Age-Specific Seroprevalence of Dengue IgG Antibodies Among Children, Adolescents, and Young Adults in North India: A Cross-Sectional Study.

Background Dengue is a major mosquito-borne viral infection in India, with substantial underestimation of the true infection burden due to asymptomatic and subclinical cases. Seroprevalence studies provide a more reliable estimate of cumulative exposure and population-level immunity. Limited data are available comparing age-specific seroprevalence across late childhood, adolescence, and early adulthood within the same population. This study aimed to determine dengue IgG seroprevalence among children, adolescents, and young adults in a tertiary care setting in North India and to assess its association with selected sociodemographic factors. Methods A cross-sectional study with prospective enrollment of participants was conducted from March 2019 to February 2022 after institutional ethics approval. A total of 240 apparently healthy participants aged nine to 30 years were enrolled consecutively and stratified into children (nine to 12 years; n=75), adolescents (15 to 18 years; n=75), and adults (25 to 30 years; n=90). Demographic data were collected using a pre-structured proforma. Serum IgG antibodies against dengue virus (DENV-1 to DENV-4) were detected using the Panbio Dengue IgG indirect enzyme-linked immunosorbent assay (ELISA) (Abbott Panbio Diagnostics, Brisbane, Australia). Seropositivity was defined as Panbio Units (PU) >11. Statistical analysis was performed using SPSS version 25.0 (IBM Corp., Armonk, NY, USA). Chi-square test and one-way ANOVA were applied where appropriate, with p<0.05 considered significant. Results The mean age of participants was 18.72 ± 6.93 years. Of the 240 individuals enrolled, 129 (53.8%) were male and 111 (46.3%) were female; 127 (52.9%) resided in rural areas and 113 (47.1%) in urban areas. Overall dengue IgG seropositivity was 51.2% (123/240; 95% CI: 44.9%-57.5%). Age-wise seroprevalence was 37.3% (95% CI: 26.4%-48.2%) among children, 62.7% (95% CI: 51.8%-73.6%) among adolescents, and 53.3% (95% CI: 43.0%-63.6%) among adults. Mean IgG titers differed significantly across age groups (F(2,237)=5.98, p=0.003), with the highest levels observed in adolescents (24.33 ± 19.52 PU), followed by adults (18.44 ± 18.21 PU) and children (13.83 ± 18.26 PU). In bivariate analysis, age group (χ²=9.88, p=0.007) and residence (χ²=8.23, p=0.004) were significantly associated with seropositivity. Urban participants showed higher seroprevalence than rural participants (61.1% vs. 42.5%). Gender (χ²=0.08, p=0.773) and socioeconomic class (χ²=1.10, p=0.578) were not significantly associated. On multivariable analysis, children had lower odds of seropositivity compared to adults (adjusted OR 0.45; 95% CI: 0.23-0.87; p=0.018), while urban residence remained independently associated with higher seropositivity (adjusted OR 2.16; 95% CI: 1.26-3.69; p=0.005). Conclusion This study demonstrates a high dengue IgG seroprevalence (51.2%) among individuals aged nine to 30 years in North India, indicating substantial cumulative exposure. Seroprevalence varied significantly across age groups, with adolescents showing the highest exposure and children having significantly lower adjusted odds compared to adults. Urban residence was independently associated with higher seropositivity, suggesting intensified transmission in urban settings. These findings highlight ongoing dengue transmission and emphasize the need for age-stratified surveillance, strengthened vector control, and context-specific vaccination strategies in endemic regions.