Somewhere in the world, a child dies before reaching their fifth birthday.
Then another.
And another.
By the time you finish reading this paragraph, several more children will have been lost.
The numbers are staggering. The World Health Organization estimates that around 4.9 million children under the age of five died globally in 2024 — roughly one child every six seconds. Nearly half of those deaths occurred in the first month of life, a period so fragile that it now accounts for almost half of all under-five mortality worldwide.
Yet this is not a story only about tragedy.
It is also one of humanity’s greatest successes — and one of its unfinished tasks.
The world that used to lose far more children
For most of human history, childhood was perilous.
Families often expected that not all of their children would survive. Disease, poor sanitation, malnutrition and the absence of modern medicine meant that childhood death was not an exception but a common part of life.
Data compiled by Our World in Data shows that child mortality was once extraordinarily high across much of the world. Today, many societies take childhood survival for granted, but that transformation is remarkably recent.
The progress since 1990 has been dramatic.
According to WHO, the global under-five mortality rate has fallen by nearly 60%, while annual under-five deaths have dropped from about 12.8 million in 1990 to fewer than 5 million today. Millions of children who would once have died now survive and grow into adulthood.
The lesson is simple but powerful: child mortality is not an unavoidable fact of life. It can be reduced, often rapidly, when societies invest in health, nutrition, sanitation and education.
What kills children today?
The causes of child deaths vary dramatically depending on where a child is born.
In poorer countries, infectious diseases remain among the biggest killers. Malaria, pneumonia and diarrhoeal diseases continue to claim hundreds of thousands of young lives each year, despite the fact that many of these deaths are preventable or treatable with relatively inexpensive interventions.
But the greatest danger often arrives even before a child has taken their first steps.
Complications linked to premature birth, birth asphyxia, infections during the neonatal period and congenital disorders account for a huge share of deaths. WHO estimates that neonatal deaths now represent roughly 47% of all under-five deaths worldwide.
The contrast between countries is striking.
In lower-income nations, infectious diseases still dominate mortality charts. In wealthier nations, where vaccines, antibiotics, sanitation and routine healthcare are widely available, deaths are more likely to be linked to prematurity, congenital conditions, cancers or other non-communicable diseases.
A child’s chances of survival are therefore shaped not only by biology but by geography.
The lottery of birthplace
Perhaps the most uncomfortable fact about child mortality is that where a child is born remains one of the strongest predictors of whether they survive.
The overwhelming majority of under-five deaths occur in sub-Saharan Africa and South Asia. Children born in the poorest countries face risks that would be considered extraordinary in wealthier parts of the world.
This gap is not primarily about advanced medical technology.
It is often about basics.
Clean drinking water.
Vaccinations.
Skilled birth attendants.
Electricity in health facilities.
Access to antibiotics.
Treatment for malaria.
Adequate nutrition.
These are not futuristic solutions. They are among the most cost-effective public health interventions ever devised. Yet millions of children still lack access to them.
The remarkable success stories
The encouraging news is that child mortality can fall extraordinarily fast.
Countries as diverse as Cambodia, Malawi and Mongolia have achieved reductions of more than 75% in child mortality since 2000. Their experiences demonstrate that rapid improvement is possible even in countries with limited resources when governments, communities and international organisations focus on maternal and child health.
The evidence from richer nations tells a similar story.
Childhood cancer survival has improved dramatically over recent decades. Deaths from road accidents among children have fallen sharply due to safer vehicles, better roads, stronger regulations and improved emergency care.
The pattern is clear: when societies identify a major threat to children and invest consistently in addressing it, mortality falls.
Why progress is slowing
Despite decades of improvement, there are growing concerns that the pace of progress is slowing.
UN agencies warn that reductions in child mortality have decelerated significantly since 2015. Conflicts, climate shocks, economic instability and pressure on health systems are making it harder to sustain earlier gains. Recent cuts in international health assistance have added further concerns.
This matters because the remaining deaths are increasingly concentrated among the hardest-to-reach populations: children living in conflict zones, remote rural communities and areas with weak healthcare systems.
The challenge is no longer discovering what works.
The challenge is delivering it everywhere.
The most important fact
Among all the statistics, one fact stands above the rest.
Most child deaths are preventable.
That is not an aspiration or a slogan. It is the conclusion reached repeatedly by global health experts.
The medicines exist.
The vaccines exist.
The knowledge exists.
The interventions needed to save millions of young lives are often neither complex nor expensive. What is missing is consistent access.
Every six seconds, the world loses a child.
But history shows something equally important: humanity has already proved that those deaths can be dramatically reduced.
The story of child mortality is therefore not merely a measure of suffering. It is a measure of what societies choose to prioritise.
And if the last three decades have demonstrated anything, it is that when the world decides children should live, millions more do.
