Rotavirus vaccines in Belgium: policy and impact

Assessment of the Impact of the Rotavirus Vaccine Against Severe Rotaviral Diarrhea in Uzbekistan

BACKGROUND

This article presents the results of a long-term study of the impact of rotavirus vaccination in Uzbekistan. Uzbekistan is the first country in the Central Asian region to introduce rotavirus vaccination into the national compulsory vaccination calendar. The study aimed to evaluate the impact of rotavirus vaccination on hospitalizations due to all-cause AGE and RVGE in children < 5 years of age in Uzbekistan.

METHODS

Detection of rotavirus antigen was performed using Rotavirus-Antigen-IFA-BEST "Vector Best" kit (Novosibirsk, Russia).

RESULTS

The total of 20,128 children under 5 years of age were hospitalized in sentinel hospitals with a diagnosis of acute gastroenteritis during the study period (2019-2020). Of this number of children, 4481 children (22.2%) were included in the study. Of 4481 children, 367 (8.2%) children tested positive for rotavirus. In our study, decrease in the rotavirus rate was noted in all age groups. The peak of rotavirus positivity occurred in the months of January and February.

CONCLUSION

The average rotavirus-positive rate in the period (2019-2020) was 8.2% and the absolute percentage decrease was 18.1% compared to the pre-vaccination period (2005-2009) where the rotavirus-positive rate was 26.3%. The percentage of prevented cases averaged 68.8%.

The Economic Value of Rotavirus Vaccination When Optimally Implemented in a High-Income Country

Rotavirus vaccination was introduced in high-income countries starting in 2006, with no recommendation for optimal implementation. Economic evaluations were presented before launch projecting potential impacts. Few economic reassessments have been reported following reimbursement. This study compares the short- to long-term economic value of rotavirus vaccination between pre-launch predictions and real-world evidence collected over 15 years, proposing recommendations for optimal vaccine launch. A cost-impact analysis compared rotavirus hospitalisation data after the introduction of vaccination between pre-launch modelled projections and observed data collected in the RotaBIS study in Belgium. A best model fit of the observed data was used to simulate launch scenarios to identify the optimal strategy. Data from other countries in Europe were used to confirm the potential optimal launch assessment. The Belgian analysis in the short term (first 8 years) indicated a more favourable impact for the observed data than predicted pre-launch model results. The long-term assessment (15 years) showed bigger economic disparities in favour of the model-predicted scenario. A simulated optimal vaccine launch, initiating the vaccination at least 6 months prior the next seasonal disease peak with an immediate very high vaccine coverage, indicated important additional potential gains, which would make vaccination very cost impactful. Finland and the UK are on such a route leading to long-term vaccination success, whereas Spain and Belgium have difficulties in achieving optimum vaccine benefits. An optimal launch of rotavirus vaccination may generate substantial economic gains over time. For high-income countries that are considering implementing rotavirus vaccination, achieving an optimal launch is a critical factor for long-term economic success.

Rotavirus vaccine-derived cases in Belgium: Evidence for reversion of attenuating mutations and alternative causes of gastroenteritis

Since the introduction of live-attenuated rotavirus vaccines in Belgium in 2006, surveillance has routinely detected rotavirus vaccine-derived strains. However, their genomic landscape and potential role in gastroenteritis have not been thoroughly investigated. We compared VP7 and VP4 nucleotide sequences obtained from rotavirus surveillance with the Rotarix vaccine sequence. As a result, we identified 80 vaccine-derived strains in 5125 rotavirus-positive infants with gastroenteritis from 2007 to 2018. Using both viral metagenomics and reverse transcription qPCR, we evaluated the vaccine strains and screened for co-infecting enteropathogens. Among the 45 patients with known vaccination status, 39 were vaccinated and 87% received the vaccine less than a month before the gastroenteritis episode. Reconstruction of 30 near complete vaccine-derived genomes revealed 0-11 mutations per genome, with 88% of them being non-synonymous. This, in combination with several shared amino acid changes among strains, pointed at selection of minor variant(s) present in the vaccine. We also found that some of these substitutions were true revertants (e.g., F167L on VP4, and I45T on NSP4). Finally, co-infections with known (e.g., Clostridioides difficile and norovirus) and divergent or emerging (e.g., human parechovirus A1, salivirus A2) pathogens were detected, and we estimated that 35% of the infants likely had gastroenteritis due to a 'non-rotavirus' cause. Conversely, we could not rule out the vaccine-derived gastroenteritis in over half of the cases. Continued studies inspecting reversion to pathogenicity should monitor the long-time safety of live-attenuated rotavirus vaccines. All in all, the complementary approach with NGS and qPCR provided a better understanding of rotavirus vaccine strain evolution in the Belgian population and epidemiology of co-infecting enteropathogens in suspected rotavirus vaccine-derived gastroenteritis cases.

