The Philippines has ordered a probe into the immunisation of more than 730,000 children with a vaccine for dengue that has been suspended after a French drug company announced it could worsen the disease.
A non-governmental organisation in the Philippines said it had received information that three children who were vaccinated with Dengvaxia in April 2016 had died, but pharmaceutical firm Sanofi said no deaths had been reported as a result of the program.
"As far as we know, as far as we are made aware, there are no reported deaths that are related to dengue vaccination," Ruby Dizon, medical director at Sanofi Pasteur Philippines, told a news conference in Manila.
Last week, the Philippines' Department of Health halted the use of Dengvaxia after Sanofi said it must be strictly limited due to evidence it can worsen the disease in people not previously exposed to the infection.
In a statement Sanofi explained the "new findings" but said the long-term safety evaluation of the vaccines showed significantly fewer hospitalisations due to dengue in vaccinated people over nine years old compared with those who had not been vaccinated.
Nearly 734,000 children aged nine and over in the Philippines have received one dose of the vaccine as part of a program that cost 3.5 billion pesos ($A97.36 million).
The Department of Justice on Monday ordered the National Bureau of Investigation (NBI) to look into "the alleged danger to public health ... and if evidence so warrants, to file appropriate charges thereon."
There was no indication that Philippines health officials knew of any risks when they administered the vaccination.
A spokesman for Philippines President Rodrigo Duterte said the government would hold to account those responsible for a program that had placed thousands of lives at risk.
"We will leave no stone unturned in making those responsible for this shameless public health scam which puts hundreds of thousands of young lives at risk accountable," spokesman Harry Roque said in a statement.
