Factors Associated With Racially and Ethnically Diverse Sample of Adolescents, Young Adults, and Parents' Intention to Receive a COVID-19 Vaccine

PURPOSE

Identify variables, including moderating variables, associated with adolescents, young adults, and parents' intention to receive a COVID-19 vaccine in January 2021.

DESIGN

Cross-sectional survey.

SETTING

United States Midwestern academic medical center.

SAMPLE

Adolescents (n = 242); young adults (n = 333); parents (n = 563).

MEASURES

Associations between predictors-participant characteristics, general vaccine hesitancy, COVID-19 and vaccine knowledge, perceptions, and normative beliefs-and intention to receive a COVID-19 vaccine (outcome) were assessed. To determine variables impacting the strength of the relationship between predictors and outcome, moderators included 2020/2021 influenza vaccine receipt, having experienced discrimination, and primary sources of information for COVID-19.

ANALYSIS

Multivariable logistic regression examined associations, including moderating effects, for adolescents, young adults, parents, and parents for child.

RESULTS

With 20,231 email addresses receiving the survey, 1138 participants were included in the analysis. Intention to receive a COVID-19 vaccine was reported by 60.7% adolescents (n = 147), 65.2% young adults (n = 217), and 38.5% parents (n = 217) and 38.2% parents (n = 215) intended to vaccinate their child. Intention was associated with lower general vaccine hesitancy for adolescents (AOR = 1.50), young adults (AOR = 1.39), parents (AOR = 1.18), and parents' intention for their child (AOR = 1.17). Parents citing reputable medical experts as primary source of COVID-19 information positively moderated vaccine perceptions and intention for self (AOR = 8.25) and child (AOR = 6.37).

CONCLUSION

Clinician training to address vaccine hesitancy may be effective at promoting positive COVID-19 vaccine perceptions.

B memory cell responses to LPS, IVP and IpaB antigen after oral vaccination with Shigella sonnei vaccine candidates WRSs2 and WRSs3

B memory (BM) cell responses were evaluated using peripheral blood mononuclear cells that were collected and cryopreserved during a Phase 1 trial of two live Shigella sonnei vaccine candidates WRSs2 and WRSs3. An ELISpot assay was used to measure IgG+ and IgA+ BM cell responses against S. sonnei LPS, IVP and IpaB antigens. Analysis of BM cell responses at baseline, and on days 28 and 56 post vaccination indicate that after a single oral dose of WRSs2 and WRSs3, both groups of vaccinees induced IgG+ and IgA+ BM cell responses that were variable in magnitude among subjects and reached significance to IVP and IpaB at several doses. The responses generally peaked at d28 after vaccination. The baseline as well as post-vaccination levels of IgA+ BM cells were relatively higher than IgG+ BM cells, but the maximum fold-increase at d28/d56 over baseline was greater for IgG+ than IgA+ BM cell responses. Furthermore, at the three highest vaccine doses, >60-90% of subjects were considered responders indicating a ≥2-fold higher IgG+ BM cell responses to IVP and IpaB post vaccination, while fewer subjects indicated the same level of response to LPS.

Safety and Immunogenicity of an Andes Virus DNA Vaccine by Needle-Free Injection: A Randomized, Controlled Phase 1 Study

BACKGROUND

Andes virus (ANDV), a rodent-borne hantavirus, causes hantavirus pulmonary syndrome (HPS). The safety and immunogenicity of a novel ANDV DNA vaccine was evaluated.

METHODS

Phase 1, double-blind, dose-escalation trial randomly assigned 48 healthy adults to placebo or ANDV DNA vaccine delivered via needle-free jet injection. Cohorts 1 and 2 received 2 mg of DNA or placebo in a 3-dose (days 1, 29, 169) or 4-dose (days 1, 29, 57, 169) schedule, respectively. Cohorts 3 and 4 received 4 mg of DNA or placebo in the 3-dose and 4-dose schedule, respectively. Subjects were monitored for safety and neutralizing antibodies by pseudovirion neutralization assay (PsVNA50) and plaque reduction neutralization test (PRNT50).

