Measles Vaccination Coverage and Anti-Measles Herd Immunity Levels in the World and WHO Regions Worsened from 2019 to 2023.

Abstract

Objectives: The objectives of this study were as follows: to determine mean percentages of measles vaccination coverage with zero, one and two doses of vaccine and anti-measles herd immunity levels in World Health Organization (WHO) regions in 2023; to assess variations in measles vaccination coverage and anti-measles herd immunity-related indicators from 2019 to 2023; and to assess whether zero-dose measles vaccination coverage indicators were on track to achieve the Immunization Agenda 2030 objective.

Methods: Mean percentages of vaccination coverage with two, one and zero doses of measles vaccine in WHO regions in 2023 were calculated using data from the WHO/UNICEF global and regional immunization information system.

Results: In 2023, the global mean two-dose measles vaccination coverage was 65.3%, and mean two-dose vaccination coverage was lower than 95% in all WHO regions; the mean prevalence of measles-protected individuals in the target vaccination population was 87.6%, and anti-measles herd immunity levels in the target vaccination population were sufficient to block the transmission of measles viruses with greater transmissibility (R_o ≥ 15) only in the Western Pacific and European WHO regions. The global mean two-dose measles vaccination coverage decreased by 3.7% from 2019 to 2023. In 2023, the mean zero-dose measles coverage and number of zero-dose measles children were, respectively, 36.7% and 40.6% greater than the values required to be on track to achieve the 2030 objective.

Conclusion: This study found that all measles-vaccination-coverage-related indicators worsened from 2019 to 2023, and the zero-dose measles vaccination coverage and number of zero-dose measles children in 2023 were not on track to achieve the AI2030 objective. Interventions to increase routine two-dose measles vaccination coverage should be developed in all WHO regions.