Protective effect of WC3 vaccine against rotavirus diarrhea in infants during a predominantly serotype 1 rotavirus season

Evaluating Acute Viral Gastroenteritis Severity: Modified Vesikari and Clark Scoring Systems

OBJECTIVE

Acute gastroenteritis (AGE) is the second leading cause of death in children worldwide. Objectively evaluating disease severity is critical for assessing future interventions. We used data from a large, prospective surveillance study to assess risk factors associated with severe presentation using modified Vesikari score (MVS) and Clark score (CS) of severity.

METHODS

From December 1, 2012 to June 30, 2016, AGE surveillance was performed for children between 15 days and 17 years old in the emergency, inpatient, and outpatient settings at Vanderbilt's Monroe Carell Jr. Children's Hospital in Nashville, TN. Stool specimens were tested for norovirus, sapovirus, rotavirus, and astrovirus. We compared demographic and clinical characteristics, along with the MVS and CS, by viral detection status and by setting.

RESULTS

Of the 6309 eligible children, 4216 (67%) were enrolled, with 3256 (77%) providing a stool specimen. The median age was 1.9 years, 52% were male, and 1387 (43%) of the stool samples were virus positive. Younger age, male sex, hospitalization, and rotavirus detection were significantly associated with higher mean MVS and CS. Non-Hispanic Black race and ethnicity was associated with a lower mean MVS and CS as compared with non-Hispanic white race and ethnicity. Prematurity and enrollment in the ED were associated with higher mean CS. The 2 scoring systems were highly correlated.

CONCLUSIONS

Rotavirus continues to be associated with more severe pediatric illness compared with other viral causes of AGE. MVS and CS systems yielded comparable results and can be useful tools to assess AGE severity.

Diarrhea Case Surveillance in the Enterics for Global Health Shigella Surveillance Study: Epidemiologic Methods

Background

Shigella is a leading cause of acute watery diarrhea, dysentery, and diarrhea-attributed linear growth faltering, a precursor to stunting and lifelong morbidity. Several promising Shigella vaccines are in development and field efficacy trials will require a consortium of potential vaccine trial sites with up-to-date Shigella diarrhea incidence data.

Methods

The Enterics for Global Health (EFGH) Shigella surveillance study will employ facility-based enrollment of diarrhea cases aged 6-35 months with 3 months of follow-up to establish incidence rates and document clinical, anthropometric, and financial consequences of Shigella diarrhea at 7 country sites (Mali, Kenya, The Gambia, Malawi, Bangladesh, Pakistan, and Peru). Over a 24-month period between 2022 and 2024, the EFGH study aims to enroll 9800 children (1400 per country site) between 6 and 35 months of age who present to local health facilities with diarrhea. Shigella species (spp.) will be identified and serotyped from rectal swabs by conventional microbiologic methods and quantitative polymerase chain reaction. Shigella spp. isolates will undergo serotyping and antimicrobial susceptibility testing. Incorporating population and healthcare utilization estimates from contemporaneous household sampling in the catchment areas of enrollment facilities, we will estimate Shigella diarrhea incidence rates.

Conclusions

This multicountry surveillance network will provide key incidence data needed to design Shigella vaccine trials and strengthen readiness for potential trial implementation. Data collected in EFGH will inform policy makers about the relative importance of this vaccine-preventable disease, accelerating the time to vaccine availability and uptake among children in high-burden settings.

A Perspective on the Strategy for Advancing ETVAX®, An Anti-ETEC Diarrheal Disease Vaccine, into a Field Efficacy Trial in Gambian Children: Rationale, Challenges, Lessons Learned, and Future Directions

For the first time in over 20 years, an Enterotoxigenic Escherichia coli (ETEC) vaccine candidate, ETVAX®, has advanced into a phase 2b field efficacy trial for children 6-18 months of age in a low-income country. ETVAX® is an inactivated whole cell vaccine that has gone through a series of clinical trials to provide a rationale for the design elements of the Phase 2b trial. This trial is now underway in The Gambia and will be a precursor to an upcoming pivotal phase 3 trial. To reach this point, numerous findings were brought together to define factors such as safe and immunogenic doses for children, and the possible benefit of a mucosal adjuvant, double mutant labile toxin (dmLT). Considering the promising but still underexplored potential of inactivated whole cells in oral vaccination, we present a perspective compiling key observations from past ETVAX® trials that informed The Gambian trial design. This report will update the trial's status and explore future directions for ETEC vaccine trials. Our aim is to provide not only an update on the most advanced ETEC vaccine candidate but also to offer insights beneficial for the development of other much-needed oral whole-cell vaccines against enteric and other pathogens.

Inferior vena cava to aorta ratio in dehydrated pediatric patients: a systematic review and meta-analysis

BACKGROUND

Dehydration due to acute diarrhea is among the leading causes of mortality. However, advancements in management and technology do not help clinicians differentiate dehydration degrees. Ultrasound using the inferior vena cava to aorta (IVC/ Ao) ratio is a promising noninvasive technique to identify significant pediatric dehydration.

PUSPOSE

Therefore, this systematic review and meta-analysis aimed to examine the diagnostic parameters of the IVC/Ao ratio for predicting clinically significant dehydration in pediatric patients.

METHODS

We searched the MEDLINE, PubMed, Cochrane Library, ScienceDirect, and Google Scholar databases for studies of pediatric patients (≤18 years old) who presented with signs and symptoms of dehydration due to acute diarrhea, gastroenteritis, or vomiting. The inclusion criteria were cross-sectional, case-control, cohort, and randomized controlled trial study design and publication in any language. We then conducted a meta-analysis using the midas and metandi commands from Stata software.

RESULTS

Five studies of 461 patients were included. The combined sensitivity was 86% (95% confidence interval [CI], 79%-91%), while the specificity was 73% (95% CI, 59%-84%). The area under the curve was 0.89 (95% CI, 0.86-0.91). The positive likelihood ratio (LR+) was 3.2 (95% CI, 2.1-5.1) with a 76% posttest probability, while the negative likelihood ratio (LR-) was 0.18 (95% CI, 0.12-0.28) with a 16% posttest probability. The combined negative predictive value was 0.83 (95% CI, 0.75-0.91), while the positive predictive value was 0.75 (95% CI, 0.68-0.82).

CONCLUSION

The IVC/Ao ratio was insufficient to exclude or confirm significant dehydration in pediatric patients. More studies are needed, especially multicenter, adequately powered diagnostic research, to will help establish the usefulness of the IVC/Ao ratio.

A Clinical Nursing Care Study on the Prevalence of Rotavirus Infection and Acute Diarrhea in Vaccinated Chinese Pediatric Population from 2019-2022

Purpose

To investigate the prevalence of rotavirus infection and acute diarrhea after immunization and further assess the quality of nursing care provided by the nurses to such patients.

Methods

A total of 432 children aged 3–36 months with acute diarrhea between February 2019 and March 2022 were enrolled, and rotavirus testing was performed within 24 h using a rotavirus enzyme immunoassay kit. Clinical characteristics were evaluated, and regression analysis was performed.

Results

Eighty vaccinated children (18.5%) were confirmed to have rotavirus infection out of 432 children. The prevalence of rotavirus positivity was the highest at 20–28 months (22 cases, 24.44%) and 11–19 months age group (27 cases, 22.50%). There is a significant association between rotavirus infection and hygiene score (p = 0.009). Based on the association with quality of nursing care, rotavirus infection was association with “appropriate care” (p = 0.001).

Conclusion

Rotavirus infection was strongly associated with poor hygiene score which may be due to the hygienic nature of the mother and her family. Nursing care assessments revealed a huge gap between nurses and the guardians, which reflects the behavior of Chinese nurses. Thus, an intervention is required by the policymakers for implementing effective strategies of quality nursing for the improvement of the pediatric patients with rotavirus gastroenteritis.

