Singapore

Dengue vaccine risk raised

Healthcare professionals here have been issued advisories on a dengue vaccine which could be harmful to people not previously infected by the virus.

The Health Sciences Authority (HSA) said all healthcare professionals here have been issued advisories on the vaccine Dengvaxia, in a response to queries from The Straits Times yesterday.

The authority added it will further strengthen the warnings and recommendations in the prescribing information of the vaccine, as well as closely monitor it to ensure its continued safety and efficacy.

The vaccine's manufacturer, French pharmaceutical giant Sanofi Pasteur, said Dengvaxia was found to have a possible harmful effect when used on people who did not previously have dengue.

Those who were vaccinated and later became infected could have "more cases of severe disease", Sanofi said in an alert earlier this month.

When asked, the HSA said there was one report of a male patient who developed a rash three days after being vaccinated but he has since recovered.

It has received no other reports of adverse reactions to Dengvaxia, it added.

Dengvaxia, the world's first dengue vaccine, has been available in Singapore since mid-March, after the HSA approved its use in patients aged between 12 and 45 in October last year.

Back then, the HSA had flagged the potential risk of severe dengue after reviewing data of the vaccine from Sanofi.

It informed healthcare professionals about the risk and recommended that patients consult their doctors before getting the vaccine.

Educational materials and the package insert of Dengvaxia also included information on the risk. Blood tests to identify previous dengue infection were also made available at major hospitals here.

HSA said it is now working with Sanofi to "strengthen the package insert" to include the warning of an increased risk of hospitalisation for dengue and clinically severe dengue in vaccinated people not previously infected by dengue.

However, in its alert, Sanofi had added that for those who had been previously infected, Dengvaxia "provides persistent benefit against dengue fever".

The HSA noted that dengue vaccination is not part of the national immunisation programme here - the vaccine is given to individuals only when benefits outweigh the risk.

MEDICAL & HEALTH