Rotavirus Incidence Research Articles

Rotavirus incidence in hospitalised Hong Kong children: 1 July 1997 to 31 March 2011

Sentinel laboratory surveillance from one hospital and passive discharge diagnosis (Clinical Management System, CMS) data from all public Hospital Authority (HA) hospitals were used to estimate disease burden and incidence of rotavirus in hospitalised Hong Kong children over 14 rotavirus seasons (1 July 1997 to 31 March 2011). A primary diagnosis of a gastroenteritis-related disorder was noted in 9.8% of children aged below 5 years, and a primary or secondary diagnosis in 11.8%. Any CMS diagnosis of rotavirus (ICD 008.61) was initially used to derive incidence estimates of rotavirus by age group. Rotavirus was recorded as any primary or any secondary diagnosis in 1.6% of children below 5 years of age. The unadjusted incidence rates per 100,000 person-years based on any CMS diagnosis of rotavirus were: 249 (0 to <1m); 612 (1 to <2m); 1066 (2 to <6m); 1383 (6 to <11m); 959 (1 to <2y); 406 (2 to <3y); 233 (3 to <4y); 124 (4 to <5y). Overall the rotavirus incidence was 1071 in children below 2 years and 542 in children below 5 years of age, with the incidence rates trending up during the time period (p=0.001). A similar but less marked upward trend (p=0.046) was noted for the incidence of all-cause gastroenteritis. Laboratory results from a single surveillance hospital (1 July 2000 to 31 March 2011) were then linked to these CMS codes to derive adjustment factors for possible over- and under-diagnosis of rotavirus based on CMS codes alone. This analysis suggested that a CMS diagnosis of rotavirus alone likely under-reported true incidence by a factor of between 1.59 and 2.02 in children below 5 years of age. Despite the availability of rotavirus vaccines in the private sector since 2006, no reduction in the incidence of hospitalisation for either rotavirus or all-cause gastroenteritis was noted in Hong Kong children below 5 years of age over 14 rotavirus seasons (1997–2011).

Bayesian parameter inference for dynamic infectious disease modelling: rotavirus in Germany

Understanding infectious disease dynamics using epidemic models based on ordinary differential equations requires the calibration of model parameters from data. A commonly used approach in practice to simplify this task is to fix many parameters on the basis of expert or literature information. However, this not only leaves the corresponding uncertainty unexamined but often also leads to biased inference for the remaining parameters because of dependence structures inherent in any given model. In the present work, we develop a Bayesian inference framework that lessens the reliance on such external parameter quantifications by pursuing a more data-driven calibration approach. This includes a novel focus on residual autocorrelation combined with model averaging techniques in order to reduce these estimates' dependence on the underlying model structure. We applied our methods to the modelling of age-stratified weekly rotavirus incidence data in Germany from 2001 to 2008 using a complex susceptible-infectious-susceptible-type model complemented by the stochastic reporting of new cases. As a result, we found the detection rate in the eastern federal states to be more than four times higher compared with that of the western federal states (19.0% vs 4.3%), and also the infectiousness of symptomatically infected individuals was estimated to be more than 10 times higher than that of asymptomatically infected individuals (95% credibility interval: 8.1–19.6). Not only do these findings give valuable epidemiological insight into the transmission processes, we were also able to examine the considerable impact on the model-predicted transmission dynamics when fixing parameters beforehand.

Epidemiology and clinical features of rotavirus and norovirus infection among children in Ji’nan, China

