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

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.

Genotype Diversity of Enteric Viruses in Wastewater Amid the COVID-19 Pandemic

Viruses remain the leading cause of acute gastroenteritis (AGE) worldwide. Recently, we reported the abundance of AGE viruses in raw sewage water (SW) during the COVID-19 pandemic, when viral AGE patients decreased dramatically in clinics. Since clinical samples were not reflecting the actual state, it remained important to determine the circulating strains in the SW for preparedness against impending outbreaks. Raw SW was collected from a sewage treatment plant in Japan from August 2018 to March 2022, concentrated by polyethylene-glycol-precipitation method, and investigated for major gastroenteritis viruses by RT-PCR. Genotypes and evolutionary relationships were evaluated through sequence-based analyses. Major AGE viruses like rotavirus A (RVA), norovirus (NoV) GI and GII, and astrovirus (AstV) increased sharply (10-20%) in SW during the COVID-19 pandemic, though some AGE viruses like sapovirus (SV), adenovirus (AdV), and enterovirus (EV) decreased slightly (3-10%). The prevalence remained top in the winter. Importantly, several strains, including G1 and G3 of RVA, GI.1 and GII.2 of NoV, GI.1 of SV, MLB1 of AstV, and F41 of AdV, either emerged or increased amid the pandemic, suggesting that the normal phenomenon of genotype changing remained active over this time. This study crucially presents the molecular characteristics of circulating AGE viruses, explaining the importance of SW investigation during the pandemic when a clinical investigation may not produce the complete scenario.

Clinical profile of children under 5 years of age with rotavirus diarrhoea in a hospital setting in Kisangani, DRC, after the introduction of the rotavirus vaccine, a cross-sectional study

BACKGROUND

The Democratic Republic of the Congo (DRC) is one of the countries with the highest rotavirus mortality rate in the world. The aim of this study was to describe the clinical features of rotavirus infection after the introduction of rotavirus vaccination of children in the city of Kisangani, DRC.

METHODS

We conducted a cross-sectional study of acute diarrhoea in children under 5 years of age admitted to 4 hospitals in Kisangani, DRC. Rotavirus was detected in children's stools by an immuno-chromatographic antigenic rapid diagnostic test.

RESULTS

A total of 165 children under 5 years of age were included in the study. We obtained 59 cases of rotavirus infection, or 36% CI95 [27, 45]. The majority of children with rotavirus infection were unvaccinated (36 cases) and had watery diarrhoea (47 cases), of high frequency per day/per admission 9.6 ± 3.4 and accompanied by severe dehydration (30 cases). A statistically significant difference in mean Vesikari score was observed between unvaccinated and vaccinated children (12.7 vs 10.7 p-value 0.024).

CONCLUSION

Rotavirus infection in hospitalized children under 5 years of age is characterized by a severe clinical manifestation. Epidemiological surveillance is needed to identify risk factors associated with the infection.

Understanding Variation in Rotavirus Vaccine Effectiveness Estimates in the United States: The Role of Rotavirus Activity and Diagnostic Misclassification

BACKGROUND

Estimates of rotavirus vaccine effectiveness (VE) in the United States appear higher in years with more rotavirus activity. We hypothesized rotavirus VE is constant over time but appears to vary as a function of temporal variation in local rotavirus cases and/or misclassified diagnoses.

METHODS

We analyzed 6 years of data from eight US surveillance sites on 8- to 59-month olds with acute gastroenteritis symptoms. Children's stool samples were tested via enzyme immunoassay (EIA); rotavirus-positive results were confirmed with molecular testing at the US Centers for Disease Control and Prevention. We defined rotavirus gastroenteritis cases by either positive on-site EIA results alone or positive EIA with Centers for Disease Control and Prevention confirmation. For each case definition, we estimated VE against any rotavirus gastroenteritis, moderate-to-severe disease, and hospitalization using two mixed-effect regression models: the first including year plus a year-vaccination interaction, and the second including the annual percent of rotavirus-positive tests plus a percent positive-vaccination interaction. We used multiple overimputation to bias-adjust for misclassification of cases defined by positive EIA alone.

RESULTS

Estimates of annual rotavirus VE against all outcomes fluctuated temporally, particularly when we defined cases by on-site EIA alone and used a year-vaccination interaction. Use of confirmatory testing to define cases reduced, but did not eliminate, fluctuations. Temporal fluctuations in VE estimates further attenuated when we used a percent positive-vaccination interaction. Fluctuations persisted until bias-adjustment for diagnostic misclassification.

CONCLUSIONS

Both controlling for time-varying rotavirus activity and bias-adjusting for diagnostic misclassification are critical for estimating the most valid annual rotavirus VE.

