Mohamed H. Al-Jeffri

HIV/AIDS epidemic features and trends in Saudi Arabia.

BACKGROUND More than 60 million persons have been infected since AIDS was described in 1981. By the end of 2003, an estimated 40 million individuals were living with HIV globally. The surveillance of HIV/AIDS still faces challenges in Saudi Arabia. This study describes the pattern and characteristics of HIV/AIDS cases in Saudi Arabia. METHODS This descriptive analytic study describes the reported HIV/AIDS data for all notifiable cases during the period 1984 to 2003 in the Kingdom of Saudi Arabia. Case definitions based on ELISA and Western Blot tests were used. Age, sex and regional distribution were studied in addition to survival rates. RESULTS As of 2003, 1743 Saudi nationals and 6064 non-Saudi HIV cases were reported. Among Saudis, 872 were AIDS cases. Males accounted for 1329 HIV infections, comprising 77%, with a male-to-female ratio of about 3:1. Adults 15–49 years constituted 78% of cases, including 46% of cases infected through sexual activity, while 33% of reported HIV seropositive cases had already died. Most cases (67%) were registered in Jeddah, Riyadh and Dammam. Infection through blood transfusion declined with no reported cases since 2001. CONCLUSION The number of reported HIV infections in KSA has increased in the last few years. Using the coverage rate estimating method, the number of Saudi HIV infections since the emergence of the epidemic was estimated to be 2640 cases as of the beginning of the year 2004. The estimated number of HIV infections is almost one and one-half times the reported number, indicating that a problem of underreporting of HIV/AIDS cases still exists.

Haemophilus Type B Meningitis in Saudi Children under 5 Years Old

This study was designed to determine the magnitude of bacterial meningitis in general and Hib meningitis in particular among children below the age of 5 years. A population-based, prospective descriptive and analytical study was conducted in five regions, one each in northern, southern, eastern, western, and central parts of Saudi Arabia. Active surveillance for cases of bacterial meningitis among the study population, which comprised 171,818 children under 5 years of age, was implemented. A total of 208 cases of meningitis were identified, of which 141 (67.8 per cent) were identified with a definite causative organism. The remaining 67 cases (32 per cent) were labeled as aseptic meningitis. The overall incidence of meningitis was 60.53/10(5) in under-fives with a disease spectrum similar to that reported in studies conducted in other countries. The three leading causes of meningitis were Hib (Haemophilus influenzae type B), MCM (Neisseria menigitides) and SPN (Streptococcus pneumoniae). Hib meningitis constituted 28 per cent of cases with an incidence rate of 16.88/10(5) children. There was a marked regional variation in Hib incidence. MCM was the second leading cause (18 per cent) of meningitis with an incidence of 10.77/10(5) while SPN comprised 11 per cent of cases and its incidence was 9.69/10(5). Almost all MCM cases were related to meningitis outbreaks that occurred in Saudi Arabia during two successive Hajj seasons (2000-2001). Hib cases showed a bimodal seasonality, one peak during March-May, the other during September-November. The fact that this study is the first national base-line data on meningitis in general and Hib incidence in particular, has augmented further justification for introducing Hib vaccine within the national Expanded Program on Immunization (EPI). Based on the experience gained during this study regarding surveillance of meningitis disease, optimal methods to strengthen meningitis surveillance were identified. A model of Meningitis Diseases Surveillance was generated that can be tested and then generalized. The study has documented beyond doubt the impact of Hajj seasons on MCM disease occurrence and further justifies the rigorous control and preventive measures being taken in this aspect.

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% Cl=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.

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.

Childhood epidemiology of hepatitis A virus in Riyadh, Saudi Arabia.

The prevalence of anti-HAV antibody in children was tested in subjects presenting at clinics in Riyadh, Saudi Arabia. A blood sample was taken to test for the presence of IgG (indicating past infection) and a questionnaire concerning personal and epidemiological data relating to hepatitis A was completed. In total, 592 children aged 6 months to 15 years were suitable for the analysis. There were 179 subjects who were positive for HAV (30.2%). The proportions of subjects positive for HAV varied significantly with age (P=0.001); 32%-49% in the 7-15 age range were positive compared with 13-20% aged 6 and below. There was a significant association between a positive HAV test and social level (P=0.044), with a higher proportion positive in the low social level. Children with jaundice, personal history of jaundice or travel abroad were significantly more likely to be HAV positive (P=0.001, P=0.006, P=0.021, respectively). There was also a significant association with nationality (P=0.022), where the lowest proportion of HAV positive children were Saudi Arabian (28%). Compared to previous studies, there is a significant decrease in the HAV exposure in Saudi children with shift from high to intermediate pattern. National strategy for prevention should be evaluated.

Follow-up of Saudi children vaccinated with Haemophilus influenzae type B vaccine.

BACKGROUND Saudi children vaccinated with a primary series of Hib vaccine (HbOC) at six weeks, three and five months have shown higher antibody titers compared to recent data from the U.S. The aim of this study was to evaluate the persistence of antibodies and to measure the immunogenicity of a booster dose of Haemophilus influenzae type b (Hib) vaccine in Saudi children. PATIENTS AND METHODS In the first phase of the trial, 210 children were divided into three groups. Group 1 received HbOC, DPT and the WHO formula of oral poliovirus vaccine (OPV); group 2 received HbOC, DPT and the FDA formula of OPV; and group 3 (control) received DPT and the WHO formula of OPV, without HbOC. Haemophilus influenzae geometric mean antibody levels after primary immunization were reported previously. In this study, blood samples were collected at 18 months (before the booster dose) and one month later to measure antibody levels against Haemophilus influenzae polysaccharide. RESULTS Following the booster doses, there was an increase in the geometric mean titers (GMTs) from 2.57 microg/mL to 39.4 microg/mL in group 1, and from 1.2 microg/mL to 48.9 microg/mL in group 2. In group 3, the GMT remained at 0.3 microg/mL. There was no significant difference in Hib GMTs after the booster dose between children given Hib vaccine with the FDA formula of DPT and OPV and those given the WHO formula. CONCLUSION Based on the high immunogenicity of the Hib vaccine in Saudi children, a booster dose is not necessary at the initial stages of immunization, and should instead be given to children in the second year of life. This option, however, needs further evaluation and close monitoring.

National serosurvey of post vaccination poliovirus antibody in Saudi Arabia.

This is a national seroprevalence study conducted in Saudi Arabai in 1991G to determine postvaccination poliovirus antibody. Two hundred and nine children vaccinated with three oral polio vaccines at three, four, and five months of age were included in the study representing the five main regions in Saudi Arabia. Blood samples were collected at the age of nine months. Cytopathic effect (CPE) neutralization was used to determine the level of polio antibody. A dilution of 1/8th or more was defined as positive. Seventy-nine percent, 88% and 65% of the children were positive for Type 1, Type 2, and Type 3, respetively. Development of a new strategy of polio vaccination is needed.