The Philippines said Friday it had suspended use of a landmark vaccine for the potentially deadly dengue virus after its manufacturer warned it could worsen the disease in some cases.

French pharmaceutical giant Sanofi announced Wednesday that its world-first dengue vaccine could lead to more severe symptoms for people who had not previously been infected.

The Philippines has vaccinated more than 700,000 children with Dengvaxia since 2016 when it became the first country to start using it on a mass scale.

But it said Friday the programme had been suspended.

‘In the light of this new analysis, the DOH (Department of Health) will place the dengue vaccination programme on hold while review and consultation is ongoing with experts, key stakeholders, and the WHO (World Health Organization),’ a government statement said.

Sanofi had initially said its Dengvaxia vaccine was ‘critical’ in the fight against dengue, the world's most common mosquito-borne virus.

It said Wednesday that a new study has confirmed Dengvaxia's benefits for ‘those who had prior infection’.

‘For those not previously infected by dengue virus, however, the analysis found that in the longer term, more cases of severe disease could occur following vaccination upon a subsequent dengue infection,’ Sanofi said.

The Philippine government stressed it had not yet received reports of any problems with Dengvaxia.

‘Currently, there is no reported case of severe dengue infection among those who received the vaccine,’ its statement said.

More than 1,000 people in the Philippines died from dengue last year, out of 211,000 suspected cases, according to the government.