Advancements in the dengue management landscape indicate a new era in the way we mitigate the impacts of the infectious disease.
by Junghun Justin Kim
Many of us living in Asia are well acquainted with dengue. It is the fastest-spreading mosquito-borne viral disease and was recognised as one of the top 10 threats1 to global health in 2019. Half of the world’s population1 is currently at risk of dengue, with Asia bearing the brunt of the burden as it is home to about 70 per cent of all dengue cases.1
Dengue is predominantly spread to people, regardless of age, through the bites of Aedes aegypti and Aedes albopictus mosquitoes. These mosquitos are mostly found in urban and semi-urban areas in tropical and sub-tropical climates, which may explain their prevalence in Asia.
Previously uninfected mosquitos can become infected with dengue after biting an individual who is already affected by the disease. This can lead to local outbreaks when the newly infected mosquito continues the spread of dengue by biting additional uninfected individuals.
Globally, there are four dengue serotypes that may affect different countries and regions at different times. However, recovery from infection with one serotype only provides lifelong immunity against that one serotype and temporary, partial protection against other serotypes. Because of this and the cyclical nature of dengue, individuals can be infected with dengue up to four times – each time worse than the previous infection.
At the forefront of healthcare efforts is the development of an effective dengue vaccine. As an intervention that can minimise the impacts of dengue on individuals, vaccinations can play a key role in tackling the dengue crisis and improving patient outcomes.
However, to ensure the positive impacts of the vaccine on human health and the economy are realised by the broader population, building trust and confidence is essential.
The Recent Rise of Dengue in Singapore
Many countries in Asia are witnessing a spike in the number of dengue cases locally. In the first half of 2022, Singapore has already seen more than 14,000 cases2 – an almost three-fold increase compared to the total number of cases reported in 2021.
Extreme weather conditions such as heatwaves and thundery showers have been a main contributor to the rising cases as it provides suitable conditions for Aedes mosquitoes to thrive and reproduce. All it takes is a tiny puddle – areas as small and as deep as a 20-cent coin are sufficient for mosquitoes to breed in.
In addition, uncontrolled urban growth, migration, and modern transportation3 of Aedes mosquitoes have likely played a role in exacerbating the spread of dengue in the region.
Current dengue prevention methods largely rely on vector controls to reduce the spread and breeding of Aedes mosquitoes. Many countries have also reinforced the role of proactive efforts, urging individuals to be responsible for removing stagnant water and keeping households clean. However, up-and-coming innovations indicate an added advantage in the fight against dengue.
The Vaccine Conversation
Takeda’s pivotal phase III clinical trials for its dengue vaccine candidate have demonstrated that the vaccine is efficacious in reducing rates of hospitalisation and in protecting against symptomatic dengue, regardless of previous exposure.
This comes at a time when conversations around vaccinations are at an all-time high, and conversely when vaccine confidence needs to be supported.4 To ensure that dengue vaccinations are seen as a boon rather than a bane, we must reinforce the crucial role that vaccines play in our lives and ensure that medical frontliners are equipped with the tools and knowledge to guide individuals who may be “vaccine hesitant”. At the same time, we also need to ensure structural factors such as high costs, lack of access, and poor healthcare infrastructures are addressed head-on.
It is helpful to remember that many infectious diseases that used to plague the world, causing 3.5 to 5 million deaths annually5 or severe disabilities, have since been eliminated as a result of vaccination mandates globally and nationally. Some examples include polio, measles, and mumps.6
Furthermore, we have also been able to prevent and mitigate the impacts of cervical cancer and chickenpox through the human papilloma virus7 (HPV) vaccine and the varicella vaccine respectively. Recently, we have seen COVID-19 vaccines curb the spread of the coronavirus, reducing hospitalisations and mortality rates.8
To create trust in the dengue vaccine, it is essential that we work closely with healthcare authorities, government agencies, and healthcare professionals to reinforce the opportunities that a dengue vaccine can provide as part of an integrated solution, especially when the burden of dengue can be significant and far-reaching.
The Impacts of Dengue and Why a Vaccine Can Support With Better Healthcare Outcomes
Dengue poses short- and long-term impacts on individuals, families, communities, and countries. Given its endemic nature, it places recurring consequences9 on these groups. In the region, local outbreaks may mean an influx of patients10 requiring healthcare resources, resulting in overwhelmed hospital systems.
The brunt of dengue11 can be felt more broadly in local economies as well, with individuals and families facing unexpected out-of-pocket costs related to medical care, absenteeism from work and school, and time spent taking care of unwell family members. In Singapore, the economic impact of dengue from 2010 to 2020 ranged from S$1.43 to 3.18 million.12
Recent advances in vector control capabilities are a source of optimism for our outlook on dengue management. A multi-factorial approach is needed to advance the game of dengue prevention and to reduce the global burden of dengue. A safe and effective dengue vaccine that can be used across the wider population regardless of previous infections, including children and adolescents, would be a crucial and added layer of protection that can help reduce the long-term risks and impacts of dengue.
Following the summit, I am extremely excited for a future where there are potentially greater protective measures against dengue that can improve the lives of people and communities in Singapore, the region, and the world, and we remain committed to working with our various stakeholders to ensure access to the vaccine once it is available. [APBN]
About the Author
Junghun Justin Kim, Country Manager, Takeda Singapore
Prior to his role as Country Head of Takeda Singapore, Justin helmed the Takeda Oncology Business Unit in Korea. He also spent almost 7 years at Shire and was most recently the Internal Medicine Franchise Head, before its acquisition by Takeda in 2019.