SINGAPORE: Healthcare professionals in Singapore have been advised not to administer a dengue vaccine to patients who have not been previously infected by the virus.
The Health Sciences Authority (HSA) told Channel NewsAsia on Wednesday (Dec 6) that it has issued an advisory to doctors on the latest findings about Dengvaxia, which is produced by French pharmaceutical giant Sanofi Pasteur.
Sanofi said in late November that a new analysis based on six years' worth of clinical trial data showed Dengvaxia could worsen symptoms for those not previously infected with dengue.
The analysis "confirmed that Dengvaxia provides persistent protective benefit against dengue fever in those who had prior infection", the alert read.
However, for those not previously infected, the analysis found that "in the longer term, more cases of severe disease could occur following vaccination upon a subsequent dengue infection", it added.
DENGVAXIA APPROVED FOR USE IN SINGAPORE IN 2016
Dengvaxia was initially approved for use in countries including Indonesia and Philippines, as well as Singapore in October last year.
In its statement, HSA said that Sanofi's findings "confirm" its 2016 assessment of "a postulated risk of higher incidence of severe dengue" following vaccination of those not previously infected.
At the time, HSA had recommended that individuals who wanted to get the vaccine first consult their doctors on its benefits and risks. HSA also shared this information with healthcare professionals, the media, as well as the public.
Additionally, the authority said it worked with the health ministry to offer serological testing, which can identify previous dengue infection, in Singapore.
Philippines has halted the sale, distribution and marketing of Dengvaxia, days after its government suspended a programme to immunise hundreds of thousands of children with the vaccine.
"In Singapore, dengue vaccination is not part of the national immunisation programme, which means that the vaccine is only given to individuals where the benefits outweigh the risk, instead of the population at large," said HSA.
It added that it would "further strengthen the warnings and recommendations in the prescribing information" to ensure safe use of Sanofi's vaccine.