Efficacy of human rotavirus vaccine against rotavirus gastroenteritis during the first 2 years of life in European infants: randomised, double-blind controlled study

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.

Vaccines for preventing rotavirus diarrhoea: vaccines in use

BACKGROUND

Rotavirus results in more diarrhoea-related deaths in children less than five years of age than any other single agent in low- and middle-income countries. It is also a common cause of diarrhoea-related hospital admissions in high-income countries. The World Health Organization (WHO) recommends that all children should be vaccinated with a monovalent rotavirus vaccine (RV1; Rotarix, GlaxoSmithKline Biologicals) or a pentavalent rotavirus vaccine (RV5; RotaTeq, Merck & Co., Inc.), with a stronger recommendation for countries where deaths due to diarrhoea comprise more than 10% of all deaths. Lanzhou lamb rotavirus vaccine (LLR; Lanzhou Institute of Biomedical Products) is used in China only.

OBJECTIVES

To evaluate rotavirus vaccines approved for use (RV1, RV5, and LLR) for preventing rotavirus diarrhoea. Secondary objectives were to evaluate the efficacy of rotavirus vaccines on all-cause diarrhoea, hospital admission, death, and safety profiles.

SEARCH METHODS

For this update, we searched MEDLINE (via PubMed) in October 2011, and in June 2011 we searched the Cochrane Infectious Diseases Group Specialized Register, CENTRAL (published in The Cochrane Library 2011, Issue 2), , EMBASE, LILACS, and BIOSIS. We also searched the ICTRP (28 June 2011) and checked reference lists of identified studies.

SELECTION CRITERIA

We selected randomized controlled trials in children comparing rotavirus vaccines approved for use with placebo, no intervention, or another vaccine.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trial eligibility, extracted data, and assessed risk of bias. They combined dichotomous data using the risk ratio (RR) and 95% confidence intervals (CI) and used GRADE to evaluate evidence quality, which was reflected as follows: high quality ("vaccine prevents..."); moderate quality ("vaccine probably prevents..."); or low quality ("vaccine may prevent...").

MAIN RESULTS

Forty-three trials, including nine new trials for this update, met the inclusion criteria and enrolled 190,551 participants. Thirty-one trials assessed RV1, and 12 trials evaluated RV5. We did not find any trials assessing LLR.In children aged less than one year, RV1, compared to placebo, probably prevents 70% of all cases of rotavirus diarrhoea (RR 0.30, 95% CI 0.18 to 0.50; seven trials, 12,130 participants; moderate-quality evidence), and 80% of severe rotavirus diarrhoea cases (RR 0.20, 95% CI 0.11 to 0.35; seven trials, 35,004 participants; moderate-quality evidence). Similarly, RV5 prevents 73% of all rotavirus diarrhoea cases (RR 0.27, 95% CI 0.22 to 0.33; four trials, 7614 participants; high-quality evidence), and 77% of severe rotavirus diarrhoea cases (RR 0.23, 95% CI 0.08 to 0.71; three trials, 6953 participants; high-quality evidence). Both vaccines prevent over 80% of rotavirus diarrhoea cases that require hospitalization. For all-cause diarrhoea, based on two multi-centred trials from South Africa, Malawi, and Europe, RV1 may reduce severe cases by 42% (RR 0.58, 95% CI 0.40 to 0.84; two trials, 8291 participants; low--quality evidence). Also, based on one trial from Finland, RV5 may reduce severe cases by 72% (RR 0.28, 95% CI 0.16 to 0.48; one trial, 1029 participants; low-quality evidence).During the second year of life, compared to placebo, RV1 probably prevents 70% of all cases of rotavirus diarrhoea of any severity (RR 0.30, 95% CI 0.21 to 0.43; six trials, 8041 participants; moderate-quality evidence), and 84% of severe rotavirus diarrhoea cases (RR 0.16, 95% CI 0.12 to 0.21; eight trials, 32,854 participants; moderate-quality evidence). RV5 prevents 49% of all rotavirus diarrhoea cases of any severity (RR 0.51, 95% CI 0.36 to 0.72; four trials, 9784 participants; high-quality evidence), and 56% of severe rotavirus diarrhoea cases (RR 0.44, 95% CI 0.22 to 0.88; four trials, 9783 participants; high-quality evidence). For all-cause diarrhoea, RV1 probably reduces severe cases by 51% (RR 0.49, 95% CI 0.40 to 0.60; two trials, 6269 participants; moderate-quality evidence), and RV5 showed no difference with placebo (three trials, 8533 participants).Reported serious adverse events (including intussusception) after vaccination were measured in 95,178 children for RV1 and 77,480 for RV5, with no difference between the vaccines.

AUTHORS' CONCLUSIONS

RV1 and RV5 vaccines are effective in preventing rotavirus diarrhoea. These data support the WHO's global vaccine recommendation. The potential for reduced vaccine efficacy in low-income countries needs to be investigated. No increased risk of intussusception was detected, but surveillance monitoring studies are probably advisable in countries introducing the vaccine nationally.

Economic evaluations of rotavirus immunization for developing countries: a review of the literature

Diarrhea is a leading cause of mortality for children under 5 years of age, and rotavirus is identified as the main cause of severe diarrhea worldwide. Since 2006, two rotavirus vaccines, Rotarix and Rotateq, have been available in the market. These vaccines have proved to have high efficacy in developed countries. Clinical trials are being undertaken in Asia and Africa, and early clinical results found that the vaccine significantly reduces severe diarrhea episodes due to rotavirus (48.3% for Asia and 30.2% for Africa). The WHO recommended that rotavirus immunization be included in all national immunization programs. Based on WHO's recommendations, the Global Alliance for Vaccines and Immunization decided to provide financial support for rotavirus immunization in the developing world. In this article, we attempted to ascertain the cost-effectiveness of universal rotavirus immunization in developing countries. After an extensive literature search, we identified and evaluated 15 cost-effectiveness studies conducted in the developing world. The results from these studies showed that rotavirus immunization is a cost-effective strategy and one of the best interventions to prevent rotavirus-related diarrheal disease. However, rotavirus vaccines are expensive and the vaccine price appears to be the most challenging and crucial factor for decision-makers regarding whether to introduce this vaccine into developing countries' immunization schedules. All the studies concluded that rotavirus immunization is cost effective but may not be affordable for the developing world at present. Developing countries will definitely rely on financial support from international organizations to introduce rotavirus vaccination. It is recommended that more research on cost-effective rotavirus immunization with updated data be conducted and new rotavirus vaccine candidates be developed at a cheaper price to speed up the introduction of rotavirus immunization to the developing world.