Clinical endpoints to inform vaccine policy: A systematic review of outcome measures from pediatric influenza vaccine efficacy trials

INTRODUCTION

We conducted a systematic review of pediatric influenza vaccine efficacy trials to assess clinical outcome measures and whether the trials defined important public health endpoints.

MATERIAL AND METHODS

We systematically identified phase 3 or 4 influenza vaccine randomized controlled trials among children ≤18 years of age with laboratory-confirmed influenza outcomes since 1980. We recorded countries, age groups, vaccine formulations, specimen collection criteria, laboratory diagnostics, primary and secondary outcome measures, and funders, and we determined income category for study countries. We used descriptive statistics to summarize study characteristics. We analyzed the studies overall and a subset of studies conducted in at least one low- and middle-income country (LMIC).

RESULTS

From 6455 potentially relevant articles, we identified 41 eligible studies. Twenty-one studies (51%) were conducted in at least one LMIC, while the remaining studies (49%) were conducted in high-income countries only. Thirty-one studies (76%) included children younger than six years. We found 40 different primary outcome measures among the 41 eligible studies. Thirty-three studies (80%) reported standardized symptoms or findings which defined a primary outcome or triggered specimen collection. One study defined a primary outcome which captured more severe illness; however, cases were mostly due to high body temperature without other severity criteria. Of the 21 studies from at least one LMIC, 15 (71%) were published since 2010 and 17 (81%) enrolled children younger than six years. Eighteen (86%) studies from at least one LMIC reported standardized symptoms or findings which defined a primary outcome or triggered specimen collection.

CONCLUSIONS

Among pediatric influenza vaccine efficacy trials, primary outcome measures and clinical specimen collection criteria were highly variable and, with one exception, focused on capturing any influenza illness. As most LMICs do not have influenza vaccination programs, our study highlights a potential data limitation affecting policy and implementation decisions in these settings.

Persistence of Maternal Anti-Rotavirus Immunoglobulin G in the Post-Rotavirus Vaccine Era

To assess whether titers of anti-rotavirus immunoglobulin G persist during the post-rotavirus vaccine era, the Pediatric Respiratory and Enteric Virus Acquisition and Immunogenesis Longitudinal (PREVAIL) Cohort analyzed serum samples collected from Cincinnati-area mothers and young infants in 2017-2018. Rotavirus-specific antibodies continue to be transferred from US mothers to their offspring in the post-rotavirus vaccine era, despite dramatic decreases in childhood rotavirus gastroenteritis.

Estimating the Effectiveness of Rotavirus Vaccine Schedules

BACKGROUND

Important questions exist regarding the comparative effectiveness of alternative childhood vaccine schedules; however, optimal approaches to studying this complex issue are unclear.

METHODS

We applied methods for studying dynamic treatment regimens to estimate the comparative effectiveness of different rotavirus vaccine (RV) schedules for preventing acute gastroenteritis-related emergency department (ED) visits or hospitalization. We studied the effectiveness of six separate protocols: one- and two-dose monovalent rotavirus vaccine (RV1); one-, two-, and three-dose pentavalent rotavirus vaccine (RV5); and no RV vaccine. We used data on all infants to estimate the counterfactual cumulative risk for each protocol. Infants were censored when vaccine receipt deviated from the protocol. Inverse probability of censoring-weighted estimation addressed potentially informative censoring by protocol deviations. A nonparametric group-based bootstrap procedure provided statistical inference.

RESULTS

The method yielded similar 2-year effectiveness estimates for the full-series protocols; weighted risk difference estimates comparing unvaccinated children to those adherent to either full-series (two-dose RV1, three-dose RV5) corresponded to four fewer hospitalizations and 12 fewer ED visits over the 2-year period per 1,000 children. We observed dose-response relationships, such that additional doses further reduced risk of acute gastroenteritis. Under a theoretical intervention to fully vaccinate all children, the 2-year risk differences comparing full to observed adherence were 0.04% (95% CI = 0.03%, 0.05%) for hospitalizations and 0.17% (95% CI = 0.14%, 0.19%) for ED visits.

CONCLUSIONS

The proposed approach can generate important evidence about the consequences of delaying or skipping vaccine doses, and the impact of interventions to improve vaccine schedule adherence.

TIPICO X: report of the 10th interactive infectious disease workshop on infectious diseases and vaccines

TIPICO is an expert meeting and workshop that aims to provide the most recent evidence in the field of infectious diseases and vaccination. The 10th Interactive Infectious Disease TIPICO workshop took place in Santiago de Compostela, Spain, on November 21-22, 2019. Cutting-edge advances in vaccination against respiratory syncytial virus, Streptococcus pneumoniae, rotavirus, human papillomavirus, Neisseria meningitidis, influenza virus, and Salmonella Typhi were discussed. Furthermore, heterologous vaccine effects were updated, including the use of Bacillus Calmette-Guérin (BCG) vaccine as potential treatment for type 1 diabetes. Finally, the workshop also included presentations and discussion on emergent virus and zoonoses, vaccine resilience, building and sustaining confidence in vaccination, approaches to vaccine decision-making, pros and cons of compulsory vaccination, the latest advances in decoding infectious diseases by RNA gene signatures, and the application of big data approaches.

