Under-five mortality: a decline that must be consolidated

Every six seconds, a child under the age of five dies somewhere in the world. In 2024, 4.9 million of them did not reach their fifth birthday, including 2.8 million in sub-Saharan Africa, or 58 % of the global total. Behind this figure lies a paradox that West African decision-makers must confront: child survival has never been so technically attainable, and yet the pace of progress has never slowed so much. The real question is no longer whether we know how to drive mortality down, several countries in the region have proven that we do, but why the reservoir of lives that could be saved remains so unevenly tapped from one country to the next.

A one-to-three gap within a single region

Behind the regional average lies a deep divide. In 2024, Nigeria (115.6 deaths per 1,000 live births) and Niger (110.7) rank among the highest under-five mortality rates in the world, within a small group of countries still above the threshold of 100. At the other end, Ghana (35.9) and Senegal (36.5) sit at levels three times lower. In other words, a child born in Lagos or Niamey is roughly three times more likely to die before age five than a child born in Accra or Dakar. This gap, within a single regional space that shares a similar climate, epidemiological profile and institutional heritage, is in itself proof that under-five mortality is less a matter of fate than of public policy choices.

The comparison with the rest of the world makes the stakes even more tangible. In sub-Saharan Africa, one child in fourteen dies before their fifth birthday, a risk roughly fourteen times higher than that of a child born in Europe or North America. The sub-Saharan regional rate, 71.6 deaths per 1,000 live births, places West Africa at the heart of this global excess mortality. For a research firm, the message is clear: the gap to be closed is not a statistical abstraction, it is a map of avoidable deaths that data makes it possible to locate.

Trajectory matters as much as level

The mortality level at a given moment says less than the slope a country is on. Senegal is the most thoroughly documented illustration: its rate fell from 128.9 deaths per 1,000 live births in 2000 to 36.5 in 2024, a reduction of 72 %. Over the 2000-2015 period alone, studied by the Exemplars in Global Health programme, under-five mortality there dropped by 56 %, from 117 to 52 deaths per 1,000 live births. Benin, for its part, brought its rate down from 107.4 in 2010 to 74.7 in 2024, a decline of 30.4 %. Benin's progress is real, but the difference in pace with Ghana and Senegal maps out precisely the catch-up room that remains.

Read over time, the Senegalese curve is no statistical accident. It is the product of a combination of levers applied with consistency: a build-up of data and health surveillance capacity, investments in supply chains and water and sanitation networks, and above all a dense network of community health workers, locally recruited and strongly empowered. The result of this alignment can be quantified. According to modelling with the Lives Saved Tool, 155,059 children's lives were saved in Senegal between 2000 and 2016 through specific interventions, the main contributors being immunisation (notably Haemophilus influenzae type b and measles), neonatal and antenatal care, and water, hygiene and sanitation interventions.

The one-to-three gap between Accra and Niamey, within a single region, is the clearest proof that child survival is a matter of public policy choices, not of fate.

The why: mortality concentrated on preventable causes

Understanding where to act requires breaking mortality down by timing and by cause. Two frontiers structure the risk. The first is the first month of life: worldwide, the 2.3 million neonatal deaths account for 47 % of all under-five deaths, and the West and Central Africa region records the highest neonatal mortality rate in the world, at 29 deaths per 1,000 live births in 2023. The second frontier, beyond the first month, is that of infectious diseases: complications of prematurity, intrapartum-related events (asphyxia, trauma), pneumonia, diarrhoea and malaria concentrate the bulk of mortality. In West Africa, malaria, pneumonia and diarrhoea together account for the majority of under-five deaths, with malaria responsible, by current estimates, for roughly one death in six.

This breakdown has a direct operational consequence: these are not diseases beyond reach, but causes for which proven and low-cost interventions exist. The twin battle is therefore clear: secure the neonatal period (emergency obstetric care, quality of delivery, newborn care) and close the doors left open to infections (immunisation, prevention, nutrition, safe water). Senegal achieved a 38 % drop in neonatal mortality (from 35 to 22 deaths per 1,000) and a 90 % reduction in malaria mortality over 2000-2015, proof that both fronts respond to action.

• Neonatal period: 47 % of under-five deaths occur within the first month; West and Central Africa holds the world's highest neonatal rate (29 per 1,000 in 2023).
• Malaria: roughly one child death in six in West Africa, by current estimates, now addressable through the RTS,S and R21 vaccines.
• Pneumonia and diarrhoea: together with malaria, they concentrate the majority of mortality beyond the first month, all largely preventable or treatable.
• Underlying determinants: nutrition, breastfeeding, water and sanitation condition a child's resistance to infection and rank among the leading contributors to lives saved.

