Indirect protection of adults from rotavirus by pediatric rotavirus vaccination

Variations in Prevalence and Characteristics of Rotavirus Diarrhea Among Outpatients - Shanghai Municipality, China, 2017-2023

Introduction

This study investigated temporal changes in rotavirus group A (RVA) prevalence, epidemiological characteristics, and genotype distribution patterns among diarrhea outpatients in Shanghai Municipality, China.

Methods

We conducted prospective active surveillance of diarrheal disease in pediatric and adult outpatients in Shanghai. Stool specimens were analyzed for five viral and twelve bacterial pathogens. Real-time reverse transcription polymerase chain reaction (rRT-PCR) was employed for RVA detection, followed by genotyping of RVA-positive specimens through partial amplification of VP7 and VP4 genes.

Results

The study analyzed 2,331 diarrhea cases in children aged 0-14 years and 8,418 cases in individuals aged ≥15 years between January 2017 and December 2023. Overall RVA positivity rates decreased significantly from 7.43% in 2017 to 1.19% in 2023 (P=0.024). The most pronounced decline occurred in children aged 2-5 years, where positivity rates fell from 13.08% to 1.72%. Adults aged ≥30 years also showed a substantial reduction. Among RVA-positive pediatric cases (≤14 years), the proportion of cases aged 6-14 years increased from 2.33% to 18.18%. While G9P[8] remained the predominant strain, its prevalence decreased from 77.78% to 31.25%, concurrent with the emergence of G8P[8] strains.

Conclusions

RVA prevalence has shown a marked decline since 2018-2019, accompanied by a shift in age distribution toward older children. The diminishing dominance of G9P[8] strains coincided with the emergence of G8P[8] strains. Continued epidemiological and genetic surveillance of rotavirus diarrhea, coupled with real-world effectiveness evaluations of domestic vaccines, remains crucial for optimizing rotavirus immunization strategies.

Effects of Rotavirus Vaccination Coverage among Infants on Hospital Admission for Gastroenteritis across All Age Groups, Japan, 2011-2019

We assessed the effect of rotavirus vaccination coverage on the number of inpatients with gastroenteritis of all ages in Japan. We identified patients admitted with all-cause gastroenteritis during 2011-2019 using data from the Diagnosis Procedure Combination system in Japan. We used generalized estimating equations with a Poisson distribution, using hospital codes as a cluster variable to estimate the impact of rotavirus vaccination coverage by prefecture on monthly numbers of inpatients with all-cause gastroenteritis. We analyzed 294,108 hospitalizations across 569 hospitals. Higher rotavirus vaccination coverage was associated with reduced gastroenteritis hospitalizations compared with the reference category of vaccination coverage <40% (e.g., for coverage >80%, adjusted incidence rate ratio was 0.87 [95% CI 0.83-0.90]). Our results show that achieving higher rotavirus vaccination coverage among infants could benefit the entire population by reducing overall hospitalizations for gastroenteritis for all age groups.

The success of publicly funded rotavirus vaccine programs for preventing community- and hospital-acquired rotavirus infections in Canadian pediatric hospitals: an observational study

BACKGROUND

Canadian immunization programs for rotavirus started in 2011. We sought to determine their effect on the burden of community-acquired admissions and hospital-acquired rotavirus at pediatric hospitals.

METHODS

The Canadian Immunization Monitoring Program Active (IMPACT) network conducted active surveillance for rotavirus-positive hospital admissions between 2005 and 2020 at 12 pediatric hospitals. We used yearly rates of community-acquired rotavirus per 10 000 admissions and hospital-acquired rotavirus infections per 1000 patient-days to determine changes in the pre- and post-vaccine program periods.

RESULTS

During the 15-year study period, 5691 rotavirus hospital admissions and hospital-acquired infections were detected, including 4323 (76%) community-acquired infections and 1368 (24%) hospital-acquired infections. The average community-acquired rate in the pre-vaccine period was 60.3 (95% confidence interval [CI] 53.7-68.3) per 10 000 admissions, with a decline to 11.0 (95% CI 7.5-15.1) per 10 000 admissions in the post-vaccine period, resulting in an average reduction of 81.7% (95% CI 74.4%-87.8%). The rate of hospital-acquired rotavirus declined from 0.35 (95% CI 0.29-0.41) per 1000 patient-days in the pre-vaccine period to 0.05 (95% CI 0.03-0.07) per 1000 patient-days in the post-vaccine period, resulting in an 85.3% (95% CI 77.7%-91.9%) average decline. Herd protection was present among children aged 2-16 years.

INTERPRETATION

Although start dates of rotavirus vaccine programs across provinces varied, there was around an 80% average decrease in both community-acquired and hospital-acquired rotavirus infections at pediatric hospitals in Canada in the 1- to 9-year interval after implementation of rotavirus vaccine programs. Herd protection is an important aspect of rotavirus vaccines for other children who are not vaccine eligible, and rotavirus vaccines continue to provide important benefits both for children and health care systems.

Economic assessment of childhood rotavirus vaccination in Bangladesh

Rotavirus is one of the most highly prevalent communicable diseases in Bangladesh. The objective of this study is to evaluate the benefit-cost ratio of childhood rotavirus vaccination program in Bangladesh. A spreadsheet-based model was used to estimate the benefit and cost of a nationwide universal rotavirus vaccination program against rotavirus infections among under-five children in Bangladesh. A benefit-cost analysis was performed to evaluate a universal vaccination program compared with a status quo. Data from various published vaccination-related studies and public reports were used. The introduction of a childhood rotavirus vaccination program in Bangladesh for 14.78 million under-five children is projected to prevent approximately 1.54 million rotavirus cases during the first 2 years including 0.7 million severe rotavirus infections. This study shows that among the WHO-prequalified rotavirus vaccines, the net societal benefit is the highest if the vaccination program adopts ROTAVAC® rather than Rotarix® or ROTASIIL®. For every dollar invested in the outreach-based ROTAVAC® vaccination program, society would gain $2.03 in return, while in a facility-based vaccination program, society would gain up to about $2.2. The findings of this study demonstrate that a universal childhood rotavirus vaccination program is a cost-beneficial investment of public money. Thus, the government should consider the introduction of rotavirus vaccination in their Expanded Program on Immunization since the rotavirus immunization policy in Bangladesh will be economically justifiable.

Model-based estimation of the impact on rotavirus disease of RV3-BB vaccine administered in a neonatal or infant schedule

Rotavirus infection is a common cause of severe diarrheal disease and a major cause of deaths and hospitalizations among young children. Incidence of rotavirus has declined globally with increasing vaccine coverage. However, it remains a significant cause of morbidity and mortality in low-income countries where vaccine access is limited and efficacy is lower. The oral human neonatal vaccine RV3-BB can be safely administered earlier than other vaccines, and recent trials in Indonesia have demonstrated high efficacy. In this study, we use a stochastic individual-based model of rotavirus transmission and disease to estimate the anticipated population-level impact of RV3-BB following delivery according to either an infant (2, 4, 6 months) and neonatal (0, 2, 4 months) schedule. Using our model, which incorporated an age- and household-structured population and estimates of vaccine efficacy derived from trial data, we found both delivery schedules to be effective at reducing infection and disease. We estimated 95-96% reductions in infection and disease in children under 12 months of age when vaccine coverage is 85%. We also estimate high levels of indirect protection from vaccination, including 78% reductions in infection in adults over 17 years of age. Even for lower vaccine coverage of 55%, we estimate reductions of 84% in infection and disease in children under 12 months of age. While open questions remain about the drivers of observed lower efficacy in low-income settings, our model suggests RV3-BB could be effective at reducing infection and preventing disease in young infants at the population level.

