New dengue vaccine could instead cause more cases, experts warn

Story highlights

  • The Dengvaxia vaccine has been licensed for use in six countries
  • A study warns that it could increase cases of severe dengue if used in low-burden areas

(CNN)This may go against what typically comes to mind when you think about vaccines, but the newly licensed vaccine against the dengue virus -- trade name Dengvaxia -- could lead to an increase in the number of cases of the disease if not implemented correctly, experts warn in a new study.

The number of people affected by dengue has increased in recent years, with 390 million people estimated to be infected each year, and cases of the disease have become more global -- with cases reported in more than 100 countries worldwide.

    The long road to a vaccine

      Dengvaxia was produced by Sanofi Pasteur, which, after spending 20 years developing the vaccine, published promising findings on its effectiveness in 2015. Trials showed the vaccine to be 59.2% effective against dengue when results were pooled across populations and age groups, though this varied when looking at the type of dengue, the age of those receiving the vaccine and whether people had been previously infected.