BackgroundAcute gastroenteritis caused by bacteria, virus and parasite is an important cause of childhood morbidity and mortality in developing countries. Rotavirus and norovirus have been recognized as the most common pathogens causing acute gastroenteritis among children. However, there is still no valuable data about infections of rotavirus and norovirus in children in Ji’nan, an eastern city in China. The aims of the present study are to determine the incidence of rotavirus and norovirus associated acute gastroenteritis in Ji’nan among children, to characterize rotavirus and norovirus strains circulating during this period; and to provide useful epidemiological and clinical data.MethodsFecal specimens and clinical data were collected from 767 children (502 outpatients and 265 inpatients) under 5 years of age with acute diarrhea at Shandong University Qilu Hospital and Qilu children’s Hospital in Ji’nan, China between February 2011 and January 2012. Virus RNA was extracted, amplified, electrophoresed, sequenced and phylogenetically analyzed to determine the prevalent genotypes. Chi-square and U test were used to compare characteristics of clinical manifestation in each group.ResultsOf the 767 specimens 263 (34.3%) were positive for rotavirus and 80 (10.4%) were positive for norovirus. Among 263 rotavirus positive cases, G3 (40.7%) was the most prevalent serotype, P[8] (46.8%) was the dominant genotype and G3P[8] (31.9%) was the most common combination. All of the norovirus strains belonged to GII genogroup including GII.3, GII.4 and GII.6, of which GII.4 (61.2%) was the predominant genotype. Phylogenetic analysis of the GII.4 sequences showed that 18 GII.4 strains belonged to GII.4 2004–2006 cluster and 31 GII.4 strains were divided into GII.4 2006b cluster. A peak number of rotavirus infections was observed during the cold season from November to next January. Higher rates of norovirus infections were detected from September to November. Most patients with rotavirus and norovirus associated diarrhea experienced vomiting (88.2% and 67.5%, respectively) and fever (79.1% and 46.3%, respectively).ConclusionsThe present study showed that rotavirus and norovirus were still the important causative agents of pediatric diarrhea in Ji’nan during this period.

Rotavirus Seasonality and Age Effects in a Birth Cohort Study of Southern India

IntroductionUnderstanding the temporal patterns in disease occurrence is valuable for formulating effective disease preventive programs. Cohort studies present a unique opportunity to explore complex interactions associated with emergence of seasonal patterns of infectious diseases.MethodsWe used data from 452 children participating in a birth cohort study to assess the seasonal patterns of rotavirus diarrhea by creating a weekly time series of rotavirus incidence and fitting a Poisson harmonic regression with biannual peaks. Age and cohort effects were adjusted for by including the weekly counts of number of children in the study and the median age of cohort in a given week. Weekly average temperature, humidity and an interaction term to reflect the joint effect of temperature and humidity were included to consider the effects of meteorological variables.ResultsIn the overall rotavirus time series, two significant peaks within a single year were observed – one in winter and the other in summer. The effect of age was found to be the most significant contributor for rotavirus incidence, showing a strong negative association. Seasonality remained a significant factor, even after adjusting for meteorological parameters, and the age and cohort effects.ConclusionsThe methodology for assessing seasonality in cohort studies is not yet developed. This is the first attempt to explore seasonal patterns in a cohort study with a dynamic denominator and rapidly changing immune response on individual and group levels, and provides a highly promising approach for a better understanding of the seasonal patterns of infectious diseases, tracking emergence of pathogenic strains and evaluating the efficacy of intervention programs.

Human milk oligosaccharides inhibit rotavirus infectivityin vitroand in acutely infected piglets

Human milk (HM) is rich in oligosaccharides (HMO) that exert prebiotic and anti-infective activities. HM feeding reduces the incidence of rotavirus (RV) infection in infants. Herein, the anti-RV activity of oligosaccharides was tested in an established in vitro system for assessing cellular binding and viral infectivity/replication, and also tested in a newly developed, acute RV infection, in situ piglet model. For the in vitro work, crude HMO isolated from pooled HM, neutral HMO (lacto-N-neotetraose, LNnT; 2'-fucosyllactose) and acidic HMO (aHMO, '-sialyllactose, 3'-SL; -sialyllactose, -SL) were tested against the porcine OSU strain and human RV Wa strain. The RV Wa strain was not inhibited by any oligosaccharides. However, the RV OSU strain infectivity was dose-dependently inhibited by sialic acid (SA)-containing HMO. 3'-SL and 6'-SL concordantly inhibited (125)I-radiolabelled RV cellular binding and infectivity/replication. For the in situ study, a midline laparotomy was performed on 21-d-old formula-fed piglets and six 10 cm loops of ileum were isolated in situ. Briefly, 2 mg/ml of LNnT, aHMO mixture (40% 6'-SL/10 % 3'-SL/50 % SA) or media with or without the RV OSU strain (1 x 10(7) focus-forming units)were injected into the loops and maintained for 6 h. The loops treated with HMO treatments þ RV had lower RV replication, as assessed by non-structural protein-4 (NSP4) mRNA expression, than RV-treated loops alone. In conclusion, SA-containing HMO inhibited RV infectivity in vitro; however, both neutral HMO and SA with aHMO decreased NSP4 replication during acute RV infection in situ.