Real-world impact of rotavirus vaccination in European healthcare settings: a systematic literature review

INTRODUCTION

Rotavirus is one of the most common pathogens causing diarrhea in children <5 years and has a major impact on childhood morbidity and mortality. Since the implementation of rotavirus vaccines into childhood immunization programs across Europe, there has been a reduction in rotavirus burden, including hospitalizations, outpatient cases, costs, and deaths.

AREAS COVERED

A systematic literature review identified publications describing the clinical and economic impact of rotavirus vaccinations across Europe, from their introduction in 2006 to the end of 2020. A total of 3,137 articles were identified, of which 46 were included in the review. Included articles reported the impact of rotavirus vaccination on disease in any age group.

EXPERT OPINION

Rotavirus vaccination has resulted in substantial reductions in hospitalizations and rotavirus-associated costs across Europe, particularly in children <5 years. There is some evidence of herd protection afforded to older age groups where vaccine uptake is high among infants, highlighting the potential for vaccination to confer a greater societal benefit as programs become more established. Increasing vaccination coverage and continuing investment in widespread rotavirus vaccination programs across countries will likely increase the substantial public health benefits associated with vaccination and further reduce the clinical and economic burden of disease.

Regional hospitalisation and seasonal variations of Pediatric rotavirus gastroenteritis pre- and post-RV vaccination: a prospective and retrospective study

BACKGROUND

Rotavirus is the primary cause of gastroenteritis in children worldwide and is a leading cause of gastroenteritis in children, with a significant burden. Rotavirus vaccine became available in Ireland in 2016. This study aimed to investigate hospital admissions and seasonal characteristics of rotavirus gastroenteritis in a pre- and post-vaccination period in a single district general hospital.

METHODS

In the post-vaccination year, from November 18th 2016 to November 18th 2017, all children up to 3 years of age who presented to Mayo University Hospital with vomiting and diarrhea, were recruited and had their stool tested for rotavirus. Retrospective analysis of hospital data of children of the same age during pre-vaccination years (2014-2016) were used for comparison.

RESULTS

Compared with the pre-vaccination years (2014-2016), the median percentages of reduction of rotavirus positive stool requests and hospital admissions were high, 48.5% and 73%, respectively. In the post-vaccination year, the median percentage of reduction of emergency department presentation (stool requests) with gastroenteritis was 9%. No delay in the onset of RV season or reduction of the peak of RV infection was noted in the post-vaccination year. The duration of rotavirus season in 2016/2017 was short.

CONCLUSIONS

Compared with 3 pre-vaccination years, the total number of gastroenteritis presentations, gastroenteritis hospital admissions, and rotavirus positive gastroenteritis cases were all reduced, and the duration of the rotavirus season was shorter.

Impact of Vaccination on Rotavirus Genotype Diversity: A Nearly Two-Decade-Long Epidemiological Study before and after Rotavirus Vaccine Introduction in Sicily, Italy