Effects of vaccine on rotavirus disease in the pediatric population

PURPOSE OF REVIEW

Rotavirus infection is the most common cause of severe diarrhea disease in infants and young children worldwide and continues to have a major global impact on childhood morbidity and mortality. Two effective rotavirus vaccines are available and recommended for routine immunization of all infants. These vaccines have been introduced in both developed and developing countries. As rotavirus vaccines are implemented, studies have been undertaken that assess the effects of vaccination on rotavirus disease in children. This review summarizes the results of these studies.

RECENT FINDINGS

Studies that assess health impact, indirect benefits, and strain changes after the introduction of rotavirus vaccine have been reported. In industrialized countries, rotavirus vaccination has led to dramatic drops in severe rotavirus-related hospitalizations and has reduced emergency room visits. Data from clinical trials in developing counties in Asia and Africa have demonstrated that rotavirus vaccines significantly reduce severe diarrhea episodes due to rotavirus. Herd (community) immunity has also been noted after routine rotavirus immunization in several countries. There have been no significant strain shifts or escape mutants noted since the introduction of rotavirus vaccines.

SUMMARY

Two well tolerated and effective rotavirus vaccines have reduced the health burden of rotavirus gastroenteritis in both developed and developing countries.

Complications in hospitalized children with acute gastroenteritis caused by rotavirus: a retrospective analysis

Acute gastroenteritis (AGE) caused by rotavirus (RV) is a common disease among infants and toddlers, often leading to hospitalization and, in resource-poor countries, to death. However, little is known on specific complications of severe RV-positive (RV+) AGE and on the clinical course in chronically ill children. This was a retrospective analysis of data for children <5 years of age hospitalized due to AGE during six rotavirus seasons in three large German pediatric hospitals. The primary study end point was the incidence and type of complications in RV+ versus RV-negative (RV-) cases. A total of 6,884 episodes of AGE in hospitalized children aged <5 years were included in this analysis. Of the 4,880 stools tested for RV, 2,118 (43.4%) were RV+. Hypernatremia was significantly more common in RV+ AGE (P < 0.001) and was associated with severe disease, need for intensive care treatment, and longer duration of hospitalization. Metabolic disorders, particularly hypoglycemia, were more common in RV+ AGE. In contrast, symptoms such as respiratory infections, neurological, and abdominal symptoms were more common in children with RV- AGE.

CONCLUSIONS

Hypernatremia is a specific complication of RV+ AGE. RV would therefore appear to be the cause of infant toxicosis, the traditional descriptive term for severe dehydration and clinical deterioration following AGE.

Rotavirus infection: an update on management and prevention

Rotavirus infection is the most common cause of severe diarrhea disease in infants and young children worldwide and continues to have a major global impact on childhood morbidity and mortality. Vaccination is the only control measure likely to have a significant impact on the incidence of severe dehydrating rotavirus disease. Rotavirus vaccines have reduced the burden of rotavirus disease in the United States. Long-term monitoring will need to continue to assess the effects of rotavirus immunization programs and epidemiologic strain surveillance is necessary to determine whether changes in strain ecology will affect the rotavirus vaccine effectiveness and whether rotaviruses with the ability to evade vaccine immunity emerge.

Vaccines for enteric infections

PURPOSE OF REVIEW

To provide a review of currently licensed enteric vaccines and their efficacy based on completed field trials.

RECENT FINDINGS

In this review, we provide a brief description of the epidemiology of the most common enteric infections, in both developing and industrialized countries. We also describe the types, dosage, age-eligibility, availability, and efficacies of currently licensed vaccines, and review the results of recently completed clinical trials around the world.

SUMMARY

Several enteric vaccines are currently available. Although some vaccines have proven highly effective in industrialized countries where the disease burden is low (so-called travelers vaccines), they have demonstrated a lower protective effect in endemic countries where the disease is more prevalent. However, due to the magnitude of disease in endemic countries, even with lower efficacy, the potential for a vaccine to reduce the absolute number of cases remains considerable. Despite the continued reduction in overall disease burden with increased public health measures, such as improved sanitation, antimicrobials, and greater public awareness, enteric infections continue to cause significant morbidity and mortality in vulnerable populations. We contend that adoption and dissemination of available vaccines at affordable prices should be accelerated, particularly in areas where the disease burden is highest.

Rotavirus vaccine series completion and adherence to vaccination schedules among infants in managed care in the United States

BACKGROUND

Two rotavirus vaccines are currently approved in the United States: 3-dose RotaTeq (RV5; Merck & Co., Inc., Whitehouse Station, NJ, USA) is administered at ages 2, 4, and 6 months; and 2-dose Rotarix (RV1; GlaxoSmithKline, Research Triangle Park, NC, USA) is administered at ages 2 and 4 months. Our objective was to compare rotavirus vaccine series completion and dosing schedule compliance between cohorts of infants who received these vaccines.

METHODS

Infants aged less than 1 year who initiated a rotavirus vaccine series between 01 January 2009 and 30 June 2009 were identified in US health insurance claims data. Cohorts were formed based on vaccine brand use. Series completion and compliance with the FDA-approved and ACIP-recommended harmonized schedules were analyzed descriptively and a log binomial model was used to estimate the difference in series completion by vaccine brand while adjusting for demographic variables.

RESULTS

Among infants in the RV1 and RV5 cohorts (N=55,584), 84.3% completed a full series. A greater proportion of the RV1 cohort than the RV5 cohort completed their series (91.0% vs. 83.4%; P<0.001; multivariate-adjusted relative risk 1.07; 95% CI 1.06-1.08). In the RV1 and RV5 cohorts, respectively, 75.0% and 59.5% of infants were fully compliant with the FDA-approved administration schedule for their vaccine (P<0.001); 83.3% and 76.4% of infants were fully compliant with the harmonized schedule (P<0.001).

