Age stratified dengue seroprevalence in Fiji:Findings from a national serosurvey — The Association Specialists
  1. Schedule
  2. Oral Presentations - Conversation starters - Communicable diseases
  3. Age stratified dengue seroprevalence in Fiji:Findings from a national serosurvey

Age stratified dengue seroprevalence in Fiji:Findings from a national serosurvey (23938)

Anaseini Ratu 1 , Isireli Koroituku 2 , Venina Naigulevu 2 , Naina Cagi 2 , Karin Leder 1 , Joelle Rosser 3 , Philip C Hill 2 , Katherine L Anders 1
  1. Infectious Disease Epidemiology, Monash University, Melbourne, Victoria, Australia
  2. Communicable Disease Research Centre, Fiji Institute of Pacific Health Research, Fiji National University, Suva, Fiji
  3. Stanford University, Stanford, California, United States

Background: Dengue control in Pacific countries requires robust burden estimates including age-stratified seroprevalence estimates to assess risk distribution and evaluate interventions. Fiji is a large Pacific country and regional hub where dengue is endemic and large outbreaks regularly occur. Samples from a national, age-stratified serological survey conducted in Fiji in 2023–2024 were used to evaluate age stratified dengue seroprevalence in Fiji.

Methods: Residual sera from two national population-based SARS-CoV-2 serosurveys conducted January–May 2023 and June–August 2024 were used. Participants were selected across all four medical divisions. Dengue IgG was measured using an indirect ELISA, and analyses applied survey weights to determine weighted seroprevalence and 95% confidence intervals by age, sex, ethnicity, urban/rural residence and division. Survey-weighted logistic regression was performed separately for participants aged <20 and ≥20 years to examine predictors of seropositivity.

Results: Results from 2,054 samples found dengue seroprevalence was 89.2% (95% CI 87.5–90.8) overall and increased with age group, from 29% in children aged 0–4 years to 96% in adults ≥40 years. Seroprevalence did not differ by sex but was higher among non-indigenous Fijians than iTaukei (93.9% vs 88.0; p=0.016) and among urban versus rural residents (92.1% vs 84.7; p<0.001). Seroprevalence varied by division (p<0.001), being highest in the Western division (92.1%) and lowest in the Eastern division (76.6%). Among children under 10 years dengue seropositivity was higher in rural than urban areas of the Central, Western and Eastern divisions. Seroprevalence at 9 years exceeded the 60% threshold recommended for dengue vaccine introduction in the Western division only.

Conclusion: Dengue exposure in Fiji is high and transmission intensity is heterogeneous, with notably higher recent exposure in the Western division. There is evidence of higher levels of recent exposure amongst rural children suggesting a shift in urban-rural risk distribution from those previously reported.