Screening of pregnant Saudi women for hepatitis B surface antigen.

BACKGROUND: The high prevalence of hepatitis B surface antigen (HBsAg) and hepatitis B e antigen (HBeAg) in pregnant women is considered the most important factor contributing to the higher carrier rate of HBsAg in some populations, including Saudi Arabia. Universal hepatitis B vaccination in infancy was implemented in Saudi Arabia in 1990 to avoid early acquisition of infection. At the same time, another program was launched to vaccinate all school children at school entry as a second target group. The aim of this study was to evaluate the HBsAg prevalence rate in Saudi pregnant women 12 years after launching the program and to assess regional variation, if any. METHODS: In a cross-sectional study, 2664 pregnant Saudi women were recruited from the five main regions in Saudi Arabia. Blood samples were tested for HBsAg. Positive samples were tested also for HBeAg. RESULTS: Of 2664 pregnant Saudi women, 65 were positive for HBsAg (2.46%, 95% CI=2.11%-2.69%). Four were positive for HBeAg (0.15%). The HBsAg prevalence rate was higher in Gizan (4.2%) and lower in Tabuk (1.4%) (P=-0.035). Only one case was positive for HBsAg in women under the age of 20 years (1/186), a 0.5% positivity rate in this age group compared with 2.6% in the older age group (P=-0.049 for the one-sided test). A history of surgical procedures was associated with a higher (3%), but not significantly higher rate of HBsAg positivity. No significant association was found between HBsAg positivity and a history of dental procedures or blood transfusion. CONCLUSION: Although the HBsAg prevalence rate among Saudi pregnant women was lower than previously published data, the full impact of the hepatitis B vaccination program in infancy and childhood will take more years to decrease the prevalence rate in pregnant women. The MOH should continue to give the first dose of hepatitis B vaccine at birth to prevent early acquisition, but in the meantime a regional policy can be adopted to deal with the high prevalence rate of HBsAg among pregnant Saudi women.

Sero-response to measles-mumps-rubella vaccine campaign in Saudi Arabia.

OBJECTIVE: To evaluate the measles-mumps-rubella vaccine campaign targeting primary school children in the Kingdom of Saudi Arabia during the months of January and February 2000. METHODS: Pre and post measles-mumps-rubella vaccine blood samples were collected from 54 children from the first grade and 96 children from the 6th grade. Antibodies against measles, mumps and rubella were assayed using enzyme immunoassay and a backup test of plaque neutralization test. This assay was carried out at the Reference Center, Koch Institute, Berlin, Germany. RESULTS: When the backup test results were added, 96%-98% of children had protection level against measles before the campaign. It is interesting to notice that pre-vaccination measles mean titer and positivity rate with enzyme linked immunoassay in the first grade were significantly lower than the 6th grade. One hundred percent and 96.8% were positive for rubella antibody before the campaign, in the first and 6th grades. Seventy-seven percent and 67% were positive for mumps before the campaign, in the first and 6th grade. After the measles-mumps-rubella vaccine campaign, protection rate reached 100% for the 3 antigens with a statistically significant boosting effect and increase in geometric mean of the titre. CONCLUSION: Measles-mumps-rubella vaccine campaign was effective in increasing protective levels and boosting antibodies against the 3 targeted diseases which can prevent epidemics in the primary schools.

Safety evaluation of MMR vaccine during a primary school campaign in Saudi Arabia.

Monitoring of adverse events following the administration of MMR vaccine containing the Urabe mumps virus vaccine strain, to over 2 million schoolchildren (aged 6-13 years) revealed that the incidence of vaccine-associated aseptic meningitis was one case per 295 000 doses given. About 92 per cent of these children had had their primary immunization against MMR at 12 months of age and, therefore, were probably not immunologically naïve. It appears from our data that the use of the Urabe-based mumps vaccine in the booster-dose format induces much less adverse effects than usually observed following the primary immunization with it. Further studies are needed to prove this conclusively.