CONCLUSIONS

The proportion of infants that completed the series was greater and compliance with respective FDA-approved and harmonized dosing schedules was higher among infants vaccinated with RV1 than among infants who received RV5.

Genetic analyses reveal differences in the VP7 and VP4 antigenic epitopes between human rotaviruses circulating in Belgium and rotaviruses in Rotarix and RotaTeq

Two live-attenuated rotavirus group A (RVA) vaccines, Rotarix (G1P[8]) and RotaTeq (G1-G4, P[8]), have been successfully introduced in many countries worldwide, including Belgium. The parental RVA strains used to generate the vaccines were isolated more than 20 years ago in France (G4 parental strain in RotaTeq) and the United States (all other parental strains). At present, little is known about the relationship between currently circulating human RVAs and the vaccine strains. In this study, we determined sequences for the VP7 and VP4 outer capsid proteins of representative G1P[8], G2P[4], G3P[8], G4P[8], G9P[8], and G12P[8] RVAs circulating in Belgium during 2007 to 2009. The analyses showed that multiple amino acid differences existed between the VP7 and VP4 antigenic epitopes of the vaccine viruses and the Belgian isolates, regardless of their G and P genotypes. However, the highest variability was observed among the circulating G1P[8] RVA strains and the G1 and P[8] components of both RVA vaccines. In particular, RVA strains of the P[8] lineage 4 (OP354-like) showed a significant number of amino acid differences with the P[8] VP4 of both vaccines. In addition, the circulating Belgian G3 RVA strains were found to possibly possess an extra N-linked glycosylation site compared to the G3 RVA vaccine strain of RotaTeq. These results indicate that the antigenic epitopes of RVA strains contained in the vaccines differ substantially from those of the currently circulating RVA strains in Belgium. Over time, these differences might result in selection for strains that escape the RVA neutralizing-antibody pressure induced by vaccines.

Rotavirus vaccines: update on global impact and future priorities

Early rotavirus vaccine adopter countries in the Americas, Europe, and in Australia have documented substantial declines in rotavirus disease burden following the introduction of vaccination.  However, the full public health impact of rotavirus vaccines has not been realized as they have not been introduced into routine immunization programs in countries of Africa and Asia with the highest rotavirus disease morbidity and mortality burden.  In this article, we review the epidemiology of rotavirus disease, the development and current status of rotavirus vaccines including newly available vaccine impact data from early-introducer countries, and future priorities for implementation and monitoring of rotavirus vaccination programs in developing countries.

Novel probiotic Bifidobacterium longum subsp. infantis CECT 7210 strain active against rotavirus infections

Rotavirus is the leading cause of severe acute gastroenteritis among children worldwide. It is well known that breast-feeding and vaccination afford infants protection. Since breast-feeding has drastically decreased in developed countries, efforts have been focused on the potential use of probiotics as preventive agents. In this study, a novel Bifidobacterium longum subsp. infantis strain was isolated from infant feces and selected, based on its capacity to inhibit in vitro rotavirus Wa replication (up to 36.05% infectious foci reduction) and also to protect cells from virus infection (up to 48.50% infectious foci reduction) in both MA-104 and HT-29 cell lines. Furthermore, studies using a BALB/c mouse model have proved that this strain provides preliminary in vivo protection against rotavirus infection. The strain has been deposited in the Spanish Type Culture Collection under the accession number CECT 7210. This novel strain has the main properties required of a probiotic, such as resistance to gastrointestinal juices, biliary salts, NaCl, and low pH, as well as adhesion to intestinal mucus and sensitivity to antibiotics. The food safety status has been confirmed by the absence of undesirable metabolite production and in acute ingestion studies of mice. Overall, these results demonstrate that Bifidobacterium longum subsp. infantis CECT 7210 can be considered a probiotic able to inhibit rotavirus infection.

[Rotavirus vaccines: a long and difficult journey]

Diarrhea is the second cause of death worldwide. The main causative agent in infants and children less than 5 years is rotavirus. Consequently, for the World Health Organization and the Global Alliance for Vaccines and Immunization (GAVI), rotavirus vaccination is an urgent priority. The global distribution of rotavirus serotypes varies from country to country, but in 80-90% of cases is caused by five types: G1P[8], G2P[4], G3P[8], G4P[8] and G9P[8]. Currently, two rotavirus vaccines are available, an attenuated monovalent G1P[8] vaccine, and a pentavalent human-bovine recombinant vaccine containing five strains of bovine WC3 rotavirus, four with a gene codifying the VP7 protein of human rotaviruses G1, G2, G3 and G4, and a fifth expressing the VP4 P[8] genotype.

Hospitalizations due to rotavirus gastroenteritis in Catalonia, Spain, 2003-2008

Background

Rotavirus is the most common cause of severe gastroenteritis among young children in Spain and worldwide. We evaluated hospitalizations due to community and hospital-acquired rotavirus gastroenteritis (RVGE) and estimated related costs in children under 5 years old in Catalonia, Spain.

Results

We analyzed hospital discharge data from the Catalan Health Services regarding hospital admissions coded as infectious gastroenteritis in children under 5 for the period 2003-2008. In order to estimate admission incidence, we used population estimates for each study year published by the Statistic Institut of Catalonia (Idescat). The costs associated with hospital admissions due to rotavirus diarrhea were estimated for the same years. A decision tree model was used to estimate the threshold cost of rotavirus vaccine to achieve cost savings from the healthcare system perspective in Catalonia. From 2003 through 2008, 10655 children under 5 years old were admitted with infectious gastroenteritis (IGE). Twenty-two percent of these admissions were coded as RVGE, yielding an estimated average annual incidence of 104 RVGE hospitalizations per 100000 children in Catalonia. Eighty seven percent of admissions for RVGE occurred during December through March. The mean hospital stay was 3.7 days, 0.6 days longer than for other IGE. An additional 892 cases of presumed nosocomial RVGE were detected, yielding an incidence of 2.5 cases per 1000 child admissions. Total rotavirus hospitalization costs due to community acquired RVGE for the years 2003 and 2008 were 431,593 and 809,224 €, respectively. According to the estimated incidence and hospitalization costs, immunization would result in health system cost savings if the cost of the vaccine was 1.93 € or less. At a vaccine cost of 187 € the incremental cost per hospitalization prevented is 195,388 € (CI 95% 159,300; 238,400).

