Public health constantly struggles to hold infectious diseases at bay, to change lifestyle behaviours, and to find enough money to do these and many other jobs.
But sometimes we need to step back and celebrate.
Commitment to the Millennium Development Goals brought focus, energy, creative innovation, and above all money to bear on some of the biggest health challenges that marred the start of this century.
We can celebrate the 19 000 fewer children dying every day, the 44% drop in maternal mortality, and the 85% of tuberculosis cases successfully cured.
Africa in particular can celebrate the 60% decline in malaria mortality, especially since the African Leaders Malaria Alliance, supported by partners, did so much to make this happen.
We can celebrate the fastest scale-up of a life-saving treatment in history. More than 15 million people living with HIV are now receiving antiretroviral therapy, up from 690 000 in 2000.
In an interconnected world characterised by profound mobility of people and goods, few threats to health are local anymore.
Air pollution is a transboundary hazard that affects the global atmosphere and contributes to climate change.
Drug-resistant pathogens, including the growing number of “superbugs”, travel well internationally in people, animals, and food.
The marketing of unhealthy foods and beverages, especially to children, is now a global phenomenon. Safeguarding the quality of pharmaceutical products has become much harder, with complex manufacturing procedures and supply chains spanning multiple companies and countries.
Ensuring the quality of the food supply is also much harder when a single meal can contain ingredients from all around the world, including some potentially contaminated with exotic pathogens.
The refugee crisis in Europe taught the world that armed conflicts in faraway places will not stay remote.
The Ebola outbreak in three small countries paralysed the world with fear and travel constraints.
Last year, a business traveller returning home to the Republic of Korea, infected with the MERS coronavirus, disrupted the country’s economy as well as its health system.
The rapidly evolving outbreak of Zika warns us that an old disease that slumbered for six decades in Africa and Asia can suddenly wake up on a new continent to cause a global health emergency.
This year’s appearance of urban yellow fever in Africa, now confirmed in the capital cities of Angola and the Democratic Republic of Congo, is yet another serious event with potential for further international spread.
For infectious diseases, you cannot trust the past when planning for the future.
Changes in the way humanity inhabits the planet have given the volatile microbial world multiple new opportunities to exploit.
The possibility that a mosquito bite during pregnancy could be linked to severe brain abnormalities in newborns alarmed the public and astonished scientists. Confirmation of a causal link between infection and microcephaly has transformed the profile of Zika from a mild disease to a devastating diagnosis for pregnant women and a significant threat to global health.
Outbreaks that become emergencies always reveal specific weaknesses in affected countries and illuminate the fault lines in our collective preparedness.
For Ebola, it was the absence of even the most basic infrastructures and capacities for surveillance, diagnosis, infection control, and clinical care, unaided by any vaccines or specific treatments.
For Zika, we are again taken by surprise, with no vaccines and no reliable and widely available diagnostic tests. To protect women of childbearing age, all we can offer is advice. Avoid mosquito bites. Delay pregnancy. Do not travel to areas with ongoing transmission.
Zika reveals an extreme consequence of the failure to provide universal access to sexual and family planning services. Latin America and the Caribbean have the highest proportion of unintended pregnancies anywhere in the world.
Above all, the spread of Zika, the resurgence of dengue, and the emerging threat from chikungunya are the price being paid for a massive policy failure that dropped the ball on mosquito control in the 1970s.
The lesson from yellow fever is especially brutal. The world failed to use an excellent preventive tool to its full strategic advantage.
For more than a decade, the WHO has been warning that changes in demography and land use patterns in Africa have created ideal conditions for explosive outbreaks of urban yellow fever. Africa’s urbanisation has been rapid, showing the fastest growth rates anywhere in the world.
Migrants from rural areas, and workers from mining and construction sites, can now carry the virus into urban areas with powder-keg conditions: dense populations of non-immune people, heavy infestations with mosquitoes exquisitely adapted to urban life, and the flimsy infrastructures that make mosquito control nearly impossible.
The world has had a safe, low-cost, and effective vaccine that confers life-long protection against yellow fever since 1937. That is nearly 80 years. Yellow fever vaccines should be and must be used more widely to protect people living in endemic countries. Yellow fever is not a mild disease.
Let me give you a stern warning. What we are seeing now looks more and more like a dramatic resurgence of the threat from emerging and re-emerging infectious diseases. The world is not prepared to cope.
High-level assessments of the Ebola response have consistently called for more resilient health systems as a first line of defence.
Given what we face right now, and the next surprises that are sure to come, the item with the most sweeping consequences, for a danger that can quickly sweep around the world, is the one on the reform of WHO’s work in health emergency management.
The programme’s design is aligned with the principles of a single programme, with one clear line of authority, one workforce, one budget, one set of rules and processes, and one set of standard performance metrics.
Few health threats are local anymore. And few health threats can be managed by the health sector acting alone.
As the international community enters the era of sustainable development, the global health landscape is being shaped by three slow-motion disasters: a changing climate, the failure of more and more mainstay antimicrobials, and the rise of chronic noncommunicable diseases as the leading killers worldwide.
These are not natural disasters. They are man-made disasters created by policies that place economic interests above concerns about the well-being of human lives and the planet that sustains them.
This is the way the world works. The burning of fossil fuels powers economies. Medicines for treating chronic conditions are more profitable than a short course of antibiotics. Highly processed foods that are cheap, convenient, and tasty gain a bigger market share than fresh fruits and vegetables.
For antimicrobial resistance, we are on the verge of a post-antibiotic era in which common infectious diseases will once again kill.
The 2030 agenda for sustainable development wants to make sure these and many other disasters are averted. The agenda aims to do nothing less than transform the way the world, and the international systems that govern it, work.
The ambition of the agenda is to tackle the root causes of the world’s many woes, from the degrading misery of poverty to the consequences of terrorism and violence, in an integrated and interactive way.
The ultimate objective of all development activities, whether concerning the design of urban environments or the provision of modern energy to rural areas, is to sustain human lives in good health.
Ambitious goals are feasible and affordable only if we cut out waste and inefficiency.
The target for universal health coverage moves us in that direction.
UHC is the target that underpins all others. It is the ultimate expression of fairness that leaves no one behind. It also has the best chance of meetings people’s expectations for comprehensive care that does not drive them below the poverty line.
It also falls to the health sector to show some principled ethical backbone in a world that, for all practical appearances, has lost its moral compass. We must express outrage at the recent bombings of hospitals and refugee camps in Syria and Yemen, the use of rape and starvation as weapons of war, and the killing of innocent civilians in the pursuit of terrorist goals.
We have victories: polio eradication has never been so close to the finish line, with Africa now free of wild poliovirus for nearly two years.
More countries are exercising their legal right to mandate plain packaging for tobacco products. One tobacco giant has decided not to appeal, adding to the victory.
These are critical victories. No country can hope to bring down the burden of noncommunicable diseases in the absence of strong legislation for tobacco control in line with the WHO Framework Convention on Tobacco Control.
World leaders are concerned about the world drug problem and the need to broaden and balance the response by adopting a public health approach.
They are concerned about a humanitarian system that is overwhelmed and badly needs reform. This concern is reflected in the first-ever World Humanitarian Summit being held this week in Istanbul.
They are concerned about the costs, to economies as well as to health, incurred by noncommunicable diseases.
We have entered an ambitious new era for health development. We have a solid foundation of success to build on.
WHO, together with its multiple partners, is poised to save many more millions of lives.
* Dr Margaret Chan is director-general of the World Health Organisation. This is an edited version of her opening speech at the 69th World Health Assembly speech in Geneva, Switzerland, on Monday.