Diphtheria, pertussis, and tetanus serosurvey in Saudi children.

OBJECTIVE: To evaluate immune protection against vaccine-preventable diseases targeted by the Expanded Program of Immunization in Saudi Arabia. METHODS: The study was carried out from September 2001 to February 2002. Using multistage sampling techniques, samples were collected from 5 regions of Saudi Arabia and sent for laboratory assay from the following age groups; 50 samples at 12 months, 50 at 6 years, and 100 at 17 years. Sera were assayed for diphtheria, tetanus, and pertussis. Sero neutralization was used for anti-diphtheria antibody assay, while enzyme linked immunoassay was used for anti-tetanus, anti-filament hemoagglutination (anti-FHA), and anti-pertussis titer (anti-PT) antibody assay. RESULTS: This survey showed that 100% of children had protection levels (>/=0.01 IU/ml) against diphtheria at one year, 100% at 6 years, and 93.7% at 17 years. For tetanus, 95.9% had protection levels (>/=0.1 IU/ml) at one year, 100% at 6 years, and 98.9% at 17 years. The geometric mean titer (GMT) of anti-FHA is 22 at one year, 29 at 6 years, and 24 IU/ml at 17 years, while the GMT of anti-PT is 36 at one year, 18 at 6 years, and 11 IU/ml at 17 years. CONCLUSION: Children at one, 6, and 17 years are well protected against diphtheria, pertussis, and tetanus.

Serosurvey of measles, mumps and rubella antibodies in Saudi children.

OBJECTIVE: A serosurvey study to evaluate the proportion of children with antibodies against diseases targeted by the Expanded Program of Immunization in the Kingdom of Saudi Arabia. METHODS: Using multistage sampling techniques, we collected samples and sent them for laboratory assay from the following age groups; 100 samples at 6 months, 12 months, 18 months, 6 years, 13 years, and 17 years. We conducted the study from September 2001 to February 2002. We assayed sera for measles, rubella, and mumps antibodies in the measles-mumps-rubella reference laboratory in Germany, using enzyme immunoassay and plaque neutralization (PN) as a backup test for equivocal and negative samples. We only carried out a backup test for measles samples. RESULTS: The age group of 6 months had the highest proportion with negative measles antibodies. After adding the backup test (PN), the proportions of children with protective measles antibody were; 64% at 6 months, 87% at 12 months, 91% at 18 months, 75% at 6 years, 96% at 13 years, and 98% at 17 years. Rubella antibody positivity rates (>7 IU) were 28% at 6 months, 49% at 12 months, 97% at 18 months, 98% at 6 years, and 100% at 13 years. While positivity rates in mumps were 14% at 6 months, 29% at 12 months, 59% at 18 months, 64% at 6 years, and 75% at 13 years. CONCLUSION: The unexpected low proportion of children with protective level at 6 years, despite being vaccinated with 2 measle doses is an important phenomenon. This reflects the interference between the first and the second measles dose. The Ministry of Health decided to conduct a catch up campaign targeting 1st through 3rd grade primary schools, who did not catch the mass campaign conducted in 2000. Also, this supports the decision taken by the ministry to change the measles immunization schedule to MMR at 12 months and a second dose at 6 years of age.

Measles in Saudi Arabia: from control to elimination.

This article describesthe 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.

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.

Disease burden and case management of bacterial meningitis among children under 5 years of age in Saudi Arabia.

OBJECTIVE: This study was designed to explore the case management and disease burden of bacterial meningitis among children below the age of 5 years in the Kingdom of Saudi Arabia. METHODS: A prospective descriptive study was conducted during June 1999 through to May 2001 in 8 hospitals from 5 cities in different areas of the country. Those were, King Fahad Specialist Hospital and Maternity & Children Hospital, Buraidah, Belgorashi General Hospital and King Fahad Specialist Hospital, Al-Baha, Maternity & Children Hospital and Ohud Hospital, Al-Madina, Al-Qatif General Hospital in the Eastern Region and Prince Abdulrahman Bin Ahmed Alsudairy Central Hospital, Sakaka. The study population was 171,818 children under the age of 5 years. RESULTS: During the study period 208 cases of bacterial meningitis were identified, 141 (67.8%) with a definite causative organism: Hemophilus influenzae type b, Neisseria meningitidis, Streptococcus pneumoniae and other bacterial species. The remaining 67 cases (32%) were labeled as aseptic meningitis. A considerable proportion of cases was found to have received an antibiotic prior to presentation. While symptoms such as fever or poor feeding were common among cases, meningeal signs were less prominent. A lumbar puncture was carried out on all cases to reach diagnosis by gram stain, latex agglutination test and cerebrospinal fluid (CSF) and blood cultures following standard procedures. The immediate burden of meningitis cases was found to be the lengthy stay of patients in the hospital wards and intensive care units. Some of the main causative agents were resistant to the conventional antimicrobial therapy, but susceptible to newer antibiotics. CONCLUSION: The study being based on a population based surveillance gave a better overview on causative organisms of meningitis emphasizing that Gram stain, serology of CSF and culture (of CSF and blood) should be used. A high index of suspicion is needed to diagnose meningitis in children. Lumbar tap should be encouraged and supported in terms of training and more authorization to apply in diagnostic tests of such conditions. Audiometric measurement is a crucial need in the assessment of meningitis cases and in the process of their follow up. This type of service is clearly missing in our system. Influential steps are to be planned to avail this service.