Characterization of rotavirus causing acute diarrhoea in children in Kathmandu, Nepal, showing the dominance of serotype G12

Diarrhoeal diseases are a major problem in developing countries. Though precise data on childhood mortality associated with diarrhoeal diseases in Nepal are not available, it has been estimated that approximately 25 % of child deaths are associated with diarrhoeal disease, particularly acute diarrhoea. The purpose of this study was to assess the incidence of rotavirus causing acute diarrhoea in children less than 5 years of age. A total of 525 children with acute diarrhoea in a children's hospital of Kathmandu, Nepal, were enrolled between April and September 2011. The incidence of acute diarrhoea due to rotavirus was 25.9 % (136/525) as determined by ELISA. The percentage of rotavirus-infected males was higher (64.5 %) than females (35.5 %). The frequency of rotavirus cases was higher in children less than 2 years of age, among which the majority of cases (80.2 %) were in children between 6 and 24 months old (P<0.01). Genotypic characterization by RT-PCR revealed that the serotype G12 represented 55.9 % of cases in this study associated with P-types of either P[6], P[4] or P[8]. Further to this, a total of eight G/P combinations were identified, G12P[6] being the most common strain type of rotavirus in Nepal, with a prevalence rate of 46.4 %. The aim of this study was to find out the major genotypes of rotavirus causing acute diarrhoea in children.

866 Paediatric Stool Testing Practices in Ireland and Potential Influence on Epidemiology of Rotavirus Gastroenterisis (RVGE) and Rotavirus Immunisation

Background and AimsRotavirus vaccination has not been taken up in Ireland. We aimed to conduct a regional audit of gastroenteritis and paediatric stool testing patterns to generate better epidemiological data...

Five-year cohort study on the burden of hospitalisation for acute diarrhoeal disease in African HIV-infected and HIV-uninfected children: Potential benefits of rotavirus vaccine

Diarrhoea remains an important cause of death in children under five years of age, including in areas with high prevalence of HIV infection. Rotavirus contributes significantly to childhood diarrhoea in South Africa but data on the burden of rotavirus disease in HIV-infected children are limited. This secondary data analysis, involving a cohort of 39,879 children enrolled into a pneumococcal conjugate vaccine efficacy trial, evaluated the incidence of hospitalisation for acute gastroenteritis in HIV-infected and HIV-uninfected children under five years of age from Soweto, South Africa. The data were used to evaluate the potential burden of hospitalisation that would be preventable with rotavirus vaccine. Acute gastroenteritis (AGE) was identified as a leading cause of hospitalisation in the cohort and was associated with 21% of all hospitalisations. Twenty-six percent of the AGE hospitalisations occurred in HIV-infected children. The incidence of AGE was greatest in the under-6 months age group and 90% of cases occurred within the first two years of life. The overall incidence of AGE was 5.4 fold (CI(95%) 4.9, 6.0) higher in HIV-infected compared to HIV-uninfected children. In addition, the estimates of rotavirus incidence were 2.3 fold (CI(95%) 1.8, 2.9) higher in HIV-infected compared to HIV-uninfected children. HIV-infected children were 1.8 fold (CI(95%) 1.4, 2.4) more likely to have prolonged hospitalisation and the case fatality rate was 4.0 (CI(95%) 2.0, 7.8) fold higher in HIV-infected compared to HIV-uninfected children. Despite rotavirus reportedly being less frequently identified in hospitalised HIV-infected children, the absolute burden of rotavirus-associated hospitalisation is likely to be greater compared to HIV-uninfected children. The introduction of rotavirus vaccine into the national immunisation program in South Africa is likely to benefit HIV-infected and HIV-uninfected children and reduce the overall burden of AGE hospitalisation in our childhood population.

