Philippines Suspends Dengue Vaccination Program

The Philippines on Friday announced the suspension of a school-based dengue immunization program, after pharmaceutical giant Sanofi Pasteur said that its drug – given already to nearly three-quarters of a million Filipino children – posed risks for people with no prior infection.

The country was the first in Asia to approve the use of Dengvaxia, and over 740,000 school children in the capital Manila and neighboring suburbs have already received at least one dose of the vaccine.

“In the light of this new analysis, the (health department) will place the dengue vaccination program on hold while review and consultation is ongoing with experts, key stakeholders, and the WHO,” Philippine Health Secretary Francisco Duque said.

The government was “intensifying its ongoing surveillance and monitoring” to ensure that all those who had taken the drug would be safe, he added.

The program had been hailed by the World Health Organization, which recommended that the government undertake a massive immunization project to combat the mosquito-borne disease.

Dengue fever and dengue hemorrhagic fever are acute viral infections that are known to affect infants, young children, and adults. It is transmitted by a bite of an Aedes aegypti mosquito infected with any one of the four dengue strains.

On Wednesday, the government received a preliminary briefing from Sanofi, a France-based pharma company, updating its information on the ground-breaking vaccine. It said clinical tests had shown that the vaccine worked well with those who had already been “previously infected” with the virus.

But it warned that for those not previously infected by the virus “the analysis found that in the longer term, more cases of severe disease could occur” following vaccination. Sanofi did not specify what the “severe diseases” were, but stressed it would clearly label the new finding on vaccine containers.

Every year an estimated 390 million dengue infections are reported. People can be infected with dengue up to four times in their lifetime and they can become severely ill after any of these infections, Sanofi said.

While the move to suspend the program was precautionary, vaccination remained essential to control and prevent dengue, which infects about 200,000 Filipinos every year, Secretary Duque said.

“The DOH (health department) assures the public that it is serious in carrying out its mandate to always guard the health and well-being of its constituents,” he said. “Thus, it shall ensure that vaccines are always safe and effective to optimize its health benefits.”

Associated risks

The health department’s lawyers were also studying the next steps in dealing with Sanofi, and health workers have been asked to track down all the children who have been immunized.

The vaccines that are now in stock would be barred from being sold unless labels are changed to reflect the latest advisory.

Sanofi, in a statement issued on Wednesday, said it would propose that national regulatory agencies update labels in their stocks of the drugs to request “healthcare professionals assess the likelihood of prior dengue infection in an individual before vaccinating.”

“Vaccination should only be recommended when the potential benefits outweigh the potential risks,” the company said, warning that vaccination should not be recommended for persons “who have not been previously infected by dengue virus.”

Health advocates had warned earlier that it was too soon to have the vaccine rolled out in 2016. In December 2015, the Philippines approved the commercial sale of Dengvaxia, the first dengue vaccine developed by Sanofi. It became commercially available here four months later.

Sanofi representatives in Manila were not immediately available for comment on Friday.

The first clue that there could be something wrong was in April last year, when an 11-year-old boy suffering from congenital heart disease died after receiving a Dengvaxia shot. The government, however, said that two were unrelated.

Felipe Villamor in Manila contributed to this report.