Originally posted by the Dengue Vaccine Initiative.

Today, the World Health Organization (WHO) published in the Weekly Epidemiological Record its first Position Paper on a dengue vaccine, based on the available evidence of CYD-TDV or Dengvaxia®, the only dengue vaccine to have received regulatory approval. Starting in December of 2015, Dengvaxia® has been approved by the regulatory authorities of Mexicothe Philippines, Brazil, El Salvador, Paraguay and Costa Rica. WHO recommends that countries should consider introduction of the dengue vaccine Dengvaxia® only in geographic settings (national or subnational) where epidemiological data indicate a high burden of disease. Read more WHO recommendations here.

The WHO’s position papers seek to provide guidance to countries on health policy matters, such as vaccines against diseases that have an international public health impact. They are intended for use primarily by national public health officials, managers of immunization programs and national dengue control programs. The papers have been reviewed by external experts and WHO staff, and are reviewed and endorsed by the WHO Strategic Advisory Group of Experts on Immunization (SAGE), which on April 15, 2016, issued recommendations on the use of Dengvaxia®.

Dengue vaccines have been under development since the 1940s, but due to the limited appreciation of the global burden of dengue, interest languished for much of the 20th century. However, recent years have seen a dramatic increase in dengue vaccine progress. Today several vaccine candidates are undergoing clinical development, some of which are in advanced stages. 

Some key recommendations found in the publication:

  • Countries should consider introduction of Dengvaxia® only in geographic settings (national or subnational) where epidemiological data indicate a high burden of disease.
  • Dengue vaccine introduction should be a part of a comprehensive dengue control strategy, including well-executed and sustained vector control, evidence-based best practices for clinical care for all patients with dengue illness, and strong dengue surveillance.
  • Dengue surveillance globally should be strengthened, particularly in the context of emerging infections with clinical similarities to dengue and in areas of the world for which data are scarce or absent. 

About Dengvaxia®
Dengvaxia® is a prophylactic, tetravalent, live attenuated (recombinant) viral vaccine. The vaccination schedule consists of 3 injections of 0.5 mL administered at 6-month intervals. The vaccine is indicated for individuals 9-45 years or 9-60 years of age (depending on the license), living in dengue-endemic areas. Based on two Phase 3 trials, the pooled estimate for vaccine efficacy against virologically-confirmed dengue illness of any serotype in the 25 months post-dose 1 (ITT) was 60.3% (95% CI 55.7%-64.5%). Vaccine efficacy varied by infecting serotype, previous exposure to dengue, age (which is correlated with previous exposure) and severity.

During the course of the hospital-based surveillance, a signal emerged from the youngest age group (2-5 years, not included in the indicated age range), for which there was an increased risk of hospitalised dengue in the third year after the first dose (RR of 7.5 (95% CI 1.2-313.8)). During year 4 and year 5, the RRs diminished. The reason for this increased risk in the youngest clinical trial participants in unknown, although hypotheses have been suggested.

Further reading