Conclusions

The burden of hospitalizations attributable to rotavirus appeared to be lower in Catalonia than in other regions of Spain and Europe. The relatively low incidence of hospitalization due to rotavirus makes rotavirus vaccination less cost-effective in Catalonia than in other areas with higher rotavirus disease burden.

Identification of lineage III of G12 rotavirus strains in diarrheic children in the Northern Region of Brazil between 2008 and 2010

This study reports on the surveillance for rotavirus genotypes and the identification of G12 human rotavirus in the Northern Region of Brazil. Rotavirus-positive samples were collected from children <5 years of age with acute diarrhea from January 2008 to October 2010. G2P[4] was the most prevalent genotype, accounting for 45.6% (126/303) of cases. Five rotavirus strains bearing G12P[6] genotype specificity were detected. Phylogenetic analysis of the VP7 gene showed that G12 strains clustered into lineage III. This is the first detection of G12 strains from lineage III in Latin America, broadening the current evidence for the worldwide emergence of this genotype.

Rotavirus in adults requiring hospitalization

OBJECTIVES

To determine the prevalence and epidemiological characteristics of rotavirus among adults admitted to the hospital with diarrhea that have bacterial stool cultures sent.

METHODS

The prevalence of rotavirus was determined by Rotaclone EIA in samples submitted for bacterial stool culture from adults requiring hospitalization at Northwestern Memorial Hospital, Chicago from December 01, 2005-November 30, 2006.

RESULTS

Rotavirus was detected in 2.9% of eligible bacterial stool cultures. A bacterial pathogen (e.g., Salmonella, Shigella, Campylobacter) was identified in 3.3%. Bacterial stool pathogens were more common from June-October while rotavirus was 2.4 times more common than all bacterial pathogens from February-May. Adults in whom rotavirus was detected were older (p < 0.05) and more often immunosuppressed (p < 0.02), particularly with HIV (p < 0.04) compared to individuals from whom bacteria were isolated. The duration of hospitalization and the number of invasive procedures performed in those with rotavirus and bacterial diarrhea were comparable.

CONCLUSIONS

In the era immediately prior to widespread rotavirus vaccination of children, rotavirus was as commonly detected from adults admitted to the hospital with diarrhea as are the bacterial gastroenteritis pathogens. Rotavirus is particularly prevalent from February-May (as in children) and in immunosuppressed or older adults.

Sequence analysis of human rotavirus strains: comparison of clinical isolates from Northern and Southern Italy

The surveillance and monitoring of rotavirus (RV)-related diseases, preferably through the establishment of sentinel surveillance sites, are essential for assessing the need for vaccination and the projected results of the vaccine in terms of reducing the burden of disease. The objective of the present study was to compare RV strains isolated in Northern (Ferrara) and Southern (Galatina-LE) Italy. During 2007-2008, 115 RV-positive stool samples were collected from children with diarrhea admitted to the hospitals of Ferrara and Galatina. The specimens were genotyped for VP7 (G-type) and VP4 (P-type) gene by reverse transcription (RT) and multiplex polymerase chain reaction (PCR). A subset of 21 RV strains was randomly selected and characterized by sequence analysis of the VP7 genes. In total, seven G/P combinations (G1P[8], G2P[4], G4P[8], G9P[8], G2P[8], G1P[9], and G2P[10]) were identified. Phylogenetic comparison of the VP7 encoding gene of selected strains showed that there was similarity among RV strains circulating in Northern and Southern Italy. The observation of nucleotide sequence diversity contributes to a better understanding of RV spreading and helps to characterize the various antigenic shifts that could have an impact on vaccine effectiveness.

Immunology of gut mucosal vaccines

Understanding the mechanisms underlying the induction of immunity in the gastrointestinal mucosa following oral immunization and the cross-talk between mucosal and systemic immunity should expedite the development of vaccines to diminish the global burden caused by enteric pathogens. Identifying an immunological correlate of protection in the course of field trials of efficacy, animal models (when available), or human challenge studies is also invaluable. In industrialized country populations, live attenuated vaccines (e.g. polio, typhoid, and rotavirus) mimic natural infection and generate robust protective immune responses. In contrast, a major challenge is to understand and overcome the barriers responsible for the diminished immunogenicity and efficacy of the same enteric vaccines in underprivileged populations in developing countries. Success in developing vaccines against some enteric pathogens has heretofore been elusive (e.g. Shigella). Different types of oral vaccines can selectively or inclusively elicit mucosal secretory immunoglobulin A and serum immunoglobulin G antibodies and a variety of cell-mediated immune responses. Areas of research that require acceleration include interaction between the gut innate immune system and the stimulation of adaptive immunity, development of safe yet effective mucosal adjuvants, better understanding of homing to the mucosa of immunologically relevant cells, and elicitation of mucosal immunologic memory. This review dissects the immune responses elicited in humans by enteric vaccines.

Comparative review of three cost-effectiveness models for rotavirus vaccines in national immunization programs; a generic approach applied to various regions in the world

BACKGROUND

This study aims to critically review available cost-effectiveness models for rotavirus vaccination, compare their designs using a standardized approach and compare similarities and differences in cost-effectiveness outcomes using a uniform set of input parameters.

METHODS

We identified various models used to estimate the cost-effectiveness of rotavirus vaccination. From these, results using a standardized dataset for four regions in the world could be obtained for three specific applications.

RESULTS

Despite differences in the approaches and individual constituting elements including costs, QALYs Quality Adjusted Life Years and deaths, cost-effectiveness results of the models were quite similar. Differences between the models on the individual components of cost-effectiveness could be related to some specific features of the respective models. Sensitivity analysis revealed that cost-effectiveness of rotavirus vaccination is highly sensitive to vaccine prices, rotavirus-associated mortality and discount rates, in particular that for QALYs.

CONCLUSIONS

The comparative approach followed here is helpful in understanding the various models selected and will thus benefit (low-income) countries in designing their own cost-effectiveness analyses using new or adapted existing models. Potential users of the models in low and middle income countries need to consider results from existing studies and reviews. There will be a need for contextualization including the use of country specific data inputs. However, given that the underlying biological and epidemiological mechanisms do not change between countries, users are likely to be able to adapt existing model designs rather than developing completely new approaches. Also, the communication established between the individual researchers involved in the three models is helpful in the further development of these individual models. Therefore, we recommend that this kind of comparative study be extended to other areas of vaccination and even other infectious disease interventions.

