Over 25 million infants missed out on life-saving vaccines, as global childhood vaccination recorded its largest decline in about 30 years, the World Health Organization and UNICEF said, sounding a red alert on children’s health.

The percentage of children who received three doses of the vaccine against diphtheria, tetanus, and pertussis (DTP3) — a marker for immunisation coverage within and across countries — fell five percentage points between 2019 and 2021 to 81 per cent, they said in a joint communication.

As a result, 25 million children missed out on one or more doses of DTP through routine immunisation services in 2021 alone. This was two million more than those who missed out in 2020 and six million more than in 2019, the UN agencies said, highlighting the growing number of children at risk from preventable diseases.

Reasons for decline

“The decline was due to many factors including an increased number of children living in conflict and fragile settings where immunisation access is often challenging, increased misinformation and Covid-19-related issues such as service and supply chain disruptions, resource diversion to response efforts, and containment measures that limited immunisation service access and availability,” they explained.

This historic backsliding in rates of immunisation is happening against a backdrop of rapidly rising rates of severe acute malnutrition.

“A malnourished child already has weakened immunity and missed vaccinations can mean common childhood illnesses quickly become lethal to them. The convergence of a hunger crisis with a growing immunisation gap threatens to create the conditions for a child survival crisis,” the note cautioned.

“This is a red alert for child health. We are witnessing the largest sustained drop in childhood immunisation in a generation. The consequences will be measured in lives,” said Catherine Russell, UNICEF’s Executive Director.

“While a pandemic hangover was expected last year as a result of Covid-19 disruptions and lockdowns, what we are seeing now is a continued decline. Covid-19 is not an excuse. We need immunisation catch-ups for the missing millions or we will inevitably witness more outbreaks, more sick children and greater pressure on already strained health systems,” she added. Backslide in immunisations

India among worst affected

About 18 million of the 25 million children who did not receive a DTP dose during the year — were largely from low- and middle-income countries, with India, Nigeria, Indonesia, Ethiopia, and the Philippines recording the highest numbers, they said.

First dose measles coverage dropped to 81 per cent in 2021, also the lowest level since 2008. This meant 24.7 million children missed their first measles dose in 2021, 5.3 million more than in 2019. A further 14.7 million did not receive their second dose.

Similarly, compared to 2019, 6.7 million more children missed the third dose of the polio vaccine and 3.5 million missed the first dose of the HPV vaccine — which protects girls against cervical cancer later in life, the agencies pointed out.

It was hoped that 2021 would be a year of recovery to catch up on immunisation missed in 2020.

Instead, DTP3 coverage was set back to its lowest level since 2008 which, along with declines in coverage for other basic vaccines, has pushed the world off its global targets including the immunisation indicators for the Sustainable Development Goals, the agencies said, calling for governments to undertake a monumental effort to catch-up on the universal coverage levels and prevent future pandemic outbreaks.