PROBLEMS IN THE EPIDEMIOLOGICAL DIAGNOSIS OF ROTAVIRUS INFECTION

The paper considers topical problems in the scientific and methodological provision of epidemiological surveillance of rotavirus infection, such as the significance of different routes of pathogen transmission, a trend in the development of an epidemic process, and mechanisms of its self-regulation. The virological and epidemiological data suggest that the role of rotavirus transmission via water is insignificant (contact transmission is typified by the age-related structure of morbidity; water basins and drinking water show noninfectious viral markers, the resistance of which is much higher than that of the pathogen). A total of 8556patients aged 0 to 14 years with acute enteric infections, who were treated at the Children ’s Infectious Diseases Unit, City Hospital One, Rostov-on-Don, were examined for rotavirus in the period from February 2006 to January 2009. Group A rotaviruses were detected in 34% of the patients. Examination of variations in the trend of rotavirus incidence in children of different ages revealed a set of epidemiological parameters reflecting the dynamics of an epidemic process -phasic development and a change in epidemic infection cycles in the urban population. There was a continuous alternation of epidemic cycles every 2-2.5 months. The developed methods for monitoring the epidemic process make it possible to accurately assess the current epidemiological situation and to predict higher morbidity among infants.

Rotavirus gastroenteritis in Latin America: A hospital-based study in children under 3 years of age

Rotavirus is the leading cause of severe diarrheal disease and dehydration in infants in both developed and developing countries. Vaccines have recently been developed, but detailed epidemiological information, which is needed for decisions about how and where to introduce vaccination, was lacking for many Latin American countries. The primary objective of this study was to measure the incidence and disease burden of rotavirus in young children presenting to Latin American hospitals with gastroenteritis. In addition it allowed to setting up the methodology to further conduct a large phase III trial with a rotavirus vaccine in the region. This was a prospective, multi-center surveillance study of gastroenteritis in children <3years old presenting to hospitals in 11 Latin American countries. Questionnaires and stool samples were collected from 6521 of 8031 enrolled cases (73% inpatients). Among these, 3122 (49%) were rotavirus positive. Of the rotavirus-positive cases, 12% were <6months, 48% <1year and 87% <2years old; 23% received antibiotics before diagnosis. Median hospital stay was 2days, 78% received intravenous rehydration. Overall strain distribution was G1 (59%), G2 (1%), G3 (12%), G4 (20%), G9 (6%), G12 (1%), untypable (7%) with large local variations. The direct economic impact on families was considerable: 48% of caregivers lost time from paid work and 69% of families were financially affected by their child's illness. This study confirms the high disease burden of rotavirus gastroenteritis among children in Latin America, which might be reduced by the use of effective vaccines.

Ecological analysis of social risk factors for Rotavirus infections in Berlin, Germany, 2007–2009

BackgroundSocioeconomic factors are increasingly recognised as related to health inequalities in Germany and are also identified as important contributing factors for an increased risk of acquiring infections. The aim of the present study was to describe in an ecological analysis the impact of different social factors on the risk of acquiring infectious diseases in an urban setting. The specific outcome of interest was the distribution of Rotavirus infections, which are a leading cause of acute gastroenteritis among infants and also a burden in the elderly in Germany. The results may help to generate more specific hypothesis for infectious disease transmission.MethodsWe analysed the spatial distribution of hospitalized patients with Rotavirus infections in Berlin, Germany. The association between the small area incidence and different socio-demographic and economic variables was investigated in order to identify spatial relations and risk factors. Our spatial analysis included 447 neighbourhood areas of similar population size in the city of Berlin. We included all laboratory-confirmed cases of patients hospitalized due to Rotavirus infections and notified between 01/01/2007 and 31/12/2009. We excluded travel-associated and nosocomial infections. A spatial Bayesian Poisson regression model was used for the statistical analysis of incidences at neighbourhood level in relation to socio-demographic variables.ResultsAltogether, 2,370 patients fulfilled the case definition. The disease mapping indicates a number of urban quarters to be highly affected by the disease. In the multivariable spatial regression model, two risk factors were identified for infants (<4 year olds): Rotavirus incidence increased by 4.95% for each additional percent of unemployed inhabitants in the neighbourhood (95% credibility interval (CI): 3.10%-6.74%) and by 0.53% for each additional percent of children attending day care in the neighbourhood (95% CI: 0.00%-1.06%). We found no evidence for an association with the proportion of foreign residents, population density, the residential quality of accommodations and resident changes in the neighbourhood.ConclusionsNeighbourhoods with a high unemployment rate and high day care attendance rate appear to be particularly affected by Rotavirus in the population of Berlin. Public health promotion programs should be developed for the affected areas. Due to the ecological study-design, risk pathways on an individual patient level remain to be elucidated.

