Clearly the dengue virus wrecked havoc in Thailand last year with more than 142,900 reported cases of infection and 141 deaths, according to the Bureau of Vector Borne Disease under the Ministry of Public Health's Department of Disease Control.
This year the situation is better given the epidemic pattern where large outbreaks mostly occur every two years. As of last week, around 54,000 dengue cases were reported, with 51 deaths. In the same period last year, there were approximately 107,500 reported cases.
But Thailand has seen worse in terms of the number of dengue-infected patients. And that was in 1987, according to Prof Usa Thrisyakorn, professor of paediatrics at Chulalongkorn University and chairman of the Asian Dengue Vaccination Advocacy (ADVA) group.
"In 1987, the country saw about 200,000 dengue patients, the highest in history. The infection does not just affect a personal level where the infected cannot go to work, but also the country's healthcare cost," said Prof Usa in an interview as part of the "From Dengue Vaccine To Dengue Vaccination" symposium at the 8th Asian Congress of Paediatric Infectious Diseases 2016, which took place last week at the Queen Sirikit National Convention Center.
According to the World Health Organization, dengue is the fastest-growing infectious disease with its incidence growing 30-fold in 50 years from 1965 to 2015. Half of the world is at risk of getting the virus with a yearly estimate of 96 million symptomatic cases and 500,000 hospitalisations globally.
The world's first ever dengue vaccine, which has been available for use since last year, has become the light at the end of the tunnel, especially for tropical countries where many fall prey to the disease annually. Mexico is the world's first nation to have allowed the sale and use of the vaccine, followed by the Philippines and Brazil. According to Prof Usa, the dengue vaccine has been licensed in 13 countries, while approval for sale is to soon follow.
In Thailand, studies and research in relation to the dengue vaccine have been consistently carried out for more than 30 years, especially by Mahidol University. The government and related public agencies are considering how the vaccine should be made available.
"Thailand's healthcare system is quite efficient in terms of dengue treatment," added Prof Usa. "But it is the responsibility of decision makers to see if the vaccine is worthwhile. As an assistive tool, mathematical modelling might come into play to help calculate if it is worth it."
Earlier this year, the Philippines launched the world's first public immunisation programme for dengue. The mass vaccination programme is designed to administer the vaccine to 1 million nine-year-old schoolchildren. The Philippine government spent 3.5 billion pesos (or around 2.6 billion baht) to administer the free vaccines.
Prof Tikki Pang, visiting professor at Lee Kuan Yew School of Public Policy, the National University of Singapore, and former director of research policy and co-operation at the WHO, considers the Philippines a country that has achieved in managing the implementation the vaccine quickly.
"The then president of the Philippines [Benigno Aquino III] understood there was a serious problem with dengue," said Prof Pang, also a panellist at last week's symposium. "And this is the first time ever there is a vaccine. He believed this would help the country in reducing the number of cases. So it's a strong political commitment right from a president."
The state of Parana in Brazil, added Prof Pang, is another clear example as to how the vaccine programme has been successfully implemented, due to its good infrastructure.
"Parana has a big dengue problem, but more importantly it has very good data. The WHO recommendation is that the vaccine should be used in areas where there are a lot of disease. So they choose the Parana state that has good infrastructure and good information.
The state has been very progressive in supporting the programme in the past so it's not surprising that it is the first state in Brazil that used the vaccine," explained the professor. In 2015, Parana had 1.5 million dengue patients. Now that the vaccine is licensed in Thailand and is expected to be available for use early next year, Prof Usa wonders how the vaccine will be made accessible -- be it through private hospitals or a state programme. According to Prof Pang, should Thailand introduce the vaccine to immunise its population, an equitable access should be the first thing to underline.
"Everyone should get the vaccine not just those who can afford to pay," he commented. "So that means it probably is going to be up to the government to provide the funding for public health immunisation. If it's available only from private doctors, then many people cannot afford to be vaccinated. There has to be a policy to make the vaccine accessible to everybody regardless of rich or poor."
"If the Thai government is not certain about the [vaccine's] cost-effectiveness and only allows private hospitals to sell it, the foreseeable issue here is in terms of inequality," added Prof Usa.
Despite the WHO's position paper recommending the use of the vaccine in countries or areas where the infection is widespread, Prof Pang said it's up to each country to make a decision for themselves.
"The WHO's main function is to set global standards. So they have published their position in a paper where they recommend the use of the vaccine in countries or areas where there is a lot of disease. All countries of the world are members of the WHO so they pay attention to what the WHO recommends.
"However, the final decision to use the vaccine is the decision of the country itself," he added. "They can get guidance from the WHO but it is the country's own experts, scientists and doctors who know the situation of the country best. The final decision to introduce the vaccine should be a national decision guided by the WHO."
By 2020, the WHO aims to reduce the mortality rate from dengue infection by 50%. To achieve this, Prof Usa said it is paramount for countries at risk to follow recommended protocols.
"There are mainly five protocols to follow," Prof Usa concluded. "First, diagnosis and treatments must be fast. Second is mosquito control. Then we also need a good database and disease surveillance.
The fourth protocol is with regard to continuous research to adjust dengue care and treatments. The last one is vaccination."
THE JAB FACT FILE
- CYD-TDV (chimeric yellow fever–dengue virus tetravalent dengue vaccine) is the first dengue vaccine to be licensed. It is a combination of the weakened form of yellow fever and dengue fever viruses.
- This CYD-TDV vaccine is claimed to be able to protect against all four strains of dengue virus, namely DEN-1, DEN-2, DEN-3 and DEN-4.
- The WHO now recommends that the vaccine be used in individuals aged nine to 45 years old living in endemic areas.
- The vaccine is to be given as a three-dose series on a 0/6/12 month schedule.
- The vaccine is able to reduce the chance of contracting the dengue virus by 60%. For those infected, it can lessen the severity of symptoms by 80-90%.
- In terms of efficacy period, once injected, the immunity level has been followed up for five years. In its six years, the level in studied subjects is still high.
