As part of the communicable disease surveillance system in Saudi Arabia, all medical facilities, both governmental and private, should report new measles cases through local health authorities to the Ministry of Health. For the purpose of surveillance, a clinical case of measles is defined as an illness with a generalized blotchy rash lasting three or more days with fever plus one or more of the following: cough, runny nose, red eyes and Koplik spots. These surveillance reports help to monitor the effect of the compulsory immunization policy that began in 1983.
In 1992, 11,229 measles cases were reported in Saudi Arabia. Incidence rates by region ranged from 15 per 100,000 in Najran to 197 per 100,000 in Hafr al-Batin (Figure 1). The proportion of cases in the 1-to-4-year-old age group declined from 28.4% in 1989 to 15% in 1992.
Since compulsory immunization began in 1983 and coverage exceeded 80%, incidence rates have declined more than six fold (Figure 2). However, from 1989 to 1992 they did not continue the downward trend, ranging from 33 per 100,000 to 82 per 100,000. During these four years, measles cases steadily increased in the 5-to-14 and 15-to-44year-old groups. They also showed a milder increase in the 1-to-4-year-old age group (Figure 3).
Editorial note:
The introduction of measles immunization has had a profound effect on the incidence and age distribution of the disease. The target for 1995 is an incidence of less than 40 per 100,000. The World Health Organization Expanded Program for Immunization (EPI) has made the following recommendations to countries participating in EPI:
- By 1995, reduction by 95% of deaths due to measles and reduction by 90% of measles cases, compared with pre-immunization levels.
- By 1995, coverage of not less than 95% by 1 year of age at all levels.
- By 1995, reduction of the case-fatality rate to less than 1%.
The surveillance data indicate that Saudi Arabia has achieved the 1% case-fatality rate and the 95% reduction in measles deaths. Incidence rates and vaccine coverage are nearing the WHO targets. In developing countries before the introduction of measles immunization, 80% of measles cases were in children from 1 to 4 years old. The 15% currently observed in this age group 10 years after initiation of the compulsory vaccination policy attests to the success of this program.
Although natural factors such as population density can explain part of the observed age distribution of measles, vaccination should have a profound effect. According to policy, all 1-to-4-year-old children in Saudi Arabia should be vaccinated. Higher proportions of total cases in this age group indicate the need for more in-depth evaluation of vaccine coverage and efficacy in the respective areas. The kingdom-wide increase in measles case in the 5-to-14year-old age group also needs close inspection. Each year the entrance of vaccinated 5-year-old children into this group and the departure of unvaccinated 15-year-old children from this group should increase the vaccine coverage of the entire group by about 10%. Thus, this age group should have the greatest decline in measles cases.
Recommendations for control:
1. Maintain high coverage by : (a) screening and immunizing all children visiting a health center for any reason; (b) ensuring that all children registering for primary school receive a dose of MMR vaccine before school entry; (c) immunizing all children upon admission to a hospital or as soon as their condition allows; (d) minimizing the drop rate between the third DPT vaccine and the measles dose.
2. Improve the health information system by using information in immunization coverage and disease trends to identify high-risk groups and high-risk areas and take action accordingly.
3. Develop the capacity for prompt and aggressive outbreak investigation and control.
4. Enhance case management (diagnosis, clinical assessment, classification and treatment) to reduce the case-fatality rate to below 1%.
