WHO advice: No dengue, no vaccine
While it prevents dengue fever in the majority of vaccine recipients, Dengvaxia vaccine should not be administered to people who have not previously been exposed to the disease, according to the World Health Organization (WHO).
The health agency issued the advisory on Wednesday following a consultation of its Global Advisory Committee on Vaccine Safety.
“This recommendation is based on new evidence communicated by the vaccine’s manufacturer (Sanofi Pasteur), indicating an increase in incidence of hospitalization and severe illness in vaccinated children never infected with dengue,” the WHO said.
“The WHO Global Advisory Committee on Vaccine Safety considered the company’s new results from clinical trial data analyses,” it added.
The WHO noted that studies indicate that increased risk of severe dengue disease in people who have never been infected affects about 15 percent of the vaccinated individuals.
“The magnitude of risk is in the order of about four out of every 1,000 seronegative patients vaccinated who developed severe dengue disease during five years of observation. The risk of developing severe dengue disease in nonvaccinated individuals has been calculated as 1.7 per 1,000 over the same period of observation,” the WHO said.
“By contrast, for the 85 percent who have had dengue disease before immunization, there is a reduction of four cases of severe dengue per 1,000 who are vaccinated,” it said.
The WHO noted that it had mentioned the possibility of risk for seronegative people and published it in a position paper in July 2016, saying “vaccination may be ineffective or may theoretically even increase the future risk of hospitalized or severe dengue illness in those who are seronegative at the time of first vaccination regardless of age.”
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