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It is a great honour to join you today at the 2025 Preventive Medicine Scientific Conference.
Let me begin by offering WHO’s sincere congratulations to NIHE on your 80th anniversary – for eight decades of excellence in protecting Viet Nam people from a huge range of infectious disease threats – from smallpox, polio and neonatal tetanus, to COVID-19 and dengue more recently.
I would especially like to express our admiration and appreciation for NIHE’s role in Viet Nam’s national immunization program – established 50 years ago – through which millions of children have been protected from deadly vaccine-preventable diseases.
So, it is a year of very big anniversaries, which are of course moments for celebration. They also provide a natural inflection point – for reflection on the past, as well as consideration of the future and the challenges and opportunities it will bring.
This is why I wanted to spend the time you have generously given to WHO in your program today, to talking about one of the greatest health threats we face in the future: climate change, and what it means for health systems, and for our work as public health professionals.
So, let me begin with a question: Is climate change the greatest threat to human health this century?
The first point to make on this topic is an obvious but important one: human health is inseparable from the health of our environment.
Clean air, safe water, nutritious food and safe living environments are the foundations of good physical and mental health – but they are all threatened by climate change. Let me briefly mention 4 specifics.
First, I already mentioned dengue as an issue we were used to dealing with in the past. But it is increasingly becoming an issue we will need to confront – and think differently about – in the future: the global burden of dengue has grown dramatically in the past few decades, as rainfall patterns change and temperatures rise. Outbreaks are less predictable and more frequent, with around half of the world’s population now considered at risk.
The burden from other climate-sensitive diseases is also growing: just this year we have seen a significant resurgence of chikungunya in our Region, and malaria elimination efforts are also now at risk.
The second issue is air pollution, not the same as but closely related to climate change.
You all know that air pollution is a major threat to health. Here in Viet Nam, at least 70,000 deaths occur every year as a result of polluted air – a problem which threatens to reduce average life expectancy by 1.4 years.
Just think about that last figure for a moment – despite all the amazing gains we have made in public health in recent decades, air pollution means that today’s Vietnamese children risk experiencing a lower life expectancy than their parents.
The third way that climate change is affecting our health is through extreme weather events. Storms, floods and landslides bring the risk of injury and death, and damage to health infrastructure – as we are experiencing in Viet Nam on an almost weekly basis at the moment. Sadly, just this week Storm Number 10 (Typhoon Bualoi) claimed at least 29 lives and caused widespread damage to infrastructure – including health facilities.
Extreme heat also increases the risk of disease and death – especially for vulnerable groups such as the very young and the very old. Globally, the number of people exposed to heat stress is growing exponentially due to climate change, with heat-related mortality for people over 65 years of age increasing by approximately 85% over the last two decades.
Fourth, climate change is accelerating the effects of slower-onset disasters like drought, saltwater intrusion and sea level rise, which harm food production, access to water and livelihoods.
I saw firsthand the effect of saltwater intrusion on health care during a visit to Cu Lao Minh Area General Hospital in Vinh Long Province (formerly Ben Tre) earlier this year. Because of its location in the Mekong Delta where saltwater intrusion is intensifying, the hospital’s usual water supply had become unsafe for patients –making medical equipment rusty, and compromising the hospital’s ability to provide safe, quality care to its patients.
So, the climate crisis is very much a public health crisis – to which Viet Nam is particularly exposed.
Around 70% of Viet Nam’s population live in coastal or low-lying areas, which highly vulnerable to extreme weather, saltwater intrusion and sea-level rise.
Nearly half of health-care facilities lack reliable access to safe water. Many are not built to withstand climate shocks.
And we are seeing more heat-related illnesses, vector-borne diseases and respiratory conditions linked to pollution.
So, this is not a distant, future threat. It is happening now – and it will get worse in the future without action to change course.
And so, the theme of this conference—preventive medicine—could not be more timely.
Here I want to mention Resolution 72, signed by His Excellency General Secretary To Lam just last month. "Disease prevention”, mentioned dozens of times in the Resolution, is described as the top priority of a “modern, equitable and sustainable health system”.
In line with this ambition, and Viet Nam’s commitment to addressing climate change, I’d like to briefly outline three priorities for the health sector – to prevent public health threats caused by the changing climate.