A slowdown that changes the nature of the effort

The most worrying signal is not the current level, but its dynamic. The global annual rate of reduction in under-five mortality fell from 3.9 % over 2000-2015 to 1.5 % over 2015-2024; since 2015, the pace of reduction has slowed by more than 60 %. This flattening is not an abstract statistic: it means that the easiest gains, those that mass campaigns could capture rapidly, have largely been secured. The next tranche of lives saved will be harder and more costly to obtain, because it lies in pockets of population that are more difficult to reach.

These pockets of excess mortality are not randomly distributed. They cluster where conflict, climate shocks and antimicrobial resistance degrade access to essential services, notably in northern Niger and north-eastern Nigeria. They also lodge in the poorest households: an analysis covering ten high-burden African countries estimates that up to 45 % of under-five deaths there are attributable to economic inequality. Residual mortality has therefore become a problem of equity and geographic targeting, not merely of average coverage. This is exactly the kind of problem that a national average masks and that disaggregated measurement reveals.

The cost of inaction, and the return on action

Changing nothing about the current trajectory has a measurable price. If the global pace stays on its slowed slope, millions of additional children will die of preventable causes in the years ahead, and West Africa will bear a disproportionate share given its demography. Conversely, investment in child survival is among the highest-return investments in global health: every dollar invested in child survival can generate up to twenty dollars in social and economic benefits, and immunisation alone shows an estimated return of around 21 dollars per dollar spent. Under-five mortality is therefore not only a human tragedy; it is a loss of human capital and future productivity that public budgets end up paying for more dearly than prevention.

The arrival of malaria vaccines illustrates this shift in what is possible. After a pilot phase that reached more than two million children in Ghana, Kenya and Malawi and demonstrated a 13 % drop in all-cause mortality, routine malaria vaccination began in 17 countries from January 2024, aiming to reach about six million children in the first year and up to 50 million children over 2026-2030. For countries where malaria accounts for roughly one child death in six, this is a first-order reduction lever, provided it is embedded in systems able to carry it to the last mile.

What averages hide, and why granular data changes the decision

A national average is a statistical convenience that can become a policy trap. A rate of 74.7 deaths per 1,000 in Benin sums up a reality that varies sharply by region, by household income level, by setting (urban or rural) and by the mother's sex. When up to 45 % of deaths, in high-burden countries, are attributable to economic inequality, acting on average coverage alone amounts to watering uniformly a field where only a few plots are thirsty. The consequence is mechanical: scarce resources scattered where the marginal return is low, instead of being concentrated where each intervention saves the most lives.

It is precisely at this juncture that the value of a research firm like CRAD lies. Securing the neonatal period, targeting fragile territories, tracking actual (not reported) immunisation coverage, all of this requires disaggregated, geolocated and reliable data, collected as close to the ground as possible and presented in a form that informs the decision. The Senegalese trajectory confirms this by implication: among its four identified drivers, the first cited is the improvement of data, research and health surveillance capacity. A health system is not steered on annual averages; it is steered on the map of its inequalities, updated often enough to direct action before deaths occur.

Acting on average coverage alone means watering uniformly a field where only a few plots are thirsty. Disaggregated data tells you where each intervention saves the most lives.

Gender and financing: two often forgotten conditions

Two cross-cutting levers condition the durability of the gains. The first is the role of women and mothers: maternal education, access to antenatal care, the mother's nutrition and breastfeeding promotion rank among the most robust determinants of child survival. Neonatal and antenatal care are among the leading contributors to the 155,059 lives saved in Senegal, which underscores that a child's health begins with the mother's and with the quality of delivery. Investing in maternal health is not a policy distinct from child survival: it is the same policy seen through its most decisive point of entry.

The second lever is the consistency of financing. The lesson of the Senegalese and Ghanaian trajectories is that a durable reduction comes not from one-off interventions, but from the coherence and steadiness of investments, in maternal and child health, in immunisation, in water and sanitation, and in community networks. In a context where international development aid is under strain, securing stable and predictable domestic financing becomes a condition for the very survival of progress. The global slowdown observed since 2015 is, in part, the symptom of gains made under urgency and then insufficiently consolidated.

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