Detection and Molecular Characterization of Rotavirus Infections in Children and Adults with Gastroenteritis from Vojvodina, Serbia

Rotaviruses (RV) are the leading cause of gastroenteritis in infants, young children, and adults, responsible for serious disease burden. In the period 2012-2018, a cross-sectional study was conducted using stool samples collected from patients with acute gastroenteritis from Vojvodina, Serbia. We described age and gender distribution, as well as seasonal patterns of RV prevalence. Out of 1853 included stool samples, RV was detected in 29%. Hospitalized children between 1-2 years old were especially affected by RV infection (45%). The highest prevalence of infection was observed during the colder, winter/spring months. We compared sequenced representative G and P genotypes circulating in Serbia with vaccine strains and determined their genetic similarity. Genotype combination G2P[4] was the most prevalent (34.6%), followed by G2P[8] (24.1%) and G1P[8] (21.1%). Given that several epitopes were conserved, neutralization motifs among circulating strains can be characterized as sufficiently matching vaccine strains Rotarix™ and RotaTeq™, but existing antigenic disparities should not be overlooked. The present results contribute to a better insight into the prevalence of rotavirus infection in our region and point out the need for epidemiological surveillance of rotaviruses before the introduction of vaccines. These data can help formulate future vaccine strategies in Serbia.

The Impact of Childhood and Parental Vaccination on SARS-CoV-2 Infection Rates in Children

BACKGROUND

The data on the indirect protection of children via the coronavirus disease 2019 (COVID-19) vaccination of household members are insufficient, and analyses to evaluate the efficacy of COVID-19 vaccines are limited.

METHODS

We gathered data on 12,442 patients under the age of 18 regarding the vaccination status of their household members, their vaccine preferences and doses, and their previous history of COVID-19 infection immediately before the patients were administered a real-time reverse transcriptase-polymerase chain reaction (RT-PCR) test for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) between September 1, 2021 and December 5, 2021.

RESULTS

A total of 18.4% (2289) were vaccinated, 91.4% with BNT162b2mRNA vaccine, 8.6% with inactivated COVID-19 vaccine; 48.7% received a single dose, and 51.3% had 2 doses. Real-time RT-PCR positivity proportions were much higher in older children ( P < 0.001) and were higher in children 12 years of age and older [odds ratio (OR), 1.34; 95% confidence interval (CI): 1.21-1.47] compared with others. SARS-CoV-2 infection was significantly lower in the vaccinated group (fully and incompletely) ( P < 0.001). Unvaccinated (OR, 4.88; 95% CI: 3.77-6.13) and incompletely vaccinated children (OR, 1.83; 95% CI: 1.52-2.12) had a higher risk of COVID-19 infection compared with fully vaccinated patients No significant association was found between the COVID-19 real-time RT-PCR positivity rates of patients and the vaccination status or vaccine preferences of household members ( P > 0.05 each).

CONCLUSIONS

SARS-CoV-2 infection rates were significantly lower in vaccinated children, especially with mRNA vaccines. The indirect protection of unvaccinated children via the vaccination of household members against COVID-19 seems inadequate. The individual vaccination of children remains crucial.

Association Between Rotavirus Vaccination and Antibiotic Prescribing Among Commercially Insured US Children, 2007-2018

Background

Vaccines may play a role in controlling the spread of antibiotic resistance. However, it is unknown if rotavirus vaccination affects antibiotic use in the United States (US).

Methods

Using data from the IBM MarketScan Commercial Database, we conducted a retrospective cohort of US children born between 2007 and 2018 who were continuously enrolled for the first 8 months of life (N = 2 136 136). We followed children through 5 years of age and compared children who completed a full rotavirus vaccination series by 8 months of age to children who had not received any doses of rotavirus vaccination. We evaluated antibiotic prescriptions associated with an acute gastroenteritis (AGE) diagnosis and defined the switching of antibiotics as the prescription of a second, different antibiotic within 28 days. Using a stratified Kaplan-Meier approach, we estimated the cumulative incidence for each study group, adjusted for receipt of pneumococcal conjugate vaccine, provider type, and urban/rural status.

Results

Overall, 0.8% (n = 17 318) of participants received an antibiotic prescription following an AGE diagnosis. The 5-year adjusted relative cumulative incidence of antibiotic prescription following an AGE diagnosis was 0.793 (95% confidence interval [CI], .761–.827) among children with complete rotavirus vaccination compared to children without rotavirus vaccination. Additionally, children with complete vaccination were less likely to switch antibiotics (0.808 [95% CI, .743–.887]). Rotavirus vaccination has averted an estimated 67 045 (95% CI, 53 729–80 664) antibiotic prescriptions nationally among children born between 2007 and 2018.

Conclusions

These results demonstrate that rotavirus vaccines reduce antibiotic prescribing for AGE, which could help reduce the growth of antibiotic resistance.

The burden of rotavirus-associated acute gastroenteritis in the elderly: assessment of the epidemiology in the context of universal childhood vaccination programs

INTRODUCTION

Rotaviruses (RVs) cause acute gastroenteritis (AGE) in infants and young children worldwide and also in older adults (≥60 years), however the burden among this age group is not well understood. Herd immunity through pediatric RV vaccination may reduce the burden of RVGE across all ages, however the impact of pediatric vaccination on burden in older adults is poorly understood.

AREAS COVERED

This systematic review was undertaken to identify studies related to the following objectives: understand the burden of RV in older adults, RV seroprevalence, and the impact of pediatric vaccination on this burden and highlight evidence gaps to guide future research. Of studies identified, 59 studies from two databases were included in this analysis following a review by two reviewers.

EXPERT OPINION

RV is an understudied disease in older adults. We found that 0-62% of patients with AGE tested positive for RV, with results varying by setting, country, and patient age. Results also suggest that pediatric vaccination benefits older adults through herd protection. Several studies showed a reduction in RV incidence after vaccination. However, there was variety in results and lack of consistency in outcomes reported. Further studies targeting older adults are needed to better characterize RV burden.

Sustained declines in age group-specific rotavirus infection and acute gastroenteritis in vaccinated and unvaccinated individuals during the five years since Rotavirus vaccine introduction in England

BACKGROUND

The introduction of an oral live-attenuated monovalent rotavirus vaccine (Rotarix ®) into the UK infant immunisation programme in July 2013 was associated with large reductions in laboratory-confirmed rotavirus infections and hospitalisations due to acute gastroenteritis (AGE) within 12 months. Here we report the five-year impact of the programme in England.

METHODS

Individuals with laboratory-confirmed rotavirus infections during 2000-2018 and all-cause hospitalisations for AGE during 2007-2018 were identified using national electronic records. Age-specific incidence rate ratios (IRR) and estimated numbers of cases averted in each of the five post-vaccination years were calculated.

RESULTS

There were 206,389 laboratory-confirmed rotavirus infections and 3,657,651 hospitalisations for all-cause AGE. Reductions of 69-83% in laboratory-confirmed rotavirus infections in all age groups and 77-88% in infants aged <1 year in each of the five post-vaccine years are reported, with 11,386-11,633 cases averted annually. All-cause AGE hospitalisations were reduced by 12-35% across all age-groups and by 25-48% in <1 year-olds in the five post-vaccine years, with 24,474-49,278 hospitalisations averted annually. There was strong evidence of indirect (herd) protection, with at least 50% and up to 80% of the non-specific end point of all-cause gastroenteritis (AGE) hospitalisations averted being in unvaccinated age-groups, primarily older adults. Seasonal changes include a possible shift from annual to biennial peaks with lower peak incidence and longer seasons.

CONCLUSIONS

There were large and sustained declines in both laboratory-confirmed rotavirus infections and AGE hospitalisations across all age groups in each of the five years since the introduction of the UK rotavirus programme.

Indirect impact of rotavirus vaccination on viral causes of acute gastroenteritis in the elderly

BACKGROUND

Rotavirus is considered a childhood infection causing acute gastroenteritis however, it also causes disease in adults which may be underestimated due to less frequent testing in this age-group.

