Measles in Saudi Arabia: from control to elimination

This article describes the tremendous efforts made in the field of measles immunization in Saudi Arabia in the past 20 years, from the control phase to the elimination phase. Mandatory measles vaccination with one-dose Schwartz vaccine was introduced in 1982 by a royal decree, a step aimed at increasing vaccine coverage. In 1991, a two-dose schedule was implemented using Edmonston-Zagreb measles vaccine, with a first dose at 6 months to protect children younger than 9 months and a second dose of MMR at 12 months of age to protect those who did not respond to the first dose. A marked reduction in the epidemic peak and a shift of infection to older age were noticed. But the same data showed that 50% of measles cases in the 1- to 4-year age group occurred in vaccinated children. In 1998, with the start of elimination phase, an MMR campaign was launched in two phases, targeting school children in 1998 [secondary schools] and in 2000 [primary and intermediate schools]. Evaluation of the MMR campaign and surveillance data was reflected in the measles immunization policy by shifting the age of measles immunization to 12 months and to preschool using the two-dose MMR schedule

Screening of pregnant Saudi women for hepatitis B surface antigen

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. 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. 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.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

use of FDA oral polio formula in vaccinating Saudi children

To evaluate the immunogenicity of USA [FDA] Oral polio vaccine versus WHO Oral polio vaccine. Open randomized trial where 210 children were randomized into three groups. First group received Hemophilus influenza type b [Hib] vaccine plus WHO DTP and OPV. The second group received Hib plus FDA DTP and OPV. The third group received WHO DTP and OPV without Hib vaccine. 3 doses were given at 6 weeks, 3 months and 5 months. Blood samples were collected at 6 months of age. Bar coded sera were used to assess for polio antibody for the three poliovirus types using microneutralization assay. The result of polio assay will be presented in this paper. Proportion of children with detectable antibody [titre =/> 1/8] polioviruses were higher in the group vaccinated with the FDA OPV formula but no significant difference was found for our sample size. FDA oral polio is not superior to WHO OPV at our sample size and there is an improvement in the seroresponse to WHO OPV compared to previous survey