Development of a diarrhoea severity scoring scale in a passive health facility-based surveillance system

Background

Diarrhoeal disease remains a leading cause of death among children mostly in low and middle-income countries. Factors contributing to disease severity are complex and there is currently no consensus on a scoring tool for use in community-based studies.

Methods

Data were collected during a passive surveillance system in an outpatient health facility in Lusaka, Zambia from March 2019 to July 2019. Diarrhea episodes were assessed for severity using an in-house severity scoring tool (CIDRZ) and previously published scores (Vesikari, Clark, CODA, and DHAKA). The CIDRZ score was constructed using fieldworker-reported clinical signs and exploratory factor analysis. We used precision-recall curves measuring severe diarrhoea (i.e., requiring intravenous rehydration or referred for hospital admission) to determine the best performing scores. Then, we used Cronbach’s alpha to assess the scale’s internal consistency. Finally, we used Cohen’s kappa to assess agreement between the scores.

Results

Of 110 diarrhea episodes, 3 (3%) required intravenous rehydration or were referred for hospital admission. The precision-recall area under the curve of each score as a predictor of severe diarrhoea requiring intravenous rehydration or hospital admission was 0.26 for Vesikari, 0.18 for CODA, 0.24 for Clark, 0.59 for DHAKA, and 0.59 for CIDRZ. The CIDRZ scale had substantial reliability and performed similarly to the DHAKA score.

Conclusions

Diarrhoea severity scores focused on characteristics specific to dehydration status may better predict severe diarrhea among children in Lusaka. Aetiology-specific scoring tools may not be appropriate for use in community healthcare settings. Validation studies for the CIDRZ score in diverse settings and with larger sample sizes are warranted.

Why We Need Precision Vaccinology

Vaccine development has moved from an empirical origin to the use of antigenic characterization, structural biology, immune function definition, protein synthesis, and precise definition of immune correlates of protection in order to deal with more difficult biology of current targets.

Pivotal Shigella Vaccine Efficacy Trials-Study Design Considerations from a Shigella Vaccine Trial Design Working Group

Vaccine candidates for Shigella are approaching phase 3 clinical trials in the target population of young children living in low- and middle-income countries. Key study design decisions will need to be made to maximize the success of such trials and minimize the time to licensure and implementation. We convened an ad hoc working group to identify the key aspects of trial design that would meet the regulatory requirements to achieve the desired indication of prevention of moderate or severe shigellosis due to strains included in the vaccine. The proposed primary endpoint of pivotal Shigella vaccine trials is the efficacy of the vaccine against the first episode of acute moderate or severe diarrhea caused by the Shigella strains contained within the vaccine. Moderate or severe shigellosis could be defined by a modified Vesikari score with dysentery and molecular detection of vaccine-preventable Shigella strains. This report summarizes the rationale and current data behind these considerations, which will evolve as new data become available and after further review and consultation by global regulators and policymakers.

The performance of licensed rotavirus vaccines and the development of a new generation of rotavirus vaccines: a review

Rotavirus, which causes acute gastroenteritis and severe diarrhea, has posed a great threat to children worldwide over the last 30 y. Since no specific drugs and therapies against rotavirus are available, vaccination is considered the most effective method of decreasing the morbidity and mortality related to rotavirus-associated gastroenteritis. To date, six rotavirus vaccines have been developed and licensed by local governments. Notably, Rotarix™ and RotaTeq™ have been recommended as universal agents against rotavirus infection by the World Health Organization; however, lower efficacies were found in less-developed and developing regions with medium and high child mortality than well-developed ones with low child mortality. For now, two promising novel vaccines, Rotavac™ and RotaSiil™ were pre-qualified by the World Health Organization in 2018. Other rotavirus vaccines in the pipeline including neonatal strain (RV3-BB) and several non-replicating rotavirus vaccines with a parenteral delivery strategy are currently undergoing investigation, with the potential to improve the performance of, and eliminate the safety concerns associated with, previous live oral rotavirus vaccines. This paper reviews the important developments in rotavirus vaccines in the last 20 y and discusses problems and challenges that require investigation in the future.

Overview of the Development, Impacts, and Challenges of Live-Attenuated Oral Rotavirus Vaccines

Safety, efficacy, and cost-effectiveness are paramount to vaccine development. Following the isolation of rotavirus particles in 1969 and its evidence as an aetiology of severe dehydrating diarrhoea in infants and young children worldwide, the quest to find not only an acceptable and reliable but cost-effective vaccine has continued until now. Four live-attenuated oral rotavirus vaccines (LAORoVs) (Rotarix^®, RotaTeq^®, Rotavac^®, and RotaSIIL^®) have been developed and licensed to be used against all forms of rotavirus-associated infection. The efficacy of these vaccines is more obvious in the high-income countries (HIC) compared with the low- to middle-income countries (LMICs); however, the impact is far exceeding in the low-income countries (LICs). Despite the rotavirus vaccine efficacy and effectiveness, more than 90 countries (mostly Asia, America, and Europe) are yet to implement any of these vaccines. Implementation of these vaccines has continued to suffer a setback in these countries due to the vaccine cost, policy, discharging of strategic preventive measures, and infrastructures. This review reappraises the impacts and effectiveness of the current live-attenuated oral rotavirus vaccines from many representative countries of the globe. It examines the problems associated with the low efficacy of these vaccines and the way forward. Lastly, forefront efforts put forward to develop initial procedures for oral rotavirus vaccines were examined and re-connected to today vaccines.

Association of Rotavirus Vaccination With Inpatient and Emergency Department Visits Among Children Seeking Care for Acute Gastroenteritis, 2010-2016

IMPORTANCE

Rotavirus vaccines have been recommended for universal US infant immunization for more than 10 years, and understanding their effectiveness is key to the continued success of the US rotavirus vaccine immunization program.

OBJECTIVE

To assess the association of RotaTeq (RV5) and Rotarix (RV1) with inpatient and emergency department (ED) visits for rotavirus infection.

DESIGN, SETTING, AND PARTICIPANTS

This case-control vaccine effectiveness study was performed at inpatient and ED clinical settings in 7 US pediatric medical institutions from November 1, 2009, through June 30, 2016. Children younger than 5 years seeking medical care for acute gastroenteritis were enrolled. Clinical and epidemiologic data, vaccination verification, and results of stool sample tests for laboratory-confirmed rotavirus were collected. Data were analyzed from November 1, 2009, through June 30, 2016.

MAIN OUTCOMES AND MEASURES

Rotavirus vaccine effectiveness for preventing rotavirus-associated inpatient and ED visits over time for each licensed vaccine, stratified by clinical severity and age.

RESULTS

Among the 10 813 children included (5927 boys [54.8%] and 4886 girls [45.2%]; median [range] age, 21 [8-59] months), RV5 and RV1 analyses found that compared with controls, rotavirus-positive cases were more often white (RV5, 535 [62.2%] vs 3310 [57.7%]; RV1, 163 [43.1%] vs 864 [35.1%]), privately insured (RV5, 620 [72.1%] vs 4388 [76.5%]; RV1, 305 [80.7%] vs 2140 [87.0%]), and older (median [range] age for RV5, 26 [8-59] months vs 21 [8-59] months; median [range] age for RV1, 22 [8-59] months vs 19 [8-59] months) but did not differ by sex. Among 1193 rotavirus-positive cases and 9620 rotavirus-negative controls, at least 1 dose of any rotavirus vaccine was 82% (95% CI, 77%-86%) protective against rotavirus-associated inpatient visits and 75% (95% CI, 71%-79%) protective against rotavirus-associated ED visits. No statistically significant difference during this 7-year period was observed for either rotavirus vaccine. Vaccine effectiveness against inpatient and ED visits was 81% (95% CI, 78%-84%) for RV5 (3 doses) and 78% (95% CI, 72%-82%) for RV1 (2 doses) among the study population. A mixed course of both vaccines provided 86% (95% CI, 74%-93%) protection. Rotavirus patients who were not vaccinated had severe infections 4 times more often than those who were vaccinated (74 of 426 [17.4%] vs 28 of 605 [4.6%]; P < .001), and any dose of rotavirus vaccine was 65% (95% CI, 56%-73%) effective against mild infections, 81% (95% CI, 76%-84%) against moderate infections, and 91% (95% CI, 85%-95%) against severe infections.

