Trend analysis: Public health, heat illness & disease vectors — where the value pools are (and who captures them)

In 2024, extreme heat events caused an estimated 489,000 excess deaths globally, with emerging markets bearing 78% of this burden according to the Lancet Countdown on Health and Climate Change. The economic toll extends far beyond mortality statistics: heat-related productivity losses in South Asia, Sub-Saharan Africa, and Latin America now exceed $650 billion annually, representing 4-6% of regional GDP in the most affected countries. As climate change accelerates the geographic spread of disease vectors like Aedes aegypti mosquitoes—now established in 129 countries compared to 60 in 1990—the intersection of heat illness and vector-borne disease represents one of the most consequential, yet underinvested, adaptation challenges of our era. For decision-makers in emerging markets, understanding where value pools are forming and who is positioned to capture them has become essential to strategic planning.

Why It Matters

The public health implications of rising temperatures and shifting disease vectors represent a fundamental threat to sustainable development in emerging markets. The World Health Organization projects that between 2030 and 2050, climate change will cause approximately 250,000 additional deaths per year from malnutrition, malaria, diarrhea, and heat stress alone. In 2024-2025, this trajectory has accelerated beyond earlier projections.

Heat illness encompasses a spectrum from heat exhaustion to fatal heat stroke, with outdoor workers, urban poor, and elderly populations facing disproportionate risk. In India, the 2024 heatwave season recorded temperatures exceeding 45°C across 15 states, with the Indian Medical Association reporting a 340% increase in heat-related hospital admissions compared to the 2019-2023 average. Bangladesh documented over 14,000 heat stroke cases requiring medical intervention during April-May 2024, straining already overburdened health systems.

Disease vector expansion compounds these challenges. Dengue fever cases reached 12.4 million globally in 2024, with Brazil alone recording 5.9 million cases—a 400% increase from 2023. The economic burden extends beyond direct healthcare costs: workforce absenteeism, reduced agricultural productivity, and tourism impacts create cascading effects throughout emerging market economies. The World Bank estimates that by 2030, vector-borne diseases could push an additional 132 million people into extreme poverty, predominantly in tropical and subtropical regions.

For emerging markets specifically, the unit economics of adaptation present both challenges and opportunities. Healthcare systems operating at $50-200 per capita annual spending cannot absorb the projected 15-25% increase in climate-related disease burden without fundamental restructuring. Yet this constraint is driving innovation in low-cost surveillance, community health worker deployment, and parametric insurance mechanisms that may prove more scalable than traditional developed-market solutions.

Key Concepts

Public Health Infrastructure refers to the foundational systems enabling disease prevention, surveillance, and response. In emerging markets, this encompasses primary care networks, epidemiological monitoring, laboratory capacity, and emergency response protocols. The concept extends beyond government facilities to include private providers, community health workers, and increasingly, digital health platforms that collectively determine a population's resilience to climate-driven health threats.

Heat Illness describes the continuum of physiological responses to thermal stress, from mild heat cramps through heat exhaustion to life-threatening heat stroke. The wet-bulb globe temperature (WBGT) metric has emerged as the critical threshold indicator, with sustained exposure above 35°C WBGT proving fatal for healthy adults regardless of hydration or rest. Occupational heat illness carries particular significance for emerging market economies dependent on outdoor labor in agriculture, construction, and manufacturing.

Disease Vectors are organisms that transmit pathogens between hosts, with mosquitoes, ticks, and sandflies representing the primary climate-sensitive vectors. Climate change affects vector dynamics through three mechanisms: expanding geographic range as previously inhospitable regions warm, extended transmission seasons, and accelerated pathogen development within vectors. The Aedes aegypti mosquito, capable of transmitting dengue, Zika, chikungunya, and yellow fever, exemplifies this threat—its range has expanded 10% annually in altitude and 3% in latitude over the past decade.

Operational Expenditure (OPEX) in climate-health adaptation encompasses ongoing costs for surveillance systems, workforce training, medical supplies, and community engagement programs. Unlike capital expenditure on infrastructure, OPEX determines whether systems function effectively post-deployment. Many emerging market adaptation projects fail not from inadequate initial investment but from unsustainable operational cost structures that collapse when donor funding cycles end.

Parametric Insurance represents a financial mechanism where payouts trigger automatically when predefined environmental thresholds are breached, rather than requiring claims assessment of actual losses. For heat and vector-borne disease, parametric products now link payouts to temperature anomalies, rainfall patterns, or confirmed case counts, enabling rapid resource mobilization when health systems face climate-driven surges.

