During the year 2004, an unusually large number of measles cases were reported from Riyadh region. High number of the cases occurred among school age children May 2004 i.e. immediately after the special vaccination campaign of measles for primary school students in Riyadh area, which prompted the authorities to ask for conduction of this investigation to identify the reasons for this probable outbreak.
Methodology
A descriptive study of the measles cases was followed by a case-control study. A case was defined as any person living in catchment area, who presented during the year 2004 G with clinical picture of measles and confirmed by positive serologic test for IgM. Controls were selected randomly from the same Primary Health care center. The investigative team interviewed each case and control on telephone.
Results
During the year 2004, 204 measles cases were reported as compared to a mean of 50.7 cases (95% CI 16.3-85.0) for the years 2000 to 2003. 37.1% cases were in age group 10-14 years. 65.7% of the cases were females. Thirty percent of cases lived in AlMansourah area. About 57% of the cases were at primary school. Maximum number of measles cases (18 cases) was reported in month of May 2004AD. A total of 70 cases and 66 controls were included in the study. 91% of the cases and 97% of the controls have received at least one dose of measles vaccine. Each increasing number of doses showed a stronger but statistically non-significant protective relationship. During the year 2004 G, 31.4% cases have received the vaccine as compared to 34.7% controls.
Conclusion
The study showed that we were dealing with an outbreak. There is no evidence to correlate the increase of measles cases with the measles campaign during 2004 G.