Sanofi warns of effects of dengue vaccine to first time victims

A pharmaceutical company has advised against prescribing the dengue vaccine Dengvaxia to patients who have not had the virus in the past, since it may cause severe diseases in the long run.

After six years of studying clinical data, Sanofi on Wednesday said it has found out that Dengvaxia was only beneficial in the prevention of dengue fever to those who have already suffered from the other serotypes of the virus.

"Based on up to six years of clinical data, the new analysis evaluated long-term safety and efficacy of Dengvaxia in people who had been infected with dengue prior to vaccination and those who had not. The analysis confirmed that Dengvaxia provides persistent protective benefit against dengue fever in those who had prior infection," Sanofi said in a press statement.

"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," it added.

Sanofi said it would propose to government regulators in each country where the vaccine is registered to update its label and include a recommendation for patients.

"Vaccination should only be recommended when the potential benefits outweigh the potential risks (in countries with high burden of dengue disease). For individuals who have not been previously infected by dengue virus, vaccination should not be recommended," Sanofi said.

Sanofi Global Medical Head Dr. Su-Peing Ng also vowed that Sanofi will work closely with government health authorities to ensure that patients are made aware of the study's results.

“These findings highlight the complex nature of dengue infection. We are working with health authorities to ensure that prescribers, vaccinators and patients are fully informed of the new findings, with the goal of enhancing the impact of Dengvaxia in dengue-endemic countries,” Ng said in the press statement.

The Department of Health has yet to respond to GMA News Online's request for their take on the latest development.

The Philippines was the first Asian country to clear the dengue vaccine and approve its distribution within a month of clearing its use. 

It was announced in May that the Department of Health will halt the dengue vaccination program after completing the third and final round of injections for recipients to await the results of the pilot program and make plans for a second iteration with their findings.

The DOH was questioned for its procurement of Dengvaxia at congressional inquiries due to the amount invested in its procurement and its initial target demographic of a million children, an unusual number for pilot programs.

More recently, Sanofi and drug and beauty products chain Watsons Personal Care Philippines were penalized by the Food and Drug Administration (FDA) for illegally promoting and advertising the dengue vaccine.

FDA classifies Dengvaxia as a prescription product.

Sanofi and Watsons were also warned that their establishments and License to Operate/Certificate of Product Registration may be revoked with future violations of FDA-implemented laws, rules and regulations. — MDM, GMA News