Increased prevalence of rotavirus among children associated gastroenteritis in Riyadh Saudi Arabia

The aim of this study is to assess the epidemiology along with the molecular structure of rotavirus causing pediatric diarrhea among Saudi patients. However, in this report we sited the epidemiological reflect coming from our project.MethodsOne thousand and seven diarrheal stool samples had been collected between Jan1st, 2008 and OCT 31st, 2010 from hospitalized patients below the age of 5 year. Samples were then examined using Enzyme-linked immunosorbent assay (ELISA). Demographic data were collected including age, sex, date of admission and discharge. Finally, the chi-squire test, α level of significance was used to test the variables in the data.ResultsOf these 1007 stool samples, rotavirus was detected in 65.5% (660/1007 samples). We observed that children who are 1 year of age or less had more infection with rotavirus 81% (534/660) than those who is over 1 year of age (19%,126/660) (P = 0.000). Infections occur throughout the year with no clear significant seasonal peaks. The difference between males (57.5%, 380/660) and females (42.4%, 280/660) in terms of rotavirus positivity is statistically significant.ConclusionsThe high rate of positivity, are at variance with previously published reports of rotavirus infection in Saudi Arabia since 2005 which reported a major decrease year by year in the incidence of rotavirus over; 2005, 2006 and 2008 with percentage of; 25%, 10%, 6% respectively explained by improvements in public health introduced in recent years. Our increasing rate result (65.5%) may suggest emerging of unusual serotypes, not been represent to our country earlier.

Modeling rotavirus strain dynamics in developed countries to understand the potential impact of vaccination on genotype distributions

Understanding how immunity shapes the dynamics of multistrain pathogens is essential in determining the selective pressures imposed by vaccines. There is currently much interest in elucidating the strain dynamics of rotavirus to determine whether vaccination may lead to the replacement of vaccine-type strains. In developed countries, G1P[8] strains constitute the majority of rotavirus infections most years, but occasionally other genotypes dominate for reasons that are not well understood. We developed a mathematical model to examine the interaction of five common rotavirus genotypes. We explored a range of estimates for the relative strength of homotypic vs. heterotypic immunity and compared model predictions against observed genotype patterns from six countries. We then incorporated vaccination in the model to examine its impact on rotavirus incidence and the distribution of strains. Our model can explain the coexistence and cyclical pattern in the distribution of genotypes observed in most developed countries. The predicted frequency of cycling depends on the relative strength of homotypic vs. heterotypic immunity. Vaccination that provides strong protection against G1 and weaker protection against other strains will likely lead to an increase in the relative prevalence of non-G1 strains, whereas a vaccine that provides equally strong immunity against all strains may promote the continued predominance of G1. Overall, however, disease incidence is expected to be substantially reduced under both scenarios and remain below prevaccination levels despite the possible emergence of new strains. Better understanding of homotypic vs. heterotypic immunity, both natural and vaccine-induced, will be critical in predicting the impact of vaccination.

