On 2/12/2006G (12/11/1427H),General Health Directorate of Jazan region reported to preventive Medicine Department, Ministry of Health, Riyadh, an unusual increase in the number of people suffering from measles. The Field Epidemiology Training Program (FETP) was assigned to verify and investigate this outbreak and recommend control measures.
Methodology
A measles case was defined as any person living in the catchments area, which presented during the year 2006G from April 1 to December 31 with clinical picture of measles and confirmed by positive serologic test for IgM. For case-control study two of the tenth health sectors in Jazan (Alardha and Baish) were selected to perform the study. A questionnaire was prepared and filled by personal interview and patient's records review of the two health sectors (Alardha and Baish). All selected cases that met the case definition and serologically positive were enrolled in a case-control study. One control from the same family or neighborhood was selected for each case.
Results
During study period, 347 cases of clinically diagnosed and serologically positive measles were reported as compared to 20 cases during 2005G in Jazan region. Out of 265 selected cases 158 (59.6%) cases were reported from Alardha sector, and 41 (15.5%) cases from Baish sector. 83% cases were from rural areas. 97% cases were Saudi. 58.6 cases were female. 46.6% cases were below one year of age and 14.8% cases were in age group 1-5 years. Among the 99 cases up to 12 months of age only 1 case was vaccinated and among 21 cases with 12 months of age only 3 (12.5%) were vaccinated. Among the children 1-5 years of age 86.2% were vaccinated, among 6-15 years of age 37.5% were vaccinated, among cases above 15 years only 5.5% were vaccinated. A total of 110 cases and 110 controls in Alardha and Baish health sectors were enrolled in the study. The highest age group affected was children aged less than one year, 49%. Females constituted 64.5% .Saudi nationals accounted for 98.2%. 73.6% of the cases and 63.6% of the control have not received any measles vaccine. Among the children 1-4 years of age 94.7% were vaccinated compared to 100% of control were vaccinated, among 15-24 years of age 13.3% were vaccinated compared to 14.3% of control were vaccinated. The risk of measles infection show no differences among non-vaccinated individuals (OR 0.627,95%CI0.353-1.114). 91.1% of cases and 60% of control had history of visiting hospital/PHC during April 2006. The risk was higher among those who visited hospital/PHC during April 2006(OR6.833, 95% CI 2.951-15.822). Among the measles cases 99 (92.5%) gave history of visiting hospital/within 3 weeks before the onset of the disease compared to 54 (60%) controls with OR of 8.250 (95% CI 3.580 - 19.010) which exhibiting a statistically significant relationship.
Conclusion
Children less than one year of age constituted the majority of measles cases in the present study. Visiting hospital/PHC before 3 weeks of the onset of the disease may have acted as an important source of infection for other cases. Implementation of two doses or more of measles vaccine was associated with a lower risk of measles infection during this outbreak.