Changes in epidemiological pattern of meningococcal disease in Saudi Arabia. Does it constitute a new challenge for prevention and control?

Meningococcal meningitis epidemics, which occurred in the Kingdom of Saudi Arabia [KSA] coincided with Hajj and Umra seasons; the 2 major pilgrims to Muslims. In many countries, the disease showed major changes of its epidemiological determinants, in particular to age and prevailing serogroup. This study was conducted to determine the epidemiological trend of meningococcal meningitis disease in KSA. All confirmed meningococcal meningitis cases reported in KSA during the period from January 1999 to December 2002 were studied retrospectively. Confirmation of cases was based on isolation of the causative organism from cerebrospinal fluid [CSF] or blood culture or detection of antigen in the CSF. Personal, clinical and laboratory results were analyzed using Epi info version 6 software. Categorical data were tested using X2 test. A total of 729 cases were reported, 304 cases [42%] were among people coming from abroad for Hajj or Umra and 425 [58%] were among local population. Nearly half of the later [48%] were reported at the 2 holy areas of Makkah and Madinah, KSA. Thirty-nine% of cases were children aged <2 years and 58% were <5 years of age. Proportion of cases affected with serogroup W135 increased over time [up to 95%] and significantly affected children aged <5 years [p<0.001]. Continuous monitoring of epidemiological determinants is essential to guide vaccination policy

Efficacy of hepatitis B vaccine in a cohort community-based study in Riyadh and Hail regions of Saudi Arabia

Saudi Arabia used to by hyperendemic for HBV infection. Most of infection occurs in early life. HBV vaccine was, therefore, introduced in 1989 as the seventh primary immunogen of the EPI Program. This study is conducted to evaluate the efficacy of this program in Riyadh and Hail Regions. Method and Patients: A cohort follow-up study of children from Riyadh and Hail, who had been vaccinated in 1989, evaluated in 1991 and tested for HBV markers six years later. The files of 303 children from Riyadh and Hail, who were investigated in 1991retrieved and only 119, were available for testing. Fifty% of the children have still a protective anti- HBs tittr. One vaccinated child was found to be positive for HBs Ag. According to this study, the efficacy rate against HBs Ag carriage is 88%. This study demonstrates the tremendous effect of HB vaccine on the HBV infection of Saudi children in these two regions

Hepatitis A in Saudi Arabia: a comparative sero-epidemiological study

To determine the prevalence of Hepatitis A Virus infection among Saudi children [1-12 years] in 1997. To compare the results with our previous study in 1989. This is a randomized community-based study involving all of the regions of Saudi Arabia. All children were tested for antibody Hepatitis A Virus immunoglobulin [IgG] class. The prevalence of anti-Hepatitis A Virus IgG among 5355 Saudi children tested ranged from 10% in Taif to 82% in Gizan regions with an overall prevalence of 25%. There is a reduction of the overall prevalence from 50.5% in 1989 to 25% in 1997. This study shows a marked decline in Hepatitis A Virus infection in Saudi children 8 years after the first study. There is an almost 50% reduction of the overall Hepatitis A Virus prevalence. This dramatic decline in Hepatitis A Virus infection among the Saudi children will lead to a later exposure of elderly population groups to the Hepatitis A Virus infection and a new preventive strategy needing to be adopted