Reduction in pediatric rotavirus-related hospitalizations after universal rotavirus vaccination in Belgium

BACKGROUND

This study investigated the effect of pediatric vaccination against rotavirus on the number of rotavirus-related hospitalizations of children in Belgium.

METHODS

This retrospective database study was conducted at 12 pediatric hospitals in Belgium (546 pediatric beds, 30.6% of Belgian total). Children ≤ 5 years attending hospital for any reason were eligible if they had a rotavirus stool test at one of the study centers. The number of rotavirus-positive stool tests and hospitalizations for acute gastroenteritis (AGE) were compared for prevaccination (June 2004-May 2006) and postvaccination (June 2007-May 2009) study periods.

RESULTS

The number of rotavirus-positive stool tests in children who were ≤ 5 years of age decreased from an average of 881 in the prevaccination period to 368 in the first year postvaccination period and 199 in the second. In children 2 to 24 months of age, the percentage reductions were 65% (95% confidence interval [CI]: 62%, 69%) and 80% (95% CI: 77%, 83%) in the first and second years after vaccination, respectively, compared with prevaccination. In children <2 months, the reductions were 50% (95% CI: 36%, 64%) and 64% (95% CI: 49%, 76%), respectively, and in children >24 months the corresponding values were 20% (95% CI: 14%, 28%) and 64% (95% CI: 56%, 72%). The number of AGE-driven hospital admissions and hospitalization days for AGE declined by 33% and 36%, respectively, from prevaccination to the second year postvaccination in children ≤ 2 years of age.

CONCLUSIONS

Pediatric rotavirus vaccination in Belgium significantly reduced rotavirus-related hospitalizations in the first and second years after introduction.

Performance of rotavirus vaccines in developed and developing countries

The World Health Organization estimates that rotavirus diarrhea results in approximately half a million deaths and approximately 2.4 million hospitalizations in developing countries each year. Two live oral rotavirus vaccines, RotaTeq® (RV 5; Merck) and Rotarix® (RV 1; GlaxoSmithKline) with good efficacy against severe rotavirus disease and a reassuring safety profile could substantially impact the burden of rotavirus disease. In April 2009, WHO provided a recommendation for global introduction of these vaccines in national immunization programs of developing countries worldwide. In this article, we review published data on previous candidate rotavirus vaccines and vaccines in current use, with emphasis on their performance in developed versus developing countries. In developed countries, both first and second generation rotavirus vaccines have demonstrated high efficacy against severe rotavirus disease (pooled efficacy = 73% and 85%, respectively). In developing countries, small early trials for the first generation vaccines failed to provide protection against rotavirus disease (pooled efficacy = 20%), however, trials of the second generation vaccines yielded substantial improvements in efficacy in developing countries (pooled efficacy of 51%), leading to a global recommendation for rotavirus vaccine introduction by WHO. Future efforts for these vaccines should focus on optimizing the efficacy and delivery of these vaccines in challenging target populations of Asia and Africa with the greatest burden of severe rotavirus disease.

Human rotavirus vaccine is highly efficacious when coadministered with routine expanded program of immunization vaccines including oral poliovirus vaccine in Latin America

BACKGROUND

The efficacy of a rotavirus vaccine against severe rotavirus gastroenteritis when coadministered with routine Expanded Program on Immunization (EPI) vaccines including oral polio vaccine (OPV) was evaluated in this study.

METHODS

Double-blind, randomized (2:1), placebo-controlled study conducted across 6 Latin American countries. Healthy infants (N = 6568) 6 to 12 weeks of age received 2 doses of RIX4414 vaccine or placebo following a 0, 1- to 2-month schedule. Routine vaccines including OPV were coadministered according to local EPI schedule. Vaccine efficacy (VE) against severe rotavirus gastroenteritis caused by circulating wild-type rotavirus from 2 weeks post-Dose 2 until 1 year of age was calculated with 95% confidence interval [CI]. Safety was assessed during the entire study period. Immunogenicity of RIX4414 and OPV was also assessed.

RESULTS

During the efficacy follow-up period (mean duration = 7.4 months), 7 and 19 cases of severe rotavirus gastroenteritis were reported in the vaccine and placebo groups, respectively, with a VE of 81.6% (95% CI: 54.4-93.5). VE against severe rotavirus gastroenteritis caused by G1 type was 100% (95% CI: <0-100) and 80.6% (95% CI: 51.4-93.2) against the pooled non-G1 rotavirus types, respectively. There was no difference (P = 0.514) in the incidence of serious adverse events reported in the 2 groups. Antirotavirus IgA seropositivity rate at 1 to 2 months post-Dose 2 was 61.4% (95% CI: 53.7-68.6) in the RIX4414 group; similar seroprotection rates (≥96.0%) against the 3 antipoliovirus types was observed 1 month post-Dose 3 of OPV in both groups.

CONCLUSION

RIX4414 was highly efficacious against severe rotavirus gastroenteritis caused by the circulating wild-type rotavirus (G1 and non-G1) when coadministered with routine EPI vaccines including OPV.

Genotypes of rotavirus strains circulating in Amman, Jordan, in 2006/07 and their significance for the potential effectiveness of future rotavirus vaccination

The prevalence, seasonality and genotypes of rotavirus circulating in Jordan were determined to provide data useful for the implementation of a rotavirus vaccine in the national childhood vaccination program. During 2006/07, rotavirus was detected in 35% of hospitalized children, and 88% of the cases occurred in children aged between 6 and 23 months. Rotavirus infection persisted throughout the year and peaked in winter. Seven genotypes were identified by RT-PCR and sequencing: G1P[8], G9P[8], G2P[4], G1P[4], G3P[8], G4P[8] and G9P[6], which represented 69%, 8.8%, 2.4%, 2.0%, 1.2%, 0.4% and 0.4% of the rotavirus strains, respectively. Thirteen percent and 2.8% of the total strains were partially typed or untypeable, respectively. Eighty-eight percent and 12% of the rotavirus strains possessed a long and short electropherotype, respectively. As more than 90% of the rotavirus strains circulating in Jordan possessed the G1 or P[8]-genotype, it is concluded that the implementation of the rotavirus vaccine in the framework of the national childhood vaccination program of Jordan would most likely be very effective. Continuous monitoring of the currently circulating genotypes in Jordan should be encouraged.

