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Biomedical subjects

Remon Abu-Elyazeed

Publications and source records attributed to Remon Abu-Elyazeed.

12 recordsLinked to original sources
PubMed2006

Lessons and implications from a mass immunization campaign in squatter settlements of Karachi, Pakistan: an experience from a cluster-randomized double-blinded vaccine trial [NCT00125047].

OBJECTIVE: To determine the safety and logistic feasibility of a mass immunization strategy outside the local immunization program in the pediatric population of urban squatter settlements in Karachi, Pakistan. METHODS: A cluster-randomized double blind preventive trial was launched in August 2003 in 60 geographic clusters covering 21,059 children ages 2 to 16 years. After consent was obtained from parents or guardians, eligible children were immunized parenterally at vaccination posts in each cluster with Vi polysaccharide or hepatitis A vaccine. Safety, logistics, and standards were monitored and documented. RESULTS: The vaccine coverage of the population was 74% and was higher in those under age 10 years. No life-threatening serious adverse events were reported. Adverse events occurred in less than 1% of all vaccine recipients and the main reactions reported were fever and local pain. The proportion of adverse events in Vi polysaccharide and hepatitis A recipients will not be known until the end of the trial when the code is broken. Throughout the vaccination campaign safe injection practices were maintained and the cold chain was not interrupted. Mass vaccination in slums had good acceptance. Because populations in such areas are highly mobile, settlement conditions could affect coverage. Systemic reactions were uncommon and local reactions were mild and transient. Close community involvement was pivotal for information dissemination and immunization coverage. CONCLUSION: This vaccine strategy described together with other information that will soon be available in the area (cost/effectiveness, vaccine delivery costs, etc) will make typhoid fever control become a reality in the near future.

Journal Article↗
PubMed2006

Clinic-based surveillance for bacterial- and rotavirus-associated diarrhea in Egyptian children.

To identify enteropathogens for vaccine development, we implemented clinic-based surveillance for severe pediatric diarrhea in Egypt's Nile River Delta. Over 2 years, a physician clinically evaluated and obtained stool samples for microbiology from patients with diarrhea and less than 6 years of age. In the first (N = 714) and second clinic (N = 561), respectively, 36% (N = 254) and 46% (N = 260) of children were infected with rotavirus, enterotoxigenic Escherichia coli (ETEC), Campylobacter, or Shigella. When excluding mixed rotavirus-bacterial infections, for the first and second clinic, 23% and 10% had rotavirus-associated diarrhea, and 14% and 17% had ETEC-associated diarrhea, respectively. Campylobacter-associated diarrhea was 1% and 3%, and Shigella-associated diarrhea was 2% and 1%, respectively, for the two clinics. Rotavirus-associated diarrhea peaked in late summer to early winter, while bacterial agents were prevalent during summer. Rotavirus-associated cases presented with dehydration, vomiting, and were often hospitalized. Children with Shigella- or Campylobacter-associated diarrhea reported as watery diarrhea and rarely dysentery. ETEC did not have any clinically distinct characteristics. For vaccine development and/or deployment, our study suggests that rotavirus is of principle concern, followed by ETEC, Shigella, and Campylobacter.

Bacterial Infections↗
PubMed2006

The feasibility of a school-based VI polysaccharide vaccine mass immunization campaign in Hue City, central Vietnam: streamlining a typhoid fever preventive strategy.

We report the coverage, safety, and logistics of a school-based typhoid fever immunization campaign that took place in Hue City, central Vietnam; a typhoid fever endemic area. A cluster-randomized evaluation-blinded controlled trial was designed where 68 schools (cluster) were randomly allocated the single dose Vi polysaccharide vaccine (Typherix) or the active control hepatitis A vaccine (Havrix). A safety surveillance system was implemented. A total of 32,267 children were immunized with a coverage of 57.5%. Strong predictors for vaccination were attending primary schools, peri-urban location of the school, and low family income. Human resources were mainly schoolteachers and the campaign was completed in about 1 month. Most adverse events reported were mild. Safe injection and safe sharp-waste disposal practices were followed. A typhoid fever school-based immunization campaign was safe and logistically possible. Coverage was moderate and can be interpreted as the minimum that could have been achievable because individual written informed consent procedures were sought for the first time in Hue City and the trial nature of the campaign. The lessons learned, together with cost-effectiveness results to be obtained by the end of follow-up period, will hopefully accelerate the introduction of Vi typhoid fever vaccine in Vietnam.

Adolescent↗
PubMed2005

Sero-epidemiology of hepatitis B infection in pregnant women in Oman, Qatar and the United Arab Emirates.