Real-world effectiveness of rotavirus vaccines, 2006-19: a literature review and meta-analysis

BACKGROUND

Since licensure in 2006, rotavirus vaccines have been introduced in more than 100 countries. The efficacy of rotavirus vaccines is variable in settings with different child mortality levels. We did an updated review of the published literature to assess the real-world effectiveness of rotavirus vaccines in a range of settings.

METHODS

In this literature review and meta-analysis, we included observational, post-licensure studies of rotavirus vaccines, published from Jan 1, 2006, to Dec 31, 2019, in English, with laboratory-confirmed rotavirus as the endpoint. In addition to product-specific results for Rotarix (GlaxoSmithKline Biologicals, Rixensart, Belgium) or RotaTeq (Merck, West Point, PA, USA), we included Rotarix and RotaTeq mixed series, and non-product-specific vaccine effectiveness estimates from countries where Rotarix and RotaTeq are both available. Studies of other infant rotavirus vaccines were excluded because little or no post-licensure data were available. We fitted random-effects regression models to estimate vaccine effectiveness among children younger than 12 months and aged 12-23 months. On the basis of 2017 UNICEF mortality estimates for children younger than 5 years, countries were stratified as having low (lowest quartile), medium (second quartile), or high mortality (third and fourth quartiles).

FINDINGS

We identified and screened 1703 articles, of which 60 studies from 32 countries were included. 31 studies were from countries with low child mortality, eight were from medium-mortality countries, and 21 were from high-mortality countries. Rotarix vaccine effectiveness against laboratory-confirmed rotavirus among children younger than 12 months old was 86% (95% CI 81-90) in low-mortality countries, 77% (66-85) in medium-mortality countries, and 63% (54-70) in high-mortality countries. Rotarix vaccine effectiveness among children aged 12-23 months was 86% (81-90) in low-mortality countries, 54% (23-73) in medium-mortality countries, and 58% (38-72) in high-mortality countries. RotaTeq vaccine effectiveness among children younger than 12 months was 86% (76-92) in low-mortality countries and 66% (51-76) in high-mortality countries. RotaTeq vaccine effectiveness among children aged 12-23 months was 84% (79-89) in low-mortality countries. There was no substantial heterogeneity (I² range: 0-36%). Median vaccine effectiveness in low-mortality countries was similar for Rotarix (83%; IQR 78-91), RotaTeq (85%; 81-92), mixed series (86%; 70-91), and non-product-specific (89%; 75-91) vaccination.

INTERPRETATION

Rotavirus vaccines were effective in preventing rotavirus diarrhoea, with higher performance in countries with lower child mortality.

FUNDING

None.

Rotavirus vaccination in the neonatal intensive care units: where are we? A rapid review of recent evidence

PURPOSE OF REVIEW

Rotavirus is a leading cause of viral acute gastroenteritis in infants. Neonates hospitalized in neonatal intensive care units (NICUs) are at risk of rotavirus infections with severe outcomes. The administration of rotavirus vaccines is only recommended, in the United States and Canada, upon discharge from the NICU despite rotavirus vaccines being proven well tolerated and effective in these populations, because of risks of live-attenuated vaccine administration in immunocompromised patients and theoretical risks of rotavirus vaccine strains shedding and transmission.We aimed to summarize recent evidence regarding rotavirus vaccine administration in the NICU setting and safety of rotavirus vaccines in preterm infants.

METHODS

We conducted a rapid review of the literature from the past 10 years, searching Medline and Embase, including all study types except reviews, reporting on rotavirus vaccines 1 and 5; NICU setting; shedding or transmission; safety in preterm. One reviewer performed data extraction and quality assessment.

RECENT FINDINGS

Thirty-one articles were analyzed. Vaccine-derived virus shedding following rotavirus vaccines existed for nearly all infants, mostly during the first week after dose 1, but with rare transmission only described in the household setting. No case of transmission in the NICU was reported. Adverse events were mild to moderate, occurring in 10-60% of vaccinated infants. Extreme premature infants or those with underlying gastrointestinal failure requiring surgery presented with more severe adverse events.

SUMMARY

Recommendations regarding rotavirus vaccine administration in the NICU should be reassessed in light of the relative safety and absence of transmission of rotavirus vaccine strains in the NICU.