OBJECTIVES

To determine if paediatric rotavirus vaccination, introduced into Ireland in December 2016, affected the viral aetiology in those aged ≥65 yrs presenting with gastroenteritis in the pre- and post-vaccination years. Additionally, rotavirus genotypes in this age-group will be described.

METHODS

Faecal samples from 2015 to 2019 for the investigation of gastroenteritis were tested by real-time (RT-) PCR for norovirus, adenovirus, rotavirus, Rotarix, astrovirus and sapovirus. Rotaviruses were genotyped by multiplex real-time RT-PCR or hemi-nested RT-PCR and a proportion confirmed by sequencing.

RESULTS

22,593 samples from adults aged ≥65 yrs were tested and 2566 (11 %) had ≥1 virus detected. Of 2566 positive samples, norovirus was detected in 82 %, rotavirus 9 %, sapovirus 6 %, astrovirus 3 % and adenovirus 1 %. Rotavirus and norovirus infections decreased between pre and post-vaccine year groups p < 0.001, whereas sapovirus, astrovirus and adenovirus remained unchanged. Between 2015-16 and 2018-19, G2P[4] increased and G4P[8] decreased, p < 0.001. In 2015-2019 there were 37 rotavirus outbreaks. Five geriatric outbreaks were genotyped and caused by G4P[8] (n = 1), G1P[8] (n = 1), G2P[4] (n = 2) and G12P[8] (n = 1).

CONCLUSION

Rotavirus causes acute gastroenteritis in older people. Paediatric vaccination may have contributed to a decline in infections in the elderly; nevertheless, rotavirus continued to circulate in older people following vaccine introduction. Genotype distribution changed between the pre- and post-vaccine era however genotypes in outbreak and endemic settings were comparable.

Associations between private vaccine and antimicrobial consumption across Indian states, 2009-2017

Vaccines can reduce antibiotic use and, consequently, antimicrobial resistance by averting vaccine-preventable and secondary infections. We estimated the associations between private vaccine and antibiotic consumption across Indian states during 2009-2017 using monthly and annual consumption data from IQVIA and employed fixed-effects regression and the Arellano-Bond Generalized Method of Moments (GMM) model for panel data regression, which controlled for income and public sector vaccine use indicators obtained from other sources. In the annual data fixed-effects model, a 1% increase in private vaccine consumption per 1000 under-5 children was associated with a 0.22% increase in antibiotic consumption per 1000 people (P < 0.001). In the annual data GMM model, a 1% increase in private vaccine consumption per 1000 under-5 children was associated with a 0.2% increase in private antibiotic consumption (P < 0.001). In the monthly data GMM model, private vaccine consumption was negatively associated with antibiotic consumption when 32, 34, 35, and 44-47 months had elapsed after vaccine consumption, with a positive association with lags of fewer than 18 months. These results indicate vaccine-induced longer-term reductions in antibiotic use in India, similar to findings of studies from other low- and middle-income countries.

The Importance of Advancing Severe Acute Respiratory Syndrome Coronavirus 2 Vaccines in Children

While the role of children in the chain of transmission of SARS-CoV-2 remains to be fully defined, they likely play an important role based on our knowledge of other respiratory viruses. Children are more likely to be asymptomatic or have milder symptoms and less likely to present for healthcare and be tested for SARS-CoV-2; thus, our current estimates are likely under-representative of the true burden of SARS-CoV-2 in children. Given the potential direct benefit of a SARS-CoV-2 vaccine in children and the substantial indirect benefit through community protection or ‘herd immunity’, we argue that planning and implementation of SARS-CoV-2 vaccines should include children. Furthermore, community protection occurred after widespread implementation of prior childhood vaccines against Streptococcus pneumoniae, rubella and rotavirus. We detail considerations for vaccine clinical trials, potential barriers to the implementation of widespread vaccination and argue why children would be an ideal target population for vaccination.

Impact of rotavirus vaccine on admissions due to acute gastroenteritis and rotavirus gastroenteritis in Israel

AIM

We examined the impact of insertion of the Rotavirus vaccine (RVV) into the Israeli National Immunisation Programme (NIP) on hospitalisations due to both acute gastroenteritis (AGE) and Rotavirus gastroenteritis (RVGE) in children.

METHODS

We retrospectively analysed the medical records of children aged <5 years admitted with a diagnosis of AGE between 2008 and 2016 in two children's hospitals in central Israel. Clinical, laboratory, microbiological data and RV immunisation status were retrieved. Data were compared before and after the introduction of the RVV into the NIP.

RESULTS

A total of 2042 children were admitted with AGE. Hospitalisations due to AGE and RVGE decreased from 3310 to 1950 and from 1027 to 585 per 100 000 admissions, respectively, after the RVV (relative risk reduction (RRR) of 41% and 43%, respectively). RV remained the most common pathogen in both study periods. There was no significant difference in the clinical course between immunised and non-immunised children admitted with RVGE.

CONCLUSION

The introduction of the RVV to the NIP significantly reduced the admissions due to both AGE and RVGE in children <5 years. However, RV is still the most common agent for admissions due to AGE in this age group.

Impact of Rotavirus Vaccines on Gastroenteritis Hospitalizations in Western Australia: A Time-series Analysis

Background

Rotavirus vaccination was introduced into the Australian National Immunisation Program in mid-2007. We aimed to assess the impact of the rotavirus vaccination program on the burden of hospitalizations associated with all-cause acute gastroenteritis (including rotavirus gastroenteritis and non-rotavirus gastroenteritis) in the Aboriginal and non-Aboriginal population in Western Australia.

Methods

We identified all hospital records, between July 2004 and June 2012, with a discharge diagnosis code for all-cause gastroenteritis. Age-specific hospitalization rates for rotavirus and non-rotavirus acute gastroenteritis before and after the introduction of the rotavirus vaccination program were compared. Interrupted time-series models were used to examine differences in the annual trends of all-cause gastroenteritis hospitalization between the two periods.

Results

Between July 2004 and June 2012, there were a total of 106,974 all-cause gastroenteritis-coded hospitalizations (1,381 rotavirus-coded [15% among Aboriginal] and 105,593 non-rotavirus gastroenteritis-coded [7% among Aboriginal]). Following rotavirus vaccination introduction, significant reductions in rotavirus-coded hospitalization rates were observed in all children aged <5 years (up to 79% among non-Aboriginal and up to 66% among Aboriginal). Among adults aged ≥65 years, rotavirus-coded hospitalizations were 89% (95% confidence interval, 16–187%) higher in the rotavirus vaccination program period. The time-series analysis suggested reductions in all-cause gastroenteritis hospitalizations in the post-vaccination period among both vaccinated and unvaccinated (age-ineligible) children, with increases observed in adults aged ≥45 years.

Conclusions

Rotavirus vaccination has been associated with a significant decline in gastroenteritis hospitalizations among children. The increase in the elderly requires further evaluation, including assessment of the cost-benefits of rotavirus vaccination in this population.

Global Impact of Rotavirus Vaccination on Diarrhea Hospitalizations and Deaths Among Children <5 Years Old: 2006-2019

BACKGROUND

Since 2006, more than 100 countries have introduced rotavirus vaccine into their immunization programs. We reviewed published data on relative reductions of rotavirus hospitalizations, acute gastroenteritis (AGE) hospitalizations, and AGE deaths among children <5 years old.

METHODS

Articles published from January 1, 2006 to December 31, 2019 with at least 12 months of data before and after rotavirus vaccine introduction were included. Relative reductions were abstracted into a standardized form. Descriptive statistics are presented as medians and interquartile ranges (IQRs).

RESULTS

We reviewed 1827 total records and included 105 articles from 49 countries. Among children <5 years old, there was a median reduction of 59% (IQR, 46-74) in rotavirus hospitalizations, 36% (IQR, 23-47) in AGE hospitalizations, and 36% (IQR, 28-46) AGE mortality. Reductions were larger in countries with low child mortality, among younger age groups, and in countries with higher coverage. The median percentage of specimens that tested positive for rotavirus among children <5 years old hospitalized for diarrhea was 40% (IQR, 28-45) before rotavirus vaccine introduction and 20% (IQR, 20-20) 4 years after introduction.