OBJECTIVE: The aim of this cross-sectional study was to evaluate the prevalence of hepatitis B 'e' antigen (HBeAg) and hepatitis B surface antigen (HBsAg) in pregnant women in the Gulf States. METHODS: A total of 1710 pregnant women aged 15-45 years were enrolled in June-July 2000 in nine centres across Oman, Qatar and Unite Arab Emirates. The percentage of HBsAg-positive and HBeAg-positive individuals was determined. RESULTS: Serology results were available for 1694 women. A total of 7.1% of the women in Oman, 1% in Qatar and 1.5% in UAE were HBsAg-positive. Three (0.5%) women in Oman were HBeAg-positive. Risk factors identified for being HBsAg-positive were younger age, being a national (i.e. not an expatriate) and residing outside the city. CONCLUSIONS: Results from this study have shown that hepatitis B virus (HBV) prevalence in pregnant women is of intermediate endemicity in Oman and of low endemicity in Qatar and UAE. Thus, universal vaccination of all female adolescents before potential pregnancy is recommended in Oman in order to prevent perinatal infection, as well as to minimize horizontal transmission of the HBV in the community.

Adolescent↗
PubMed2005

Diarrhea associated with Cryptosporidium parvum among young children of the Nile River Delta in Egypt.

Over a 2-year period, the prevalence and clinical characteristics of Cryptosporidium-associated diarrhea in the Nile River Delta of Egypt was studied. A stool sample was obtained from children with diarrhea attending one of two study hospitals and of the 1275 children evaluated, 214 (17%) were found to be infected with Cryptosporidium. Younger age was a risk factor for developing Cryptosporidium-associated diarrhea. Children <12 months of age were 2.4 times more likely to be infected with Cryptosporidium (p<0.01) and children 12 to 23 months were 1.9 (p<0.05) times more likely to be infected with the organism as compared to older children. Breastfeeding had a trend towards protection against Cryptosporidium-associated diarrhea (p=0.07). Clinical findings associated with Cryptosporidium diarrhea included vomiting, persistent diarrhea and the need for hospitalization. Our data suggest that Cryptosporidium is common in Egyptian children and may be associated with severe diarrhea.

Age Distribution↗
PubMed2005

Serologic correlates of protection against enterotoxigenic Escherichia coli diarrhea.

BACKGROUND: We conducted a nested case-control study in 397 rural Egyptian children <36 months of age to assess the correlation between serum levels of antibodies against toxin and colonization factors (CFs) and the risk of homologous enterotoxigenic Escherichia coli (ETEC) diarrhea. METHODS: Active case detection was performed via semiweekly home visits, and blood was obtained at 3-month intervals. After each serosurvey, case subjects were selected from children experiencing a CF antigen (CFA)/I-, CFA/II-, CFA/IV-, or heat-labile enterotoxin (LT)-ETEC diarrheal episode during the subsequent 3 months. Up to 5 control subjects per case subject were selected from children who did not experience an ETEC diarrheal episode during the corresponding interval. Serum titers of immunoglobulin G antibodies against CFA/I, coli surface antigen (CS) 3, CS6, and LT were measured by enzyme-linked immunosorbant assay. RESULTS: The distribution of serum titers of LT, CS3, and CS6 antibodies did not differ between the case and control subjects. For children <18 months of age, serum titers of CFA/I antibody were inversely related to the risk of CFA/I-ETEC diarrhea; reciprocal serum titers of CFA/I antibody > or =76 were associated with a 77% reduction in the odds of CFA/I-ETEC diarrhea. CONCLUSION: Induction of reciprocal serum titers of antibodies against CFA/I within or above the 76-186 range should be further evaluated as a predictor for assessment of the ability of candidate vaccines to protect against CFA/I-ETEC diarrhea.

Antibodies, Bacterial↗
PubMed2005

Hepatitis a in Lebanon: a changing epidemiological pattern.

In this multicenter study in Lebanon, hepatitis A virus (HAV) seroprevalence rates were surveyed by age, gender, and socioeconomic factors. Blood samples collected from 606 subjects aged 1 to 30 years were analyzed for anti-HAV IgG. Age was the most important factor influencing HAV seroprevalence. HAV seroprevalence rates in the current study were about 78% in the > or = 21 years age group, 28% in the 6-10 years age group, and 11% in the 1-5 years age group as compared with 97.7% in adults, 85% in children aged 6-12 years, and 40% in children aged 1 to 5 years in previous studies, demonstrating a shift in HAV seroprevalence from the younger to the higher age groups. In light of the severity of the disease in adults and availability of safe and effective vaccines against HAV infection, introduction of HAV vaccination into the national immunization schedule of Lebanon should be considered.

Adolescent↗
PubMed2004

Development of pathogenicity-driven definitions of outcomes for a field trial of a killed oral vaccine against enterotoxigenic Escherichia coli in Egypt: application of an evidence-based method.

