By Alisa Tang
BANGKOK (Thomson Reuters Foundation) - The Philippines this week launched the world's first public dengue immunisation programme, vaccinating 600 children at a school in the capital Manila with the goal of reaching 1 million students across the country this year.
Dengue, also known as "breakbone fever", has spread rapidly around the world in recent decades, and about half the world's population is now at risk.
Scientists have been working on a vaccine for decades, and the first one received market approval in December in Mexico.
Several other vaccines are under development, while researchers are also looking at ways to control the mosquitoes that spread dengue and other viruses such as Zika.
Here are some facts about dengue and prevention efforts.
WHAT IS DENGUE? * Dengue, a mosquito-borne viral disease, often causes aflu-like illness, with symptoms including high fever, severeheadache, muscle and joint pain, nausea, vomiting and rash. * It can develop into the deadly severe dengue, or denguehaemorrhagic fever, characterised by severe abdominal pain,persistent vomiting, rapid breathing, bleeding gums and blood invomit. * There is no specific treatment for dengue. Patients aregenerally asked to rest, drink plenty of fluids and takemedication to reduce fever and joint pains. * Fatality rates can be below 1 percent with proper medicalcare, but without care, can be as high as 20 percent in patientswith severe dengue.WHO IS AFFECTED? * The annual number of dengue cases has increased 30-fold inthe last 50 years, and there are now an estimated 390 millioninfections per year. * The disease is now endemic in more than 100 countries inAfrica, the Americas, the Eastern Mediterranean, Southeast Asiaand the Western Pacific. * Severe dengue was first recognised in the 1950s duringdengue epidemics in the Philippines and Thailand. Before 1970,only nine countries had experienced severe dengue epidemics. * Severe dengue has become a leading cause ofhospitalisation and death among children in Asia and LatinAmerica. Asia has the most cases, with 67 million peopleinfected per year.HOW CAN DENGUE BE PREVENTED? * Dengue transmission can be prevented by fighting themosquitoes which carry the disease, getting rid of places forthem to lay eggs by covering or emptying outdoor watercontainers, and disposing of solid waste properly. * Protection such as window screens for houses, long-sleevedclothes and insecticide are also used. * Health experts have called for an integrated approach tofight dengue and for vaccines to be part of the toolbox to fightthe virus.HOW EFFECTIVE IS THE VACCINE? * Sanofi studies of Dengvaxia, a three-dose vaccineadministered over the course of a year, said it prevented eightout of 10 dengue hospitalisations. * A new dengue vaccine developed by scientists from the U.S.National Institutes of Health (NIH) shows promise, with 100percent protection in a small group, according to a studypublished in March.WHERE IS THE VACCINE AVAILABLE? * Dengvaxia, which is approved for use in individuals aged 9to 45, is registered in the Philippines, Mexico, Brazil and ElSalvador, with regulatory review processes underway in othercountries. * In the Philippines, fourth grade students who are nine orolder will be vaccinated, with an injection in the upper arm. * The free vaccinations are taking place at public schoolsin the capital Manila and adjacent regions to the north andsouth, which have the highest number of dengue cases.Sources: World Health Organization, Philippines Department of Health, Sanofi Pasteur.
(Reporting by Alisa Tang, editing by Alex Whiting. Please credit the Thomson Reuters Foundation, the charitable arm of Thomson Reuters, that covers humanitarian news, women’s rights, corruption and climate change. Visit http://news.trust.org to see more stories)