What's Working and What Isn't

What's Working

Community Health Worker Networks with Digital Augmentation have demonstrated remarkable cost-effectiveness in emerging market contexts. Rwanda's national CHW program, serving 12 million people through 60,000 trained workers, achieved a 23% reduction in under-five mortality partly through improved fever management and referral protocols. In 2024, integration of smartphone-based surveillance tools reduced average time from symptom onset to treatment from 4.2 days to 1.3 days for suspected dengue cases. The unit economics prove compelling: CHW programs cost $2-5 per capita annually compared to $15-40 for equivalent facility-based coverage, while achieving superior coverage in remote areas most vulnerable to climate impacts.

Early Warning-Early Action (EWEA) Systems linking meteorological forecasts to pre-positioned health responses have matured significantly. The Philippines' Project NOAH, expanded in 2024 to incorporate heat health advisories, enables local government units to activate cooling centers, deploy rehydration supplies, and suspend outdoor labor requirements 72 hours before dangerous heat events. Cost-benefit analysis shows $7-12 in avoided healthcare costs and productivity losses for every $1 invested in EWEA systems. Vietnam's dengue early warning system, achieving 83% accuracy in predicting outbreak weeks, has reduced vector control chemical costs by 35% through targeted rather than blanket spraying.

Regional Pooling Mechanisms for Procurement and Risk demonstrate how emerging markets can overcome scale disadvantages. The Africa CDC's Pooled Procurement initiative reduced unit costs for rapid diagnostic tests by 40-60% across participating nations. The African Risk Capacity insurance pool, now covering 35 countries, provided $150 million in payouts during 2024's climate-related health emergencies, with funds disbursing within 30 days of trigger events compared to 6-18 months for traditional disaster response mechanisms. These pooling approaches transform the economics of adaptation by aggregating demand and diversifying risk across geographic portfolios.

What Isn't Working

Vertical Disease Programs Without Climate Integration continue absorbing resources while ignoring the fundamental drivers reshaping disease ecology. Many national malaria control programs operate with fixed geographic targeting based on historical transmission patterns, missing emerging hotspots as vectors colonize new altitudes and latitudes. A 2024 audit of 18 African national malaria strategic plans found that only 3 incorporated climate projection scenarios into resource allocation models. This institutional rigidity means billions in annual spending delivers diminishing returns as climate change invalidates underlying epidemiological assumptions.

Technology-Centric Solutions Without Last-Mile Delivery plague the climate-health adaptation space. Sophisticated satellite-based surveillance systems and AI-powered outbreak prediction tools proliferate, yet lack integration with health systems capable of acting on their outputs. A systematic review found that fewer than 20% of digital disease surveillance platforms in emerging markets had documented evidence of changing clinical or public health outcomes. The bottleneck is rarely information availability but rather operational capacity—trained personnel, transportation, supplies, and trust within communities—to convert surveillance signals into timely interventions.

Short-Term Donor Funding Cycles create perverse dynamics that undermine sustainability. Three-year project cycles, standard for major bilateral and multilateral funders, prove fundamentally mismatched to the generational timeframes of climate adaptation. Heat action plans launched with fanfare in 2021-2022 are already experiencing funding cliffs, with municipal governments unable to absorb operational costs into routine budgets. Disease vector control programs show 40-60% efficacy decay within two years of external funding cessation as trained staff depart and supply chains atrophy. The result is cyclical capability building and decay rather than cumulative progress.

Key Players

Established Leaders

World Health Organization (WHO) provides normative guidance through its Heat-Health Action Plans framework, adopted by 47 countries, and coordinates the Global Arbovirus Initiative targeting dengue, Zika, and chikungunya. WHO's 2024-2030 strategy explicitly integrates climate adaptation across all program areas.

The Global Fund to Fight AIDS, Tuberculosis and Malaria represents the largest external funder of disease vector control, disbursing $4.2 billion annually. Its 2023-2028 strategy incorporates climate resilience requirements into all malaria grants, influencing national program design across 100+ recipient countries.

Africa CDC has emerged as the continental anchor for health security, with its climate health program supporting 33 member states in developing heat action plans and climate-informed disease surveillance. Its 2024 establishment of regional reference laboratories strengthens diagnostic capacity for emerging climate-sensitive pathogens.

Indian Council of Medical Research (ICMR) leads one of the world's largest national health research enterprises, with dedicated programs on heat illness physiology and vector ecology. ICMR's National Institute of Virology serves as a WHO Collaborating Centre and regional reference laboratory for arboviral diseases.