Diversity and zoonotic potential of rotaviruses in swine and cattle across Europe

Group A rotaviruses can infect both humans and animals. Individual rotavirus strains can occasionally cross species barriers and might hereby contribute to the emergence of new genotypes in heterologous hosts. The incidence and impact of zoonotic rotavirus are not well defined, and one reason for this is a lack of data about strains circulating in suspected reservoir animal hosts. In this study we report the incidence, genetic diversity, and molecular epidemiology of rotaviruses detected in domestic cattle and swine in 6 European countries. From 2003 to 2007, 1101 and more than 2000 faecal specimens were collected from swine and cattle, both healthy and diarrhoeic, and tested for rotaviruses. Viruses from positive stools were genotyped and a subset of strains was characterized by nucleotide sequencing and phylogenetic analysis of the VP7 (G) and VP4 (P) genes. Rotaviruses were detected in 43% of bovine samples and in 14% of porcine samples. In cattle, 10 different combinations of G and P types were identified and the most common strains were G6P[11] and G6P[5]. In swine, the number of identified G–P combinations was higher (n=21), however, no single combination was predominant across Europe. Newly described genotype specificities, P[27] and P[32], were identified in swine. When compared at the nucleotide sequence level, the identified porcine rotavirus strains and contemporary human strains grouped together phylogenetically, whereas bovine rotavirus strains formed separate clades. These data demonstrate large genetic diversity of porcine and bovine rotavirus strains across Europe, and suggest that livestock herds may serve as potential reservoirs for human infections.

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.

Monitoring of Group A Rotaviruses in Wild-Living Birds in Hungary

Rotavirus is a common pathogen causing gastroenteritis in humans and domesticated animals. The incidence of rotavirus in wild-living animals, particularly in avian species, has not been systematically investigated. In this study 1220 fecal samples and cloacal swabs collected from wild-living birds during 2008 in Hungary were tested for the presence of group A rotaviruses by a VP6 gene-specific reverse-transcription-polymerase-chain-reaction assay. Of the 1220 samples, 276 and 944 were processed as individual and pooled specimens, respectively. Rotavirus was identified in two pooled pheasant (Phasianus colchicus) samples and two individual reed bunting samples (Emberiza schoeniclus). These data indicated a very low prevalence of group A rotaviruses (0.3%) in our sample set. Nonetheless, the present study, together with existing literature data, implies that rotavirus infections occur in a wide spectrum of feral bird species. These findings are exciting and suggest that pursuing rotavirus monitoring is needed to uncover avian rotavirus strain diversity and understand rotavirus ecology in nature.

Rotavirus incidence and genotype distribution before and after national rotavirus vaccine introduction in Belgium

Rotarix™ was introduced into the Belgian market in 2006 and RotaTeq™ in 2007, quickly reaching more than 85% vaccine coverage of all newborns in Belgium. The incidence of rotavirus gastroenteritis has been monitored in the Gasthuisberg University Hospital (GUH), Belgium since 1986, and since 1999 the genotypes of circulating rotavirus strains have been determined. The average percentage of rotavirus positive cases out of all hospitalized gastro-enteritis cases tested (>95% of these cases are younger than 5 years old) at the GUH between 1986 and 2006 was 19.0%. This percentage dropped to 12.4%, 9.6% and 6.4% in the three seasons post vaccine introduction (2006–2009), which is a decline of 34.7%, 49.4% and 66.3% respectively. In addition the rotavirus season was found to be shortened and delayed. The prevalence of the G2 genotype sharply increased in the 2006–2007 rotavirus season compared to the previous seasons and remained high (30–40%) in the 2007–2008 and 2008–2009 seasons. Rotavirus vaccines have strongly reduced the number of children hospitalized due to a rotavirus infection at the GUH; it is however unclear if the predominance of G2 genotypes is related to the vaccine introduction, or if this is attributable to normal genotype fluctuations. Continued surveillance will be pivotal to answer this question in the future.

