Dengue vaccine found to worsen disease symptoms

Story highlights

  • The Philippines has halted a massive dengue fever vaccination effort
  • The country has launched an investigation into the approval of Dengvaxia

(CNN)The Philippines has suspended its large-scale dengue vaccination effort amid the surprising results of a new study conducted by the vaccine's manufacturer.

On Wednesday, French pharmaceutical giant Sanofi Pasteur published clinical trial data showing that its dengue vaccine, Dengvaxia, could have unintended consequences in patients who had never been infected with the mosquito-borne virus.
    "The analysis confirmed that Dengvaxia provides persistent (protective) benefit against dengue fever in those who had prior infection," Sanofi said in a statement. "For those not previously infected by dengue virus, however, the analysis found that in the longer term, more cases of severe disease could occur following vaccination upon a subsequent dengue infection."
      New dengue vaccine could instead cause more cases, experts warn