The proportion of children who received all three doses of the vaccine against diphtheria, tetanus and poliomyelitis (DTP) fell from 86% in 2019 to only 81% in 2021. This vaccine is used as a key indicator of vaccination coverage in worldwide.
This decline recorded in 2020 and 2021 follows a decade of improvements.
"This is a red alert for children's health. We are witnessing the largest continuous decline in childhood immunization in a generation," UNICEF chief executive Catherine Russell said in a statement.
"The consequences will be measured in the number of lives."
Some 25 million children missed one or more doses of this DTP vaccine in 2021. This is 2 million more than in 2020, and 6 million more than in 2019.
Of those 25 million, 18 million received no dose, the majority of them in middle- or low-income countries, including India, Nigeria, Indonesia, Ethiopia and the Philippines.
The reasons for this fall are multiple: conflicts, increased misinformation and problems with the supply or continuity of care linked to the Covid-19 pandemic.
It was hoped that 2021 would start to catch up after the lockdowns but instead vaccination rates continued to decline in all regions of the world.
This undercoverage has led to preventable outbreaks of measles and polio over the past 12 months, the report said.
About 24.7 million children missed their first measles dose in 2021, more than 5 million more than in 2019. And an additional 14.7 million children did not receive their second dose.
Vaccination coverage for the first dose against measles was thus 81% in 2021, the lowest since 2008.
The bad news comes as malnutrition rates are otherwise on the rise.
A malnourished child already has weaker immune defenses, and is therefore more likely to develop severe cases of these preventable diseases.
"We need to catch up on immunization for the millions (of children) missing, or we will inevitably see more epidemics, sick children and great strain on already stretched health systems," he said. pleaded Catherine Russell.
© 2022 AFP