WHO urges intensified anti-dengue measures in Dengvaxia areas

The World Health Organization has recommended intensified anti-dengue measures in areas where Dengvaxia had been administered as part of the government's immunization program.

In a statement, WHO also urged that greater access to medical care be given to vaccine recipients who exhibited symptoms of dengue infection.

"To minimize illness for seronegative vaccinated people, WHO recommends enhancing measures that reduce exposure to dengue infection among populations where the vaccine has already been administered," WHO said in its latest statement after the dengue vaccine controversy came to fore in the country.

"For vaccine recipients who present with clinical symptoms compatible with dengue virus infection, access to medical care should be expedited to allow for proper evaluation, identification, and management of severe forms of the disease," it added.

The WHO issued the statement after Sanofi Pasteur, the manufacturer of Dengvaxia, issued an advisory in November that the vaccine should not be administered to those who had not been infected with the dengue virus.

The advisory has caused an uproar among parents who had their children vaccinated against dengue using Dengvaxia.

The government has since pulled the plug on its dengue immunization program that started under the Aquino administration.

President Benigno Aquino III, his health secretary Janette Garin and other members of his Cabinet attended the Senate Blue Ribbon Committee inquiry on the controversy on Thursday.

In its latest statement, the WHO also said that Dengvaxia must only be administered on people previously infected with dengue.

"Following a consultation of the Global Advisory Committee on Vaccine Safety, the World Health Organization (WHO) finds that the dengue vaccine CYD-TDV, sold under the brand name Dengvaxia, prevents disease in the majority of vaccine recipients but it should not be administered to people who have not previously been infected with dengue virus," the WHO said.

The WHO gave the advisory more than a week after it clarified that it had never recommended to countries the introduction of the controversial Dengvaxia vaccine to their immunization program.

The WHO Global Advisory Committee on Vaccine Safety studied data from manufacturer Sanofi Pasteur's clinical trials to give its new recommendation.

According to their study of the data, about four out of every 1,000 vaccinated seronegative patients or people who never had dengue disease prior to vaccination developed severe dengue during the five year observation period of the study.

"Those studies indicate that increased risk of severe dengue disease in people who have never been infected affects about 15% of the vaccinated individuals," the WHO wrote.

Non-vaccinated individuals had a 1.7 per 1,000 risk of developing severe dengue in the same period.

On the other hand, the WHO observed a reduction of four cases of severe dengue per 1,000 vaccinated seropositive individuals or people who had dengue before immunization.

The WHO clarified that it issued a conditional recommendation for the use of the vaccine in seropositive populations in its position paper in July 2016.

It said in the same paper that "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." —NB, GMA News