Researcher Pedro Plans-Rubió at the College of Physicians of Barcelona assessed zero-, one-, and two-dose vaccination coverage across 2030 across all World Health Organization (WHO) regions. They compared data from WHO and the United Nations Children’s Fund (UNICEF) databases between 2019 and 2023 to evaluate if current immunization coverage is on track to meet Immunization Agenda 2030 (IA2030) objectives.
Study findings revealed several alarming trends: 1. Global two-dose vaccination coverage in 2023 decreased by 3.7% compared with 2019 levels; 2. One-dose vaccination coverage improved by 7.8% globally, but most measles vaccination coverage indicators depict lower values than those from 2019; and 3. Current vaccination coverage is not on track to achieve IA2030 agreements. These findings highlight a need for policy and public health implementations to increase two-dose vaccination globally.
Additionally, the study found that zero-dose measles vaccination coverage — indicating children who received no doses — increased by 7.8% globally between 2019 and 2023, with a particularly concerning 24.9% rise in the African region. As of 2023, the number of zero-dose measles children was 40.6% higher than the level needed to remain on track for halving zero-dose children by 2030, a key IA2030 target.
Study
The present study aims to update this information by assessing: 1. The 2023 global measles vaccination coverage in WHO member nations (zero-, one-, and two-dose coverage); 2. Comparing current variations in measles vaccination coverage to 2019 levels; and 3. Assessing whether measles vaccination indicators are on track to meet IA2030 goals.
Study data was obtained from the WHO and the United Nations Children’s Fund (UNICEF) databases (global and regional). This data is recorded annually in all WHO member nations across its six designated regions: Africa, the Americas, the Eastern Mediterranean, Europe, Southeast Asia, and the Western Pacific.
For estimating anti-measles herd immunity levels and similar measles vaccination indicators, this study assumed that one vaccination dose provided 92% immunity to individuals, while two doses imparted 95% immunity. Correspondingly, required immunity percentages were calculated based on R0 thresholds — for example, 93.3% population immunity is needed to block measles viruses with an R0 of 15.
Results
Analyses results revealed that, on average, only 85.2% and 77.1% of WHO region children had received one or two doses of MCV vaccine, respectively. This corresponds to a 3.7% reduction in two-dose vaccination coverage compared to 2019 and is significantly below the on-track estimates for meeting IA2030 targets. Notably, only the Western Pacific region met MCV two-dose requirements of 95.5%, while the European region reached 92.5% coverage and all other regions were below 95%.
Dose-specific findings revealed that global zero-dose coverage was 65.3%, one-dose at 27.8%, and two-dose at 6.9%, with Africa’s zero-dose rate at 21.1% — far higher than other regions (less than 3%). These rates are more than 31% lower than IA2030 requirements. The African region demonstrated the lowest one-dose coverage, with 48.1%, while the Western Pacific region had the highest coverage (93.2%). Only 17 WHO member nations (8.7%) were found to have two-dose vaccination coverage of 95% or above.
Regarding herd immunity, the study found that only 41.5% of countries achieved sufficient immunity to stop measles virus transmission with R0 values of 15 or lower, and no region achieved immunity sufficient to block viruses with R0 ≥ 19 or 20. Only the Western Pacific region and some countries in the European region reached levels to prevent community-level outbreaks of highly contagious strains (R0 ≥ 15).
Despite some regional variations—the Western Pacific region has shown modest improvements since 2019—most areas, especially Africa, showed deteriorations in vaccination coverage and herd immunity levels.
The study noted that these trends were compounded by disruptions from the COVID-19 pandemic, which significantly impacted routine immunization programs and delayed recovery efforts.
In addition, the paper highlighted limitations such as reliance on WHO/UNICEF data, which may underrepresent gaps in certain populations, and emphasized the need for serological surveys to assess real-world immunity.
Conclusion
The present study highlights the decrease in the effectiveness of WHO-endorsed anti-measles vaccination programs in its six regions between 2019 and 2023 (-3.7% for two-dose coverage), with only one region (Western Pacific) depicting improvements from 2019 findings. While one-dose coverage increased by 7.8% globally, all metrics of measles vaccination coverage indicate that current efforts are not on track to meet IA2030 goals.
This underscores the need for policy improvements and enhanced vaccination dissemination programs aimed at both education and successful two-dose vaccine administration to help eradicate this childhood disease from the human population.
The study also calls for broader international cooperation and targeted efforts in regions like Africa to close immunization gaps and build sustainable herd immunity.
Source:
https://www.news-medical.net/news/20250310/How-falling-measles-vaccination-rates-put-millions-of-children-at-risk.aspx