CONCLUSIONS AND RELEVANCE

Evidence from this large postlicensure study of rotavirus vaccine performance in the United States from 2010 to 2016 suggests that RV5 and RV1 rotavirus vaccines continue to perform well, particularly in preventing inpatient visits and severe infections and among younger children.

Efficacy of live oral rotavirus vaccines by duration of follow-up: a meta-regression of randomised controlled trials

BACKGROUND

The duration of protection offered by rotavirus vaccines varies across the world, and this variation is important to understanding and predicting the effects of the vaccines. There is now a large body of evidence on the efficacy of live oral rotavirus vaccines in different settings, but these data have never been synthesised to obtain robust estimates of efficacy by duration of follow-up. Our aim is to estimate the efficacy of live oral rotavirus vaccines at each point during follow-up and by mortality stratum.

METHODS

In our meta-regression study, we identified all randomised controlled trials of rotavirus vaccines published until April 4, 2018, using the results of a Cochrane systematic review, and cross checked these studies against those identified by another systematic review. We excluded trials that were based on special populations, trials without an infant schedule, and trials without clear reporting of numbers of enrolled infants and events in different periods of follow-up. For all reported periods of follow-up, we extracted the mean duration of follow-up (time since administration of the final dose of rotavirus vaccination), the number of enrolled infants, and case counts for rotavirus-positive severe gastroenteritis in both non-vaccinated and vaccinated groups. We used a Bayesian hierarchical Poisson meta-regression model to estimate the pooled cumulative vaccine efficacy (VE) and its waning with time for three mortality strata. We then converted these VE estimates into instantaneous VE (iVE).

FINDINGS

In settings with low mortality (15 observations), iVE pooled for infant schedules of Rotarix and RotaTeq was 98% (95% credibility interval 93-100) 2 weeks following the final dose of vaccination and 94% (87-98) after 12 months. In medium-mortality settings (11 observations), equivalent estimates were 82% (74-92) after 2 weeks and 77% (67-84) after 12 months. In settings with high mortality (24 observations), there were five different vaccines with observation points for infant schedules. The pooled iVE was 66% (48-81) after 2 weeks of follow-up and 44% (27-59) after 12 months.

INTERPRETATION

Rotavirus vaccine efficacy is lower and wanes more rapidly in high-mortality settings than in low-mortality settings, but the earlier peak age of disease in high-mortality settings means that live oral rotavirus vaccines are still likely to provide substantial benefit.

FUNDING

Bill & Melinda Gates Foundation.

Norovirus and Rotavirus Disease Severity in Children: Systematic Review and Meta-analysis

BACKGROUND

Rotaviruses (RVs) and noroviruses (NoVs) are the most common causes of severe acute gastroenteritis in children. It is generally accepted that RVs cause severe acute gastroenteritis in a higher proportion of cases compared with NoVs. To our knowledge, there are no systematic reviews and meta-analyses comparing the severity of NoV and RV disease.

METHODS

We searched MEDLINE for studies reporting data for NoV and RV medically attended disease severity in children. We included studies where all children had been tested for both NoV (reverse transcription polymerase chain reaction) and RV (enzyme-linked immunosorbent assay or reverse transcription polymerase chain reaction) and that reported disease severity using the Vesikari or modified Vesikari score, or provided clinical information on severity. We generated pooled estimates of the mean with 95% confidence intervals using random effects meta-analysis.

RESULTS

We identified 266 publications, of which 31 were retained for qualitative analysis and 26 for quantitative analysis. Fourteen studies provided data on severity score for the meta-analysis. The pooled mean severity scores (95% confidence interval) among outpatients were 10 (8-12) and 11 (8-14) for NoV and RV, respectively. Among inpatients, they were 11 (9-13) for NoV and 12 (10-14) for RV. The difference was statistically significant among inpatients, but relatively small (1 point in a 20-point scale). About 20% more children with RV required rehydration when compared with children with NoV.

CONCLUSIONS

NoV causes moderate to severe disease similar to RV in young children. This information should be useful for future evaluations of an eventual introduction of NoV vaccines in national immunization programs.

Challenges to Developing a Rotavirus Vaccine

Rotavirus is the most important cause of gastroenteritis worldwide. In developing countries, the virus is a major cause of death in infants and young children. In the United States, before the licensure of vaccines, rotavirus infections accounted for ∼2.7 million cases of gastroenteritis annually. Here are described the history and challenges surrounding the development of a rotavirus vaccine.

Histo-blood group antigens as receptors for rotavirus, new understanding on rotavirus epidemiology and vaccine strategy

The success of the two rotavirus (RV) vaccines (Rotarix and RotaTeq) in many countries endorses a live attenuated vaccine approach against RVs. However, the lower efficacies of both vaccines in many low- and middle-income countries indicate a need to improve the current RV vaccines. The recent discovery that RVs recognize histo-blood group antigens (HBGAs) as potential receptors has significantly advanced our understanding of RV diversity, evolution and epidemiology, providing important new insights into the performances of current RV vaccines in different populations and emphasizing a P-type-based vaccine approach. New understanding of RV diversity and evolution also raises a fundamental question about the ‘Jennerian' approach, which needs to be addressed for future development of live attenuated RV vaccines. Alternative approaches to develop safer and more cost-effective subunit vaccines against RVs are also discussed.

A Comparison of Diarrheal Severity Scores in the MAL-ED Multisite Community-Based Cohort Study

OBJECTIVES

There is a lack of consensus on how to measure diarrheal severity. Within the context of a multisite, prospective cohort study, we evaluated the performance of a modified Vesikari score (MAL-ED), 2 previously published scores (Clark and CODA [a diarrheal severity score (Community DiarrheA) published by Lee et al]), and a modified definition of moderate-to-severe diarrhea (MSD) based on dysentery and health care worker diagnosed dehydration.

METHODS

Scores were built using maternally reported symptoms or fieldworker-reported clinical signs obtained during the first 7 days of a diarrheal episode. The association between these and the risk of hospitalization were tested using receiver operating characteristic analysis. Severity scores were also related to illness etiology, and the likelihood of the episode subsequently becoming prolonged or persistent.

RESULTS

Of 10,159 episodes from 1681 children, 143 (4.0%) resulted in hospitalization. The area under the curve of each score as a predictor of hospitalization was 0.84 (95% confidence interval: 0.81, 0.87) (Clark), 0.85 (0.82, 0.88) (MAL-ED), and 0.87 (0.84, 0.89) (CODA). Severity was also associated with etiology and episode duration. Although families were more likely to seek care for severe diarrhea, approximately half of severe cases never reached the health system.

CONCLUSIONS

Community-based diarrheal severity scores are predictive of relevant child health outcomes. Because they require no assumptions about health care access or utilization, they are useful in refining estimates of the burden of diarrheal disease, in estimating the effect of disease control interventions, and in triaging children for referral in low- and middle-income countries in which the rates of morbidity and mortality after diarrhea remain high.

