Drug firm warns of 'severe disease' from dengue vaccine for people with no prior infection

Metro Manila (CNN Philippines, November 30) — Pharmaceutical company Sanofi on Wednesday said new clinical data analysis showed its dengue vaccine is more risky for people not previously infected by the virus.

In a statement, Sanofi said Dengvaxia provided persistent protection against dengue fever to 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," it said.

Sanofi, one of the world's top companies in pharmaceutical research and development, said it would ask national regulatory agencies to update the product label to reflect the new findings.

"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," the statement read.

Dengvaxia is a three-dose series licensed for use on people between 9 and 45 years old.

The vaccine has been commercially available in eleven countries-the Philippines, Mexico, Indonesia, Brazil, El Salvador, Costa Rica, Paraguay, Guatemala, Peru, Thailand, and Singapore -- as part of their national immunization programs.

In 2016, the Philippines became the first country to implement the use of Dengvaxia through a school-based dengue immunization program, which initially covered Grade 4 students in the National Capital Region, Central Luzon, and CALABARZON (Cavite, Laguna, Rizal, Quezon).

The Department of Health (DOH) spent P3.5 billion on the immunization program, a move questioned by some doctors as Dengvaxia had not yet been approved by the World Health Organization then.

The program was halted in 2016 by then Health Secretary Paulyn Ubial to await the results of the pilot program.

Health authorities earlier said the vaccine would have side effects, including fever, headache, muscle pain, weakness, redness and swelling.

According to a study by the University of the Philippines National Institute of Health, Dengvaxia was expected to reduce dengue cases in the country by over 24 percent in five years.

The number of dengue cases in the country spiked from around 120,000 in 2014 to over 200,000 in 2015.

In 2017, the DOH reported 97,287 cases of dengue nationwide from January to September. Of these, 526 deaths were reported.