Incidence of Rotavirus and All-Cause Diarrhea in Northeast Brazil Following the Introduction of a National Vaccination Program

Rotavirus vaccines were introduced in Brazil in 2006; we evaluated their effects in the state of Sergipe, Brazil. We performed a cross-sectional survey of children with diarrhea attending emergency services in Aracaju, Brazil, between October 2006 and April 2008 and a cluster sampling survey to assess vaccination coverage. Vaccine efficacy was assessed using the screening method. Diarrhea consultation and hospitalization data (2003-2007) were obtained from state and national surveillance systems. Rotavirus was detected in 59 of 534 stool samples (11%) from children attending emergency services. The number of rotavirus-positive samples decreased from 18 of 74 (24%) in 2006 to 31 of 321 (9.5%) in 2007 and 10 of 136 (7.4%) in 2008 (P < .01). Diarrhea severity was greater in children with rotavirus (P < .01) but decreased over time (P < .001). Of the rotaviruses detected, 56 of 59 (95%) were P[4]G2 genotype, 1 was P[4]G-non-typeable (NT), 1 was P[NT]G2, and 1 was P[NT]GNT. Diarrhea consultations decreased from 3020 in 2004 to 604 in 2007; reductions were greatest among children under 5 years old. Diarrhea hospitalizations decreased from 2121 in 2003 to 1176 in 2007. Vaccine coverage was 90.3%. Vaccines were highly effective against the strain P[8]G1; efficacy against P[4]G2 genotype was 89% (95% confidence interval: 0.87-0.92) in Aracaju and 95% in Sergipe. Since vaccines were introduced in 2006, there has been an overall reduction in diarrhea consultations and hospitalizations in northeast Brazil, with the greatest reductions in young children. This might have resulted from vaccination and improved sanitation. Although a single rotavirus genotype (P[4]G2) was recovered, vaccine efficacy was high against this genotype.

Estimating the incidence of symptomatic rotavirus infections: a systematic review and meta-analysis.

BackgroundWe conducted for the first time a systematic review, including a meta-analysis, of the incidence of symptomatic rotavirus (RV) infections, because (1) it was shown to be an influential factor in estimating the cost-effectiveness of RV vaccination, (2) multiple community-based studies assessed it prospectively, (3) previous studies indicated, inconclusively, it might be similar around the world.MethodologyPubmed (which includes Medline) was searched for surveys assessing prospectively symptomatic (diarrheal) episodes in a general population and situation, which also reported on the number of the episodes being tested RV+ and on the persons and the time period observed. A bias assessment tool was developed and used according to Cochrane guidelines by 4 researchers with different backgrounds. Heterogeneity was explored graphically and by comparing fits of study-homogenous ‘fixed effects’ and -heterogeneous ‘random effects’ models. Data were synthesized using these models. Sensitivity analysis for uncertainty regarding data abstraction, bias assessment and included studies was performed.Principal FindingsVariability between the incidences obtained from 20 studies is unlikely to be due to study groups living in different environments (tropical versus temperate climate, slums versus middle-class suburban populations), nor due to the year the study was conducted (from 1967 to 2003). A random effects model was used to incorporate unexplained heterogeneity and resulted in a global incidence estimate of 0.31 [0.19; 0.50] symptomatic RV infections per personyear of observation for children below 2 years of age, and of 0.24 [0.17; 0.34] when excluding the extreme high value of 0.84 reported for Mayan Indians in Guatemala. Apart from the inclusion/exclusion of the latter study, results were robust.Conclusions/SignificanceRather than assumptions based on an ad-hoc selection of one or two studies, these pooled estimates (together with the measure for variability between populations) should be used as an input in future cost-effectiveness analyses of RV vaccination.

Impact of transmission dynamics on the cost-effectiveness of rotavirus vaccination

The objective of this study is to estimate the cost-effectiveness of mass vaccination of US infants with the recently available rotavirus vaccine, RotaTeq. We developed a dynamic transmission model of rotavirus to incorporate herd immunity into cost-effectiveness analysis. Our study indicates that a rotavirus vaccination program would prevent about 90% of rotavirus incidence, mortality, hospitalization and emergency department visits annually. We conclude that a universal rotavirus vaccine program in the US would cost $77.30 per case averted from the health care and give a net saving of $80.75 per case averted from the societal perspectives, respectively. The cost per QALY gained was found to be $104,610 when we considered child with one caregiver, making the rotavirus vaccination program a cost-effective intervention.