Breastfeeding linked to the reduction of both rotavirus shedding and IgA levels after Rotarix® immunization in Mexican infants

We examined potential risk factors on vaccine virus shedding and antibody seroresponse to human rotavirus vaccine (Rotarix) in Mexican infants. Two doses of Rotarix were administered to infants during the first two visits for their routine childhood immunization (∼8 and 15weeks of age) in Mexico City. Infant's characteristics and socioeconomic indicators were obtained, including history of long-term feeding practices (exclusively/predominantly breastfed and exclusively/predominantly non-breastfed). Two serum specimens were collected, one during the second rotavirus vaccine visit and one 7weeks later. Stool specimens were collected between days 4-7 after each of the two rotavirus vaccine doses. Rotavirus IgA and IgG titers in serum were determined by enzyme immunoassays (EIA) and rotavirus shedding in stool was assessed by EIA and confirmed by RT-PCR. The overall rotavirus IgA geometric mean titers (GMT) increased significantly post dose 2 from post dose 1 [176 (95%CI: 113-273) to 335 (238-471); p=0.020). Infants who were exclusively/predominantly breastfed were less likely to shed vaccine virus in stool than those who were formula-fed (22% vs. 43%, p=0.016). Infants who were breastfed had lower rotavirus IgA titers than those who were formula-fed after dose 1 [GMT: 145 (84-250) vs. 267 (126-566) p=0.188] and dose 2 [236 (147-378) vs.578 (367-910), p=0.007]. Infants who shed vaccine virus post dose 1 had significantly higher serum IgA GMT than those who did not shed [425 (188-965) vs. 150 (84-266), p=0.038]. Breastfeeding was linked with the reduction of both stool vaccine shedding, and IgA seroresponse. The reduced rotavirus replication in the gut and shedding after dose 1 may explain in part the lower IgA response in serum.

Tropical and travel-associated norovirus: current concepts

PURPOSE OF REVIEW

We highlight recent advances relevant to understanding norovirus infections in the tropics, both in populations living in developing settings and travelers to these regions.

RECENT FINDINGS

Because of the decrease in diarrheal disease associated with the global rollout of vaccines against rotavirus, norovirus is emerging as the predominant cause of diarrhea morbidity among children in the tropics, and evidence suggests that it contributes to adult disease in endemic populations and travelers. In addition to identifying potential target populations for preventive measures, we provide an update on norovirus vaccine development and concepts related to their implementation in low-income and middle-income countries.

SUMMARY

These current concepts related to norovirus-attributable disease burden, clinical significance, and economic impact can potentially be applied to tailoring efforts to prevent and mitigate the effects of this important enteropathogen.

An instrument for the assessment of diarrhoeal severity based on a longitudinal community-based study

OBJECTIVE

Diarrhoea is a significant contributer to morbidity and is among the leading causes of death of children living in poverty. As such, the incidence, duration and severity of diarrhoeal episodes in the household are often key variables of interest in a variety of community-based studies. However, there currently exists no means of defining diarrhoeal severity that are (A) specifically designed and adapted for community-based studies, (B) associated with poorer child outcomes and (C) agreed on by the majority of researchers. Clinical severity scores do exist and are used in healthcare settings, but these tend to focus on relatively moderate-to-severe dehydrating and dysenteric disease, require trained observation of the child and, given the variability of access and utilisation of healthcare, fail to sufficiently describe the spectrum of disease in the community setting.

DESIGN

Longitudinal cohort study.

SETTING

Santa Clara de Nanay, a rural community in the Northern Peruvian Amazon.

PARTICIPANTS

442 infants and children 0-72 months of age.

MAIN OUTCOME MEASURES

Change in weight over 1-month intervals and change in length/height over 9-month intervals.

RESULTS

Diarrhoeal episodes with symptoms of fever, anorexia, vomiting, greater number of liquid stools per day and greater number of total stools per day were associated with poorer weight gain compared with episodes without these symptoms. An instrument to measure the severity was constructed based on the duration of these symptoms over the course of a diarrhoeal episode.

CONCLUSIONS

In order to address limitations of existing diarrhoeal severity scores in the context of community-based studies, we propose an instrument comprised of diarrhoea-associated symptoms easily measured by community health workers and based on the association of these symptoms with poorer child growth. This instrument can be used to test the impact of interventions on the burden of diarrhoeal disease.

Diagnosis of viral gastroenteritis in children: interpretation of real-time PCR results and relation to clinical symptoms

Molecular methods such as real-time polymerase chain reaction (PCR) are rapidly replacing traditional tests to detect fecal viral pathogens in childhood diarrhea. This technique has now increased the analytical sensitivity so drastically that positive results are found in asymptomatic children, leading to complex interpretation of real-time PCR results and difficult distinction between asymptomatic shedding and etiological cause of disease. We performed a review of the literature including pediatric studies using real-time PCR and a minimal inclusion period of one year to exclude bias by seasonality. We searched for studies on rotavirus, norovirus, adenovirus, astrovirus, and sapovirus, known to be the most common viruses to cause gastroenteritis in the pediatric population. For these viruses, we summarized the detection rates in hospitalized and community-based children with clinical symptoms of gastroenteritis, as well as subjects with asymptomatic viral shedding. Moreover, insight is given into the different viral sero- and genotypes causing pediatric gastroenteritis. We also discuss the scoring systems for severity of disease and their clinical value. A few published proposals have been made to improve the clinical interpretation of real-time PCR results, which we recapitulate and discuss in this review. We propose using the semi-quantitative measure of real-time PCR, as a surrogate for viral load, in relation to the severity score to distinguish asymptomatic viral shedding from clinically relevant disease. Overall, this review provides a better understanding of the scope of childhood gastroenteritis, discusses a method to enhance the interpretation of real-time PCR results, and proposes conditions for future research to enhance clinical implementation.

TRIVAC decision-support model for evaluating the cost-effectiveness of Haemophilus influenzae type b, pneumococcal and rotavirus vaccination

The TRIVAC decision support model has been used widely in Latin America and other regions to help national teams evaluate the cost-effectiveness of Haemophilus influenzae type b (Hib) vaccine, pneumococcal conjugate vaccine (PCV) and rotavirus vaccine (RV). We describe the structure and functioning of this model, and identify the parameters with the greatest influence on the results. The TRIVAC model is a spreadsheet software program that calculates incremental cost-effectiveness ratios (ICERs) and other indicators for three childhood vaccines (Hib, PCV and RV) utilising parameters such as demography, disease burden, vaccine costs, vaccine coverage, vaccine efficacy, health service utilisation and costs. There is a good deal of uncertainty about the local values of many of the parameters that have most influence on the cost-effectiveness of these new vaccines. Cost-effectiveness models can be used to explore the implications of different values of these parameters. However, for such models to be seen as relevant and helpful by decision-makers, they need to be transparent, flexible, easy to use, and embedded in a process which is owned and led by national teams. In this paper the key drivers of cost-effectiveness in the model are identified by one-way sensitivity analyses, run for each vaccine in 147 countries. The data used are mainly from standard international sources and the published literature. The primary indicator was the discounted cost per Disability Adjusted Life-Year (DALY) averted, from a government perspective, over a 20-year period (2013-2032). For all three vaccines, the ICER was most sensitive to changes in relative coverage (the coverage of the children who would have become diseased or, more importantly, died if the population had not been vaccinated, as a % of overall national coverage) and the herd effect multiplier. Other influential parameters for all three vaccines were: the incidence and case fatality of disease, the baseline trend in disease mortality in the absence of vaccination, vaccine efficacy, vaccine price and the % decline in vaccine price per year. Important vaccine-specific parameters included the cost of Hib meningitis sequelae, PCV serotype coverage and the rotavirus gastro-enteritis (RVGE) admission rate. While vaccine efficacy, herd effects, disease mortality and vaccine price are commonly cited as important drivers of cost-effectiveness, this analysis highlights the potentially important influence of relative coverage, a parameter rarely considered in models of vaccine impact and cost-effectiveness.