Sicily was the first Italian region to introduce rotavirus (RV) vaccination with the monovalent G1P[8] vaccine Rotarix® in May 2012. In this study, the seasonal distribution and molecular characterization of RV strains detected over 19 years were compared to understand the effect of Rotarix® on the evolutionary dynamics of human RVs. A total of 7846 stool samples collected from children < 5 years of age, hospitalized with acute gastroenteritis, were tested for RV detection and genotyping. Since 2013, vaccine coverage has progressively increased, while the RV prevalence decreased from 36.1% to 13.3% with a loss of seasonality. The local distribution of RV genotypes changed over the time possibly due to vaccine introduction, with a drastic reduction in G1P[8] strains replaced by common and novel emerging RV strains, such as equine-like G3P[8] in the 2018−2019 season. Comparison of VP7 and VP4 amino acid (aa) sequences with the cognate genes of Rotarix® and RotaTeq® vaccine strains showed specific aa changes in the antigenic epitopes of VP7 and of the VP8* portion of VP4 of the Italian RV strains. Molecular epidemiological surveillance data are required to monitor the emergence of novel RV strains and ascertain if these strains may affect the efficacy of RV vaccines.

Defining the Recipe for an Optimal Rotavirus Vaccine Introduction in a High-Income Country in Europe

Observational data over 15 years of rotavirus vaccine introduction in Belgium have indicated that rotavirus hospitalisations in children aged <5 years plateaued at a higher level than expected, and was followed by biennial disease peaks. The research objective was to identify factors influencing these real-world vaccine impact data. We constructed mathematical models simulating rotavirus-related hospitalisations by age group and year for those children. Two periods were defined using different model constructs. First, the vaccine uptake period encompassed the years required to cover the whole at-risk population. Second, the post-uptake period covered the years in which a new infection/disease equilibrium was reached. The models were fitted to the observational data using optimisation programmes with regression and differential equations. Modifying parameter values identified factors affecting the pattern of hospitalisations. Results indicated that starting vaccination well before the peak disease season in the first year and rapidly achieving high coverage was critical in maximising early herd effect and minimising secondary sources of infection. This, in turn, would maximise the reduction in hospitalisations and minimise the size and frequency of subsequent disease peaks. The analysis and results identified key elements to consider for countries initiating an optimal rotavirus vaccine launch programme.

Explaining the formation of a plateau in rotavirus vaccine impact on rotavirus hospitalisations in Belgium

BACKGROUND

Observational data on the reduction in hospitalisations after rotavirus vaccine introduction in Belgium suggest that vaccine impact plateaued at an unexpectedly high residual hospitalisation rate. The objective of this analysis was to identify factors that influence real-world vaccine impact.

METHODS

Data were collected on hospitalisations in children aged ≤ 5 years with rotavirus disease from 11 hospitals since 2005 (the RotaBIS study). The universal rotavirus vaccination campaign started late in 2006. A mathematical model simulated rotavirus hospitalisations in different age groups using vaccine efficacy and herd effect, influenced by vaccine coverage, vaccine waning, and secondary infection sources. The model used optimisation analysis to fit the simulated curve to the observed data, applying Solver add-in software. It also simulated an 'ideal' vaccine introduction maximising hospitalisation reduction (maximum coverage, maximum herd effect, no waning), and compared this with the best-fit simulated curve. Modifying model input values identified factors with the largest impact on hospitalisations.

RESULTS

Compared with the 'ideal' simulation, observed data showed a slower decline in hospitalisations and levelled off after three years at a higher residual hospitalisation rate. The slower initial decline was explained by the herd effect in unvaccinated children. The higher residual hospitalisation rate was explained by starting the vaccine programme in November, near the rotavirus seasonal peak. This resulted in low accumulated vaccine coverage during the first rotavirus disease peak season, with the consequential appearance of secondary infection sources. This in turn reduced the herd effect, resulting in a diminished net impact.

CONCLUSIONS

Our results indicate that countries wishing to maximise the impact of rotavirus vaccination should start vaccinating well ahead of the rotavirus seasonal disease peak. This maximises herd effect during the first year leading to rapid and high reduction in hospitalisations. Secondary infection sources explain the observed data in Belgium better than vaccine waning.

Impact analysis of rotavirus vaccination in various geographic regions in Western Europe

BACKGROUND

Universal mass vaccination (UMV) against rotavirus has been implemented in many but not all European countries. This study investigated the impact of UMV on rotavirus incidence trends by comparing European countries with UMV: Belgium, England/Wales and Germany versus countries without UMV: Denmark and the Netherlands.