RESULTS

While 98% and 65% of subjects had at least 1 local or systemic solicited adverse event (AE), respectively, most AEs were mild or moderate; no related serious AEs were detected. Cohorts 2, 3, and 4 had higher seroconversion rates than cohort 1 and seropositivity of at least 80% by day 197, sustained through day 337. PsVNA50 geometric mean titers were highest for cohort 4 on and after day 197.

CONCLUSIONS

This first-in-human candidate HPS vaccine trial demonstrated that an ANDV DNA vaccine was safe and induced a robust, durable immune response. Clinical Trials Registration. NCT03682107.

An Exploration of Social Norms That Restrict Girls' Sexuality and Facilitate Child Marriage in Bangladesh to Inform Policies and Programs

PURPOSE

Despite international commitments and increases in education and economic opportunities for girls and young women, child marriage persists and, in some contexts, reductions have stagnated. In order to accelerate and sustain progress, a better understanding of the social norms that continue to support the practice is required.

METHODS

This qualitative study used 20 in-depth interviews with adolescent girls and another 10 with boys, a total of 16 focus group discussions with girls, boys, and parents of adolescent girls, and 8 key informant interviews with community leaders, to identify and understand the expectations that support the practice of child marriage, in communities in northern Bangladesh.

RESULTS

Expectations that girls will restrict their mobility, limit their engagement with male peers, and take extremely limited decision-making roles in their marriage reinforce the practice of child marriage. Girls, and their families, that are considered at risk of or are perceived to have violated these norms face immense pressure for early marriage to mitigate damage to both their own and their families' reputations.

DISCUSSION

Social norms that are primarily engineered to control girls' sexuality continue to underpin the practice of child marriage in Bangladesh. Efforts to reduce child marriage such as through increased education or economic opportunities must also address these norms if substantial reductions are to be achieved and sustained in the long-term.

Pivotal Phase 3 Randomized Clinical Trial of the Safety, Tolerability, and Immunogenicity of 20-Valent Pneumococcal Conjugate Vaccine in Adults 18 Years and Older

BACKGROUND

Pneumococcal conjugate vaccines (PCVs) have significantly reduced pneumococcal disease, but disease from non-PCV serotypes remains. Safety, tolerability, and immunogenicity of a 20-valent PCV (PCV20) were evaluated.

METHODS

This pivotal phase 3, randomized, double-blind study enrolled adults into 3 age groups (≥60, 50-59, 18-49 years) at US and Swedish sites. Participants were randomized to receive one PCV20 or PCV13 dose. After 1 month, participants ≥60 years also received one dose of saline or 23-valent polysaccharide vaccine (PPSV23). Safety assessments included local reactions, systemic events, adverse events, serious adverse events, and newly diagnosed chronic medical conditions. Opsonophagocytic activity (OPA) geometric mean titers (GMTs) 1 month after PCV20 were compared to 13 matched serotypes after PCV13 and to 7 additional serotypes after PPSV23 in participants ≥60 years; noninferiority was declared if lower bound of the 2-sided 95% CI for OPA GMT ratio (PCV20/saline:PCV13/PPSV23 group) was >0.5. PCV20-elicited immune responses in younger participants were also bridged to those in 60-64-year-olds.

RESULTS

Severity and frequency of prompted local reactions and systemic events were similar after PCV20 or PCV13; no safety concerns were identified. Primary immunogenicity objectives were met, with immune responses after PCV20 noninferior to 13 matched serotypes after PCV13 and to 6 additional PPSV23 serotypes in participants ≥60 years; serotype 8 missed the statistical noninferiority criterion. PCV20 induced robust responses to all 20 vaccine serotypes across age groups.

CONCLUSIONS

PCV20 was safe and well tolerated, with comparable immunogenicity to PCV13/PPSV23. PCV20 is anticipated to expand protection against pneumococcal disease in adults.