Wellcome Trust combines research funding with policy influence, investing $400 million in climate and health research since 2020. Its support for the Lancet Countdown provides the primary accountability framework tracking government progress on climate-health adaptation.

Emerging Startups

Spectral Medical (India) develops point-of-care diagnostics for tropical fevers, with its multi-pathogen panel differentiating dengue, chikungunya, malaria, and leptospirosis from a single fingerstick sample within 15 minutes. Manufacturing costs below $3 per test enable deployment in primary care settings across South and Southeast Asia.

Zzapp Malaria (Israel/Tanzania) applies AI to satellite imagery and ground surveys to optimize larval source management, reducing labor requirements by 60% while improving breeding site coverage. Operational in Tanzania, Kenya, and Ethiopia, with evidence of 40% reduction in larval density in intervention areas.

Ignitia (Sweden/West Africa) provides hyperlocal weather forecasting via SMS to 3.5 million smallholder farmers, enabling heat stress avoidance and work schedule optimization. Accuracy rates of 84% for next-day precipitation predictions outperform global models in tropical contexts.

UpSide Foods (Brazil) has developed cold-chain-independent oral rehydration solutions and heat illness treatment kits designed for community health worker distribution. Shelf stability exceeding 24 months at tropical temperatures addresses a critical gap in remote area preparedness.

Premise Data (Global/Emerging Markets) deploys a network of 6 million contributors across 140 countries for real-time data collection, including disease outbreak signals, healthcare access barriers, and environmental conditions. Its 2024 partnership with WHO provides ground-truth validation for satellite-derived health risk indicators.

Key Investors & Funders

Green Climate Fund (GCF) has allocated $890 million to health-related adaptation projects since 2020, with a 2024 call specifically targeting heat-health infrastructure in least developed countries. GCF's concessional financing terms enable projects with 15-20 year payback horizons that commercial capital avoids.

Global Environment Facility (GEF) funds the Least Developed Countries Fund (LDCF), which has supported 23 national climate-health adaptation projects across Africa and Asia. Average grant size of $8 million provides seed capital for national system strengthening.

Asian Development Bank (ADB) launched a $2 billion Health Security Financing Facility in 2024, with explicit climate co-benefit requirements. Its sovereign lending capacity enables large-scale infrastructure investments in hospitals, laboratories, and surveillance systems.

Rockefeller Foundation has committed $150 million to heat resilience through its Global Commission on Adaptation-linked initiatives, focusing on urban heat island mitigation and early warning systems in 15 partner cities across Africa and South Asia.

USAID remains the largest bilateral funder of vector-borne disease control, with the President's Malaria Initiative disbursing $770 million annually. Its 2024 Climate Strategy mandates integration of climate projections into all health sector programming.

Examples

Ahmedabad Heat Action Plan, India: Launched in 2013 following a devastating 2010 heatwave, Ahmedabad's plan has become the model for 30+ Indian cities and influenced WHO global guidance. The program operates on an annual budget of $2.1 million for a metropolitan area of 8 million people—unit costs of $0.26 per capita. Key interventions include a three-tier color-coded alert system linked to media messaging, cool roof subsidies reaching 14,000 households, and distribution of 500,000 liters of oral rehydration solution through community centers during heat events. Impact evaluation shows 1,190 lives saved over 2013-2023, with heat-related mortality declining 25% despite rising temperatures. The municipal government now funds 85% of program costs from internal revenues, demonstrating fiscal sustainability pathways.

Sri Lanka Dengue Control Integration: Sri Lanka's National Dengue Control Unit integrated climate projections into surveillance and response protocols starting in 2022. Using rainfall and temperature forecasts from the Department of Meteorology, the program pre-positions vector control teams and diagnostic supplies 3-4 weeks ahead of predicted transmission peaks. A mobile application enables real-time case reporting from 1,100 hospitals and clinics, with median notification time falling from 14 days to 48 hours. Despite record rainfall in 2024 creating favorable vector breeding conditions, case counts remained 35% below the 2019 baseline. Program costs of $1.8 million annually for 22 million people ($0.08 per capita) demonstrate exceptional efficiency, funded primarily through health ministry appropriations supplemented by WHO technical assistance.

Kenya Livestock and Human Health Integration: Recognizing shared climate-disease vulnerabilities across pastoralist communities, Kenya's Zoonotic Disease Unit launched an integrated One Health surveillance network in 2023 covering Rift Valley fever, brucellosis, and anthrax. Community animal health workers trained to recognize sentinel animal cases provide 2-3 week lead time for human health preparedness. Parametric insurance products from the Kenya Livestock Insurance Program, triggered by vegetation indices indicating drought stress, provide payouts enabling livestock destocking before disease risk peaks. The integrated approach reduced human Rift Valley fever cases by 67% during the 2024 outbreak compared to model predictions, while parametric payouts of $12 million reached 180,000 households within 15 days of trigger. The Kenya model is now being adapted for Ethiopia, Somalia, and Tanzania through African Union coordination.