Validation of the modified Vesikari score in children with gastroenteritis in 5 US emergency departments

OBJECTIVES

The burden of acute gastroenteritis (AGE) in US children is substantial. Research into outpatient treatment strategies has been hampered by the lack of easily used and validated gastroenteritis severity scales relevant to the populations studied. We sought to evaluate, in a US cohort, the reliability, construct validity, and generalizability of a gastroenteritis severity scale previously derived in a Canadian population, the modified Vesikari score (MVS).

METHODS

We conducted a prospective, cohort, clinical observational study of children 3 to 48 months of age with acute gastroenteritis presenting to 5 US emergency departments. A baseline MVS score was determined in the emergency department, and telephone follow-up 14 days after presentation was used to assign the follow-up MVS. We determined reliability using inter-item correlations; construct validity via principal component factor analysis; cross-sectional construct validity via correlations with the presence of dehydration, hospitalization, and day care and parental work absenteeism; and generalizability via score distribution among sites.

RESULTS

Two hundred eighteen of 274 patients (80%) were successfully contacted for follow-up. Cronbach α was 0.63, indicating expectedly low internal reliability because of the multidimensional properties of the MVS. Factor analysis supported the appropriateness of retaining all variables in the score. Disease severity correlated with dehydration (P < 0.001), hospitalization (P < 0.001), and subsequent day care (P = 0.01) and work (P < 0.001) absenteeism. The MVS was normally distributed, and scores did not differ among sites.

CONCLUSIONS

The MVS effectively measures global severity of disease and performs similarly in varying populations within the US health care system. Its characteristics support its use in multisite outpatient clinical trials.

Lack of nonspecific protection against all-cause nonrotavirus gastroenteritis by vaccination with orally administered rotavirus vaccine

OBJECTIVES

Acute gastroenteritis (AGE) is recognized as a global, common threat to child survival, especially in developing countries. Rotavirus, in particular, has been implicated as a leading cause of severe AGE; however, there are numerous other pathogens that also cause AGE. Several studies have demonstrated that oral vaccination against rotavirus has generated the unanticipated benefit of protecting against AGE caused by nonrotavirus pathogens.

METHODS

Safety and efficacy of the pentavalent bovine-human reassortant rotavirus vaccine were studied in multiple populations, including children of the Navajo and White Mountain Apache tribes in the southwestern United States. Stool specimens were collected from children with AGE and tested for rotavirus using an enzyme immunoassay. Analyses were conducted to detect the presence or absence of a vaccine effect on incidence, severity, and duration of AGE in which rotavirus was not detected.

RESULTS

The majority of AGE (N = 558: 472 nonrotavirus vs 86 rotavirus) occurred between August 2002 and March 2004 among children ranging from ages 4 to 23 months. The incidence of nonrotavirus AGE was similar by vaccine groups with an incidence rate ratio of 1.07 (incidence rate ratio = vaccinated/unvaccinated, 95% confidence interval 0.89-1.29). The hazards of first, second, third, or any AGE in which rotavirus was not detected differed little by vaccination status (P > 0.05). Duration of symptoms and severity of nonrotavirus AGE were similar by vaccine group.

CONCLUSIONS

There was no vaccine effect on frequency or severity of nonrotavirus AGE.

The Global Enteric Multicenter Study (GEMS) of diarrheal disease in infants and young children in developing countries: epidemiologic and clinical methods of the case/control study

BACKGROUND

Diarrhea is a leading cause of illness and death among children aged <5 years in developing countries. This paper describes the clinical and epidemiological methods used to conduct the Global Enteric Multicenter Study (GEMS), a 3-year, prospective, age-stratified, case/control study to estimate the population-based burden, microbiologic etiology, and adverse clinical consequences of acute moderate-to-severe diarrhea (MSD) among a censused population of children aged 0-59 months seeking care at health centers in sub-Saharan Africa and South Asia.

METHODS

GEMS was conducted at 7 field sites, each serving a population whose demography and healthcare utilization practices for childhood diarrhea were documented. We aimed to enroll 220 MSD cases per year from selected health centers serving each site in each of 3 age strata (0-11, 12-23, and 24-59 months), along with 1-3 matched community controls. Cases and controls supplied clinical, epidemiologic, and anthropometric data at enrollment and again approximately 60 days later, and provided enrollment stool specimens for identification and characterization of potential diarrheal pathogens. Verbal autopsy was performed if a child died. Analytic strategies will calculate the fraction of MSD attributable to each pathogen and the incidence, financial costs, nutritional consequences, and case fatality overall and by pathogen.

CONCLUSIONS

When completed, GEMS will provide estimates of the incidence, etiology, and outcomes of MSD among infants and young children in sub-Saharan Africa and South Asia. This information can guide development and implementation of public health interventions to diminish morbidity and mortality from diarrheal diseases.

Severity of rotavirus gastroenteritis in Indian children requiring hospitalization

INTRODUCTION

The burden of rotavirus gastroenteritis is greatest in India and other developing countries. With the availability of two licensed vaccines and a number of additional vaccines in various stages of development and trial, analysis of detailed clinical information is essential for the development of a uniform method of severity assessment.

METHODS

Diarrhoeal stool samples from 1001 children <5 years of age hospitalized with gastroenteritis were screened for rotavirus using a commercial enzyme immunoassay. Positive samples were confirmed by genotyping using hemi nested multiplex RT-PCR. Detailed clinical data was collected for gastroenteritis assessment for 934 children and extraintestinal presentations were analyzed in 470 children. Severity scoring was carried out for all children using the Vesikari score and in a subset by Clark's scoring system.

RESULTS

Rotavirus was detected in 35.4% of samples tested between December 2005 and November 2008. Clark's and Vesikari scores showed moderate correlation but varied greatly in the categorization of severe disease. Using Clark's scoring, only 1.6% were categorized as presenting with severe disease in comparison to 66.1% by the Vesikari score. Association of extraintestinal symptoms with rotavirus gastroenteritis was not documented in this study.

CONCLUSION

The assessment of disease severity using two common severity scoring systems highlights the difference in the categorization of "severe" disease. This underscores the need for a robust scoring system which is needed for vaccine trial and in post-licensure surveillance, because vaccine efficacy is estimated for protection against severe rotavirus gastroenteritis.

Epidemiologic and clinical features of other enteric viruses associated with acute gastroenteritis in American Indian infants

OBJECTIVE

To investigate the viral etiology, through the use of molecular methods, of acute gastroenteritis (AGE), which is a considerable public health burden in Native American infants.

STUDY DESIGN

From March 2002 through February 2004, AGE and non-diarrheal stools were collected from Navajo and White Mountain Apache infants who received placebo during a rotavirus vaccine trial. Case (n=247) and control (n=344) specimens were tested for enteric adenovirus, astrovirus, norovirus, rotavirus, and sapovirus with real-time polymerase chain reaction. The odds of AGE were compared with population-averaged logistic regression models.

RESULTS

In 65% of the cases of AGE (161/247), at least one virus was detected; norovirus (n=80, 32%) and rotavirus (n=70, 28%) were the most common. A virus was detected in 38% of control specimens (132/344). Detection of "any virus" was associated with AGE (OR=3.22; 95% CI, 2.11-4.91), as was detection of norovirus (OR=2.00; 95% CI, 1.22-3.26) and rotavirus (OR=2.69; 95% CI, 1.52-4.79).