CONCLUSIONS

Overall, we found sustained impact on rotavirus and AGE hospitalizations and deaths. These results should encourage countries still considering rotavirus vaccine implementation.

Rotavirus disease and genotype diversity in older children and adults in Australia

Background

Rotavirus is a major cause of gastroenteritis in children <5 years of age. The disease burden in older children, adults, and the elderly is underappreciated. This study describes rotavirus disease and genotypic diversity in the Australian population comprising children ≥5 years of age and adults.

Methods

Rotavirus positive fecal samples were collected from laboratories Australia-wide participating in the Australian Rotavirus Surveillance Program between 2010 and 2018. Rotavirus samples were genotyped using a heminested multiplex reverse-transcription polymerase chain reaction. Notification data from the National Notifiable Diseases Surveillance System were also analyzed.

Results

Rotavirus disease was highest in children aged 5–9 years and adults ≥85 years. G2P[4] was the dominant genotype in the population ≥5 years of age. Genotype distribution fluctuated annually and genotypic diversity varied among different age groups. Geographical differences in genotype distribution were observed based on the rotavirus vaccine administered to infants <1 year of age.

Conclusions

This study revealed a substantial burden of rotavirus disease in the population ≥5 years of age, particularly in children 5–9 years and the elderly. This study highlights the continued need for rotavirus surveillance across the population, despite the implementation of efficacious vaccines.

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.

High prevalence of DS-1-like rotavirus infection in Thai adults between 2016 and 2019

Rotavirus infection is the most common cause of viral diarrhea in infants and young children but uncommon and usually asymptomatic in adults. In the winter of 2017-2018, a large-scale outbreak of rotavirus in both children and adults was reported in Thailand. The current study focused on the prevalence, genotyping, and molecular characterization of rotavirus infections in Thai adults from July 2016 to December 2019. In 2,598 stool samples collected from adult residents of Bangkok (aged #x2265; 15 years) with acute gastroenteritis, rotavirus was detected via real-time RT-PCR analysis of the VP6 gene. G, P and I genotypes were determined by direct sequencing of VP7, VP4, and VP6 genes, respectively. Our results showed 8.7% (226/2,598) of stool samples were positive for rotavirus. The incidence of rotavirus was high during the winter season of 2017-2018 (17.7%) compared to another studied periods (4.5% between July 2016- October 2017 and 2.8% between March 2018- December 2019). Nucleotide sequencing of VP7 and VP4 revealed G3P[8] as the predominant strain (33.2%,75/226), followed by G9P[8] (17.3%,39/226), and G2P[4] (15.0%,34/226). Uncommon G and P combinations were additionally detected at low frequencies. VP6 sequencing was conducted to discriminate I genotype between the Wa and DS-1 genogroup. The unusual DS-1-like G3P[8] strain was most prevalent amomg rotavirus strains detected in this study (29.6%, 67/226), and the corresponding VP7 sequences showed high nucleotide identity with unusual DS-1-like globally circulating strains. Our study demonstrates that rotavirus outbreaks in adults are attributable not only to high prevalence of RV infection but also the unusual DS-like genogroup. The collective findings reinforce the importance of investigating rotavirus diagnosis in adults suffering from acute gastroenteritis and taking appropriate preventive measures.

Longer-term Direct and Indirect Effects of Infant Rotavirus Vaccination Across All Ages in the United States in 2000-2013: Analysis of a Large Hospital Discharge Data Set

BACKGROUND

Rotavirus disease rates dramatically declined among children <5 years of age since the rotavirus vaccine was introduced in 2006; population-level impacts remain to be fully elucidated.

METHODS

Data from the Healthcare Cost and Utilization Project State Inpatient Databases were used to conduct a time-series analysis of monthly hospital discharges across age groups for acute gastroenteritis and rotavirus from 2000 to 2013. Rate ratios were calculated comparing prevaccine and postvaccine eras.

RESULTS

Following vaccine introduction, a decrease in rotavirus hospitalizations occurred with a shift toward biennial patterns across all ages. The 0-4-year age group experienced the largest decrease in rotavirus hospitalizations (rate ratio, 0.14; 95% confidence interval, .09-.23). The 5-19-year and 20-59-year age groups experienced significant declines in rotavirus hospitalization rates overall; the even postvaccine calendar years were characterized by progressively lower rates, and the odd postvaccine years were associated with reductions in rates that diminished over time. Those aged ≥60 years experienced the smallest change in rotavirus hospitalization rates overall, with significant reductions in even postvaccine years compared with prevaccine years (rate ratio, 0.51; 95% confidence interval, .39-.66).

CONCLUSIONS

Indirect impacts of infant rotavirus vaccination are apparent in the emergence of biennial patterns in rotavirus hospitalizations that extend to all age groups ineligible for vaccination. These observations are consistent with the notion that young children are of primary importance in disease transmission and that the initial postvaccine period of dramatic population-wide impacts will be followed by more complex incidence patterns across the age range in the long term.

Evidence for Household Transmission of Rotavirus in the United States, 2011-2016

BACKGROUND

Rotavirus is a leading cause of acute gastroenteritis (AGE) in children and is highly transmissible. In this study, we assessed the presence of AGE in household contacts (HHCs) of pediatric patients with laboratory-confirmed rotavirus.

METHODS

Between December 2011 and June 2016, children aged 14 days to 11 years with AGE were enrolled at 1 of 7 hospitals or emergency departments as part of the New Vaccine Surveillance Network. Parental interviews, medical and vaccination records, and stool specimens were collected at enrollment. Stool was tested for rotavirus by an enzyme immunoassay and confirmed by real-time or conventional reverse transcription-polymerase chain reaction assay or repeated enzyme immunoassay. Follow-up telephone interviews were conducted to assess AGE in HHCs the week after the enrolled child's illness. A mixed-effects multivariate model was used to calculate odds ratios.

RESULTS

Overall, 829 rotavirus-positive subjects and 8858 rotavirus-negative subjects were enrolled. Households of rotavirus-positive subjects were more likely to report AGE illness in ≥1 HHC than were rotavirus-negative households (35% vs 20%, respectively; P < .0001). A total of 466 (16%) HHCs of rotavirus-positive subjects reported AGE illness. Of the 466 ill HHCs, 107 (23%) sought healthcare; 6 (6%) of these encounters resulted in hospitalization. HHCs who were <5 years old (odds ratio, 2.2 [P = .004]) were more likely to report AGE illness than those in other age groups. In addition, 144 households reported out-of-pocket expenses (median, $20; range, $2-$640) necessary to care for an ill HHC.

CONCLUSIONS

Rotavirus-associated AGE in children can lead to significant disease burden in HHCs, especially in children aged <5 years. Prevention of pediatric rotavirus illness, notably through vaccination, can prevent additional illnesses in HHCs.

Protecting the Community Through Child Vaccination

The direct impact of vaccines on children is well described, but the major public health impact of indirect protection provided to the community by vaccines is underappreciated. Community protection occurs when vaccinated persons block the chain of transmission, protecting undervaccinated or unvaccinated susceptible community members by preventing exposure and limiting the spread of the pathogen through the community. Substantial declines in disease incidence have occurred shortly after implementing new childhood vaccines, including declines among vaccine-ineligible children, adolescents, and adults. Protection of susceptible community members depends on maintaining high vaccination rates. Improved recognition of community protection will strengthen childhood vaccination strategies that will protect our communities into the future.

Effect of Concomitant Antibiotic and Vaccine Administration on Serologic Responses to Rotavirus Vaccine

Data from 1174 infants enrolled in a previous rotavirus vaccine study were analyzed to determine the effect of antibiotic exposure (from 14 days before to 7 days after vaccination) on rotavirus serum immunoglobulin A (IgA) responses. Serum IgA responses 1 month after the completion of vaccination were similar among antibiotic-exposed and nonexposed infants.