BACKGROUND: To design an efficacy trial of a killed oral vaccine against enterotoxigenic Escherichia coli (ETEC) diarrhea in Egyptian children, we derived for ETEC diarrhea an empirical definition that increased the probability that diarrhea associated with excretion of ETEC was caused by the detected ETEC. METHODS: We conducted a cohort study of 397 Egyptian children <24 months old and monitored them until they were 3 years old. Vaccine-preventable (VP) ETEC was defined as ETEC expressing >/=1 of the toxin- (heat-labile [LT] toxin) and colonization-factor antigens (CFA I, II, and IV) in the vaccine. RESULTS: Although fecal excretion of VP-ETEC was highly associated with diarrhea, excretion of LT-ETEC per se was not related to diarrhea (adjusted odds ratio [OR(A)], 1.16 [95% confidence interval [CI], 0.90-1.49]). The fecal excretion of antigenic types of VP-ETEC other than LT-ETEC (non-LT VP-ETEC) was highly associated with diarrheal symptoms (OR(A), 3.91 [95% CI, 2.78-5.49]; P<.001), and this association was greater for nonbloody than for bloody diarrhea. CONCLUSIONS: Because the vaccine had been anticipated to protect primarily against symptomatic ETEC diarrhea, these results indicate that the primary-outcome definition of ETEC diarrhea for the trial should be restricted to nonbloody diarrheal episodes associated with fecal excretion of non-LT VP-ETEC.

Bacterial Toxins↗
PubMed2004

The role of epidemiology in the introduction of vi polysaccharide typhoid fever vaccines in Asia.

Despite the availability of at least two licensed typhoid fever vaccines--injectable sub-unit Vi polysaccharide vaccine and live, oral Ty21a vaccine--for the last decade, these vaccines have not been widely introduced in public-health programmes in countries endemic for typhoid fever. The goal of the multidisciplinary DOMI (Diseases of the Most Impoverished) typhoid fever programme is to generate policy-relevant data to support public decision-making regarding the introduction of Vi polysaccharide typhoid fever immunization programmes in China, Viet Nam, Pakistan, India, Bangladesh, and Indonesia. Through epidemiological studies, the DOMI Programme is generating these data and is offering a model for the accelerated, rational introduction of new vaccines into health programmes in low-income countries. Practical and specific examples of the role of epidemiology are described in this paper. These examples cover: (a) selection of available typhoid fever vaccines to be introduced in the programme, (b) generation of policy-relevant data, (c) providing the 'backbone' for the implementation of other multidisciplinary projects, and (d) generation of unexpected but useful information relevant for the introduction of vaccines. Epidemiological studies contribute to all stages of development of vaccine evaluation and introduction.

Asia↗
PubMed2003

Antimicrobial susceptibility trends in Campylobacter jejuni and Campylobacter coli isolated from a rural Egyptian pediatric population with diarrhea.

Comparative and trend analysis was conducted on annual prevalence of antimicrobial susceptibility among Campylobacter jejuni and Campylobacter coli recovered from rural Egyptian children from 1995 through 2000. C. jejuni and C. coli demonstrated significant decreasing trends in ciprofloxacin susceptibility over the study period (p < 0.001 for both). In general, C. coli demonstrated a higher degree of susceptibility than C. jejuni, however, there was no statistical difference (p = 0.2) comparing the linear trends over the duration of the study. There was no indication of frank macrolide (erythromycin or azithromycin) resistance among any Campylobacter. Moreover, there were statistically significant positive trends in both the MIC(50) and MIC(90) values for the erythromycin and azithromycin during the study period, suggesting a possible decreasing trend in susceptibility among Campylobacter. This study demonstrated that antimicrobial susceptibility in Campylobacter has significantly decreased from 1995 through 2000 among pediatric diarrhea cases in rural Egypt.

Anti-Bacterial Agents↗
PubMed2002

Introductory evaluation of an oral, killed whole cell enterotoxigenic Escherichia coli plus cholera toxin B subunit vaccine in Egyptian infants.

BACKGROUND: We conducted the first trial to assess the safety and immunogenicity of an oral, killed enterotoxigenic Escherichia coli plus cholera toxin B-subunit vaccine in children <2 years old. METHODS: Three doses of vaccine or killed E. coli K-12 control were given at 2-week intervals to 64 Egyptian infants, 6 to 18 months old, in a randomized, double blind manner. Adverse events were monitored for 3 days after each dose. Blood was collected before immunization and 7 to 10 days after each dose to assess vaccine-specific serologic responses. RESULTS: There was no statistically significant intergroup difference in the percentage of subjects reporting the primary safety endpoint (diarrhea or vomiting) after the first (31%, vaccine; 30%, control) or third (14%, vaccine; 18%, control) dose, whereas there was a trend toward greater reporting in the vaccine group after Dose 2 (36%, vaccine; 18%, control; P = 0.052). The percentage of children showing IgA seroconversion after any dose was higher in the vaccine than the control group for recombinant cholera toxin B-subunit (97% vs. 46%), colonization factor antigen I (61% vs. 18%) and coli surface antigen 4 (39% vs. 4%) (P < 0.001 for each comparison). IgG seroconversion rates in the vaccine and control groups were 97 and 21% to recombinant cholera toxin B-subunit (P < 0.001), 64 and 29% for colonization factor antigen I (P < 0.01), 53 and 21% for coli surface antigen 2 (P < 0.05) and 58 and 4% for coli surface antigen 4 (P < 0.001), respectively. The third vaccine dose was followed by augmented IgG antitoxin titers. CONCLUSION: The oral enterotoxigenic E. coli vaccine was safe and immunogenic in this setting in Egyptian infants.

Adjuvants, Immunologic↗