Epidemiology of invasive pneumococcal disease in Saudi Arabian children younger than 5years of age.

This study evaluated the incidence, serotype distribution, and antimicrobial susceptibility of invasive pneumococcal disease (IPD) in Saudi Arabian children. This multicenter, prospective, clinical surveillance study included children under 5years of age, residents of one of the seven study health areas, who were brought to a study hospital with suspicion of IPD. Bacterial isolates from sterile site samples, collected less than 24h after hospital visit/admission, were identified, serotyped, and tested for antibiotic susceptibility. Between June 2007 and January 2009, 631 episodes of suspected IPD were recorded, and 623 were included in the analysis. One child (0.2%) had previously received one dose of a pneumococcal vaccine. Forty-seven episodes were positive for Streptococcus pneumoniae and three for Haemophilus influenzae. The incidence of confirmed IPD cases was estimated to be 2.5-21.6 per 100,000 children (<5years). Among the 46 S. pneumoniae isolates serotyped and tested for antibiotic susceptibility, the most common serotypes were 5 and 23F (20% each), 6B (17%), and 1 and 14 (11% each). Sixty-three percent of isolates were multidrug-resistant. Vaccination of Saudi Arabian children with expanded-coverage conjugate pneumococcal vaccines containing serotypes 1 and 5 could have a substantial impact to prevent IPD in this population.

Gastroenteritis attributable to rotavirus in hospitalized Saudi Arabian children in the period 2007-2008.

PURPOSE: Rotavirus (RV) is a leading cause of severe gastroenteritis (GE) in children across the world. As there is a lack of epidemiological data for RV gastroenteritis (RVGE) in Saudi Arabia, this hospital-based study was designed to estimate the disease burden of RVGE and assess the prevalent RV types in Saudi children younger than 5 years of age. PATIENTS AND METHODS: Children hospitalized for acute GE were enrolled at four pediatric referral hospitals in Saudi Arabia. The study was conducted from February 2007 to March 2008 and used the World Health Organization's generic protocol for RVGE surveillance. The Vesikari severity scale was used to assess the severity of RVGE. Stool samples were tested for RV using an enzyme-linked immunosorbent assay. Samples were further typed by reverse transcriptase-polymerase chain reaction and hybridization assay for determining the G and P types. RESULTS: A total of 1,007 children were enrolled; the final analysis included 970 children, of whom 395 were RV positive, 568 were RV negative, and seven had unknown RV status. The proportion of RVGE among GE hospitalizations was 40.7% (95% confidence interval: 37.6-43.9). The highest percentage of RVGE hospitalizations (83.1%) was seen in children younger than 2 years of age. The highest proportion of RV among GE hospitalizations was in June 2007 with 57.1%. The most common RV types detected were G1P[8] (49.3%), G1G9P[8] (13.2%), and G9P[8] (9.6%). Before hospitalization, severe GE episodes occurred in 88.1% RV-positive and 79.6% RV-negative children. Overall, 94% children had recovered by the time they were discharged. Two children (one RV positive and one RV negative) died due to GE complications. CONCLUSION: RVGE is responsible for a high proportion of hospitalizations in Saudi children younger than 5 years of age. Routine RV vaccination has therefore been introduced into the national immunization program and may help reduce the morbidity, mortality, and disease burden associated with RVGE in Saudi Arabia.

Rotavirus gastroenteritis in children under 5 years in the Kingdom of Bahrain: hospital-based surveillance.

PURPOSE: Rotavirus (RV) is the leading cause of morbidity and mortality in children under 5 years of age worldwide. This study assessed the role of RV as a cause of gastroenteritis (GE)-associated hospitalization in children, generating baseline information to evaluate the potential impact of the RV vaccine in reducing RVGE disease burden in the Kingdom of Bahrain. METHODS: This single, pediatric hospital-based surveillance study was conducted over a period of 12 months beginning April 1, 2006. A total of 314 children aged under 5 years and hospitalized due to GE were enrolled in the study, following collection of written informed consent from parents/guardians. Stool samples were tested for the presence of RV using enzyme immunoassay, and a random subset of RV-positive samples was further genotyped using reverse transcriptase-polymerase chain reaction and reverse hybridization assay. RESULTS: Of 314 enrolled children, 239 were included in the final analysis. RV was detected in 107 children (44.8%), mostly in the 6-23 months age group (82/107; 76.6%). RVGE occurred throughout the year, with the highest proportion occurring during April (26/42; 61.9%). G1P[8[ was the most commonly detected RV strain (10/17; 58.8%) in the limited number of samples analyzed. Vomiting and severe RVGE were more commonly observed in RV-positive than RV-negative children before hospitalization (P = 0.0008 and 0.0204, respectively). CONCLUSION: In our study, RV accounted for over 40% of GE-associated hospitalizations and particularly affected children under 2 years of age. These data will serve as a baseline for assessing the potential changes in the epidemiology of RV disease and for evaluating the potential impact of the introduction of RV vaccination.