Antibody in Lymphocyte Supernatant (ALS) responses after oral vaccination with live Shigella sonnei vaccine candidates WRSs2 and WRSs3 and correlation with serum antibodies, ASCs, fecal IgA and shedding

The levels of antigen-specific Antibodies in Lymphocyte Supernatant (ALS) using an ELISA are being used to evaluate mucosal immune responses as an alternate to measuring the number of Antibody Secreting Cells (ASCs) using an ELISpot assay. A recently completed trial of two novel S. sonnei live oral vaccine candidates WRSs2 and WRSs3 established that both candidates were safe, well tolerated and immunogenic in a vaccine dose-dependent manner. Previously, mucosal immune responses were measured by assaying IgA- and IgG-ASC in peripheral blood mononuclear cells (PBMCs). In this report, the magnitude of the S. sonnei antigen-specific IgA- and IgG-ALS responses was measured and correlated with previously described ASCs, serum antibodies, fecal IgA and vaccine shedding. Overall, the magnitude of S. sonnei anti-Invaplex50 ALS was higher than that of LPS or IpaB, and both vaccines demonstrated a more robust IgA-ALS response than IgG; however, compared to WRSs3, the magnitude and percentage of responders were higher among WRSs2 recipients for IgA- or IgG-ALS. All WRSs2 vaccinees at the two highest doses responded for LPS and Invaplex50-specific IgA-ALS and 63–100% for WRSs3 vaccinees responded. Regardless of the vaccine candidate, vaccine dose or detecting antigen, the kinetics of ALS responses were similar peaking on days 7 to 9 and returning to baseline by day 14. The ALS responses were vaccine-specific since no responses were detected among placebo recipients at any time. A strong correlation and agreement between responders/non-responders were noted between ALS and other mucosal (ASC and fecal IgA) and systemic (serum antibody) immune responses. These data indicate that the ALS assay can be a useful tool to evaluate mucosal responses to oral vaccination, an observation noted with trials of other bacterial diarrheal pathogens. Furthermore, this data will guide the list of immunological assays to be conducted for efficacy trials in different populations. It is hoped that an antigen-specific-ALS titer may be a key mucosal correlate of protection, a feature not currently available for any Shigella vaccines candidates. https://clinicaltrials.gov/show/NCT01336699.

A site assessment tool for inpatient controlled human infection models for enteric disease pathogens

The use of the controlled human infection model to facilitate product development and to advance understanding of host-pathogen interactions is of increasing interest. While administering a virulent (or infective) organism to a susceptible host necessitates an ongoing evaluation of safety and ethical considerations, a central theme in conducting these studies in a safe and ethical manner that yields actionable data is their conduct in facilities well-suited to address their unique attributes. To that end, we have developed a framework for evaluating potential sites in which to conduct inpatient enteric controlled human infection model to ensure consistency and increase the likelihood of success.

Warp Speed for Coronavirus Disease 2019 (COVID-19) Vaccines: Why Are Children Stuck in Neutral?

While adult clinical trials of coronavirus disease 2019 (COVID-19) vaccines have moved quickly into phase 3 clinical trials, clinical trials have not started in children in the United States. The direct COVID-19 impact upon children is greater than that observed for a number of other pathogens for which we now have effective pediatric vaccines. Additionally, the role of children in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transmission has clearly been underappreciated. Carefully conducted phase 2 clinical trials can adequately address potential COVID-19 vaccine safety concerns. Delaying phase 2 vaccine clinical trials in children will delay our recovery from COVID-19 and unnecessarily prolong its impact upon children’s education, health, and emotional well-being, and equitable access to opportunities for development and social success. Given the potential direct and indirect benefits of pediatric vaccination, implementation of phase 2 clinical trials for COVID-19 vaccines should begin now.

Novel Treatment of Infant With COVID-19 With the Sialidase Fusion Protein, DAS181

We describe the successful treatment of a 10-month-old female with respiratory distress secondary to Coronavirus disease 2019 (COVID-19) with the nebulized investigational drug, DAS181. Therapy was well tolerated, and the patient had minimal side effects. The patient's respiratory distress and positive viral polymerase chain reaction rapidly resolved after initiation of therapy.

