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Measles immunization: early two-doses policy experience
Y Y al-Mazrou1, M al-Jeffri, O M Ahmed
1Department of Preventive Medicine, Ministry of Health, Riyadh, Saudi Arabia.
Insights
Saudi Arabia
Area of Science:
- Pediatrics
- Immunology
- Public Health
Background:
- Measles posed a significant threat to infants under one year old in Saudi Arabia, with 50% of cases occurring in 6-8 month olds before 1991.
- The Expanded Programme on Immunization (EPI) in Saudi Arabia historically faced challenges in measles control among young children.
Purpose of the Study:
- To evaluate the impact of a two-dose measles vaccination policy on measles incidence across different age groups in Saudi Arabia.
- To assess the effectiveness of the integrated measles-mumps-rubella (MMR) vaccine as part of the national immunization program.
Main Methods:
- Implementation of a two-dose measles vaccination schedule (6 and 12 months) in 1991, with the second dose combined with MMR.
- Monitoring vaccination coverage, which exceeded 90% for the second dose since 1993.
- Utilizing routine monthly reports validated by WHO 30-cluster surveys to track measles incidence.
Main Results:
- Significant reduction in measles incidence observed in infants: a 50% drop in 9-11 month olds and over 75% in 6-8 month olds.
- Measles incidence remained stable in infants under 6 months.
- Post-policy, 80% of measles cases occurred in children over 5 years, primarily unvaccinated individuals lacking two doses.
Conclusions:
- The two-dose measles vaccination strategy has dramatically reduced measles incidence in young children in Saudi Arabia.
- Achieving measles elimination necessitates continued adherence to the two-dose policy and consideration of broader vaccination measures, such as targeting school-aged children.
- The policy's success highlights the importance of robust immunization programs in controlling vaccine-preventable diseases.
Abstract:
Before the implementation of the two-dose measles immunization policy in Saudi Arabia, 50 per cent of measles cases in children below the age of one year were reported for the age group 6-8 months. In 1991 two doses of measles vaccine, at 6 months and 12 months, the second dose incorporated with MMR, were integrated into the expanded programme of immunization (EPI). Since 1993, vaccination coverage for the second dose has been above 90 per cent. While measles incidence remains stable in infants below 6 months of age, the incidence in children 9-11 months of age dropped by 50 per cent. The greatest impact was seen in the 6-8-month age group where the incidence dropped by more than 75 per cent. Moreover this two-dose strategy resulted in a situation in which 80 per cent of the measles cases were in children above the age of 5 years, mostly those who had not had two doses of measles vaccine. Further control measures should include non-selective vaccination of school children against measles. The two-dose measles vaccination policy is visualized as a necessity if the goal of measles elimination is to be achieved. Routine monthly reports validated by surveys using the WHO standard 30 cluster technique was used for the study.