Identification of Conserved Candidate Vaccine Antigens in the Surface Proteome of Giardia lamblia

Giardia lamblia, one of the most common protozoal infections of the human intestine, is an important worldwide cause of diarrheal disease, malabsorption, malnutrition, delayed cognitive development in children, and protracted postinfectious syndromes. Despite its medical importance, no human vaccine is available against giardiasis. A crude veterinary vaccine has been developed, and experimental vaccines based on expression of multiple variant-specific surface proteins have been reported, but poorly defined vaccine components and excessive antigen variability are problematic for pharmaceutical vaccine production. To expand the repertoire of antigen candidates for vaccines, we reasoned that surface proteins may provide an enriched source of such antigens since key host effectors, such as secretory IgA, can directly bind to such antigens in the intestinal lumen and interfere with epithelial attachment. Here, we have applied a proteomics approach to identify 23 novel surface antigens of G. lamblia that show >90% amino acid sequence identity between the two human-pathogenic genetic assemblages (A and B) of the parasite. Surface localization of a representative subset of these proteins was confirmed by immunostaining. Four selected proteins, uridine phosphorylase-like protein-1, protein 21.1 (GL50803_27925), α1-giardin, and α11-giardin, were subsequently produced in recombinant form and shown to be immunogenic in mice and G. lamblia-infected humans and confer protection against G. lamblia infection upon intranasal immunization in rodent models of giardiasis. These results demonstrate that identification of conserved surface antigens provides a powerful approach for overcoming a key rate-limiting step in the design and construction of an effective vaccine against giardiasis.

Experiences with rotavirus vaccines: can we improve rotavirus vaccine impact in developing countries?

Rotavirus vaccines have been introduced into over 95 countries globally and demonstrate substantial impact in reducing diarrheal mortality and diarrheal hospitalizations in young children. The vaccines are also considered by WHO as "very cost effective" interventions for young children, particularly in countries with high diarrheal disease burden. Yet the full potential impact of rotavirus immunization is yet to be realized. Large countries with big birth cohorts and where disease burden is high in Africa and Asia have not yet implemented rotavirus vaccines at all or at scale. Significant advances have been made demonstrating the impact of the vaccines in low- and lower-middle income countries, yet the modest effectiveness of the vaccines in these settings is challenging. Current research highlights these challenges and considers alternative strategies to overcome them, including alternative immunization schedules and host factors that may inform us of new opportunities.

Inactivation Mechanisms of Human and Animal Rotaviruses by Solar UVA and Visible Light

Two rotavirus (RV) strains (sialidase-resistant Wa and sialidase-sensitive OSU) were irradiated with simulated solar UVA and visible light in sensitizer-free phosphate buffered solution (PBS) (lacking exogenous reactive oxygen species (ROS)) or secondary effluent wastewater (producing ROS). Although light attenuated for up to 15% through the secondary effluent wastewater (SEW), the inactivation efficacies increased by 0.7 log₁₀ for Wa and 2 log₁₀ for OSU compared to those in sensitizer-free phosphate buffered solution (PBS) after 4 h of irradiation. A binding assay using magnetic beads coated with porcine gastric mucin containing receptors for rotaviruses (PGM-MB) was developed to determine if inactivation influenced RV binding to its receptors. The linear correlation between the reduction in infectivity and the reduction in binding after irradiation in sensitizer-free solution suggests that the main mechanism of RV inactivation in the absence of exogenous ROS was due to damage to VP8*, the RV protein that binds to host cell receptors. For a given reduction in infectivity, greater damage in VP8* was observed with sialidase-resistant Wa compared to sialidase-sensitive OSU. The lack of correlation between the reduction in infectivity and the reduction in binding, in SEW, led us to include RNase treatment before the binding step to quantify virions with intact protein capsids and exclude virions that can bind to the receptors but have their capsid permeable after irradiation. This assay showed a linear correlation between the reduction in RV infectivity and RV-receptor interactions, suggesting that RV inactivation in SEW was due to compromised capsid proteins other than the VP8* protein. Thus, rotavirus inactivation by UVA and visible light irradiation depends on both the formation of ROS and the stability of viral proteins.

Molecular characterisation and clinical correlates of rotavirus in children and adults in a tertiary care centre, Chennai, South India

AIMS

This study was undertaken to determine the rate of detection of rotavirus causing diarrhoea among children and adults, identify the common genotypes circulating and determine clinical correlates.

SETTINGS AND DESIGN

This is a cross-sectional study in a tertiary care centre.

MATERIALS AND METHODS

Stool samples were collected from adults and children, transported on ice, aliquoted and stored at - 80°C. Rotavirus antigen detection enzyme-linked immunosorbent assay was performed on all samples. Representative samples were typed by conventional hemi-nested VP7 and VP4 reverse transcription-polymerase chain reaction.

STATISTICAL ANALYSIS USED

Test of proportion, Student's t-test and Chi-square test were used for statistical analysis.

RESULTS

A total of 444 stool samples were collected and tested over 14 months. Among these, 116 were paediatric with a rate of positivity of 36.21% and 328 were adults with rate of positivity of 20.73%. Among children under 5 years (n = 90), the rate of positivity was 41.11%. Vesikari scale was used for clinical assessment. The mean ± standard deviation Vesikari score in rotavirus-infected children and rotavirus-uninfected children was 11.2 ± 3.2 and 8.9 ± 3.6, respectively, and the difference was statistically significant. Nineteen samples were genotyped in children < 5 years, 94.7% were of G1P[8] and 5.3% were of G9P[4] genotype. Genotyping of 14 adult samples, G1P[8](85.7%) was found as the predominant genotype, two samples (14.3%) were partially typed (G9PUT and G12PUT).

CONCLUSIONS

The rate of positivity of rotavirus in children under 5 years was 41.11%. G1P[8] is the most common strain circulating across all age groups.

Rotavirus vaccines: why continued investment in research is necessary

PURPOSE OF REVIEW

Rotavirus vaccines were first introduced more than a decade ago and have had a tremendous impact on reducing the number of hospitalizations and deaths due to rotavirus-associated diarrhea. This review will discuss current rotavirus vaccines, post-licensure surveillance, progress in non-replicating vaccine development, and why continued research is important for understanding a virus that remains a globally leading cause of death due to diarrhea.

RECENT FINDINGS

Research advances have enhanced our understanding of how vaccines induce protection against subsequent severe disease, how the virus replicates and spreads in the face of the host immune system, and basic mechanisms governing the viral life cycle.

SUMMARY

Much remains to be learned about how to improve vaccine success, what are the molecular determinants of host range and virulence, and what are the interactions of the virus with the host that drive its replicative success, among many other important questions.

Enhancing the Thermostability and Immunogenicity of a Respiratory Syncytial Virus (RSV) Live-Attenuated Vaccine by Incorporating Unique RSV Line19F Protein Residues

Respiratory syncytial virus (RSV) is the leading cause of lower respiratory tract infections in infants, and an effective vaccine is not yet available. We previously generated an RSV live-attenuated vaccine (LAV) candidate, DB1, which was attenuated by a low-fusion subgroup B F protein (BAF) and codon-deoptimized nonstructural protein genes. DB1 was immunogenic and protective in cotton rats but lacked thermostability and stability of the prefusion conformation of F compared to strains with the line19F gene. We hypothesized that substitution of unique residues from the thermostable A2-line19F strain could thermostabilize DB1 and boost its immunogenicity. We therefore substituted 4 unique line19F residues into the BAF protein of DB1 by site-directed mutagenesis and rescued the recombinant virus, DB1-QUAD. Compared to DB1, DB1-QUAD had improved thermostability at 4°C and higher levels of prefusion F as measured by enzyme-linked immunosorbent assays (ELISAs). DB1-QUAD was attenuated in normal human bronchial epithelial cells, in BALB/c mice, and in cotton rats but grew to wild-type titers in Vero cells. In mice, DB1-QUAD was highly immunogenic and generated significantly higher neutralizing antibody titers to a panel of RSV A and B strains than did DB1. DB1-QUAD was also efficacious against wild-type RSV challenge in mice and cotton rats. Thus, substitution of unique line19F residues into RSV LAV DB1 enhanced vaccine thermostability, incorporation of prefusion F, and immunogenicity and generated a promising vaccine candidate that merits further investigation.IMPORTANCE We boosted the thermostability and immunogenicity of an RSV live-attenuated vaccine candidate by substituting 4 unique residues from the RSV line19F protein into the F protein of the heterologous vaccine strain DB1. The resultant vaccine candidate, DB1-QUAD, was thermostable, attenuated in vivo, highly immunogenic, and protective against RSV challenge in mice and cotton rats.