Phase I/II study of COVID-19 RNA vaccine BNT162b1 in adults

In March 2020, the World Health Organization (WHO) declared coronavirus disease 2019 (COVID-19), which is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)¹, a pandemic. With rapidly accumulating numbers of cases and deaths reported globally², a vaccine is urgently needed. Here we report the available safety, tolerability and immunogenicity data from an ongoing placebo-controlled, observer-blinded dose-escalation study (ClinicalTrials.gov identifier NCT04368728) among 45 healthy adults (18-55 years of age), who were randomized to receive 2 doses-separated by 21 days-of 10 μg, 30 μg or 100 μg of BNT162b1. BNT162b1 is a lipid-nanoparticle-formulated, nucleoside-modified mRNA vaccine that encodes the trimerized receptor-binding domain (RBD) of the spike glycoprotein of SARS-CoV-2. Local reactions and systemic events were dose-dependent, generally mild to moderate, and transient. A second vaccination with 100 μg was not administered because of the increased reactogenicity and a lack of meaningfully increased immunogenicity after a single dose compared with the 30-μg dose. RBD-binding IgG concentrations and SARS-CoV-2 neutralizing titres in sera increased with dose level and after a second dose. Geometric mean neutralizing titres reached 1.9-4.6-fold that of a panel of COVID-19 convalescent human sera, which were obtained at least 14 days after a positive SARS-CoV-2 PCR. These results support further evaluation of this mRNA vaccine candidate.

Consensus Report on Shigella Controlled Human Infection Model: Clinical Endpoints

The Shigella controlled human infection model (CHIM) is valuable for assessing candidate Shigella vaccine efficacy and potentially accelerating regulatory approval. The Shigella CHIM is currently being conducted at 3 sites in the United States using Shigella flexneri 2a strain 2457T and Shigella sonnei strain 53G. Shigellosis can present variably as watery diarrhea alone or with dysentery, and can be accompanied by manifestations including fever, abdominal cramps, tenesmus, and malaise. For comparability, it is important to harmonize the primary clinical endpoint. An expert working group was convened on 2 February 2018 to review clinical data from Shigella CHIM studies performed to date and to develop a consensus primary endpoint. The consensus endpoint enabled "shigellosis" to present as severe diarrhea or moderate diarrhea or dysentery. The latter 2 criteria are met when concurrent with fever of 38.0°C and/or vomiting, and/or a constitutional/enteric symptom graded at least as "moderate" severity. The use of a blinded independent committee to adjudicate the primary endpoint by subject was also regarded as important. As safety of volunteers in challenge studies is of paramount importance and treatment timing can affect primary outcomes, a standard for early antibiotic administration was established as follows: (1) when the primary endpoint is met; (2) if a fever of ≥39.0°C develops; or (3) if the study physician deems it appropriate. Otherwise, antibiotics are given at 120 hours postinfectious challenge. The working group agreed on objective and subjective symptoms to be solicited, and standardized methods for assessing subject-reported severity of symptoms.

RNA-Based COVID-19 Vaccine BNT162b2 Selected for a Pivotal Efficacy Study

BACKGROUND

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections and the resulting disease, coronavirus disease 2019 (COVID-19), have spread to millions of people globally. Multiple vaccine candidates are under development, but no vaccine is currently available.

METHODS

Healthy adults 18-55 and 65-85 years of age were randomized in an ongoing, placebo-controlled, observer-blinded dose-escalation study to receive 2 doses at 21-day intervals of placebo or either of 2 lipid nanoparticle-formulated, nucleoside-modified RNA vaccine candidates: BNT162b1, which encodes a secreted trimerized SARS-CoV-2 receptor-binding domain, or BNT162b2, which encodes a prefusion stabilized membrane-anchored SARS-CoV-2 full-length spike. In each of 13 groups of 15 participants, 12 received vaccine and 3 received placebo. Groups were distinguished by vaccine candidate, age of participant, and vaccine dose level. Interim safety and immunogenicity data of BNT162b1 in younger adults have been reported previously from US and German trials. We now present additional safety and immunogenicity data from the US Phase 1 trial that supported selection of the vaccine candidate advanced to a pivotal Phase 2/3 safety and efficacy evaluation.

RESULTS

In both younger and older adults, the 2 vaccine candidates elicited similar dose-dependent SARS-CoV-2-neutralizing geometric mean titers (GMTs), comparable to or higher than the GMT of a panel of SARS-CoV-2 convalescent sera. BNT162b2 was associated with less systemic reactogenicity, particularly in older adults.

CONCLUSION

These results support selection of the BNT162b2 vaccine candidate for Phase 2/3 large-scale safety and efficacy evaluation, currently underway.

