Washington (AFP) - A dengue vaccine candidate by French drugmaker Sanofi protects more than three quarters of participants, an analysis found Monday.
The experimental drug allowed 80.8 percent of children aged nine and older to avoid hospitalization, according to three trials analyzed by the New England Journal of Medicine.
For younger children, those less than nine years old, vaccine efficacy was 56.1 percent.
For severe dengue, the vaccine protected 93.2 percent of participants aged nine to 16, and 44.5 percent of the younger set.
The researchers also noted an unexplained increase in hospitalizations for dengue fever during the third year of vaccination for the younger children.
This trend should be "carefully monitored during long-term follow-up," the study said.
But overall, the researchers noted a "reduction in dengue disease in the efficacy surveillance phase among children who received the vaccine" in regions where the disease is endemic.
"The dengue vaccine candidate has the potential to significantly reduce disease burden in endemic countries," Sanofi said in a statement.
The data analyzed referred to three clinical trials with 10,275 participants, 20,869 participants and 4,002 participants respectively.
The trials were conducted in Asian-Pacific and Latin American tropical and subptropical regions.
Dengue has grown more prevalent since the 1950s, with 50 million cases annually, including 500,000 of dengue hemorrhagic fever, which the World Health Organization estimates kills in more than 20 percent of cases.
The disease is still rare in non-tropical regions.