MANILA (Reuters) - The Philippines will seek the return of 3 billion pesos ($59 million) it paid French drugmaker Sanofi for a dengue vaccine used to immunize hundreds of thousands of children that Sanofi has said could worsen the disease in some cases.

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“We will demand the refund of the 3 billion (pesos) paid for the Dengvaxia and (demand) that Sanofi set up an indemnification fund to cover the hospitalization and medical treatment of all children who might have severe dengue,” Health Secretary Francisco Duque told reporters on Friday.

The Philippines last week suspended a national immunization program after Sanofi’s recent findings that there was a risk of severe dengue occurring in previously uninfected people who were inoculated with Dengvaxia. Manila also halted sale of the vaccine in the country and has ordered a probe into the matter.

Duque said the number of children, ages 9 and above, inoculated with Dengvaxia has risen to about 830,000 from an initial estimate of nearly 734,000 after further verification by the Department of Health.

The state program, which was launched in 2016, cost 3.5 billion pesos and Duque earlier said the government has already paid 3 billion pesos to Sanofi.

Sanofi’s Philippines office did not immediately respond to a request for comment.

Sanofi officials said on Monday in Manila that there had been no reported deaths related to the vaccine.

Duque, citing the drugmaker’s disclosure and studies, said Dengvaxia was meant to provide 30-month protection against dengue to those vaccinated, including those who did not have any prior dengue infection.

But he said the case of a 12-year old girl in Tarlac province, north of the capital Manila, who completed the three-dose vaccine treatment and showed symptoms of severe dengue, seemed to have defied that.

She was first inoculated with Dengvaxia in March 2016 and received the third and last dose in August this year, the health minister said.

Asked whether the case showed the effectiveness of the vaccine was questionable, Duque said: “Most certainly.”

Dengue is a mosquito-borne tropical disease that kills about 20,000 people a year and infects hundreds of millions.