Exploring Overlooked Health  Frontiers: Navigating the Landscape of Tropical and Topical Diseases, Spotlight on Malaria, Dengue and Flu Vaccinations

Nearly 42 children globally succumb to malaria every hour, while since the onset of 2024, approximately 6 individuals perish daily due to dengue fever worldwide. 

Over the past several years, focus on infectious diseases has predominantly revolved around COVID-19 and its significant toll on humanity, society and the economy. Remarkable progress has been made, spurred on by significant investments that have driven scientific advancements, particularly evident in the development of vaccines and early treatment strategies. As part of the multilateral crisis response, the World Bank Group delivered an unprecedented $204 billion in financial support to public and private sector clients in the first two years of the crisis to support vaccine rollout in 78 countries. 

However, a notable drawback has emerged: due to the re-diversion of funding towards COVID-19 efforts, other areas of concern were overshadowed. 

Prevalence of Malaria and Dengue

In 2022, an estimated 249 million malaria cases and 608,000 malaria deaths in 85 countries were reported globally. While the WHO African Region was home to 94% of malaria cases (233 million) and 95% (580,000) of malaria deaths, the WHO Southeast Asia region accounted for 5.2 million malaria cases and 8,000 malaria deaths and the WHO Western Pacific Region accounted for 1.9 million malaria cases and 3600 malaria deaths. 

In the WHO Southeast Asia region, 10 out of 11 Member States are known to be endemic for dengue virus. In 2023, several countries, including Bangladesh and Thailand, have reported a notable surge in dengue cases compared to previous years. The Western Pacific Region continues to face a high burden of mosquito-borne arboviral diseases, particularly dengue. Between 1 January 2023 to 7 December 2023, over 500,000 dengue cases and 750 deaths were reported from eight countries/territories/areas in the WHO Western Pacific Region: Australia, Cambodia, China, Lao People’s Democratic Republic, Malaysia, Philippines, Singapore and Vietnam. 

Battlegrounds against dengue in Asia include India, Vietnam, Indonesia, Thailand, Malaysia and Singapore and the global incidence of dengue has markedly increased over the past two decades. WHO documented a ten-fold surge in reported cases of dengue worldwide increasing from 500 000 to 5.2 million which poses a substantial public health challenge.  

The disease is now endemic in more than 100 countries in the WHO Regions of Africa, the Americas, the Eastern Mediterranean, Southeast Asia and the Western Pacific. The Americas, Southeast Asia and Western Pacific regions are the most seriously affected, with Asia representing around 70% of the global disease burden. 

Key factor leading to rise in prevalence

In the past, mortality from malaria and dengue was low to very low — now there is significant mortality. Currently, the key aspect of concern is that the diseases’ epidemiology is changing worldwide, moving them towards becoming deadly diseases.  

This element is greatly influenced by climate change and rampant sub-optimally planned urbanisation, which has led to ideal breeding conditions for the Anopheles mosquito (Spreads Malaria) and Aedes aegypti mosquito (Spreads Dengue). This has resulted in incidences of both malaria and dengue manifesting even outside their season of circulation across countries. 

Widespread and increasing insecticide resistance has been posing a threat to effective malaria and dengue vector control respectively. Failure to mitigate and manage insecticide resistance is likely to result in an increased burden of disease, potentially reversing some of the substantial gains made in controlling the two vector-borne diseases over the last decade. 

Moreover, the growing incidence of dengue and malaria represents not only a critical health concern but also imposes a hefty economic toll on affected countries, impacting direct and indirect income for families, estimated at approximately US$950 million annually in Southeast Asia. As reported by the Lancet, global malaria spending – accounting both for government and out-of-pocket spending – amounted to $4.3 billion in 2016 and annual losses arising from malaria and dengue-infected families are estimated to be in tens of billions of dollars. 

A Path Forward

With prevention and control being the most effective methods in tackling the spread of both dengue and malaria, affected countries will need to focus on programmatic use of preventive measures like vaccines to address vector-borne diseases in children living in endemic areas, prioritizing areas of moderate and high transmission. Vaccine makers like Serum Institute of India, have already begun repurposing their COVID vaccine manufacturing facilities to develop shots against malaria and dengue. Pending necessary approvals for use, Takeda has tied up with India-based firm Biological E Ltd to manufacture its dengue vaccine. 

Other than vaccine roll-out, given the scale of public health issues emanating from malaria and dengue, governments will need to take the lead on screening measures and under respective national programs, will need to engage in effective mass-communication campaigns to promote prevention tools to lower the risk of getting infected by malaria and dengue-carrying mosquitoes. Such campaigns are also needed to re-educate citizens in high-risk areas about ways to avoid creating breeding conditions for disease-carrying mosquitoes. In doing so, governments must also direct attention towards systematic planning of urbanization. 

At present, malaria has an effective treatment regime and vaccination in place, but dengue has no specific curative measures. While a dengue vaccination exists (Qdenga [TAK-003] vaccine – developed by Takeda in Japan), its availability is limited in Southeast Asia and the Western Pacific Region due to ongoing clinical trials in most countries in these regions. Since existing curative measures only help in managing symptoms, governments will also need to continue collaborating to fill knowledge gaps, explore potential treatments and test drug candidates with a primary focus on producing cost-effective and accessible treatments within the next five years. 

It is expected that forums like the upcoming Asia Dengue Summit in June will help policymakers in the region facilitate discussions on recent advancements in vector control, modeling techniques and emerging dengue vaccines to identify new strategies to reduce fatality rates.