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.

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

OBJECTIVE: 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. METHODS: 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 chi2 test. RESULTS: 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 percent 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). CONCLUSION: Continuous monitoring of epidemiological determinants is essential to guide vaccination policy.

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.

Disease burden and case management of bacterial meningitis among children under 5 years of age in Saudi Arabia.

OBJECTIVE: This study was designed to explore the case management and disease burden of bacterial meningitis among children below the age of 5 years in the Kingdom of Saudi Arabia. METHODS: A prospective descriptive study was conducted during June 1999 through to May 2001 in 8 hospitals from 5 cities in different areas of the country. Those were, King Fahad Specialist Hospital and Maternity & Children Hospital, Buraidah, Belgorashi General Hospital and King Fahad Specialist Hospital, Al-Baha, Maternity & Children Hospital and Ohud Hospital, Al-Madina, Al-Qatif General Hospital in the Eastern Region and Prince Abdulrahman Bin Ahmed Alsudairy Central Hospital, Sakaka. The study population was 171,818 children under the age of 5 years. RESULTS: During the study period 208 cases of bacterial meningitis were identified, 141 (67.8%) with a definite causative organism: Hemophilus influenzae type b, Neisseria meningitidis, Streptococcus pneumoniae and other bacterial species. The remaining 67 cases (32%) were labeled as aseptic meningitis. A considerable proportion of cases was found to have received an antibiotic prior to presentation. While symptoms such as fever or poor feeding were common among cases, meningeal signs were less prominent. A lumbar puncture was carried out on all cases to reach diagnosis by gram stain, latex agglutination test and cerebrospinal fluid (CSF) and blood cultures following standard procedures. The immediate burden of meningitis cases was found to be the lengthy stay of patients in the hospital wards and intensive care units. Some of the main causative agents were resistant to the conventional antimicrobial therapy, but susceptible to newer antibiotics. CONCLUSION: The study being based on a population based surveillance gave a better overview on causative organisms of meningitis emphasizing that Gram stain, serology of CSF and culture (of CSF and blood) should be used. A high index of suspicion is needed to diagnose meningitis in children. Lumbar tap should be encouraged and supported in terms of training and more authorization to apply in diagnostic tests of such conditions. Audiometric measurement is a crucial need in the assessment of meningitis cases and in the process of their follow up. This type of service is clearly missing in our system. Influential steps are to be planned to avail this service.

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.

Serogroup W-135 meningococcal disease during the Hajj, 2000.

An outbreak of serogroup W-135 meningococcal disease occurred during the 2000 Hajj in Saudi Arabia. Disease was reported worldwide in Hajj pilgrims and their close contacts; however, most cases were identified in Saudi Arabia. Trends in Saudi meningococcal disease were evaluated and the epidemiology of Saudi cases from this outbreak described. Saudi national meningococcal disease incidence data for 1990 to 2000 were reviewed; cases from January 24 to June 5, 2000, were retrospectively reviewed. The 2000 Hajj outbreak consisted of distinct serogroup A and serogroup W-135 outbreaks. Of 253 identified cases in Saudi Arabia, 161 (64%) had serogroup identification; serogroups W-135 and A caused 93 (37%) and 60 (24%) cases with attack rates of 9 and 6 cases per 100,000 population, respectively. The 2000 Hajj outbreak was the first large serogroup W-135 meningococcal disease outbreak identified worldwide. Enhanced surveillance for serogroup W-135, especially in Africa, is essential to control this emerging epidemic disease.