CONCLUSION

This study highlights the significant burden of viral AGE in American Indian infants and identifies pathogen targets for future prevention efforts in this population.

Efficacy and immunogenicity of live-attenuated human rotavirus vaccine in breast-fed and formula-fed European infants

BACKGROUND

Rotavirus is the main cause of severe gastroenteritis and diarrhea in infants and young children less than 5 years of age. Potential impact of breast-feeding on the efficacy and immunogenicity of human rotavirus G1P[8] vaccine was examined in this exploratory analysis.

METHODS

Healthy infants (N = 3994) aged 6-14 weeks who received 2 doses of human rotavirus vaccine/placebo according to a 0-1 or 0-2 month schedule were followed for rotavirus gastroenteritis during 2 epidemic seasons. Rotavirus IgA seroconversion rate (anti-IgA antibody concentration ≥ 20 mIU/mL) and geometric mean concentrations were measured prevaccination and 1-2 months post-dose 2. Vaccine efficacy against any and severe rotavirus gastroenteritis was analyzed according to the infants being breast-fed or exclusively formula-fed at the time of vaccination.

RESULTS

Antirotavirus IgA seroconversion rate was 85.5% (95% confidence interval [CI]: 82.4-88.3) in breast-fed and 89.2% (95% CI: 84.2-93) in exclusively formula-fed infants; geometric mean concentrations in the respective groups were 185.8 U/mL (95% CI: 161.4-213.9) and 231.5 U/mL (95% CI: 185.9-288.2). Vaccine efficacy was equally high in breast-fed and exclusively formula-fed children in the first season but fell in breast-fed infants in the second rotavirus season. During the combined 2-year efficacy follow-up period, vaccine efficacy against any rotavirus gastroenteritis was 76.2% (95% CI: 68.7-82.1) and 89.8% (95% CI: 77.6-95.9) and against severe rotavirus gastroenteritis 88.4% (95% CI: 81.6-93) and 98.1% (95% CI: 88.2-100) in the breast-fed and exclusively formula-fed infants, respectively.

CONCLUSIONS

The difference in immunogenicity of human rotavirus vaccine in breast-fed and exclusively formula-fed infants was small. Vaccine efficacy was equally high in breast-fed and exclusively formula-fed children in the first season. Breast-feeding seemed to reduce slightly the efficacy in the second season.

Systematic review of diarrhea duration and severity in children and adults in low- and middle-income countries

Background

Diarrhea is a leading cause of morbidity and mortality globally; yet the overall burden of diarrhea in terms of duration and severity has not been quantified. As improvements in treatment lead to decreases in diarrhea mortality, it is important to understand the substantial impact of diarrhea morbidity on disability among children and adults worldwide.

Methods

We conducted a systematic review to generate estimates of duration and severity outcomes for individuals 0-59 mos, 5-15 yrs, and ≥ 16 yrs, and for 3 severity indexes: mild, moderate, and severe.

Results

We estimate that among children under-five, 64.8% of diarrheal episodes are mild, 34.7% are moderate, and 0.5% are severe. On average, mild episodes last 4.3 days, and severe episodes last 8.4 days and cause dehydration in 84.6% of cases. We estimate that among older children and adults, 95% of episodes are mild; 4.95% are moderate; and 0.05% are severe. Among individuals ≥ 16 yrs, severe episodes typically last 2.6 days and cause dehydration in 92.8% of cases.

Conclusions

Moderate and severe episodes constitute a substantial portion of the total envelope of diarrhea among children under-five (35.2%; about 588 million episodes). Among older children and adults, moderate and severe episodes account for a much smaller proportion of the total envelope of diarrhea (5%), but the absolute number of such episodes is noteworthy (about 21.5 million episodes among individuals ≥ 16 yrs). Hence, the global burden of diarrhea consists of significant morbidity, extending beyond episodes progressing to death.

Group A rotavirus genotypes circulating prior to implementation of a National Immunization Program in Estonia

Group A rotaviruses (RVA) are a major cause of acute gastroenteritis in children ≤ 5 y worldwide which could be prevented with two recently introduced vaccines - monovalent Rotarix (live-attenuated G1P[8] strain) and pentavalent RotaTeq (human-bovine reassortant containing serotypes G1, G2, G3, G4 and P[8]). Prior to implementation of vaccines into national immunization program we aimed to describe RVA genotype distribution in hospitalized children aged < 5 y in Estonia during 2007-2008. A total of 671 children with confirmed RVA gastroenteritis from three major pediatric hospitals were prospectively enrolled. G- and P-genotypes were detected from 124 stool samples by semi-nested reverse transcription-PCR. Severity of disease was assessed using Clark scoring system. The majority of cases (65%) occurred in infants aged 7 to 24 mo and were of moderate severity (mean Clark score 12.1 (SD 3.2)). The prevailing strain was G2P[4] (34.7%), causing significantly more cases than G4P[8] (12.9%), G1P[8] or G9P[8] (both 4.0%), G3P[8] (1.6%). Yearly differences in genotype distribution occurred, as G2P[4] (52.8%) dominated in 2007, but G4P[8] (26.9%) in 2008. One third of strains remained non-typeable. The distribution of RVA genotypes in Estonia differs from that seen in other Central and Eastern European countries, although one should bear in mind the large proportion of P-untypeable strains and natural fluctuations of dominating RVA genotypes. Nevertheless, considering the high genotype-independent efficacy of the vaccines, introduction of national immunization should be considered.

Efficacy of a pentavalent human-bovine reassortant rotavirus vaccine against rotavirus gastroenteritis among American Indian children

BACKGROUND

Before the widespread use of rotavirus vaccines, rotavirus was a leading cause of gastroenteritis among children. Navajo and White Mountain Apache children suffer a disproportionate burden of severe rotavirus disease compared with the general U.S. population.

METHODS

We enrolled Navajo and White Mountain Apache infants in a multicenter, double-blind, placebo-controlled trial of pentavalent human-bovine reassortant rotavirus vaccine (PRV). Subjects received 3 doses of vaccine or placebo at 4 to 10 week intervals, with the first dose given between 6 and 12 weeks of age. Gastroenteritis episodes were identified by active surveillance. Disease severity was determined by a standardized scoring system.

RESULTS

There were 509 and 494 randomized children who received vaccine and placebo, respectively. Among placebo recipients, the incidence of rotavirus gastroenteritis was 34.2 episodes/100 child-years (95% confidence interval [95% CI]: 25.8-38.9) versus 8.1 episodes/100 child-years (95% CI: 5.4-12.5) in the vaccine group. The percentage of rotavirus episodes caused by serotypes G1, G2, and G3 was 72.3%, 23.4%, and 2.1%, respectively. There were no severe rotavirus episodes among vaccinees and 4 among placebo recipients. PRV was 77.1% (95% CI: 59.7-87.6), 89.5% (95% CI: 65.9-97.9), and 82.9% (95% CI: 61.1-93.6) effective against G1-G4 rotavirus disease, severe and moderate rotavirus disease combined, and outpatient visits for rotavirus disease, respectively. The risk of adverse events was similar for the vaccine and placebo groups.

CONCLUSIONS

PRV was highly effective in preventing rotavirus disease and related health care utilization in these American Indian infants. Vaccine efficacy and immunogenicity were similar to the overall study population enrolled in the multicenter trial.

Usefulness of fecal lactoferrin in predicting and monitoring the clinical severity of infectious diarrhea

AIM: To explore the value of fecal lactoferrin in predicting and monitoring the clinical severity of infectious diarrhea.

