Infections now cause under half of deaths in the world’s poorest countries, WHO’s new estimates show. The conditions taking their place call for care, connection and prevention as much as cures.
In 2023, for the first time, communicable diseases caused less than half of all deaths in low-income countries. The finding comes from the World Health Organization’s Global Health Estimates, published on 2 October and covering 2000 to 2023. Global life expectancy reached 73.3 years, almost back to its 2019 level of 73.4. COVID-19 had pulled it down to 71.5 in 2021. That year the virus was the world’s leading cause of death, with 9.4 million direct deaths.
Deaths from HIV and AIDS fell 62% between 2000 and 2023. The disease dropped from seventh to 22nd among causes of death. COVID-19 left the global top 10 for the first time since the pandemic began, falling to 14th. In low-income countries, though, seven of the top 10 causes of death are still communicable, led by lower respiratory infections.
In Global Fund countries, 26.9 million people were on HIV treatment in 2025, up from 25.6 million in 2024. Diagnosis is moving closer to patients too, as cheaper TB tests reach primary care clinics.
The conditions taking over
Noncommunicable diseases caused 74% of deaths worldwide in 2023, up from 58% in 2000. Ischaemic heart disease remains the biggest killer, at 9.5 million deaths a year. Dementia has climbed from 19th place in 2000 to fifth, and its death toll has tripled. Kidney disease has risen from 17th to ninth. Deaths from diabetes have more than doubled to 2 million a year.
Between 2019 and 2023, the age-standardised burden of anxiety disorders rose by nearly 45%, and of depression by about 20%. People live with these conditions for years, so they show up in lost healthy years more than in death counts.
Healthy life expectancy reached 62.8 years in 2023, still 0.4 years below its 2019 level, while lifespan had almost recovered. Dr Alain Labrique directs WHO’s Department of Data, Digital Health, Analytics and AI. “The next challenge is to ensure that those additional years are lived in good health,” he said.
Weight-loss drugs start to show up
In the US, 11% of adults were taking GLP-1 medicines for weight loss in mid-2026, up from 3% in 2024. A Gallup survey of 5,065 adults, run from 28 May to 5 June, also put adult obesity at 36.8%. That is down from a peak of 39.9% in 2022, although the figures are self-reported.
In the SELECT trial, published in November 2023, semaglutide cut the risk of heart attack, stroke or cardiovascular death by 20%. Its 17,000-plus participants had heart disease and excess weight, without diabetes. Swiss Re, a reinsurer, has modelled what wider use could mean in commercial research. Its baseline scenario cuts cumulative US all-cause mortality by 4% by 2045, and UK mortality by 3.2%. Those gains depend on people staying on treatment, because weight can fully return within a year of stopping.
WHO expects fewer than 10% of people who could benefit to get these drugs by 2030. More than a billion people live with obesity, and the gains so far sit mainly in wealthier populations. In India, semaglutide lost patent protection on 20 March, and at least six companies launched generics the next day. They cost Rs1,300 to Rs4,200 a month, against Rs8,800 to Rs10,850 for Novo Nordisk’s brands.
What AI promises
Demis Hassabis is chief executive of Google DeepMind. In April 2025, he told 60 Minutes the end of disease could be within reach in the next decade. “On average, it takes, you know, 10 years and billions of dollars to design just one drug,” he said. “We can maybe reduce that down from years to maybe months or maybe even weeks.”
The Chan Zuckerberg Initiative works to a longer timetable. Its mission is “to help cure, prevent, and manage all disease by the end of this century”. Co-founder Priscilla Chan set it out in June 2025, as the charity moved its science work towards biology and AI.
In February, Isomorphic Labs, DeepMind’s drug discovery spin-out, was still at the preclinical stage. It hoped to reach clinical trials by the end of 2026. Faster drug design could help with cancers, heart disease and perhaps dementia. The daily care that dementia and mental illness need will still fall to people.
Care, connection and prevention
Around 57 million people were living with dementia in 2021, with nearly 10 million new cases each year. In 2019, dementia cost economies US$1.3 trillion, and about half of that came from care by informal carers. Women provide 70% of care hours for people living with dementia.
WHO’s Commission on Social Connection linked loneliness to about 871,000 deaths a year. It found that one in six people worldwide are affected. Its remedies include national policy and social infrastructure such as parks, libraries and cafés.
WHO also estimates that 29 low-cost measures, from tobacco taxes to blood pressure control, could save 12 million lives. They cost US$3 per person a year, and WHO puts the economic return at US$1 trillion by 2030.
Twenty-five years of investment against infection shows up clearly in the 2023 data. The next test is whether health budgets move towards care workers, community spaces and prevention. The gap between lifespan and healthy lifespan, about 10.5 years in 2023, will show whether they do.
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