Rotavirus vaccine impact and socioeconomic deprivation: an interrupted time-series analysis of gastrointestinal disease outcomes across primary and secondary care in the UK

BACKGROUND

Rotavirus causes severe gastroenteritis in infants and young children worldwide. The UK introduced the monovalent rotavirus vaccine (Rotarix®) in July 2013. Vaccination is free of charge to parents, with two doses delivered at 8 and 12 weeks of age. We evaluated vaccine impact across a health system in relation to socioeconomic deprivation.

METHODS

We used interrupted time-series analyses to assess changes in monthly health-care attendances in Merseyside, UK, for all ages, from July 2013 to June 2016, compared to predicted counterfactual attendances without vaccination spanning 3-11 years pre-vaccine. Outcome measures included laboratory-confirmed rotavirus gastroenteritis (RVGE) hospitalisations, acute gastroenteritis (AGE) hospitalisations, emergency department (ED) attendances for gastrointestinal conditions and consultations for infectious gastroenteritis at community walk-in centres (WIC) and general practices (GP). All analyses were stratified by age. Hospitalisations were additionally stratified by vaccine uptake and small-area-level socioeconomic deprivation.

RESULTS

The uptake of the first and second doses of rotavirus vaccine was 91.4% (29,108/31,836) and 86.7% (27,594/31,836), respectively. Among children aged < 5 years, the incidence of gastrointestinal disease decreased across all outcomes post-vaccine introduction: 80% (95% confidence interval [CI] 70-87%; p < 0.001) for RVGE hospitalisation, 44% (95% CI 35-53%; p < 0.001) for AGE hospitalisations, 23% (95% CI 11-33%; p < 0.001) for ED, 32% (95% CI 7-50%; p = 0.02) for WIC and 13% (95% CI -3-26%; p = 0.10) for GP. The impact was greatest during the rotavirus season and for vaccine-eligible age groups. In adults aged 65+ years, AGE hospitalisations fell by 25% (95% CI 19-30%; p < 0.001). The pre-vaccine risk of AGE hospitalisation was highest in the most socioeconomically deprived communities (adjusted incident rate ratio 1.57; 95% CI 1.51-1.64; p < 0.001), as was the risk for non-vaccination (adjusted risk ratio 1.54; 95% CI 1.34-1.75; p < 0.001). The rate of AGE hospitalisations averted per 1,000 first doses of vaccine was higher among infants in the most deprived communities compared to the least deprived in 2014/15 (28; 95% CI 25-31 vs. 15; 95% CI 12-17) and in 2015/16 (26; 95% CI 23-30 vs. 13; 95% CI 11-16).

CONCLUSIONS

Following the introduction of rotavirus vaccination, incidence of gastrointestinal disease reduced across the health-care system. Vaccine impact was greatest among the most deprived populations, despite lower vaccine uptake. Prioritising vaccine uptake in socioeconomically deprived communities should give the greatest health benefit in terms of population disease burden.

Cost-effectiveness analysis of introducing universal childhood rotavirus vaccination in Bangladesh

Diarrhea is one of the world's leading killers of children, and globally, rotavirus is the most common cause of severe diarrhea among under 5 children. In Bangladesh, rotavirus kills nearly 6,000 under 5 children in each year. To reduce the burden of childhood rotavirus diseases, universal rotavirus vaccination is recommended by World Health Organization. The objective of this study is to assess the cost-effectiveness of introducing universal childhood rotavirus vaccination with the newly developed ROTAVAC vaccine in national Expanded Programme of Immunization in Bangladesh. We developed a decision model to examine the potential impact of vaccination in Bangladesh and to examine the effect if the vaccination is applied in the nationwide immunization program schedule. Introduction of childhood universal rotavirus vaccination in Bangladesh scenario appears as highly cost-effective and would offer substantial future benefits for the young population if vaccinated today. The cost per DALY averted of introducing the rotavirus vaccine compared with status quo is approximately US$ 740.27 and US$ 728.67 per DALY averted from the health system and societal perspective respectively which is "very cost-effective" using GDP threshold level according to World Health Organization definition. The results of this analysis seek to contribute to an evidence-based recommendation about the introduction of universal rotavirus vaccination in national Expanded Programme of Immunization (EPI) in Bangladesh.

2017 Infectious Diseases Society of America Clinical Practice Guidelines for the Diagnosis and Management of Infectious Diarrhea

These guidelines are intended for use by healthcare professionals who care for children and adults with suspected or confirmed infectious diarrhea. They are not intended to replace physician judgement regarding specific patients or clinical or public health situations. This document does not provide detailed recommendations on infection prevention and control aspects related to infectious diarrhea.

Italian Physicians' Opinions on Rotavirus Vaccine Implementation

Rotavirus (RV) infection is the main cause of severe acute gastroenteritis (GE) in the pediatric population and has a major impact in both developing and industrialized countries. The reduction of severe RVGE cases, followed by death or hospitalization, is considered the main benefit of RV vaccination, even though its implementation often faces obstacles. In Italy, the recently approved National Immunization Plan aims to overcome the differences among regions, offering a universal free RV vaccination. The aim of the study was to evaluate the opinions on benefit and acceptability of RV vaccination related to the perception of the burden of RV disease. Data were collected from 108 physicians in 2015 by a questionnaire consisting of 12 questions; some answers were compared with those obtained with a similar tool in 2011. The majority of respondents (76.2%) was convinced of the benefit of the vaccine and 57.4% recommended it routinely, but more than half indicated a <25% adherence to RV vaccination among their patients. As the main reasons of vaccine refusal, skepticism about the vaccine (60.4%) and its cost (34.1%) were indicated. Our data confirm that more information and counselling are needed to increase RV vaccine coverage.

Resurgence of Rotavirus Genotype G12 in St. Louis During the 2014-2015 Rotavirus Season

BACKGROUND

Rotaviruses are a leading cause of gastroenteritis. Rotavirus vaccination has dramatically reduced rotavirus occurrence; however, we have noticed mild to moderate recurrences in the St. Louis area in alternate years. In 2013, we found rotavirus genotype G12 to be the dominant strain in the St. Louis region. In this study, we again determined the distribution of genotypes and ascertained vaccine history in patients infected with rotavirus G12 during the 2014-15 season.

METHODS

Samples submitted to the St. Louis Children's Hospital Microbiology Laboratory were tested for rotavirus using an antigen assay. We determined the VP7 genotype using amplicon sequence analysis. We determined genome sequences using high-throughput sequencing. We evaluated rotavirus immunization records when available.

RESULTS

Of 30 typed viruses from 2014-15, 29 were G12 (97%). Whole-genome sequencing revealed few changes from G12 viruses analyzed in 2012-13. VP4 and VP7 sequences were >99% identical to previously sequenced G12 strains from St. Louis, and immune epitopes were conserved. Vaccination histories were available from 17 patients. Of these, 4 had been vaccinated, 3 had received incomplete vaccination or had a vaccine history that could not be confirmed, and 10 had not been vaccinated.

