Periods of high dengue transmission defined by rainfall do not impact efficacy of dengue vaccine in regions of endemic disease.

Source:   PLoS ONE 2018 . 13 ( 12 ) : e0207878 . doi: 10.1371/journal.pone.0207878 . 2018 12 13
PMID: 30543657
DOI: 10.1371/journal.pone.0207878



To evaluate the association of rainy season with overall dengue disease incidence and with the efficacy of the Sanofi Pasteur recombinant, live, attenuated, tetravalent vaccine (CYD-TDV) in two randomized, controlled multicenter phase III clinical trials in Asia and Latin America.


Rainy seasons were defined for each study site using climatological information from the World Meteorological Organization. The dengue attack rate in the placebo group for each study month was calculated as the number of symptomatic, virologically-confirmed dengue events in a given month divided by the number of participants at risk in the same month. Time-dependent Cox proportional hazard models were used to test whether rainy season was associated with dengue disease and whether it modified vaccine efficacy in each of the two trials and in both of the trials combined.


Rainy season, country, and age were all significantly associated with dengue disease in both studies. Vaccine efficacy did not change during the rainy season in any of the analyses.


Although dengue transmission and exposure are expected to increase during the rainy season, our results indicate that CYD-TDV vaccine efficacy remains constant throughout the year in endemic regions.

Author information
  1. Université de Bordeaux, INSERM U1219 Bordeaux Population Health center, INRIA SISTM, Bordeaux, France.
  2. Vaccine Research Institute, Creteil, France.
  3. ENS Cachan, Université Paris-Saclay, Cachan, France.
  4. Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America.
  5. University of Washington, Seattle, Washington, United States of America.
  6. Sanofi Pasteur, Marcy L'Etoile, France.
  7. Sanofi Pasteur, Singapore, Singapore.
  8. Vaccine Trial Centre and Department of Clinical Tropical Medicine, Faculty of Tropical Medicine, Mahidol University, Nakorn Pratum, Thailand.
  9. Research Institute for Tropical Medicine, Alabang, Muntinlupa City, Philippines.
  10. Fundación Santa Fe de Bogotá, Bogotá, Colombia.
  11. Sanofi Pasteur, Bogotá, Colombia.
Full Text links:
Subscribe to our Newsletter

Subscribe now to receive latest newsletter in your inbox