Outbreak reported across Southeast Asia but the Philippines has the highest number of cases and confirmed deaths.

Manila, Philippines – Emie Angeles and her husband, Rico Reyes, have not had a decent night’s sleep for days.

Two weeks ago, the couple rushed two of their children, two-year-old Katelyn and seven-year-old KD, to hospital with a fever of over 39C (102.2 Fahrenheit) that would not subside.

Katelyn had contracted dengue last year and the couple did not want to take any chances.

Her blood test was positive for dengue while KD’s showed no infection but indicated a low platelet level, so the parents decided to have both children admitted.

Two days later, Katelyn no longer had a fever. “She was already singing her favourite song about balloons … We were getting ready to go home,” Reyes said.

Then Katelyn’s fever came back.

“It all happened so fast. She vomited blood, her nose began bleeding and she began to convulse. The doctors tried to revive her but …” said Katelyn’s mother, still dazed.

Katelyn was pronounced dead on September 8.

Dengue outbreak

Over the past months, the Philippines has been grappling to stem its worst dengue outbreak since 2012.

According to the Department of Health, a total of 271,480 dengue cases were reported from January to August 31 of this year, prompting the declaration of a national dengue epidemic.

In 2012, 187,031 cases of dengue were recorded.

As of August 31 this year, an estimated 1,107 people have died of dengue in the Philippines, almost half were children between five and nine years of age.

At Manila’s Tondo Medical Center, where Katelyn was treated, 21 dengue patients were crowded into one room in the paediatric ward.

Two to three patients have to share a bed, with additional beds set up in the corridors to deal with the overflow.

“Children are particularly susceptible to dengue because they have weaker immune systems compared to adults,” said Amado Parawan, health and nutrition officer at Save the Children Philippines.

The Philippines is grappling to stem its worst dengue outbreak since 2012. There have been 271,480 #dengue cases from the start of this year until end of Aug. Almost half of the estimated 1,107 deaths are among children. Two-year old Katelyn Reyes is one of the victims. pic.twitter.com/hZYjVpe43K — Ana P. Santos (@iamAnaSantos) September 17, 2019

An attempt in 2016 to run a dengue vaccination programme – using the Dengvaxia vaccine – ended abruptly when the efficacy and safety of the vaccine were called into question.

Tens of thousands of dengue cases have been reported in neighbouring Southeast Asian countries but the Philippines appears to be the worst-hit in terms of the number of cases and fatalities, according to a report by the World Health Organization (WHO).

According to the WHO report, 124,751 cases of dengue were recorded in Vietnam, 85,270 in Malaysia and 10,206 in Singapore as of the end of August – as much as a three-fold increase compared with the previous year.

Trying to contain the disease

A patient infected with dengue exhibits flu-like symptoms and a fever that runs for two to seven days.

The fever may go down temporarily after three days, making many patients think it is over. However, this is a critical phase that must be monitored as it may progress to severe dengue, according to Leila Jane Narag, the doctor overseeing the paediatric ward at the Tondo medical facility.

In reaction to the outbreak, the health department has intensified its dengue prevention campaign, destroying mosquito breeding sites and ensuring adequate blood supply in hospitals.

Dengue is transmitted by the Aedes aegypti mosquito, common in all parts of the Philippines.

The rainy season, typically June to February, is the peak period for dengue as water collects in blocked gutters and street drains, turning them into breeding grounds for mosquitoes.

According to Narag, reducing mosquito populations by cleaning water sources like wells and water storage containers is essential to preventing further spikes in dengue cases.

“A dengue outbreak is not exactly a new phenomenon. We have seen this happen every four to five years and it is often linked to changing weather patterns,” said Rabindra Abeyasinghe, Philippines representative for the WHO.

The rainy season from June to February is the peak period for dengue in the Philippines [File: Romeo Ranoco/Reuters]

But higher temperatures and longer rainy seasons contribute to the scale of the outbreak, as can a change in the type of dengue virus, he added.

Among the four types of dengue, the “Asian” genotypes of DEN-2 and DEN-3 are frequently associated with severe diseases like pneumonia, accompanying secondary dengue infections.

An estimated 64 percent of profiled dengue cases in the Philippines are DEN-3, according to the health department.

Dengvaxia controversy

In 2016, large dengue outbreaks were reported worldwide.

More than 375,000 suspected cases of dengue were reported in the Western Pacific region, almost half were in the Philippines.

Children are particularly susceptible to dengue because they have weaker immune systems [Leo Solinap/EPA]

The same year, the Philippines rolled out a large-scale school-based dengue immunisation campaign using Dengvaxia, touted at the time as the world’s first dengue vaccine.

However, the programme was suspended in 2017 after Sanofi Pasteur, which manufactured the vaccine, issued new clinical findings saying that taking it may not be effective in some cases and may lead to more severe symptoms of dengue among those who have not been previously infected.

Consequently, the Philippines’ Food and Drug Administration permanently revoked the use of Dengvaxia, although several investigations had concluded that no deaths could be directly linked to it.

Officials of President Rodrigo Duterte’s administration were criticised for their “knee-jerk” reaction to the vaccine controversy, given that the programme was introduced during the previous government.

As dengue cases escalated in August, Duterte said he would consider the resumption of the use of the vaccine upon the recommendation of the health department.

But Health Secretary Francisco Duque was adamant that Dengvaxia would not be appropriate for an outbreak response.

Currently, the vaccine is licensed for use in some countries in Europe, the United States and Latin America.

Doctors for Truth and Public Welfare, a group of medics and scientists led by former Health Secretary Esperanza Cabral, is appealing to the government to allow Dengvaxia back onto the market.

“It is not a perfect vaccine, but we think that it should be made available to those who need it and can benefit from it,” Cabral said.

“This (outbreak) is not normal. We cannot accept the 1,000 deaths related to dengue. With proper treatment, you do not die from dengue.”