METHODS: Patients with acute infectious diarrhea ranging from 3 mo to 10 years in age were enrolled, and one to three stool samples from each subject were collected. Certain parameters, including white blood cells /differential count, C-reactive protein, fecal mucus, fecal pus cells, duration of fever, vomiting, diarrhea and severity (indicated by Clark and Vesikari scores), were recorded and analyzed. Fecal lactoferrin was determined by enzyme-linked immunosorbent assay and compared in different pathogen and disease activity. Generalized estimating equations (GEE) were also used for analysis.

RESULTS: Data included 226 evaluations for 117 individuals across three different time points. Fecal lactoferrin was higher in patients with Salmonella (11.17 μg/g ± 2.73 μg/g) or Campylobacter (10.32 μg/g ± 2.94 μg/g) infections and lower in patients with rotavirus (2.82 μg/g ± 1.27 μg/g) or norovirus (3.16 μg/g ± 1.18 μg/g) infections. Concentrations of fecal lactoferrin were significantly elevated in patients with severe (11.32 μg/g ± 3.29 μg/g) or moderate (3.77 μg/g ± 2.08 μg/g) disease activity compared with subjects with mild (1.51 μg/g ± 1.36 μg/g) disease activity (P < 0.05). GEE analysis suggests that this marker could be used to monitor the severity and course of gastrointestinal infections and may provide information for disease management.

CONCLUSION: Fecal lactoferrin increased during bacterial infection and with greater disease severity and may be a good marker for predicting and monitoring intestinal inflammation in children with infectious diarrhea.

Healthy-days time equivalents for outcomes of acute rotavirus infections

Rotavirus is the most common cause of severe gastroenteritis in infants and young children worldwide. Health-state utility measures used in economic evaluations of rotavirus vaccines do not reflect differences between mild and severe symptoms of rotavirus gastroenteritis and, therefore, do not adequately capture preferences for non-fatal outcomes associated with rotavirus common in industrialized countries. This paper describes the development and results of a survey specifically designed to develop quality-adjusted time equivalents for rotavirus gastroenteritis among a sample of parents with young children in the United States as an alternative to conventional QALY measures in assessing cost-effectiveness.

Why does the world need another rotavirus vaccine?

A “Meeting on Upstream Rotavirus Vaccines and Emerging Vaccine Producers” was held at the World Health Organization in Geneva, Switzerland on March 28–30, 2006. The purpose was to discuss, evaluate, and weigh the importance of additional rotavirus vaccine candidates following the successful international licensure of rotavirus vaccines by two major pharmaceutical companies (GlaxoSmithKline and Merck) that had been in development for many years. Both licensed vaccines are composed of live rotaviruses that are delivered orally as have been all candidate rotavirus vaccines evaluated in humans. Each is built on the experience gained with previous candidates whose development had either been discontinued or, in the case of the previously licensed rhesus rotavirus reassortant vaccine (Rotashield), was withdrawn by its manufacturer after the discovery of a rare association with intussusception. Although which alternative candidate vaccines should be supported for development and where this should be done are controversial topics, there was general agreement expressed at the Geneva meeting that further development of alternative candidates is a high priority. This development will help insure that the most safe, effective and economic vaccines are available to children in Third World nations where the vast majority of the >600,000 deaths due to rotavirus occur each year. This review is intended to provide the history and present status of rotavirus vaccines as well as a perspective on the future development of candidate vaccines as a means of promulgating plans suggested at the Geneva meeting.

Uniformity of rotavirus strain nomenclature proposed by the Rotavirus Classification Working Group (RCWG)

In April 2008, a nucleotide-sequence-based, complete genome classification system was developed for group A rotaviruses (RVs). This system assigns a specific genotype to each of the 11 genome segments of a particular RV strain according to established nucleotide percent cutoff values. Using this approach, the genome of individual RV strains are given the complete descriptor of Gx-P[x]-Ix-Rx-Cx-Mx-Ax-Nx-Tx-Ex-Hx. The Rotavirus Classification Working Group (RCWG) was formed by scientists in the field to maintain, evaluate and develop the RV genotype classification system, in particular to aid in the designation of new genotypes. Since its conception, the group has ratified 51 new genotypes: as of April 2011, new genotypes for VP7 (G20-G27), VP4 (P[28]-P[35]), VP6 (I12-I16), VP1 (R5-R9), VP2 (C6-C9), VP3 (M7-M8), NSP1 (A15-A16), NSP2 (N6-N9), NSP3 (T8-T12), NSP4 (E12-E14) and NSP5/6 (H7-H11) have been defined for RV strains recovered from humans, cows, pigs, horses, mice, South American camelids (guanaco), chickens, turkeys, pheasants, bats and a sugar glider. With increasing numbers of complete RV genome sequences becoming available, a standardized RV strain nomenclature system is needed, and the RCWG proposes that individual RV strains are named as follows: RV group/species of origin/country of identification/common name/year of identification/G- and P-type. In collaboration with the National Center for Biotechnology Information (NCBI), the RCWG is also working on developing a RV-specific resource for the deposition of nucleotide sequences. This resource will provide useful information regarding RV strains, including, but not limited to, the individual gene genotypes and epidemiological and clinical information. Together, the proposed nomenclature system and the NCBI RV resource will offer highly useful tools for investigators to search for, retrieve, and analyze the ever-growing volume of RV genomic data.

Efficacy of pentavalent rotavirus vaccine against severe rotavirus gastroenteritis in infants in developing countries in sub-Saharan Africa: a randomised, double-blind, placebo-controlled trial

BACKGROUND

Rotavirus gastroenteritis causes many deaths in infants in sub-Saharan Africa. Because rotavirus vaccines have proven effective in developed countries but had not been tested in developing countries, we assessed efficacy of a pentavalent rotavirus vaccine against severe disease in Ghana, Kenya, and Mali between April, 2007, and March, 2009.

METHODS

In our multicentre, double-blind, placebo-controlled trial, undertaken in rural areas of Ghana and Kenya and an urban area of Mali, we randomly assigned infants aged 4-12 weeks without symptoms of gastrointestinal disorders in a 1:1 ratio to receive three oral doses of pentavalent rotavirus vaccine 2 mL or placebo at around 6 weeks, 10 weeks, and 14 weeks of age. Infants with HIV infection were not excluded. Randomisation was done by computer-generated randomisation sequence in blocks of six. We obtained data for gastrointestinal symptoms from parents on presentation to health-care facilities and clinical data were obtained prospectively by clinicians. The primary endpoint was severe rotavirus gastroenteritis (Vesikari score >or=11), detected by enzyme immunoassay, arising 14 days or more after the third dose of placebo or vaccine to end of study (March 31, 2009; around 21 months of age). Analysis was per protocol; infants who received scheduled doses of vaccine or placebo without intervening laboratory-confirmed naturally occurring rotavirus disease earlier than 14 days after the third dose and had complete clinical and laboratory results were included in the analysis. This study is registered with ClinicalTrials.gov, number NCT00362648.

FINDINGS

5468 infants were randomly assigned to receive pentavalent rotavirus vaccine (n=2733) or placebo (n=2735). 2357 infants assigned to vaccine and 2348 assigned to placebo were included in the per-protocol analysis. 79 cases of severe rotavirus gastroenteritis were reported in 2610.6 person-years in the vaccine group, compared with 129 cases in 2585.9 person-years in the placebo group, resulting in a vaccine efficacy against severe rotavirus gastroenteritis of 39.3% (95% CI 19.1-54.7, p=0.0003 for efficacy >0%). Median follow-up in both groups was 527 days starting 14 days after the third dose of vaccine or placebo was given. 42 (1.5%) of 2723 infants assigned to receive vaccine and 45 (1.7%) of 2724 infants assigned to receive placebo had a serious adverse event within 14 days of any dose. The most frequent serious adverse event was gastroenteritis (vaccine 17 [0.6%]; placebo 17 [0.6%]).

