Vaccine rolled out in Philippines offers new hope against dengue

Over a two-year period, Annie Bojas-Imperio’s entire family was stricken by dengue, a debilitating and sometimes deadly mosquito-borne virus.

“Mommy, daddy and my two sons. It’s like dengue mosquitos love us,” Bojas-Imperio said with a laugh in her home in the Philippine’s capital, Manila.

But she wasn’t laughing when the first family member to get the flu-like illness was her son Lucky, who was little more than a year old in 2012.

Her son remained true to his name and was discharged from the hospital after three days. Bojas-Imperio, now 42, was next to contract dengue, followed by her husband and then her youngest son in 2014.

While the whole family survived without major complications, the chances of it becoming more severe on a second occurrence are high. Bojas-Imperio said she is now “very paranoid” whenever one of her children gets a fever.

With a 30-fold increase in dengue cases over the past half a century, according to the World Health Organization, millions of people live in fear of the virus. But a new vaccine should help ease those concerns.

After two decades of work, the French pharmaceutical giant Sanofi Pasteur has licensed it to Mexico and the Philippines. Last month, Sanofi Pasteur rolled out its first ever dengue mass-vaccination programme. Fourth graders are being vaccinated in three areas in the Philippines where dengue cases were highest last year.

Mario Baquilod is in charge of the Disease Prevention and Control Bureau of the Philippine Department of Health. He said last year there were 200,415 reported cases of dengue in the Philippines, one of the largest numbers in recent years.

Baquilod said the department wanted to add the vaccine to its arsenal of tools that combat the virus. The government aims to get one million children immunized against dengue by June - so far 263,000 kids have received the vaccine.

Baquilod said they decided to pilot the programme in three public schools because they wanted to have a “captive” population for the vaccine, which takes three doses – one every six months – to be effective. The medical world is now watching what happens in the Philippines.

“There (is) pressure for us to perform well,” said Baquilod.

Infections on the rise

Dengue is carried by the female Aedes mosquito, which has distinctive white stripes on its body and legs and tends to bite early in the morning or at dusk. Many infected people think they have a terrible bout of flu, because the symptoms are quite similar. But the exhaustion, fever and joint pains that accompany dengue are far worse. The worst-case scenario is that the victims develop haemorraghic fever, which can be deadly.

Aside from a saline drip to boost a patient’s blood platelet count there is no treatment. And because there are four types of dengue virus, people can get the disease more than once, and more severe fevers are common in repeat infections.

The World Health Organization traced the first severe dengue cases in the 1950s in Thailand and the Philippines, and said before 1970 just nine countries in the world had severe dengue (or the deadly Dengue Hemorrhagic Fever). Today it is endemic in 100 countries and severe cases have become the leading cause of death for children in some Asian and Latin American nations.

With the number of dengue cases growing, symptoms becoming more severe, and deaths rising, pressure is on to find an effective vaccine.

SEE: Record dengue outbreak fans fears in Malaysia

Imperfect but better than nothing

Sanofi Pasteur’s vaccine is a major step forward, but it isn’t perfect.

The vaccine, which works against all four variations of the disease, is close to 66 percent effective in preventing dengue and 93 percent effective against severe dengue. The vaccine is for individuals between the ages of nine and 45. Trials found it was not effective on children younger than that.

With young children excluded from the vaccine, it offers little comfort to families like Bojas-Imperio’s.

“It would be better if there was a vaccine available for small children,” she said. “Isn’t it sensible?”

Until that happens, Bojas-Imperio’s family is forced to take less effective measures. They get their house fumigated regularly during the rainy season, and she puts citronella patches on the children’s clothes daily.

Citronella oil, extracted from oranges and lemons, drives mosquitos away. It’s far from guaranteed protection against dengue, but it’s the best they have until a truly effective vaccine becomes available.

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