By Jake Maxwell Watts 

The Philippines suspended a dengue fever vaccine that was given to thousands of children and launched an investigation, after the drug's manufacturer said new evidence showed it could worsen symptoms in some cases.

The tropical country last year became the first nation to widely distribute the vaccine, branded Dengvaxia, after a fast-track approval process. The government says more than 730,000 people, mostly children older than nine, were given the vaccine, manufactured by the vaccinations division of French pharma giant Sanofi SA.

A person can be infected by dengue as many as four times due to the existence of different strains. Subsequent infections are often more severe.

Sanofi said last week new data found the vaccine was effective for people who had already had dengue, but for those who hadn't, "more cases of severe disease could occur following vaccination." The company said it had asked regulators to change the vaccine label to recommend that people don't take the vaccine if they haven't been infected previously.

Dengvaxia was recommended for use by the World Health Organization in April last year. It was the first of its kind, targeting a mosquito-borne disease that afflicts some of the world's poorest countries.

However, a few months later, the WHO noted that the vaccination "may be ineffective or may theoretically increase the future risk of hospitalized or severe dengue illness" in those who haven't had dengue at the time of vaccination.

So far, no deaths or cases of severe dengue have been definitively linked to the vaccine in the Philippines. The government said Monday it had a record of all the children who had received the vaccine, which was approved under the previous administration, and would monitor them for five years for signs of the disease.

The case has quickly turned political, as allies of President Rodrigo Duterte call for an investigation into the vaccine's approval process. Others called for swift action to advise and protect those at risk. "This is our most urgent task. Laxity is not an option. We are racing against time," said opposition Senator Risa Hontiveros.

Philippine Health Secretary Francisco Duque III told local media Monday that the government would assess responsibility for the vaccine, and consider charges against its manufacturer.

Sanofi said it doesn't comment on legal topics, but noted that "the vast majority of those vaccinated to date live in high endemic settings and, therefore, will have had a prior dengue infection before vaccination."

In a statement last week, Sanofi Pasteur, the firm's vaccinations division, said the new analysis of clinical data highlights the complex nature of dengue infection. "We are working with health authorities to ensure that prescribers, vaccinators and patients are fully informed of the new findings, with the goal of enhancing the impact of Dengvaxia in dengue-endemic countries," said Su-Peing Ng, global medical head of Sanofi Pasteur.

Dengue infects about 390 million people a year globally, 96 million of whom require treatment, according to the WHO. Of those, about half a million are admitted to hospital, and 2.5% of all cases are lethal. The virus causes a severe flu-like illness marked by painful joints and extreme fatigue.

Write to Jake Maxwell Watts at jake.watts@wsj.com

 

(END) Dow Jones Newswires

December 04, 2017 07:00 ET (12:00 GMT)

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