Hospital-acquired Pneumonia and Ventilator-associated Pneumonia in Children: A Prospective Natural History and Case-Control Study

BACKGROUND

Clinical trials for antibiotics designed to treat hospital-acquired and ventilator-associated bacterial pneumonias (HABP/VABP) are hampered by making these diagnoses in a way that is acceptable to the United States Food and Drug Administration and consistent with standards of care. We examined laboratory and clinical features that might improve pediatric HABP/VABP trial efficiency by identifying risk factors predisposing children to HABP/VABP and describing the epidemiology of pediatric HABP/VABP.

METHODS

We prospectively reviewed the electronic medical records of patients <18 years of age admitted to intensive and intermediate care units (ICUs) if they received qualifying respiratory support or were started on antibiotics for a lower respiratory tract infection or undifferentiated sepsis. Subjects were followed until HABP/VABP was diagnosed or they were discharged from the ICU. Clinical, laboratory and imaging data were abstracted using structured chart review. We calculated HABP/VABP incidence and used a stepwise backward selection multivariable model to identify risk factors associated with development of HABP/VABP.

RESULTS

A total of 862 neonates, infants and children were evaluated for development of HABP/VABP; 10% (82/800) of those receiving respiratory support and 12% (103/862) overall developed HABP/VABP. Increasing age, shorter height/length, longer ICU length of stay, aspiration risk, blood product transfusion in the prior 7 days and frequent suctioning were associated with increased odds of HABP/VABP. The use of noninvasive ventilation and gastric acid suppression were both associated with decreased odds of HABP/VABP.

CONCLUSIONS

Food and Drug Administration-defined HABP/VABP occurred in 10%-12% of pediatric patients admitted to ICUs. Risk factors vary by age group.

Melody Valve Bartonella henselae Endocarditis in an Afebrile Teen: A Case Report

Significant advancements in the care of children with cardiac valve disease over the past 15 years have led to the increasingly common use of percutaneous transcatheter valve implantation as an alternative to surgical replacement in selected patient populations. Although the transcatheter approach has several advantages, this approach and the valves used are not without complications. Bacterial endocarditis is a known and concerning complication after transcatheter pulmonary valve replacement (TPVR). Most reported cases have involved organisms that are common etiologic agents of bacterial endocarditis and are readily identified via blood culture. However, culture-negative endocarditis in the setting of TPVR has not been well described. We present our experience with one afebrile teenager with culture-negative, serology-positive Bartonella henselae endocarditis of a Melody valve 18 months after TPVR for management of tetralogy of Fallot. The teen was successfully managed with long-term antibiotic therapy followed by surgical replacement of the valve. To our knowledge, this is the first reported case of culture-negative endocarditis of a Melody TPVR in the absence of fever. This report discusses the importance of considering culture-negative endocarditis in the differential diagnosis of an afebrile patient with TPVR presenting with constitutional symptoms and valve dysfunction, particularly in the primary care setting. It is anticipated that with an increase in the successfully aging population of children who have undergone cardiac repair, the evaluation of these patients will become an increasingly important and common task for the community pediatrician.

Burden of Aeromonas hydrophila-associated diarrhea among children younger than 2 years in rural Egyptian community

INTRODUCTION

Between 2004 and 2007, a birth cohort of Egyptian children was analysed to evaluate the epidemiology of enteric diseases.

METHODOLOGY

A stool sample was collected from the study children every two weeks as well as whenever they experienced diarrhea. Samples were tested for routine bacterial pathogens as well as enteropathogenic viruses and parasites. A secondary goal of the study was to evaluate the burden of less commonly reported pathogens including Aeromonas hydrophila.

RESULTS

Of the 348 study subjects, 79 had A. hydrophila isolated from their stool at some point during the study.  Thirty-six children had exclusively symptomatic (S) infections while 33 had exclusively asymptomatic (AS) infections. However, 10 children had both S and AS infections. Among symptomatic cases, A. hydrophila was the sole pathogen isolated 36% of the time. An important aspect of A. hydrophila associated diarrhea was the high level of resistance to cephalosporins.