CONCLUSIONS

G12 re-emerged as the predominant rotavirus genotype in 2014-15, comprising a higher percentage of cases than in 2012-13. The majority of patients with G12 and available vaccination histories were unvaccinated. There was no genomic evidence to indicate that the G12 strains in St. Louis had evolved to escape vaccine protection. Our work emphasizes the need for continued surveillance.

Time Trends and Predictors of Acute Gastroenteritis in the United States: Results From National Health and Nutrition Examination Survey 2005-2014

GOALS

To investigate the time trends of the prevalence and predictors of acute gastroenteritis (AGE) in the United States from 2005 to 2014 using nationally representative data.

BACKGROUND

AGE results in numerous visits to emergency departments and outpatient clinics annually in the United States with the estimated attributable cost to the US economy up to $145 billion dollars. However, time trends and predictors of AGE are not fully understood.

METHODS

Data were obtained from the National Health and Nutrition Survey (NHANES) 2005 to 2014, a nationally representative health survey. AGE was defined by a medical question (Do you have a stomach or intestinal illness with vomiting or diarrhea that started during last 30 d?). Prevalence of AGE was estimated in the total population as well as by selected demographic variables. Predictors of AGE and time trends of prevalence over survey periods were also investigated.

RESULTS

Overall monthly prevalence of AGE was 8.31% (95% confidence interval, 7.81-8.81), corresponding to 22.8 million people. AGE was associated with a younger age group, the highest in ages 0 to 9 years old, females, winter to early spring season, US born, divorced/separated/widowed individuals, current smokers, heavy alcohol users, and low household income. In the trends analyses, the prevalence of AGE significantly decreased over the study periods: 10.23% in 2005 to 2006, 9.89% in 2007 to 2008, 7.58% in 2009 to 2010, 6.44% in 2011 to 2012, and 7.47% in 2013 to 2014 (trend P<0.001).

CONCLUSION

In the United States from 2005 to 2014, the monthly prevalence of AGE was 8.31% and has been significantly decreasing over time.

Rotavirus genotypes as etiological agents of diarrhoea in general populations of two geographic regions of Brazil

Rotavirus is the main global cause of severe childhood diarrhoea among children. In 2006, Rotarix^® (G1P[8]) was introduced into Brazil’s National Immunization Program. The vaccine coverage rate was 84.4% in 2009. Evidences of increasing G2P[4] after 2006 opened up the discussion about the vaccine effectiveness to non-G1 strains. The aim of this study was to identify the circulating rotavirus genotypes in two Brazilian regions during 2009. A total of 223 positive samples by immunochromatography and latex agglutination assay from the Northeast (Bahia/Pernambuco States) and Southeast (São Paulo/Rio de Janeiro States) regions were included in the study. The samples were submitted to genotyping by nested-PCR according to VP7(G) and VP4(P) and 175 samples (78.5%) were able to be characterized. Considering the characterization of VP7, the G-types detected were G1, G2, and G4 in the Northeast, and G2, G3, G5, and G9 in the Southeast. Considering the characterization of VP4, the P-types detected were P[4], P[8], and P[6]/P[9] in the Northeast and the Southeast. The most frequent mixed types found were G2P[4]/G2P[NT](81.4%), G2P[6](5.2%), G1P[6](5.2%) in the Northeast, and G2P[4]/G2P[NT](78.8%), G2P[6](8.2%), G9P[8](4.7%) in the Southeast. Among immunized individuals whose age ranged from 0-4 years, the G2P[4]/G2P[NT] genotype was identified in 91,0% of cases, and among non-immunized individuals of the same age, the G2P[4]/G2P[NT] genotype was identified in 85.7% of the cases. In accordance with the high level of vaccine coverage, the data suggest that the circulation of G2P[4] in these regions had a considerable increase after the introduction of Rotarix^®.

Risk of intussusception following rotavirus vaccination: An evidence based meta-analysis of cohort and case-control studies

BACKGROUND

International post-licensure studies on rotavirus vaccines have identified an increased risk of intussusception in infants after administration. The first developed rotavirus vaccine (Rotashield (RRV-TV)) was suspended post-licensure in 1999 after an association with intussusception was found. The currently available second-generation rotavirus vaccines (Rotateq (RV5) and Rotarix (RV1)), are recommended as a routine vaccine by the World Health Organisation (WHO). Post-licensure studies of these vaccines have shown a smaller but temporal increased risk for developing intussusception.

METHODS

A meta-analysis was performed to summarise available evidence and to give an overall risk of developing intussusception from case-control and cohort studies for all rotavirus vaccines that have been manufactured up to date. A search was conducted on MEDLINE, PubMed, EMBASE and Google Scholar up to May 2017. Eligible studies assessed the relationship between the rotavirus vaccine administration and subsequent development of intussusception both after receiving the first dose and after receiving all doses combined. Data was extracted on study characteristics, methods and outcomes. Results were pooled using the random-effect model.

RESULTS

Six cohort studies involving 4506265 total first doses and five case-control studies involving a total sample of 9643 children were included in this analysis. The cohort data revealed that there was an associated increased risk of intussusception after the first 7days post first dose of the vaccine (RR:3.71, 95% CI:1.08-12.69) and after receiving all doses of the rotavirus vaccine (RR:3.47, 95% CI:1.23-9.78). Similarly, the case-control data found an increased risk of intussusception following the first dose (OR: 8.45, 95% CI: 4.08-17.50) and following all doses (OR: 1.59, 95% CI: 1.11-2.27).

CONCLUSIONS

Findings of this meta-analysis suggest that the rotavirus vaccine is associated with an increased risk on the development of intussusception, principally seen after administration of the first dose of vaccine.

Changes in the numbers of patients with acute gastroenteritis after voluntary introduction of the rotavirus vaccine in a Japanese children's primary emergency medical center

Background

Acute gastroenteritis (AGE) is a major reason for presentation to pediatric primary emergency medical centers. Because rotavirus vaccines were introduced in November 2011 for voluntary vaccination in Japan, we analyzed the changes in the numbers of AGE patients.

Methods

The number and proportion of patients visiting Kobe children’s primary emergency medical center from January 2011 to February 2015 due to AGE, out of all visiting children, were investigated retrospectively. The rotavirus and norovirus epidemic periods were defined as the periods from March to June and from November to February, respectively, based on their disease prevalence.

Results

In patients ≤2 years of age, the numbers and proportions of patients with AGE were significantly decreased from 2464/14098 (17%) in 2011 to 1888/12321 (15%) in 2014 (p < 0.01). In patients ≤2 and 3–5 years of age, significant decreases in AGE patients between 2011 and 2014 were observed during the rotavirus season (from 20% [1090/5329] to 14% [642/4482] in patients aged ≤2 years and from 23% [704/3047] to 20% [572/2807] in patients aged 3–5 years, p < 0.01 and p < 0.05, respectively), but not during the norovirus season (from 19% [834/4436] to 19% [797/4160] in patients aged ≤2 years and from 20% [679/3334] to 25% [710/2852] in patients aged 3–5 years).

Conclusions

The estimated rotavirus vaccine coverage in our area increased from 1% in 2011 to 49% in 2014; this coverage may have resulted in a reduction in AGE patients, both directly and indirectly, in our Japanese children’s primary emergency medical center.

Rotavirus epidemiology 5-6 years after universal rotavirus vaccination: persistent rotavirus activity in older children and elderly

BACKGROUND

Rotavirus (RV) vaccination using RotaTeq^® vaccine exclusively was introduced into Finnish National Immunization Program (NIP) in 2009, and soon reached high (≥90%) coverage. Since mid-2013, all stool samples from laboratory diagnosed cases of RV gastroenteritis in the entire country have been typed.

METHODS

364 RV positive stool samples collected from clinical laboratories over a 2-year period were G- and P-typed using RT-PCR, and the results were confirmed by sequencing. In addition, the genome segment encoding for VP6 was sequenced to distinguish between wild-type and vaccine origin (bovine) RVs.

