“The problem with disease in Africa is that often, the tools are there, the knowledge is there, the people who can do it are there, and yet people keep on suffering from illness, and outbreaks and deaths.” This insightful commentary by Abraham Aseffa, Scientific Director at Ethiopia’s Armauer Hansen Research Institute, starts The Guardian Labs–Center for Global Development (CGD) video on the vaccine MenAfriVac, and the initiative to eliminate meningitis A across Africa’s meningitis belt. MenAfriVac, a meningococcal A conjugate vaccine, was administered to more than 217 million people in 2010–14, resulting in an estimated 142 000 lives saved and more than a million cases of meningitis prevented.

“Gender diversity exists in every culture and geographic context. It is to be celebrated, not pathologised”, says Sari Reisner, lead author of a paper in The Lancet’s first Series on transgender health. Reisner’s work is helping to advance this agenda. Based in Boston, USA, he enjoys a varied career as Assistant Professor at Harvard Medical School and Boston Children’s Hospital, with a secondary appointment at the Harvard T H Chan School of Public Health, and as Affiliated Research Scientist at The Fenway Institute at Fenway Health.

It was entirely coincidence that I changed employment in 1988 as I was awaiting confirmation from the doctors at Stanford University that I was a worthy candidate for sex reassignment. I had researched and soul-searched for years, struggling with the decision to apply to that programme. I had learned that their entrance criteria were rigorous, and I wanted the validation the programme would give me. I could tell my mother that I had been diagnosed by real doctors, and that there was no doubt my health would benefit from the transition from female to male.

Over dinner last week, a friend turned to the subject of methods (pitiable, but true). He had just been lecturing about how to make epidemiology more meaningful. The two-by-two table was a wonderful creation, but it may not be well adapted to understanding the hypothetical causes and associative consequences of poverty, war, or climate change. Making connections between seemingly disparate settings and events—in other words, interpreting the complexity of the world—was the chief challenge for the health sciences today, he suggested.

The Lancet’s commitment to improving public health practice and research has long been established. From the publication of seminal studies to the hosting of annual public health conferences (in the UK and China), The Lancet has sought to strengthen the part public health can play in ensuring the right to the highest attainable standard of health for every citizen.

People around the world are living longer and a striking and sustained increase in life expectancy has occurred in high-income countries in the past 30 years. A key question for researchers and policy makers is how much of the improvement in mortality and active years of life is due to medical care, and how much to factors such as improved lifestyle and reduced smoking. For coronary heart disease, commonly quoted figures are that around half of the reduction in mortality could be due to improvements in medical care.