INTERPRETATION

Pentavalent rotavirus vaccine is effective against severe rotavirus gastroenteritis in the first 2 years of life in African countries with high mortality in infants younger than 5 years. We support WHO's recommendation for adoption of rotavirus vaccine into national expanded programmes on immunisation in Africa.

FUNDING

PATH (GAVI Alliance grant) and Merck.

Measurement issues in trials of pediatric acute diarrheal diseases: a systematic review

BACKGROUND

Worldwide, diarrheal diseases rank second among conditions that afflict children. Despite the disease burden, there is limited consensus on how to define and measure pediatric acute diarrhea in trials.

OBJECTIVES

In RCTs of children involving acute diarrhea as the primary outcome, we documented (1) how acute diarrhea and its resolution were defined, (2) all primary outcomes, (3) the psychometric properties of instruments used to measure acute diarrhea and (4) the methodologic quality of included trials, as reported.

METHODS

We searched CENTRAL, Embase, Global Health, and Medline from inception to February 2009. English-language RCTs of children younger than 19 years that measured acute diarrhea as a primary outcome were chosen.

RESULTS

We identified 138 RCTs reporting on 1 or more primary outcomes related to pediatric acute diarrhea/diseases. Included trials used 64 unique definitions of diarrhea, 69 unique definitions of diarrhea resolution, and 46 unique primary outcomes. The majority of included trials evaluated short-term clinical disease activity (incidence and duration of diarrhea), laboratory outcomes, or a composite of these end points. Thirty-two trials used instruments (eg, single and multidomain scoring systems) to support assessment of disease activity. Of these, 3 trials stated that their instrument was valid; however, none of the trials (or their citations) reported evidence of this validity. The overall methodologic quality of included trials was good.

CONCLUSIONS

Even in what would be considered methodologically sound clinical trials, definitions of diarrhea, primary outcomes, and instruments employed in RCTs of pediatric acute diarrhea are heterogeneous, lack evidence of validity, and focus on indices that may not be important to participants.

Evaluation of a gastroenteritis severity score for use in outpatient settings

OBJECTIVE

The objective of this study was to evaluate the internal reliability, construct validity, and ease of administration of a gastroenteritis disease severity score, the modified Vesikari score (MVS), which does not require in-person assessment.

METHODS

The MVS was created by replacing 1 variable (percent dehydration) in the original score with the need for future health care visits. We used the MVS to assess the global severity of disease in a cohort of children 3 to 48 months of age with acute gastroenteritis who were evaluated in 1 of 11 participating pediatric emergency departments. In this prospective study, caregivers recorded symptoms at home in a diary and reported the results via telephone at follow-up evaluation 14 days later. To evaluate internal reliability, we examined correlations between the items included in the score. Construct validity was evaluated by assessing the correlation between the total score and other proxy outcomes of disease severity, MVS distribution, and consistency between sites.

RESULTS

A total of 455 children were enrolled, and 415 were successfully contacted for follow-up evaluation. Internal reliability was acceptable, with Cronbach's alpha of 0.59. Disease severity was correlated with day care (P = .01) and work (P = .002) absenteeism. The MVS was normally distributed, and mean scores did not differ between the 11 sites.

CONCLUSIONS

The MVS seems to measure effectively the global severity of disease in a cohort of children with acute gastroenteritis. These data support the use of the MVS as an outcome measure in future clinical trials.

Development of a rotavirus vaccine: clinical safety, immunogenicity, and efficacy of the pentavalent rotavirus vaccine, RotaTeq

Initial approaches for rotavirus vaccines were based on the classical "Jennerian" approach and utilized simian and bovine rotavirus strains, which provided cross-protection against human rotavirus strains but did not cause illness in infants and young children because of their species-specific tropism. The demonstrated efficacy of these vaccines was not consistent across studies. Thus, human-animal reassortants containing an animal rotavirus backbone with human rotavirus surface G and/or P proteins were developed, which demonstrated more consistent efficacy than that observed with the non-reassortant rotavirus strains. The pentavalent rotavirus vaccine, RotaTeq, contains 5 human-bovine reassortant rotaviruses consisting of a bovine (WC3) backbone with human rotavirus surface proteins representative of the most common G (G1, G2, G3, G4) or P (P1A[8]) types worldwide. The present review focuses on the development of the pentavalent rotavirus vaccine RotaTeq. Results of a large-scale Phase III clinical study showed that three doses of RotaTeq were immunogenic, efficacious, and well tolerated with no increased clinical risk of intussusception. RotaTeq was efficacious against rotavirus gastroenteritis of any severity (74%) and severe disease (98-100%), using a validated clinical scoring system. Reductions in rotavirus-associated hospitalizations and emergency department (ED) visits, for up to 2 years post-vaccination, were 95% in Europe, 97% in the United States, and 90% in the Latin American/Caribbean regions. RotaTeq was recently shown to be up to 100% effective in routine use in the US in reducing hospitalizations and ED visits and 96% effective in reducing physician visits. Additional studies in 8 different locations in the US have shown 85-95% reduction in rotavirus-associated hospitalizations and/or ED visits in the first 2-2.5 years of routine use.

Sibling transmission of vaccine-derived rotavirus (RotaTeq) associated with rotavirus gastroenteritis

Although rotavirus vaccines are known to be shed in stools, transmission of vaccine-derived virus to unvaccinated contacts resulting in symptomatic rotavirus gastroenteritis has not been reported to our knowledge. We document here the occurrence of vaccine-derived rotavirus (RotaTeq [Merck and Co, Whitehouse Station, NJ]) transmission from a vaccinated infant to an older, unvaccinated sibling, resulting in symptomatic rotavirus gastroenteritis that required emergency department care. Results of our investigation suggest that reassortment between vaccine component strains of genotypes P7[5]G1 and P1A[8]G6 occurred during replication either in the vaccinated infant or in the older sibling, raising the possibility that this reassortment may have increased the virulence of the vaccine-derived virus. Both children remain healthy 11 months after this event and are without underlying medical conditions.

Burden of childhood rotavirus disease on health systems in the United States

BACKGROUND

To determine the burden of rotavirus disease before the introduction of rotavirus vaccines.

METHODS

From February 2005 to June 2006, prospective rotavirus surveillance was conducted in Cincinnati, Ohio, and Durham, North Carolina. Children < 5 years of age presenting at hospitals and outpatient clinics with acute gastroenteritis (AGE) of < 72 hours duration were enrolled. Stool samples were first tested for rotavirus by EIA and the VP7 type was determined by RT-polymerase chain reaction for rotavirus-positive samples. Medical costs were obtained from billing or accounting data.

RESULTS

A total of 1998 children were enrolled, with a mean age of 16.9 months. Among 1601 (80%) patients with a stool specimen, 44% were rotavirus positive. The rotavirus detection rate was 38% for patients admitted to hospital, 60% for patients requiring a short-stay hospital visit (< 24 hour hospitalization), 49% for emergency department visits, and 37% for outpatient visits. During the rotavirus season, rotavirus accounted for 56% of all AGE cases. Only 11% of rotavirus-positive children were assigned the rotavirus-specific ICD-9-CM code and this proportion varied considerably by clinical setting. The VP7 genotypes identified were G1, 79%; G2, 14%; G3, 5%; G9, 1%; and G12, 1%. For children hospitalized with rotavirus, the estimated median direct cost was $4565, the average length of stay was 1.9 days, and parents lost 3.4 days of work. For short-stay, emergency department, and outpatient visits, the estimated median costs were $3160, $867, and $75, respectively.

CONCLUSIONS

Before the widespread use of rotavirus vaccines in the United States, rotavirus was prevalent among children treated in hospital-based and outpatient settings and was associated with a substantial proportion of pediatric medical visits for AGE.