[NAIROBI, SciDev.Net] More than 14 million children missed out on lifesaving vaccines against diphtheria, tetanus and whooping cough last year, putting global goals off track, new UN data shows.

Despite an overall record number of child vaccinations in low- and middle-income countries, these countries accounted for more than two-thirds of the so-called “zero-dose” children, according to analysis.

In 2024, about 115 million children — 89 per cent of infants globally — received at least one dose of the diphtheria, tetanus and pertussis (DTP)-containing vaccine, and roughly 109 million — 85 per cent — completed all three doses, according to figures released today (15 July) by the WHO and UNICEF. This represents a modest gain from the previous year.

However, almost 20 million infants missed at least one dose of DTP-containing vaccine, including 14.3 million zero-dose children who didn’t receive a single dose of any vaccine, the agencies said.

The figure, a key indicator of global vaccine coverage, marks an increase of 1.4 million from 2019 and is 4 million over the 2024 target needed to stay on track to meet global goals on immunisation by 2030, they noted.

Kate O’Brien, director of the WHO’s department of immunization, vaccines and biologicals, said the latest estimates presented “a really worrying trajectory”.

“The world is currently off track for the goal to halve zero-dose children and achieve at least 90 per cent global immunisation coverage,” O’Brien said during a virtual press conference Monday (14 July).

“We have hit this stubborn glass ceiling and breaking through that glass ceiling to protect more children against vaccine preventable diseases is becoming more difficult,” she added.

With support from Gavi, the Vaccine Alliance, lower-income countries protected more than 72 million children against a range of infectious diseases in 2024, more than any previous year on record, according to the new data, which tracks national immunisation coverage for 16 diseases across 195 countries.

Vaccination rates have been steadily rising since the declines seen during the COVID-19 pandemic.

However, population growth, fragility, and conflict still present major barriers to achieving true equity, leaving millions of the most vulnerable — and the world — at risk, the UN agencies warn.

Sweeping cuts to aid by the US, including funding for global immunisation programmes, also cast a shadow over the progress made.

WHO director-general Tedros Adhanom Ghebreyesus said: “Drastic cuts in aid, coupled with misinformation about the safety of vaccines, threaten to unwind decades of progress.”

He said the WHO was working with partners to develop local solutions and increase domestic investment to reach all children with vaccines.

“Continued commitment from governments and partners will be critical to saving lives and protecting the world from infectious disease threats,” said Sania Nishtar, CEO of Gavi.

Due to population growth, countries are having to reach more children each year to maintain coverage levels, according to Gavi. In 2024, there were 2.5 million (three per cent) more births in the 57 lower-income countries the alliance supports compared to 2019.

Despite a decline of half a million, there are still 10.2 million zero-dose children in lower-income countries who have received no doses of the DTP vaccine, Gavi notes. It says coverage with the first dose of the DTP vaccine is an important measure of how many children still don’t have access to life-saving vaccines.

Nearly half (4.9 million) of these live in five populous countries — Nigeria, DR Congo, India, Pakistan and Ethiopia. Nearly 30 per cent (2.9 million) live in fragile and conflict-affected settings.

Coverage rates of children for all three doses of the vaccine remained stable at 61 per cent in the 12 countries Gavi classifies as experiencing fragility and conflict.

However, there were large declines in Sudan (down 12 percentage points) and Yemen (down 4 percentage points), counteracting improvements in countries such as Mali, Syria and Haiti, the alliance said.

There were half a million fewer zero-dose children in lower-income countries in 2024, mainly as a result of the targeted efforts in populous countries like India, DR Congo and Ethiopia, according to Gavi’s analysis.

Targeted efforts to reach missed children are yielding improvements, but face challenges, Nishtar noted.

Meanwhile, more girls in lower-income countries were vaccinated in 2024 with the HPV vaccine than in the whole of the previous decade. The vaccine protects against cervical cancer, one of the leading killers of women and girls in lower-income countries.

HPV vaccine coverage in lower-income countries reached 25 per cent in 2024, up from just three per cent in 2019.

Coverage with the first dose of measles vaccine reached 80 per cent in 2024, up two percentage points from the previous year.

Ephrem T Lemango, associate director for health, and global chief of immunisation at UNICEF, said there were encouraging signs of recovery.

“The growing immunity gaps between different countries are fueling outbreaks,” he said.

“Despite this, an additional 1.7 million children have been reached with measles vaccine and this represents progress in the right direction.”

This piece was produced by SciDev.Net’s Global desk.