CONCLUSION

Although relatively uncommon, A. hydrophila was found to be associated with diarrhea among children living in Egypt and was frequently multi-drug resistant.

Predicting susceptibility to norovirus GII.4 by use of a challenge model involving humans

BACKGROUND

GII.4 is the predominant norovirus genotype worldwide. Challenge models involving humans have shown the association of human histo-blood group antigens (HBGAs) and susceptibility to infection with Norwalk virus (GI.1 norovirus), but the association of HBGAs and infection with other noroviruses is based on results of epidemiological studies. We performed the first GII.4 challenge study involving humans and prospectively evaluated the relationship between HBGAs and norovirus infection and associated illness.

METHODS

Forty healthy adults (23 secretors and 17 nonsecretors of HBGAs) were challenged with 5 10(4) reverse-transcription polymerase chain reaction (RT-PCR) units of GII.4 norovirus. Subjects were assessed daily for clinical illness, and stool specimens were evaluated for norovirus by RT-PCR. Infection was defined by detection of norovirus and/or seroconversion to GII.4 antibody.

RESULTS

Of the 23 secretors, 16 (70%) were infected with norovirus, 13 (57%) became ill (characterized by vomiting and/or diarrhea), and 12 (52%) developed norovirus-associated illness. In contrast, only 1 nonsecretor (5.9%) became ill, and another nonsecretor shed virus for a single day (P < .001 for each variable, compared with secretors). Infection occurred in secretors regardless of ABO blood group. Illness was mild to moderate in severity and lasted 1-3 days.

CONCLUSIONS

Secretor status determined the susceptibility to norovirus GII.4 challenge. This human challenge model should be useful for evaluating norovirus vaccines and antiviral agents. Clinical trials registration. NCT01322503.

Are immunosuppressive medications associated with decreased responses to routine immunizations? A systematic review

BACKGROUND

Long-term immunosuppressive medications are being used more commonly for a variety of medical conditions, including immune-mediated diseases and organ transplantation. While these medications are often necessary, they are associated with an increased risk of serious infections. Vaccination may be a way to prevent a variety of infections but vaccine responses among patients receiving immunosuppressive therapies have been variable.

PURPOSE

To systematically review the literature describing immune responses among patients on immunosuppressive therapies to vaccinations including influenza, pneumococcal, meningococcal, hepatitis A and B, tetanus toxoid, pertussis, varicella, and zoster.

DATA SOURCES

English language citations in the MEDLINE and EMBASE databases from 1985 to 2010.

STUDY SELECTION

Two reviewers independently screened titles and abstracts to identify prospective, controlled studies reporting pre- and post-vaccination titers of recommended vaccines in patients receiving long-term immunosuppressive therapies for full-text review.

DATA EXTRACTION

Three reviewers independently assessed study characteristics including treatment regimens and pre- and post-vaccination titers.

DATA SYNTHESIS

Of the 972 identified titles, fifteen met inclusion criteria. Ten studies assessed the effects of immunosuppressive medications on responses to influenza vaccine, four studies investigated responses following pneumococcal vaccination, and one study assessed both influenza and pneumococcal vaccination. Five of the studies that evaluated influenza vaccination showed partially diminished responses among individuals receiving immunosuppressive therapies, while one of the pneumococcal vaccine studies showed significantly decreased responses following vaccination. Patients treated with more than one immunosuppressive medication were the least likely to respond to vaccination.

LIMITATIONS

The heterogeneity of reported outcomes limits generalizeability.

CONCLUSIONS

Immunosuppressive therapy, particularly combination regimens, may blunt response to influenza and pneumococcal vaccinations. To ensure the best chance of response, immunizations should be administered prior to initiation of immunosuppressive medications whenever possible.

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.

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.