METHODS

For this observational retrospective cohort study, time series data (2001-2016) on rotavirus detections, meteorological factors and population demographics were collected. For each country, several meteorological and population factors were investigated as possible predictors of rotavirus incidence. The final set of predictors were incorporated in negative binomial models accounting for seasonality and serial autocorrelation, and time-varying incidence rate ratios (IRR) were calculated for each age group and country separately. The overall vaccination impact two years after vaccine implementation was estimated by pooling the results using a random effects meta-analyses. Independent t-tests were used to compare annual epidemics in the pre-vaccination and post-vaccination era to explore any changes in the timing of rotavirus epidemics.

RESULTS

The population size and several meteorological factors were predictors for the rotavirus epidemiology. Overall, we estimated a 42% (95%-CI 23;56%) reduction in rotavirus incidence attributable to UMV. Strongest reductions were observed for age-groups 0-, 1- and 2-years (IRR 0.47, 0.48 and 0.63, respectively). No herd effect induced by UMV in neighbouring countries was observed. In all UMV countries, the start and/or stop and corresponding peak of the rotavirus season was delayed by 4-7 weeks.

CONCLUSIONS

The introduction of rotavirus UMV resulted in an overall reduction of 42% in rotavirus incidence in Western European countries two years after vaccine introduction and caused a change in seasonal pattern. No herd effect induced by UMV neighbouring countries was observed for Denmark and the Netherlands.

Rotavirus gastroenteritis surveillance in Azerbaijan, 2011-2016

INTRODUCTION

Rotavirus is a leading cause of acute gastroenteritis and mortality among children worldwide but data describing rotavirus disease in Azerbaijan are lacking. This analysis describes the rotavirus disease burden in Baku, the largest city in Azerbaijan.

METHODS

We conducted active, prospective, sentinel hospital surveillance with laboratory confirmation for rotavirus among children under 5 years of age hospitalized at a large pediatric hospital in Baku during 2011-2016. Children with bloody diarrhea, or prior use of antibiotics or intravenous fluids were excluded. The guardians of enrolled children completed a questionnaire documenting clinical and demographic information. A stool specimen was collected from each enrolled child. We report the number and proportion of rotavirus positive hospitalizations during the surveillance period and a clinical description of rotavirus-positive and rotavirus-negative children.

RESULTS

From July 2011 through June 2016, 3139 children <5 years of age were enrolled into the surveillance system. Of these, 523 (17%) were positive for rotavirus, varying from 13% to 21% by surveillance year, with a median of 16% over the surveillance period. Increase in rotavirus detections occurred during December-May. Most rotavirus infections (303/523; 58%) occurred in children aged 6-23 months.

CONCLUSION

Rotavirus is responsible for approximately 16% of annual hospital admissions for acute gastroenteritis in children <5 years of age in Baku. This is lower than regional estimates. Exclusion of children with a history of antibiotic use or intravenous fluids may be accounting for this lower prevalence, and expansion of surveillance to include these groups could provide a more comprehensive picture of acute rotavirus gastroenteritis in Baku.

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.

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.

Group A rotavirus gastroenteritis: post-vaccine era, genotypes and zoonotic transmission

This article provides a review of immunity, diagnosis, and clinical aspects of rotavirus disease. It also informs about the changes in epidemiology of diarrheal disease and genetic diversity of circulating group A rotavirus strains following the introduction of vaccines. Group A rotavirus is the major pathogen causing gastroenteritis in animals. Its segmented RNA genome can lead to the emergence of new or unusual strains in human populations via interspecies transmission and/or reassortment events.

