Dengvaxia, the world’s first vaccine to prevent dengue hemorrhagic fever, is now being administered in Valenzuela City.

Personnel of the City Health Department (CHD) have been making rounds of elementary schools since April 19, giving nine-year-old Grade Four pupils with the first of the required three doses.

On the first day, a total of 1,074 pupils at the Lingunan Elementary School and Malinta Elementary School received the vaccine that was developed by French pharmaceutical Sanofi Pasteur.

The local health bureau is expected to have inoculated with the first dose a total of 11, 951 schoolchildren in 41 public schools by the time it finishes on April 27. The same children would be given the second and third doses on October to December 2016 and April to June 2017, respectively.

Andrea Marie de Jesus, co-coordinator of the local Dengue Prevention and Control Program, said the children are vaccinated with consent of their parents.

The Philippines is one of the only two countries so far where the vaccine is used, along with Mexico. In March, after the national government approved the vaccine in December, the Department of Health began an immunization drive that targets nine-year-olds in Metro Manila, Central and South Luzon.

On April 18, the WHO's Strategic Advisory Group of Experts (WHO SAGE) on Immunization told a press conference in Geneva, Switzerland that Dengvaxia is “efficacious and safe”, but not recommended for children under nine years.

Transmitted by the day-biting Aedes aegypti mosquito, dengue is among the major illnesses in the Philippines, afflicting as many as 200,000 in 2015, DOH data show. Symptoms–high fever, vomiting, skin rash and muscle or joint pain–usually manifest themselves three days after infection.

In Valenzuela, 105 people in Valenzuela were infected with dengue from January 1 to April 16, the CHD reports. This is 39.3 percent lower than the 173 cases during the same period in 2015.