Dengvaxia: The world's first anti-dengue vaccine
In April, the Department of Health (DOH) launched the first school-based dengue immunization program on Monday with around 250 Grade 4 students of Parang Elementary School in Marikina City.
The DOH chose Grade 4 students from the National Capital Region, Calabarzon, and Central Luzon four regions with the highest number of dengue cases.
The vaccine called Dengvaxia, took scientists 20 years to develop and is considered the world’s first anti-dengue vaccine, and the Philippines is the first country where it is commercially available.
Dengue is a high-motile and ongoing public health concern in the Philippines. The first known epidemic of severe dengue or dengue hemorrhagic fever anywhere in the world was recorded in Manila in 1953.1 By the mid 19705 severe dengue had become a leading cause of hospitalization and death among children in the region 2 Between 2004 and 2010, the Philippines experienced the seventh highest number of dengue cases in the world according to the World Health Organization (WHO).
In 2013, DOH reported 204,906 cases of dengue, the highest number recorded since the establishment of the National Dengue Prevention and Control Program in 1993. More than 200,000 dengue cases were reported in the Philippines in 2015, 80,000 more than were reported in 2014. In both September and October 2015, the number of reported cases rose above the epidemic threshold. d
Although the number of reported dengue cases slightly decreased in 2014, the 2015 data suggest an increasing trend in cases in the coming years. Recent data gathered by the Department of Health from January to 24 September this year shows an increase of 11.5 percent year on year across the country, with t otal dengue Infections at 142,247 compared to 127,525 last year and 604 recorded fatalities.
Based on Philippine surveillance data collected between 2011 and 2015, an average of 220 dengue cases were reported in the country every day.8 In 2015, almost 50% of reported cases came from three most urbanized regions Region 3 (17.6%), Region 4 (17.3%), and the National Capital Region (12.6%).9 Cases stemming from all four serotypes of dengue were reported in 2015.
Disease burden: US$345 million per year
The economic burden of dengue in the Philippines is substantial. A study published in 2015 estimated that between 2008 and 2012. clinically diagnosed dengue cases in the Philippines were associated with a direct medical cost (in 2012 US dollars) of $345 million annually. The study calculated the average cost of treatment per case to be $409, representing 16% of the Philippines’ 2012 per capita GDP. Sixty-live percent of cases were treated in inpatient hospitals, representing 90% of direct costs.
In addition to dengue‘s burden on a household, the illness can adversely impact a country’s economy through a loss of productivity caused by the illness and pre-mature death, increased healthcare costs and a possible reduction in tourism.
DENGVAXIA THE FIRST DENGUE VACCINE (Source)
Sanofi Pasteur’s vaccine is the culmination of over two decades of scientific innovation and collaboration, as well as 25 clinical studies in 15 countries around the world. Over 40,000 volunteers participated in the Sanofi Pasteur dengue vaccine clinical study program (phase I, II and III), of whom, 29,000 volunteers received the vaccine. Dengvaxia successfully completed phase III clinical studies in 2014 to evaluate the primary objective of vaccine efficacy.
Long-term follow-up studies of the vaccine, recommended by WHO for all dengue vaccines in development, are currently ongoing. Additional pooled efficacy and integrated safety analyses from the 25-month Phase III efficacy studies and the ongoing long-term studies, respectively, were recently published in The New England Journal of Medicine reconfirming the vaccine’s consistent efficacy and longer-term safety profile in populations 9 years of age and older. In a pooled efficacy analysis in volunteers aged 9-16 who participated in the two Phase III 25-month efficacy studies, Dengvaxia was shown to reduce dengue due to all four serotypes in two-thirds of the participants. Furthermore, this pooled efficacy analysis showed that Dengvaxia prevented 9 out of 10 cases of severe dengue and 8 out 10 hospitalizations due to dengue in this age group.
Dengvaxia is the first vaccine licensed for the prevention of dengue in the world. First doses of the vaccine have been produced and full scale production capacity will be reaching 100 million vaccine doses annually.
Seasonality and global climate change
Dengue has become a year-round threat in the Philippines. However, data suggests that the number of dengue cases increases one to two months after the onset ofthe rainy season, resulting in a peak of dengue cases between July and November each year.13
The Philippines is severely affected by extreme weather events and is vulnerable to the effects of climate change Vector-borne diseases like dengue may be particularly sensitive to both periodic tiuctuations and sustained changes in global and local climates.“ Additionally, a study examining data from eight Asian countries including the Philippines over 18 years revealed a strong correlation between regional dengue epidemics and elevated temperatures associated with El Nino.
In a recent vaccine cost-effectiveness study performed by Professor Hilton Lam of the UP-National Institute of Health, a nationwide annual routine vaccination of nine year olds starting in 2016 would lead to an estimated 24.2 reduction in dengue cases in the country over a five year period. This would translate to 775,053 avoided cases of dengue, 502,000 avoided hospitalizations, 22,010 avoid deaths and almost P21 billion in avoided cost to society.