Rotavirus vaccine RIX4414 (Rotarix™): a pharmacoeconomic review of its use in the prevention of rotavirus gastroenteritis in developed countries

The most common cause of severe diarrhoea in infants and young children is rotavirus gastroenteritis (RVGE), which is associated with significant morbidity, healthcare resource use and direct and indirect costs in industrialized nations. The monovalent rotavirus vaccine RIX4414 (Rotarix™) is administered as a two-dose oral series in infants and has demonstrated protective efficacy against RVGE in clinical trials conducted in developed countries. In addition, various naturalistic studies have demonstrated 'real-world' effectiveness after the introduction of widespread rotavirus vaccination programmes in the community setting. Numerous cost-effectiveness analyses have been conducted in developed countries in which a universal rotavirus vaccination programme using RIX4414 was compared with no universal rotavirus vaccination programme. There was a high degree of variability in base-case results across studies even when conducted in the same country, often reflecting differences in the selection of data sources or assumptions used to populate the models. In addition, results were sensitive to plausible changes in a number of key input parameters. As such, it is not possible to definitively state whether a universal rotavirus vaccination programme with RIX4414 is cost effective in developed countries, although results of some analyses in some countries suggest this is the case. In addition, international guidelines advocate universal vaccination of infants and children against rotavirus. It is also difficult to draw conclusions regarding the cost effectiveness of rotavirus vaccine RIX4414 relative to that of the pentavalent rotavirus vaccine, which is administered as a three-dose oral series. Although indirect comparisons in cost-effectiveness analyses indicate that RIX4414 provided more favourable incremental cost-effectiveness ratios when each vaccine was compared with no universal rotavirus vaccination programme, results were generally sensitive to vaccine costs. Actual tender prices of a full vaccination course for each vaccine were not known at the time of the analyses and therefore had to be estimated.

Effectiveness of the monovalent G1P[8] human rotavirus vaccine against hospitalization for severe G2P[4] rotavirus gastroenteritis in Belém, Brazil

BACKGROUND

Brazil initiated universal immunization of infants with the G1P[8] human rotavirus (RV) vaccine in March 2006. This study evaluated vaccine effectiveness (VE) against severe rotavirus gastroenteritis (RVGE) hospitalizations.

METHODS

Matched case-control study conducted at 4 hospitals in Belém from May 2008 to May 2009. Cases were children hospitalized with RVGE age-eligible to have received 2 doses of the human RV vaccine (≥ 12 weeks of age and born after March 6, 2006). For each case, 1 neighborhood and 1 hospital control without gastroenteritis was selected, matching by birth date (± 8 and ± 6 weeks, respectively). Matched odds ratio of 2-dose RV vaccination in cases versus controls was used to estimate VE (1 - odds ratio × 100%).

RESULTS

Of 538 RVGE cases, 507 hospital controls and 346 neighborhood controls included, 54%, 61%, and 74% had received both RV vaccine doses. VE against RVGE hospitalization was 75.8% (95% confidence interval [CI]: 58.1-86.0) using neighborhood controls and 40.0% (95% CI: 14.2-58.1) using hospital controls. VE in children 3 to 11 months and ≥ 12 months of age was 95.7% (95% CI: 67.8-99.4) and 65.1% (95% CI: 37.2-80.6) using neighborhood controls, and 55.6% (95% CI: 12.3-77.5) and 32.1% (95% CI: -3.7-55.5) using hospital controls. G2P[4] accounted for 82.0% of RVGE hospitalizations. G2P[4]-specific VE was 75.4% (95% CI: 56.7-86.0) using neighborhood controls and 38.9% (95% CI: 11.1-58.0) using hospital controls.

CONCLUSIONS

Although fully heterotypic G2P[4] was the predominant RV strain, good VE was demonstrated. VE was highest in children aged 3 to 11 months. However, protection in children ≥ 12 months of age, important for optimal public health impact, was significantly sustained based on estimates obtained using neighborhood controls.

Influence of birth rates and transmission rates on the global seasonality of rotavirus incidence

Rotavirus is a major cause of mortality in developing countries, and yet the dynamics of rotavirus in such settings are poorly understood. Rotavirus is typically less seasonal in the tropics, although recent observational studies have challenged the universality of this pattern. While numerous studies have examined the association between environmental factors and rotavirus incidence, here we explore the role of intrinsic factors. By fitting a mathematical model of rotavirus transmission dynamics to published age distributions of cases from 15 countries, we obtain estimates of local transmission rates. Model-predicted patterns of seasonal incidence based solely on differences in birth rates and transmission rates are significantly correlated with those observed (Spearman's ρ = 0.65, p < 0.05). We then examine seasonal patterns of rotavirus predicted across a range of different birth rates and transmission rates and explore how vaccination may impact these patterns. Our results suggest that the relative lack of rotavirus seasonality observed in many tropical countries may be due to the high birth rates and transmission rates typical of developing countries rather than being driven primarily by environmental conditions. While vaccination is expected to decrease the overall burden of disease, it may increase the degree of seasonal variation in the incidence of rotavirus in some settings.

Rotavirus vaccine and diarrhea mortality: quantifying regional variation in effect size

Background

Diarrhea mortality remains a leading cause of child death and rotavirus vaccine an effective tool for preventing severe rotavirus diarrhea. New data suggest vaccine efficacy may vary by region.

Methods

We reviewed published vaccine efficacy trials to estimate a regional-specific effect of vaccine efficacy on severe rotavirus diarrhea and hospitalizations. We assessed the quality of evidence using a standard protocol and conducted meta-analyses where more than 1 data point was available.

Results

Rotavirus vaccine prevented severe rotavirus episodes in all regions; 81% of episodes in Latin America, 42.7% of episodes in high-mortality Asia, 50% of episodes in sub-Saharan Africa, 88% of episodes low-mortality Asia and North Africa, and 91% of episodes in developed countries. The effect sizes observed for preventing severe rotavirus diarrhea will be used in LiST as the effect size for rotavirus vaccine on rotavirus-specific diarrhea mortality.

