Throughout my career in public health—as Director of Health in Hong Kong and subsequently as Director-General of the World Health Organization (WHO)—I have been closely involved in local and global responses to numerous outbreaks, epidemics and pandemics, including avian influenza H5N1, the H1N1 2009 pandemic, Zika, SARS, MERS and Ebola. Over the past two decades, a wealth of reviews, high-level panels and independent inquiries were established following the many global health crises that the world has faced. Their conclusions and recommendations have been remarkably consistent. I am frequently asked, “What can we have learned from these events that can help us prevent them from happening again?” To paraphrase a well-known saying, those who do not learn from past pandemics are condemned to repeat them.

As the COVID-19 pandemic has painfully shown, those who wrote the WHO Constitution in 1946 were prescient in their recognition of health as basic to the “happiness, harmonious relations and security of all peoples.” The first lesson my time in office and career in health has taught me is that respiratory pathogens with pandemic potential pose an existential threat as serious as climate change, environmental degradation and nuclear war. However, although political commitment is the first prerequisite—national and global leaders must put health high on the political agenda—all too often, the health and wellbeing of people is seen as a distant cousin in the race for resources when countries determine their spending on economics, defense, infrastructure and other priorities.

The second lesson is to build trust. This is a long and slow process, and the consequences of a deficit in trust are devastating. It divides populations, fuels conspiracy theories and disinformation, and discourages adherence with public-health measures such as early detection, contact tracing, isolation, social distancing and mask wearing that are the foundation of an effective response to the pandemic before safe and effective vaccines become available. Yet trust is so easily destroyed in a moment. This pandemic has demonstrated the importance of the compact between political leaders and the people they govern, between technical experts and the public—a compact based on trust, respect and cooperation, founded on responsibility, honesty, transparency and accountability. Building trust involves responsible leadership, empowering communities, engaging with civil society and encouraging health literacy.

The third lesson I have learned is that those involved in maintaining good public health must broaden their view of health security beyond infectious diseases. Heath security must be based on the principle of universal health coverage and must include noncommunicable diseases. Health security must recognize the critical importance of animal health—the ‘one health’ approach—and of food security and a harmonious relationship with nature. It must acknowledge that ‘none are safe until all are safe’, which requires a firm commitment to solidarity and equity. Nowhere is this more clearly apparent than in the tragic consequences of ‘vaccine nationalism’.

The fourth lesson is the need for a long-term perspective. Health security at national and global levels demands long-term political commitment with sustained financing for investment in systems that are agile, flexible and responsive and evolve rapidly with new technologies and new threats. Countries in Asia and Africa have done better during the COVID-19 pandemic because they learned from experiences with SARS, MERS and Ebola, with long-term planning and investments in public health for surveillance, detection, healthcare systems and social protection. In addition, they have also invested heavily in education and research.

Education is absolutely crucial going forward. It will be central for building back stronger and more-resilient public-health security systems, and universities and schools are critical partners. I began my professional career as a high-school teacher, and I am now returning to my roots in education. As the inaugural dean of the new Vanke School of Public Health at Tsinghua University, I seize this unique opportunity to promote, inspire and nurture the next generation of policymakers, researchers, health workers and community leaders on the imperative of public-health security. With the strong support of Tsinghua leadership, our team has initiated a public-health course for all undergraduate programs at Tsinghua; we stimulate transdisciplinary research and innovation for health protection; we are introducing a new model of education and training for teachers and students to nurture a new cadre of public-health leaders and professionals with perspectives and competencies fit for national and global health cooperation; and, collaborating with the government, the community, non-governmental organizations and business, we will translate research outcomes into policy options and health solutions for action. Last but not least, international cooperation and collaboration with other universities and institutions engaged in research and development, in training and education, and in mutual learning and capacity building are in the DNA of the Tsinghua Vanke School of Public Health. We are not unique; this is the path that many centers of excellence for education and research are vigorously pursuing.

In conclusion, the most important lesson of all is that complacency kills. It is not for a lack of learning that the world is struggling to bring the COVID-19 pandemic to an end. We do not lack solutions; we lack action to implement them. Now is the time to act.