Over half of infectious diseases – including neglected ones such as dengue and leishmaniasis – are aggravated by climatic hazards, according to a new, devastating study published by Nature. We have yet to see the full impact of climate change on these climate-sensitive diseases, but one thing is sure: the most vulnerable populations will once again bear the brunt of a global crisis, warns Joelle Tanguy, Director of External Affairs at the Drugs for Neglected Diseases initiative (DNDi). 

She explains why DNDi has a critical role to play in supporting adaptation to the expected impacts of climate change. 

How serious is the impact of the climate crisis on health?  

Numerous studies have established that the climate crisis is the biggest health threat humanity is facing. Increased pollution, disruption of food systems, population displacements, and climate-sensitive infectious diseases will all have a devastating impact on people’s health around the world. The World Health Organization (WHO) estimates that between 2030 and 2050, climate change will cause 250,000 additional deaths per year from heat stress, malnutrition, dengue, and malaria alone.  

The emergence of zoonotic diseases (illnesses jumping from animals to humans) is facilitated by deforestation and damage to ecosystems. Higher temperatures combined with changes in land cover and increasing rainfall can make more areas suitable for the transmission of vector-borne diseases, and they can also lead to an increase in transmission through higher frequency of biting and an extended transmission season.  

All of this has been well documented in the latest report of the Intergovernmental Panel on Climate Change (IPCC, 2022).  

Take dengue: reported cases have increased by 85% in 30 years. Rising temperatures have led to increased survival and reproduction of the mosquitoes which carry the disease. The number of people at risk of dengue is predicted to reach 60% of the world’s population by 2080.

What risks do climate-sensitive diseases pose? How will people’s health be affected?  

These are difficult questions. There are serious evidence gaps on the impact of the climate crisis on the epidemiology of neglected diseases, and more research is needed.  

What we know for sure is that the people who will be disproportionately affected by climate-sensitive diseases will be, once again, the poorest and the most vulnerable. The climate crisis will bring further immense suffering to an increasing number of already neglected people – and to their families and communities. Climate change acts as a ‘poverty multiplier’ that forces millions into poverty because of diseases, but also loss of livelihoods, displacement, and lack of access to food and clean water. 

According to estimates, the number of people exposed to leishmaniasis may double by 2080. In central Africa, the 55 million people at risk of sleeping sickness could increase by a similar range by 2090. 

Whilst we are already seeing some neglected diseases spreading to new areas in the global north, such as Chagas disease in Spain or the United States, the brunt of the impact is projected to take place in low- and middle-income countries (LMICs).  

We need to act now to develop better medical tools for these already neglected populations. Such tools include drugs, but also diagnostics, vaccines, and vector control measures – as one single tool is not enough for effective disease control and elimination. 

Is the current medical and pharmaceutical ecosystem ready to tackle these global health challenges? 

There is a pressing need to prioritize R&D for climate-sensitive diseases for which drugs and diagnostics are not developed or are not available, as the medical and pharmaceutical industry focuses on more profitable markets. This has historically been the case with neglected tropical diseases (NTDs). 

And even where there is innovation, the last two and a half years have shown that during an emergency, in the middle of a global pandemic, the most vulnerable do not have access to life-saving prevention and treatment tools. COVID-19 vaccines were developed at an unprecedented speed, but they did not reach most people who needed them in many LMICs.  

Unless we act, we will face the same issue of innovation and access inequity with the looming climate crisis. We cannot afford to repeat the NTD experience or have another HIV or COVID-19 moment, when we find ourselves with few or very expensive drugs or vaccines, reserved for the wealthy. We need to act now to prevent history from repeating itself again, or it will be too late.

We are therefore investing in efforts to discover and develop drugs for climate-sensitive NTDs such as leishmaniasis and dengue with academic, public, and industry partners, especially from the Global South; but we are also engaging in policy discussions and advocating for a more equitable, inclusive, sustainable, and access-oriented R&D ecosystem. 

Access must be considered from step one when developing a new drug. The needs of the target populations and health systems, and the necessity to produce affordably and at scale must be fully integrated in the pharmaceutical R&D process. For example, a complex injectable drug that requires weeks of hospitalization would be difficult to administer in remote or resource-limited settings. 

We need to start from today designing an innovation system in such a way that public investments made in academia, in the pharma industry, in hospital capacity for clinical trials, reap the rewards in terms of public health and help build climate resilience. 

We also need to ensure that the medical R&D agenda is included in climate change discussions and bring the topic to high-level meetings. Few are connecting the dots between climate change and the need for medical R&D. Innovation to find new medicines must be an integral part of climate adaptation efforts.  

What is DNDi’s approach to the climate crisis? 

DNDi is developing a four-pronged approach, to power both mitigation and adaptation to the climate crisis. 

First, innovation: we will discover and develop new, adapted, and affordable treatments for climate-sensitive diseases for neglected patients. Many infectious diseases affected by the climate crisis are already in our R&D portfolio. 

Second, greening R&D: we want to proactively contribute to the movement for greening pharmaceutical R&D and manufacturing practices. 

Third, advocating for a responsible biomedical innovation ecosystem. We will advocate for an inclusive and sustainable R&D system and climate adaptation policies that ensure innovation, affordability, and equitable access for all people affected by climate-sensitive, vector-borne diseases, wherever they are.  

And fourth, halving our carbon emissions and our environmental footprint by 2030. To reach that target, we are developing an environmental roadmap in collaboration with our allies, and in dialogue with our pharmaceutical development partners.  

I would like to highlight that our work is not peripheral to the climate issue. Human health needs to be a major pillar of the climate adaptation agenda so that countries are ready for what is coming, and what is already here.  

Because of what we do, because of our ambition to deliver 25 new treatments by 2028, DNDi is at the forefront of climate adaptation strategies to respond effectively to the climate crisis, possibly the greatest challenge humanity has ever faced.   

Photo credit: Ana Ferreira-DNDi