Conclusions

Vaccine trials have not measured the effect of vaccine on diarrhea mortality. The overall quality of the evidence and consistency observed across studies suggests that estimating mortality based on a severe morbidity reduction is highly plausible.

Molecular characterization of group A rotaviruses detected in children with gastroenteritis in Ireland in 2006–2009

Community and hospital-acquired cases of human rotavirus are responsible for millions of gastroenteritis cases in children worldwide, chiefly in developing countries, and vaccines are now available. During surveillance activity for human rotavirus infections in Ireland, between 2006 and 2009, a total of 420 rotavirus strains were collected and analysed. Upon either PCR genotyping and sequence analysis, a variety of VP7 (G1–G4 and G9) and VP4 (P[4], P[6], P[8] and P[9]) genotypes were detected. Strains G1P[8] were found to be predominant throughout the period 2006–2008, with slight fluctuations seen in the very limited samples available in 2008–2009. Upon either PCR genotyping and sequence analysis of selected strains, the G1, G3 and G9 viruses were found to contain E1 (Wa-like) NSP4 and I1 VP6 genotypes, while the analysed G2 strains possessed E2 NSP4 and I2 VP6 genotypes, a genetic make-up which is highly conserved in the major human rotavirus genogroups Wa- and Kun-like, respectively. Upon sequence analysis of the most common VP4 genotype, P[8], at least two distinct lineages were identified, both unrelated to P[8] Irish rotaviruses circulating in previous years, and more closely related to recent European humans rotaviruses. Moreover, sequence analysis of the VP7 of G1 rotaviruses revealed the onset of a G1 variant, previously unseen in the Irish population.

Inhibition of rotavirus infectivity by a neoglycolipid receptor mimetic

Group A rotaviruses are a major cause of diarrhea in the young of many mammalian species. In rotavirus infected piglets mortality can be as high as 60%. Previous research in this laboratory has identified a porcine intestinal GM₃ ganglioside receptor that is required for sialic acid-dependent rotavirus recognition of host cells. In addition, we previously demonstrated exogenously added GM₃ can competitively inhibit porcine rotavirus binding and infectivity of host cells in vitro. Sialyllactose, the carbohydrate moiety of GM₃, is approximately 3 orders of magnitude less effective than GM₃ at inhibiting rotavirus binding to cells. Furthermore, production of therapeutic quantities of GM₃ ganglioside for use as an oral carbomimetic in swine is cost prohibitive. In an effort to circumvent these problems, a sialyllactose-containing neoglycolipid was synthesized and evaluated for its ability to inhibit rotavirus binding and infectivity of host cells. Sialyllactose was coupled to dipalmitoylphosphatidylethanolamine (PE) by reductive amination and the product (SLPE) purified by HPLC. Characterization of the product showed a single primulin (lipid) and resorcinol (sialic acid) positive band by thin layer chromatography and quantification of phosphate and sialic acid yielded a 1:1 molar ratio. Mass spectroscopy confirmed a molecular weight coinciding with SLPE. Concentration-dependent binding of rotavirus to SLPE was demonstrated using a thin-layer overlay assay. Using concentrations comparable to GM₃, SLPE was also shown to inhibit rotavirus binding to host cells by 80%. Furthermore, SLPE was shown to decrease rotavirus infection of host cells by over 90%. Finally, preliminary results of in vivo animal challenge studies using newborn piglets in their natural environment, demonstrated SLPE afforded complete protection from rotavirus disease. The efficacy of SLPE in inhibiting rotavirus binding and infection in vitro and in vivo, coupled with its relatively low-cost, large-scale production capabilities make SLPE a promising candidate for further exploration as a possible prophylactic or therapeutic nutriceutical for combating rotavirus disease in animals. Most importantly, the results presented here provide proof of concept that the nutriceutical approach of providing natural or synthetic dietary receptor mimetics for protection against gastrointestinal virus infectious disease in all species is plausible.

Molecular and clinical characterization of rotavirus from diarrheal infants admitted to pediatric emergency units in france

BACKGROUND

rotaviruses are the major cause of acute gastroenteritis in young children worldwide, and require careful surveillance, especially in the context of vaccination programs. Prospective surveillance is required to monitor and characterize rotavirus infections, including viral and clinical data, and to detect the emergence of potentially epidemic strains.

METHODS

between 2006 and 2009, stool samples and clinical records were collected from 2044 children with acute diarrhea admitted to the pediatric emergency units of 13 French university hospitals. Rotaviruses were detected in stools, then genotyped by reverse transcription-polymerase chain reaction with regard to their outer capsid proteins VP4 and VP7.

RESULTS

the genotyping of 1947 rotaviruses showed that G1 (61.7%) and G9 (27.4%) strains were predominant and stable, followed by G2 (6.5%), G3 (4.0%), and G4 (2.5%) strains. Most strains were associated with P[8] (92.9%). Overall, 31 uncommon strains and possible zoonotic reassortants were detected including G12 and G8 strains, some being closely related to bovine strains. No difference in clinical presentation and severity was found among genotypes.

CONCLUSIONS

the relative stability of rotavirus genotypes currently cocirculating in France may ensure vaccine effectiveness in the short and medium term. However, the likely emergence of G12 and G8 strains should be monitored during ongoing and future vaccination programs, especially as all genotypes can cause severe infections. Special attention should be paid to the emergence of new rotavirus reassortants not included in current rotavirus vaccines.

Safety, Reactogenicity, and Immunogenicity of Human Rotavirus Vaccine RIX4414 in Human Immunodeficiency Virus-positive Infants in South Africa

BACKGROUND

rotavirus and human immunodeficiency virus (HIV) infections are a cause of great public health concern in developing countries. The current study evaluated the safety, reactogenicity, and immunogenicity of RIX4414 vaccine in asymptomatic or mildly symptomatic (clinical stages I and II according to WHO classification) HIV-infected South African infants.