Meningococcal disease in the Middle East and North Africa: an important public health consideration that requires further attention.

This paper reviews the epidemiological data describing meningococcal disease in the Middle East and North Africa (MENA). While meningococcal disease remains an important cause of endemic and epidemic disease in many MENA countries, existing published epidemiological data appear limited, fragmented, and collected via disparate methodologies. Children aged 5 years and younger are predominantly affected, though outbreaks of the disease often affect older age groups. Whilst serogroup A remains a main cause of meningococcal disease in the region, cases of serogroup B, W-135, and Y have been increasingly reported over the last two decades in some countries. The Hajj pilgrimage is a key factor influencing outbreaks and transmission, and the use of vaccines has minimized the effects on the home countries of the pilgrims and has decreased global dissemination of disease. Wider use of available polyvalent meningococcal conjugate vaccines may provide broader protection against the range of serogroups causing disease or posing a threat in the region. In addition, strengthening regional surveillance systems and regularly publishing reports with reliable estimates of disease incidence, carriage, disease-related mortality, and sequelae may facilitate the development of appropriate interventions and public health strategies regarding meningococcal disease within the region.

The tetravalent meningococcal serogroups A, C, W-135, and Y tetanus toxoid conjugate vaccine is immunogenic with a clinically acceptable safety profile in subjects previously vaccinated with a tetravalent polysaccharide vaccine.

OBJECTIVES: The immunogenicity and safety of the tetravalent meningococcal serogroups A, C, W-135, and Y tetanus toxoid conjugate vaccine (MenACWY-TT) were evaluated in subjects previously vaccinated with a tetravalent meningococcal polysaccharide vaccine and in subjects without previous meningococcal vaccination. METHODS: In this phase II, open, controlled study (NCT00661557), healthy subjects aged 4.5-34 years received one dose of MenACWY-TT at month 0. Subjects in the MPS group (n=192) had received polysaccharide vaccine in a study conducted 30-42 months earlier; age-matched subjects in the noMPS control group (n=79) had received no meningococcal vaccination within the past 10 years. Serum bactericidal activity using rabbit complement (rSBA) was measured at month 0 and month 1. RESULTS: At month 1, ≥97.0% of subjects had rSBA titers ≥1:128. Post-vaccination rSBA geometric mean titers (GMTs) were ≥3.9-fold higher than pre-vaccination in both treatment groups. Exploratory analyses showed no statistically significant differences between groups in percentages of subjects with rSBA titers ≥1:8 and ≥1:128, but significantly lower rSBA GMTs and vaccine response rates for each serogroup in the MPS versus the noMPS group. MenACWY-TT had an acceptable safety profile in both groups. CONCLUSIONS: These results suggest that MenACWY-TT could be used in vaccination programs irrespective of the pre-vaccination status with polysaccharide vaccine.

Multicenter prospective study on the burden of rotavirus gastroenteritis in Turkey, 2005-2006: a hospital-based study.

Rotavirus is the main cause of gastroenteritis and dehydration requiring hospitalization among infants and children. Despite the high diarrhea-related mortality rate, there are limited studies describing the prevalence of rotavirus in Turkey. The disease burden of rotavirus gastroenteritis in Turkey was assessed by active, prospective surveillance conducted in accordance with a modified World Health Organization generic protocol from 1 June 2005 through 1 June 2006. A total of 411 children aged <5 years who were hospitalized for gastroenteritis in 4 centers were enrolled. Rotavirus was identified in 53% of samples from the 338 children tested; the range for individual centers was 32.4%-67.4%. Overall, 83.8% of rotavirus-positive children were aged <2 years. Rotavirus gastroenteritis occurred year-round but peaked in the winter. G1P[8] was the most widely prevalent strain (76% of strains), followed by G2P[4] (12.8%). G9P[8] was reported in samples from 3.9% of children. These data support the need for a rotavirus vaccine in Turkey.