Progress with the Second Dose Measles Vaccine Introduction and Coverage in the WHO African Region

Area of Science:

• Immunization and Vaccine Research
• Global Public Health
• Pediatric Infectious Diseases

Background:

• The World Health Organization (WHO) recommends 95% coverage for two doses of measles-containing vaccine (MCV) to achieve elimination goals.
• The second dose of MCV (MCV2) is typically given after 12 months of age.

Purpose of the Study:

• To assess national coverage rates for the first (MCV1) and second (MCV2) doses of measles-containing vaccine.
• To calculate MCV1-MCV2 drop-out rates in the WHO African Region from 2013 to 2023.
• To identify factors associated with MCV2 coverage and drop-out rates.

Main Methods:

• Utilized WHO-UNICEF estimates of national immunization coverage (WUENIC) data.
• Analyzed MCV1 and MCV2 coverage and drop-out rates for countries in the WHO African Region.
• Compared MCV2 coverage and drop-out rates based on the number of antigens provided in the second year of life.

Main Results:

• Estimated regional MCV2 coverage rose from 7% to 49% between 2013 and 2023.
• By the end of 2023, 91% of countries in the region had introduced MCV2 into routine immunization.
• Countries offering more antigens in the second year of life showed higher MCV2 coverage and lower drop-out rates.

Conclusions:

• Despite progress, MCV2 coverage remains insufficient for measles elimination.
• High drop-out rates between MCV1 and MCV2 indicate challenges in vaccinating children over 12 months.
• Improving MCV2 and other second-year-of-life vaccine coverage is crucial for achieving and sustaining high immunization rates.