METHODS

a total of 100 HIV-positive infants aged 6 to 10 weeks enrolled in this double-blind, 1:1 randomized, placebo-controlled study were allocated into 2 groups to receive 3 doses of RIX4414 vaccine/placebo according to a 0-, 1-, and 2-month schedule. Routine vaccines were concomitantly administered. Solicited and unsolicited symptoms were recorded for 15 and 31 days after each dose, respectively. Serious adverse events were recorded throughout the study period. Serum antirotavirus IgA concentrations (enzyme-linked immunosorbent assay, cut-off ≥ 20 U/mL) and the immunodeficiency status were determined at screening and 2 months post-Dose 3. Stool samples were analyzed for rotavirus using enzyme-linked immunosorbent assay at predetermined points and during diarrhea episodes.

RESULTS

all symptoms (solicited and unsolicited) occurred at a similar frequency in both groups. Six fatal serious adverse events in RIX4414 and 9 in placebo groups were reported. At 2 months post-Dose 3, the seroconversion rates were 57.1% (95% CI: 34-78.2) in RIX4414 and 18.2% (95% CI: 5.2-40.3) in the placebo group. The mean absolute CD4 cell count, CD4 percentage, and HIV-1 viral load were comparable in both groups at screening and 2 months post-Dose 3. Rotavirus shedding peaked at Day 7 after Dose 1 of RIX4414 with prolonged shedding was observed in 1 infant only.

CONCLUSIONS

: Three doses of RIX4414 vaccine was tolerated well by the South African HIV-positive infants. A satisfactory immune response was mounted without aggravating their immunologic or HIV condition.

Rotarix in Japan: Expectations and Concerns

A live-attenuated, orally-administered, monovalent, human rotavirus vaccine, Rotarix® (GlaxoSmithKline Biologicals, Rixensart, Belgium), was licensed and launched in 2011 as the first rotavirus vaccine in Japan. The rotavirus causes a substantial disease burden with an estimated 790,000 outpatient visits, 27,000–78,000 hospitalizations, and approximately 10 deaths each year in Japan. Since a recent clinical trial showed that Rotarix was as efficacious in Japan as in other industrialized countries, it is expected that the annual number of rotavirus hospitalizations will be reduced to between 1000–3000, and that outpatient visits will be reduced to 200,000. The universal rotavirus immunization program with Rotarix was calculated to be at the threshold of being cost-effective, even from the healthcare perspective, and it was highly cost-effective from the societal perspective, assuming that Rotarix is co-administered with other childhood vaccines. While Rotarix contains only a single G1P[8] human rotavirus, the postlicensure studies in Brazil showed that Rotarix provided a 75%–85% protective efficacy against severe dehydrating diarrhea or hospitalizations due to fully-heterotypic G2P[4] strains. While postlicensure studies detected a small and finite risk of intussusception associated with the administration of Rotarix, the authors conclude that Rotarix is safe to administer to infants between 6-12 weeks of age for the first dose and by 24 weeks of age for the second dose. However, the authors strongly discourage the delayed administration of the first dose between 13-20 weeks of age, which is allowed without any warning. Given the high incidence of naturally-occurring intussusception in Japan (185 cases per 100,000 children/year among children less than 1 year of age), this should prevent pediatricians and parents from having ill-perceptions of Rotarix being associated with an increased number of temporally-associated intussusception, and fully appreciate the benefit of the rotavirus vaccine.

Laboratory-based rotavirus surveillance during the introduction of a vaccination program, Brazil, 2005-2009

BACKGROUND

: Brazil introduced universal antirotavirus vaccination in March 2006. This article reports the results of rotavirus A (RV-A) surveillance from January 2005 to December 2009.

METHODS

: A total of 6109 fecal samples were collected in 18 Brazilian states. RV-A was detected by enzyme immunoassay and/or polyacrylamide gel electrophoresis, and genotyped through seminested reverse transcription-polymerase chain reaction.

RESULTS

: RV-A was detected in 20.3% (n = 1242) of the samples. Among children less than 2 years old, regardless the antirotavirus vaccination status, the rates of RV-A detection were 33.8% in 2005, 23.7% in 2006, 16.8% in 2007, 22.9% in 2008, and 18.3% in 2009 (P < 0.001; χ test for linear trend). Among RV-A-positive samples, genotype G1P[8] or G1P[not typed(NT)] was detected in 14% in 2005, 12.3% in 2006, 9.5% in 2007, 0.7% in 2008, and 20.4% in 2009; G2P[4]/G2P[NT] was characterized in 9% in 2005, 49% in 2006, 66% in 2007, 85% in 2008, and 37.5% in 2009; G3P[8]/G3P[NT] was observed in 8.7% in 2005, 3.5% in 2006, and 5.7% in 2009; G9P[8]/G9P[NT] was observed in 52% in 2005, 22% in 2006, 12.3% in 2007, 3.2% in 2008, and 3.4% in 2009.

CONCLUSIONS

: Our data demonstrate the reemergence of RV-A genotype G2P[4] in Brazil from 2005 to 2008, and that the rate of G2P[4] detection decreased in 2009, probably reflecting natural oscillations of RV-A genotypes.

Uptake, impact, and effectiveness of rotavirus vaccination in the United States: review of the first 3 years of postlicensure data

BACKGROUND

Rotavirus vaccine was recommended for routine use in US infants in 2006. Before the introduction of vaccine, rotavirus was the most common cause of severe gastroenteritis in children <5 years of age in the United States.

METHODS

We reviewed published data to summarize the US experience during the first 3 years of its rotavirus vaccination program.

RESULTS

Rotavirus seasons have been delayed and diminished in magnitude during the postvaccine era compared with the prevaccine era. Hospitalizations, emergency department visits, and outpatient visits due to gastroenteritis have declined dramatically in children < 5 years of age including in children age-ineligible to have received vaccine, suggesting indirect benefits of vaccination. Rotavirus vaccine has been widely accepted by pediatricians. Vaccine coverage is steadily increasing but remains lower than coverage levels of other routine infant immunizations.

CONCLUSIONS

The implementation of routine childhood immunization against rotavirus has rapidly and dramatically reduced the large health burden of rotavirus gastroenteritis in US children. Continued monitoring of rotavirus diarrhea is needed to determine if immunity wanes as vaccinated children get older and to better quantify the indirect benefits of vaccination. Ongoing surveillance will also enable monitoring of the long-term impact of vaccination on rotavirus epidemiology.