Comparative analysis of the Rotarix™ vaccine strain and G1P[8] rotaviruses detected before and after vaccine introduction in Belgium

G1P[8] rotaviruses are responsible for the majority of human rotavirus infections worldwide. The effect of universal mass vaccination with rotavirus vaccines on circulating G1P[8] rotaviruses is still poorly understood. Therefore we analyzed the complete genomes of the Rotarix™ vaccine strain, and 70 G1P[8] rotaviruses, detected between 1999 and 2010 in Belgium (36 before and 34 after vaccine introduction) to investigate the impact of rotavirus vaccine introduction on circulating G1P[8] strains. All rotaviruses possessed a complete Wa-like genotype constellation, but frequent intra-genogroup reassortments were observed as well as multiple different cluster constellations circulating in a single season. In addition, identical cluster constellations were found to circulate persistently over multiple seasons. The Rotarix™ vaccine strain possessed a unique cluster constellation that was not present in currently circulating G1P[8] strains. At the nucleotide level, the VP6, VP2 and NSP2 gene segments of Rotarix™ were relatively distantly related to any Belgian G1P[8] strain, but other gene segments of Rotarix™ were found in clusters also containing circulating Belgian strains. At the amino acid level, the genetic distance between Rotarix™ and circulating Belgian strains was considerably lower, except for NSP1. When we compared the Belgian G1P[8] strains collected before and after vaccine introduction a reduction in the proportion of strains that were found in the same cluster as the Rotarix™ vaccine strain was observed for most gene segments. The reduction in the proportion of strains belonging to the same cluster may be the result of the vaccine introduction, although natural fluctuations cannot be ruled out.

Changing molecular epidemiology of rotavirus infection after introduction of monovalent rotavirus vaccination in Scotland

BACKGROUND

Rotaviruses (RV) are the leading cause of gastroenteritis in children less than five years of age worldwide. Rotarix®, a live attenuated monovalent vaccine containing a RV strain of G1P[8] specificity has been included in the childhood immunisation schedule from June 2013 in Scotland. This study aimed to characterise the prevalent RV strains in Scotland before and after the introduction of the RV vaccine.

METHODS

RV positive faecal samples from Scottish virology laboratories covering the years 2012-2015 were genotyped. Viral RNA was extracted from faecal suspensions. VP7 and VP4 gene specific primers were used for multiplex hemi-nested PCRs and sequencing. Mann-Whitney U test and Chi-square test were used for statistical comparison.

RESULTS

There was a decrease in RV positive samples from the Scottish virology laboratories from 7409 samples in the pre-vaccination years (2009-2013) to 760 in 2014-2015, with an annual reduction of RV infections by 74.4% (RR-3.95; 95%-CI, 3.53-4.42, p<0.001). 362 samples from the pre-vaccination period and 278 samples from the post-vaccination were genotyped. There was a drop in prevalence of G1P[8] strains (72.1%, 95%-CI, 67.42-76.33 to 15%, 95%-CI, 11.38-19.79) after introduction of the vaccine. In the post-vaccination period G2P[4] was the dominant strain in Scotland (21.9%, 95%-CI, 17.48-27.17) with increase in G9P[8] (12.9%, 95%-CI, 9.50-7.41), G12P[8] (12.2%, 95%-CI, 8.89-16.60) and G3P[8] (11.9%, 95%-CI, 8.58-16.20) infections. Phylogenetic analysis of the VP7 and VP4 genes showed no major differences between the pre and post-vaccination G1P[8] strains.

CONCLUSION

This laboratory based surveillance study shows significant reduction in reported RV cases and a shift in proportion from G1P[8] to G2P[4] strains after introduction of RV vaccination in Scotland. The genotyping data from a subset of the total reported RV cases will be used to ascertain cross protection against strains and identify vaccine induced RV strain shifts in the years to come.

The Sustained Rotavirus Vaccination Impact on Nosocomial Infection, Duration of Hospital Stay, and Age: The RotaBIS Study (2005-2012)

Introduction

The benefits of rotavirus (RV) vaccination in developed countries have focused on reductions in mortality, hospitalization and medical visits, and herd protection. We investigated other aspects related to RV-induced nosocomial infection, duration of hospital stay, age shift, and sustained vaccine impact (VI) over time.

Method

RotaBIS (Rotavirus Belgian Impact Study; ClinicalTrials.gov identifier, NCT01563146) annually collects retrospective data on hospitalization linked to RV testing in children up to 5 years old from 11 pediatric wards located all over Belgium. Data from 2005 to 2012 have been split in pre- (2005–2006) and post-vaccination (2007–2012) period. Information was collected on age, gender, RV test result, nosocomial infection caused by RV and duration of hospital stay.