RESULTS

RV winter epidemic seasons 2013-2014 and 2014-2015 lasted until July each. The age distribution of RV cases showed two unusual clusters: one in children 6-16 years of age, too old to have been vaccinated in NIP, and the other in elderly over 70 years of age. In children, diverse genotypes were observed without any obvious predominance. The most common ones were G1P[8] (30.0%), G2P[4] (22.4%), G9P[8] (15.8%), G3P[8] (12.2%) and G4P[8] (11.2%). The genotype distribution was not different among vaccinated and unvaccinated children. Most cases in the elderly were associated with G2P[4].

CONCLUSIONS

Even at high vaccine coverage and high effectiveness of RV vaccine, RV activity continues to persist, particularly in unvaccinated older children. RV genotypes show greater diversity than before RV vaccinations. We conclude that RV disease can be controlled but not eliminated by vaccinations. Herd-protection in long-term follow-up may be less than at the start of RV vaccinations.

ROTAVIRUS GENOTYPES CIRCULATING IN BRAZIL, 2007-2012: IMPLICATIONS FOR THE VACCINE PROGRAM

Regarding public health in Brazil, a new scenario emerged with the establishment of universal rotavirus (RV) vaccination programs. Herein, the data from the five years of surveillance (2007-2012) of G- and P-type RV strains isolated from individuals with acute gastroenteritis in Brazil are reported. A total of 6,196 fecal specimens were investigated by ELISA and RT-PCR. RVs were detected in 19.1% (1,181/6,196). The peak of RV incidence moved from June-August to September. RV was detected less frequently (19.5%) among children ≤ 5 years than in older children and adolescents (6-18 years) (40.6%). Genotype distribution showed a different profile for each year: G2P[4] strains were most prevalent during 2007-2010, G9P[8] in 2011, and G12P[8] in 2012. Mixed infections (G1+G2P[4], G2+G3P[4]+P[8], G2+G12P[8]), unusual combinations (G1P[4], G2P[6]), and rare strains (G3P[3]) were also identified throughout the study period. Widespread vaccination may alter the RV seasonal pattern. The finding of RV disease affecting older children and adolescents after vaccine implementation has been reported worldwide. G2P[4] emergence most likely follows a global trend seemingly unrelated to vaccination, and G12, apparently, is emerging in the Brazilian population. The rapidly changing RV genotype patterns detected during this study illustrate a dynamic population of co-circulating wildtype RVs in Brazil.

Population-Level Impact of Ontario's Infant Rotavirus Immunization Program: Evidence of Direct and Indirect Effects

OBJECTIVE

To evaluate the direct and indirect population impact of rotavirus (RV) immunization on hospitalizations and emergency department (ED) visits for acute gastroenteritis (AGE) in Ontario before and after the publicly-funded RV immunization program.

METHODS

Administrative data was used to identify ED visits and hospitalizations for all Ontarians using ICD-10 codes. We used two outcome definitions: RV-specific AGE (RV-AGE) and codes representing RV-, other viral and cause unspecified AGE ("overall AGE"). The pre-program and public program periods were August 1, 2005 to July 31, 2011; and August 1, 2011 to March 31, 2013, respectively. A negative binominal regression model that included the effect of time was used to calculate rates and rate ratios (RRs) and 95% confidence intervals (CIs) for RV-AGE and overall AGE between periods, after adjusting for age, seasonality and secular trends. Analyses were conducted for all ages combined and age stratified.

RESULTS

Relative to the pre-program period, the adjusted RRs for RV-AGE and overall AGE hospitalizations in the public program period were 0.29 (95%CI: 0.22-0.39) and 0.68 (95%CI: 0.62-0.75), respectively. Significant reductions in RV-AGE hospitalizations were noted overall and for the following age bands: < 12 months, 12-23 months, 24-35 months, 3-4 years, and 5-19 years. Significant declines in overall AGE hospitalizations were observed across all age bands, including older adults > = 65 years (RR 0.80, 95%CI: 0.72-0.90). The program was associated with adjusted RRs of 0.32 (95% CI: 0.20-0.52) for RV-AGE ED visits and 0.90 (95% CI: 0.85-0.96) for overall AGE ED visits.

CONCLUSIONS

This large, population-based study provides evidence of the impact of RV vaccine in preventing hospitalizations and ED visits for RV-AGE and overall AGE, including herd effects.

Burden of Rotavirus Disease in Norway: Using National Registries for Public Health Research

BACKGROUND

Norway introduced routine rotavirus immunization for all children born on or after September 1, 2014. We estimated the healthcare burden of all-cause gastroenteritis and rotavirus disease in children <5 years old to establish the prevaccine baseline and support the ongoing immunization program.

METHODS

We examined national registry data on gastroenteritis-associated primary care consultations and hospitalizations for 2009-2013 and data on all deaths in children <5 years old reported during 2000-2013. We also established rotavirus hospital surveillance from February 2014 through January 2015.

RESULTS

Before vaccine introduction, 114.5 cases per 1000 children <5 years old were treated in primary care and 11.8 children per 1000 were hospitalized with gastroenteritis annually. During hospital surveillance, rotavirus was detected in 65% (95% confidence interval: 60-70) of inpatient gastroenteritis cases. We estimated that 4.0 inpatient and 2.3 outpatient cases per 1000 children were seen in hospital with rotavirus disease annually, suggesting that 1 in 32 children was hospitalized by age 5. Additional 30.6 rotavirus cases per 1000 children consulted primary care annually or 1 in every 7 children by the age of 5 years. Rotavirus-associated mortality was estimated at 0.17 deaths per 100,000 children <5 years old, corresponding to 1 death every second year.

CONCLUSIONS

Rotavirus remains the primary cause of severe gastroenteritis in children in Norway. The unique population-based registers, in combination with an established rotavirus surveillance platform, provide a well-suited setting to evaluate the impact of rotavirus vaccination.

Clinical and Microbiologic Assessment of Cases of Pediatric Community-associated Clostridium difficile Infection Reveals Opportunities for Improved Testing Decisions

BACKGROUND

Most children with Clostridium difficile infection (CDI) experience community onset of CDI symptoms.

METHODS

We retrospectively compared hospital-onset healthcare facility-associated CDI cases to community-associated (CA) CDI cases diagnosed by Cepheid Xpert tcdB polymerase chain reaction (PCR) at an academic children's hospital over a 1-year period. Saved stools from CDI cases additionally underwent anaerobic stool culture and multiplex gastrointestinal pathogen PCR testing.

RESULTS

Compared with 25 hospital-onset healthcare facility-associated CDI cases, the 74 CA-CDI cases were more frequently <2 years old (18% vs. 0%, P = 0.034) and less frequently had antibiotic exposure in the past 30 days (26% vs. 88%, P < 0.0001), proton pump inhibitor exposure (16% vs. 36%, P = 0.036) or a gastrostomy tube (11% vs. 32%, P = 0.013). Among children diagnosed with CA-CDI, 19 (26%) had no identified CDI risk factors (immunocompromised; gastrostomy tube; recent antibiotic, proton pump inhibitor or inpatient/outpatient healthcare exposures). Clinical testing for viral pathogens was uncommon among children thought to have CA-CDI. Multiplex PCR testing of saved stool samples failed to identify C. difficile among 23% of cases diagnosed with CA-CDI by the Cepheid Xpert tcdB PCR assay. CDI antibiotic therapy was provided to nearly all patients testing positive by tcdB PCR irrespective of CDI risk factors.

CONCLUSIONS

Many children diagnosed with CA-CDI by PCR lack CDI risk factors and have discordant results when additional CDI testing methods are performed, suggesting overdiagnosis of CDI in children with community-onset diarrhea. More selective CDI testing of low-risk pediatric patients is needed to more accurately diagnose CDI and limit unnecessary CDI antibiotic treatment in children.