcome, the ELISA with a 0.9OD cut-off showed 96.8% sensitivity, 96.6% specificity, 3.4% false positivity and 3.2% false negativity. The sensitivity of the IgG ELISA was especially poor (77.1%) among children with immunity to just one DENV serotype. Of the 11 sera that were false positive by ELISA, 7 (63.6%) were seropositive for Zika or Japanese Encephalitis viruses by FRNT. Interpretation: A majority of the cohort were not only DENV seropositive, but had a multitypic response by FRNT indicating past infection by two or more serotypes. While the ELISA had a high sensitivity and specificity, the false-negative and false-positive rates may render the test less than optimal for determining DENV serostatus prior to vaccination. Children with primary immunity to just one serotype would benefit the most from vaccination but the sensitivity of the IgG ELISA was much lower in this group. Trial Registration: ClinicalTrials.gov Identifier: NCT03465254 Funding Statement: Philippine Department of Health, Hanako Foundation, World Health Organization, Swedish International Development Cooperation Agency through the International Vaccine Institute, and University of North Carolina at Chapel Hill. Declaration of Interests: The authors declare no conflicts of interest. Ethics Approval Statement: The protocol was reviewed and approved by the University of the Philippines – Manila Research Ethics Board (UPM-REB). A parent or legal guardian of the participants provided written informed consent.