Dengue fever claimed 141 lives in Thailand last year, with more than 142,000 people being infected. The tropical disease is expected to not stop wreaking its havoc this year. Only two months into 2016 and almost 10,000 Thais have fallen victim to it, with three reported deaths, according to figures from the Bureau of Vector Borne Disease under the Ministry of Public Health's Department of Disease Control.
This is why the dengue vaccine -- the first of its kind in the world -- is indeed the light at the end of the tunnel for countries at risk around the world, especially Thailand, said Assoc Prof Chukiat Siriwichayakul, head of the Department of Tropical Paediatrics, Mahidol University.
"This is one of the vaccines that take so long to develop. We have been waiting 70 years, and now the dengue vaccine has been approved in four countries -- namely, Mexico, the Philippines, Brazil and a fourth country, which has yet to be revealed," said Dr Chukiat at last week's public lecture entitled "Dengue Vaccine: A Hope for Thai people", organised at the Hospital for Tropical Diseases, Mahidol University's Faculty of Tropical Medicine. Dr Chukiat is one of the Thai researchers who have been involved in the development of the dengue vaccine.
Dengue fever can be fatal, and this explains why a vaccine is crucial in preventing the disease before it manifests in a more serious form, the doctor added. Based on statistics, 53% of people infected with the dengue virus only suffer mild flu-like symptoms, while 36% of the infected are likely to have serious conditions, also referred to as dengue fever, including severe headache, severe pain behind the eyes, muscle and bone pain, joint pain and rashes. The rest, or around 11%, might suffer the most severe form of all, which is called dengue haemorrhagic fever. At this stage, patients might fall prey to plasma leakage from blood vessels, resulting in thickening blood and shock.
"Dengue infection might lead to death, although this is not common," he added. "But this does not mean we should not keep it under a watchful eye."
Thailand's Food and Drug Administration (FDA) is now reviewing related studies to ensure the vaccine is safe and effective. According to Dr Chukiat, the dengue vaccine is expected to be available in the country around mid-year.
The approval of the vaccine will then surely be followed by questions from consumers asking if it is worth it for them to have the shot.
When it comes to deciding whether or not to get the jab, Dr Chukiat said there are two things to take into account: safety and effectiveness, both in terms of the vaccine's efficacy and its cost-effectiveness. For safety, studies in Singapore -- which were conducted among people who received the dengue vaccine and those who got a placebo and other types of vaccines -- revealed that the dengue vaccine has fewer and lesser side effects when compared to other protective shots, particularly with regard to pain, redness and swelling at the injection site.
In terms of the vaccine's performance, studies revealed that it's able to reduce the chance of contracting the virus by around 60%, especially among people above the age of nine. For children below the age of nine, it is found that the vaccine renders better protective results in those who had been infected before.
"But the vaccine can prevent the severe form of dengue fever by about 80% in people above the age of nine," Dr Chukiat noted. "For those below the age of nine, the vaccine can shield them against severe dengue conditions by 56%."
"In all, the vaccine does not yield 100% efficacy," said the specialist, adding that the dengue shot will be most effective for people between the ages of nine and 45.
According to the researcher, the vaccine, which requires three doses over a period of one year to be fully effective, still needs more follow-up studies to determine how long it would need to take effect. But it has been reported that after years of vaccination, it renders a higher immunity level in countries where people can get natural boosters. And Thailand is one of those countries.
"In Thailand, when you are bitten by a mosquito and are infected with the dengue virus even though you are vaccinated you get a natural booster, which also means you are still immune against the virus," he explained. "This is not the case in Singapore [where there is no natural booster]. We found that people there who took the dengue shot had a very low immunity level five years later."
The price of the dengue vaccine in Thailand has yet to be specified, leaving some health-conscious people in doubt as to whether such a preventive measure will be affordable. Some have raised concerns if the government should include the vaccine in its national healthcare scheme, allowing people, especially the underprivileged, access to it at no cost.
Dr Chukiat said he could definitely not answer this query on behalf of the state, but in theory, he said, there are three criteria for the Ministry of Public Health in considering whether the vaccine will be part of national healthcare policy. The first is disease burden, or the impact of a public-health issue as measured by financial cost, mortality and other indicators. Second, it's a matter of the ministry's budget. And, third, there is the effectiveness of the vaccine itself.
"In most cases, any vaccine qualified for inclusion in the national healthcare scheme must demonstrate over 90% efficacy," the doctor said.
In the meantime, while the vaccine is not yet available in Thailand, Dr Chukiat urged people to not turn a blind eye to any symptoms that are likely to be caused by the dengue virus.
"Just come for a doctor's visit if you have a fever or develop [other] signs of the disease," he concluded. "This is to prevent symptoms from progressing and turning into something severe when they are left unattended."
