The Philippines on Friday put on hold its dengue immunisation programme, the world's first, after new findings by the vaccine manufacturer that severe cases of dengue can occur in the longer term among those vaccinated without prior infection.

Philippines Health Secretary Francisco Duque III said further recommendation will be released on December 12 or 13 by the Strategic Advisory Group of Experts on immunisation, an advisory body of the World Health Organisation (WHO).

More than 730,000 public school children aged 9 and above in three highly endemic Philippine regions have received at least the first dose of Dengvaxia, the first licensed dengue vaccine manufactured by France-based Sanofi Pasteur.

The Department of Health launched last year its $69.5 million public dengue immunisation drive the world's first such programme.

Sanofi said on Wednesday that an analysis based on up to six years of clinical data showed that in the longer term, more cases of severe dengue can occur following vaccination among people who have not had previous dengue infection.

It said it will ask health authorities to update information provided to physicians and patients.

The analysis confirmed Dengvaxia provides persistent protective benefit in those who had prior infection, Sanofi said.

For those who were not previously infected by the dengue virus, the analysis found that vaccination prevented severe illness for at least 30 months, Duque told reporters.

People who catch dengue more than once can be at risk of a hemorrhagic version of the disease.

The mosquito-spread disease is found in tropical and sub-tropical climates worldwide. It causes a flu-like disease that can cause joint pain, nausea, vomiting and a rash. In severe cases, dengue can cause breathing problems, haemorrhaging and organ failure.

The WHO says that about half the world's population is at risk of dengue and estimates that about 96 million people are sickened by the viral infection every year.

Duque said there are currently no reports of severe dengue infection among those vaccinated. He did not say whether legal action will be taken pending conclusion of a review he has ordered of the contract and other documents on the Dengvaxia immunisation.

Duque said the government will profile all those who received the vaccination and heighten its surveillance mechanisms. That will include mandatory history taking of those vaccinated, mandatory reporting of all hospitalised vaccine recipients regardless of symptoms and 5 years of post-vaccination surveillance.

Khristine Estrada-Cabanayan, a Sanofi spokeswoman in the Philippines, said the company is working closely with the Department of Health and will release a statement to address concerns regarding the vaccine.