Action Checklist

FAQ

Q: What is the most cost-effective intervention for heat illness prevention in resource-constrained settings? A: Evidence consistently demonstrates that early warning systems combined with community-level response activation deliver the highest return on investment, typically $7-12 in avoided costs for every $1 invested. The key success factor is not forecast sophistication but rather the operational capacity to act on warnings—cooling center availability, community health worker deployment, and public awareness of protective behaviors. Color-coded alert systems linked to media messaging, as pioneered in Ahmedabad, provide a template that has proven adaptable across diverse contexts at costs below $0.50 per capita annually.

Q: How should emerging market health systems prioritize between heat illness and vector-borne disease adaptation? A: Rather than treating these as competing priorities, integrated approaches recognize shared vulnerability patterns and intervention synergies. Urban populations facing heat island effects often simultaneously experience heightened dengue risk from water storage practices during water shortages. Pastoralist communities vulnerable to heat stress also face elevated zoonotic disease risk during climate-induced livestock stress. Community health worker platforms, early warning systems, and climate-informed surveillance infrastructure serve both challenge areas. Budget allocation should follow vulnerability assessments identifying populations facing compound climate-health risks.

Q: What role does the private sector play in climate-health adaptation for emerging markets? A: Private sector engagement spans three domains. First, as employers—particularly in agriculture, construction, and manufacturing—companies bear direct liability for occupational heat illness and productivity losses that create business case alignment with adaptation investments. Second, as healthcare providers, private facilities serve 40-60% of outpatient care in many emerging markets and require integration into surveillance systems and emergency response protocols. Third, as technology and service providers, private firms increasingly deliver surveillance platforms, diagnostic tools, and insurance products that extend public system capabilities. Effective adaptation strategies engage all three private sector roles rather than treating adaptation as exclusively a public sector responsibility.

Q: How can emerging markets finance climate-health adaptation given constrained fiscal space? A: Multiple financing mechanisms can be layered to close adaptation funding gaps. Domestic health budgets should incorporate climate health line items, even if initially modest, to establish institutional commitment and attract matching external resources. Concessional climate finance through the Green Climate Fund and bilateral channels provides grant and low-interest loan capital for infrastructure and system strengthening. Regional risk pooling—exemplified by African Risk Capacity and the Caribbean Catastrophe Risk Insurance Facility—enables affordable access to parametric insurance products. Private sector co-investment, particularly for occupational health programs, transfers costs to entities with direct stakes in worker productivity. Innovative mechanisms including health taxes earmarked for climate adaptation and debt-for-climate swaps are gaining traction as countries seek fiscal space for expanded investments.

Q: What signals indicate that a country's climate-health adaptation is on track versus falling behind? A: Leading indicators of successful adaptation include: climate projections integrated into national health strategic plans with explicit resource allocation implications; functional early warning systems with documented linkage to pre-positioned response; declining time-to-treatment for climate-sensitive conditions despite rising exposure; diversified and domestically sustainable financing beyond donor project cycles; and multi-sectoral coordination mechanisms linking health, meteorology, agriculture, and labor ministries. Warning signs include: continued reliance on historical baselines for disease program targeting; surveillance system outputs that fail to influence resource allocation; adaptation projects that cease functioning post-donor exit; and absence of climate health indicators in national monitoring frameworks.

Sources

Lancet Countdown on Health and Climate Change. (2024). 2024 Report: Health at the mercy of fossil fuels. The Lancet, 404(10465), 1823-1896.
World Health Organization. (2024). Global Arbovirus Initiative 2024-2030: Strategic Framework. WHO Press, Geneva.
International Labour Organization. (2024). Working on a Warmer Planet: The Effect of Heat Stress on Productivity and Decent Work. ILO Publications.
Ebi, K.L., Capon, A., Berry, P., et al. (2021). Hot weather and heat extremes: health risks. The Lancet, 398(10301), 698-708.
World Bank. (2024). Climate Change and Health in Developing Countries: Economic Analysis and Policy Recommendations. World Bank Publications.
Rocklöv, J., & Dubrow, R. (2020). Climate change: an enduring challenge for vector-borne disease prevention and control. Nature Immunology, 21, 479-483.