The global vaccination gap is not only about the first dose

Vaccination coverage can look like a single race: reach a child, give a first dose, move the global percentage upwards. The latest figures from the World Health Organization and UNICEF show why that picture is incomplete. A first contact matters, but so does whether routine services remain within reach for the doses that follow.

The agencies’ 2025 estimates say 90 percent of infants globally, nearly 116 million, received at least one dose of a vaccine protecting against diphtheria, tetanus and pertussis. Coverage with the third DTP dose was 85 percent, or about 110 million infants. Both measures increased by one percentage point from 2024, yet both remained one point below 2019 and within a range that has barely shifted since 2009.

Those two percentages describe different tests of a health system. The first DTP dose, commonly shortened to DTP1, is used as a signal of whether routine immunization services reached a child at all. DTP3 asks whether contact was sustained through a multi-dose series. The gap between them cannot be collapsed into one success rate.

There was real progress at the first threshold. WHO and UNICEF estimate that 13.5 million children received no routine vaccine in their first year in 2025, nearly 750,000 fewer than in 2024. These children are described in global monitoring as “zero-dose”, using the absence of DTP1 as the operational marker. The term is a programme indicator, not a description of every possible vaccine a child may have encountered in every setting.

The follow-up threshold is less reassuring. WHO’s updated fact sheet estimates that another 6 million infants were partially vaccinated. The joint release also identifies 7.3 million infants who received DTP1 but had not received a first measles dose. That is a different start-and-finish comparison, so the two figures should not be treated as interchangeable. Together, they show why reaching a clinic once and completing later contacts are separate public-health problems.

Measles makes the distinction especially visible. In 2025, an estimated 84 percent of children received a first measles-containing dose and 77 percent received a second. WHO and UNICEF say both figures remain well below the 95 percent population coverage threshold needed to prevent outbreaks of this highly contagious virus. They report that 57 countries experienced large or disruptive measles outbreaks during the year. That threshold concerns community coverage, not a calculation of any one child’s protection.

The shortfall is not spread evenly. More than half of zero-dose children live in fragile, conflict-affected or vulnerable settings, although those settings contain about one-third of the world’s children. In such places, insecurity, displacement, disrupted transport and underfunded services can break the route between appointments. The agencies also point to slippage in some middle- and high-income countries, where political commitment, structural obstacles and vaccine hesitancy can all affect coverage.

A global average can therefore improve while many national programmes stand still. Of 195 countries in the dataset, 100 have maintained at least 90 percent DTP3 coverage since 2019. Among countries that were below 90 percent in 2019, 30 improved over the following six years, while 65 stagnated or moved backwards. Regional averages also diverged: the Americas and South-East Asia recovered past their 2019 performance, while several other regions remained below it.

The figures are estimates, not a perfect census of injections. WHO and UNICEF combine administrative reports, official national estimates, household surveys, published evidence and consultation with local programme experts. For 2025, 185 countries supplied coverage data, representing most of the global birth cohort. Reporting gaps, outdated population denominators, incomplete birth registration, inaccessible communities and caregiver recall can all affect the underlying evidence.

The latest release contains a further warning about that evidence base. Only 18 national immunization surveys were undertaken and submitted in this round, down from 50 in 2024 and an annual average of 33 before the pandemic. WHO and UNICEF revise the historical series when new information arrives, which is why they caution against comparing a current estimate with a number copied from an older annual release. The current time series, rather than a stack of old press releases, is the sounder basis for a trend.

For readers, the useful discipline is to ask what a vaccination headline is measuring. Is it a first dose, the final dose in a series, a particular vaccine, a national estimate or a global average? Which year does it describe, and has the historical series been revised? Those questions do not settle the reasons for a gap, but they prevent one improving indicator from standing in for the whole programme.

This is not a prompt to improvise an individual schedule. Vaccines, dose timing and catch-up arrangements vary by age, country and health authority. Personal questions belong with a qualified local health professional or the relevant public-health service. The global data serve a different purpose: they show whether systems can reach children and retain contact over time.

The first dose is a door opening. Completion measures whether the health system kept that door within reach. The 2025 estimates show modest movement at the entrance, but the route beyond it remains the harder part of the vaccination story.