Prevalence of hantavirus antibody in patients with chronic renal disease in Egypt

In Egypt, the etiology of chronic renal failure (CRF) is not well defined. A hospital-based case-control study was initiated in February 1998, to determine whether hantavirus infection is involved in chronic renal disease (CRD) in Egypt. The study enrolled 350 study patients with a history of CRF and 695 matched controls with CRD due to renal calculus or renal cancer, but with normal renal functions. Sera from cases and controls were tested for anti-hantavirus IgG using ELISA with a cell-lysate antigen from Hantaan virus prototype strain 76-118. A demographic questionnaire was completed for each study participant. Five of the 350 cases (1.4%), and seven of the 695 controls (1.0%) were antibody-positive to hantavirus, with a titer > or =1:400. The difference in antibody prevalence between the study cases and the control cases was not statistically significant (P = 0.48). All antibody-positive study cases and controls had been exposed to rodents. Data indicated that in Egypt, hantavirus seroprevalence in CRD patients is low, and hantavirus infections do not appear to be a significant cause of CRF.

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.

Trends of multiple-drug resistance among Salmonella serotype Typhi isolates during a 14-year period in Egypt

A total of 853 isolates of Salmonella serotype Typhi recovered from patients with typhoid fever who were admitted to a major infectious disease hospital in Cairo, Egypt, from 1987 through 2000 underwent antibiotic susceptibility testing to determine multiple-drug resistance. The observed resurgence of chloramphenicol susceptibility (P=.002) may suggest reuse of this drug for the treatment of typhoid fever in Egypt.

Pathogenicity and convalescent excretion of Campylobacter in rural Egyptian children

Campylobacter infection in developing countries has not received much public health attention because of the observation that infections are not associated with disease beyond the first 6 months of life. A cohort of 397 Egyptian children aged less than 3 years, who were observed twice weekly during 1995--1998, experienced an incidence of 0.6 episodes of Campylobacter diarrhea per child-year. A total of 13% of the Campylobacter diarrheal episodes were characterized by severe dehydration. Age-specific incidence rates (episodes per year) were 0.9 in infants aged less than 6 months, 1.5 in those 6--12 months, and 0.4 and 0.2 in the second and third years of life, respectively. Convalescent excretion of Campylobacter after a diarrheal episode might be enhancing transmission and contributing to this high incidence. Observed risk factors for Campylobacter diarrhea were poor hygienic conditions and the presence of animals in the house. Regardless of the child's age, a first infection by Campylobacter was associated with diarrhea (odds ratio = 2.45; 95% confidence interval: 1.61, 3.71); however, subsequent infections were associated with diarrhea only in children aged less than 6 months. This observation that natural infection did not confer protection during the first 6 months of life poses a challenge to vaccine development.

Molecular evidence that childhood monosomy 7 syndrome is distinct from juvenile chronic myelogenous leukemia and other childhood myeloproliferative disorders

The observation that juvenile chronic myelogenous leukemia (JCML) and childhood bone marrow monosomy 7 syndrome (Mo 7) are similar in many clinical and epidemiologic respects suggests a shared pathogenic basis and raises the possibility that the bone marrows of patients with JCML might lose chromosome 7 alleles by mechanisms that do not result in detectable cytogenetic deletions. We used a series of polymorphic markers mapped to chromosome 7 to test this hypothesis in 22 children with MPS and MDS, including 19 with JCML. All MPS and MDS samples demonstrated allelic heterozygosity with at least one chromosome 7 marker; 16 were heterozygous with probes from both 7p and 7q. Furthermore, the percentage of patient bone marrow samples heterozygous at each locus tested was similar to the frequency observed in the normal population. Whereas these data demonstrate that submicroscopic loss of large segments of chromosome 7 alleles is uncommon in children with MPS and MDS who do not have Mo 7, they do not exclude small deletions around an uncharacterized tumor-suppressor locus. Our results suggest that a number of distinct molecular events contribute to leukemogenesis, and we propose a multistep model to explain the similarities and differences between the major subtypes of childhood MPS and MDS.

Parental origins of chromosome 7 loss in childhood monosomy 7 syndrome

Bone marrow monosomy 7 (Mo 7) is associated with childhood preleukemic myeloproliferative and myelodysplastic syndromes (MPS and MDS). We used a series of polymorphic markers to investigate the parental origins of chromosomes lost from the bone marrows of 12 children with MPS/MDS and Mo 7. Eight Mo 7 bone marrows lost a maternal chromosome 7 and four cases lost the paternal homologue. Our data and the results of previous laboratory and clinical observations in the familial and sporadic forms of childhood Mo 7 suggest that chromosome 7 deletions contribute to leukemogenesis by gene dosage.