Results

Over the 6-year period after the introduction of the RV vaccine, an 85% reduction in nosocomial infections was observed (221 in 2005 to 33 in 2012, p < 0.001). A significant reduction of almost 2 days in average duration of hospital stay per event was observed overall (7.62 days in 2005 to 5.77 days in 2012, p < 0.001). The difference is mainly explained by the higher reduction in number of nosocomial infections. A pronounced age shift (+24%, p < 0.01) of RV nosocomial infection to infants ≤2 months old was observed, increasing with length of post-vaccination period. VI was maintained over the follow-up (±79% VI per birth cohort). A decrease was seen depending on age, 85% (95% CI 76–91%) in the youngest to 63% (95% CI 22–92%) in the oldest age group.

Conclusion

The higher reduction in nosocomial infection may affect the overall average duration of hospital stay for RV infection. No change in VI by birth cohort, but a reduction by age group was observed. These findings could be important for decision-makers considering the introduction of universal mass RV vaccination programs.

Trial registration

ClinicalTrials.gov identifier, NCT01563146.

Funding

GlaxoSmithKline Biologicals SA (Rixensart, Belgium).

Cost-Effectiveness of Rotavirus Vaccination in France-Accounting for Indirect Protection

BACKGROUND

Vaccination against rotavirus has shown great potential for reducing the primary cause of severe childhood gastroenteritis. Previous economic evaluations of rotavirus vaccination in France have not modeled the potential impact of vaccines on disease burden via reduced transmission.

OBJECTIVE

To determine the cost-effectiveness of the introduction of pentavalent rotavirus vaccination into the French infant vaccination schedule.

METHODS

We developed an age-structured model of rotavirus transmission calibrated to 6 years of French gastroenteritis incidence and vaccine clinical trial data. We evaluated the cost-effectiveness of pentavalent rotavirus vaccination considering that 75% of infants would receive the three-dose vaccine course.

RESULTS

Our model predicts that rotavirus vaccination will decrease rotavirus gastroenteritis incidence and associated clinical outcomes in vaccinated and unvaccinated individuals, delay the seasonal peak of infection, and increase the age of infection. From the societal perspective, our base-case scenario predicts that vaccination coverage would be cost-effective at €115 or €135 per vaccine course at €28,500 and €39,500/quality-adjusted life-year (QALY) gained, respectively, and suggests that almost 95% of the financial benefits will be recouped within the first 5 years following vaccination implementation. From the third-party payer perspective, incremental cost-effectiveness ratios ranged from €12,500 to €20,000/QALY, respectively. Our uncertainty analysis suggests that findings were sensitive to various assumptions including the number of hospitalizations, outpatient visits, and the extent of QALY losses per rotavirus episode.

CONCLUSIONS

Introducing pentavalent rotavirus vaccination into the French infant vaccination schedule would significantly reduce the burden of rotavirus disease in children, and could be cost-effective under plausible conditions.

Diarrheal Diseases Hospitalization in Yemen before and after Rotavirus Vaccination

The study aims to assess the impact of rotavirus vaccine introduction on diarrheal diseases hospitalization and to identify the rotavirus genotypes most prevalent before and after vaccine introduction among children ≤ 5 years of age. Rotarix™ ® rotavirus vaccine is currently licensed for infants in Yemen and was introduced in 2012. The vaccination course consists of two doses. The first dose is administrated at 6 weeks of age and the second dose is completed by 10 weeks. Based on a longitudinal observational study, we assessed the impact of vaccination on rotavirus hospitalization before and after vaccination among children ≤ 5 years of age at the Yemeni-Swedish Hospital (YSH) in Taiz, Yemen. Prevaccination covered January 2009-July 2012 during which 2335 fecal samples were collected from children ≤ 5 years old. Postvaccination covered January 2013-December 2014 during which 1114 fecal samples were collected. Rotavirus was detected by Enzyme Linkage Immunosorbent Assay (ELISA). The incidence of rotavirus hospitalization decreased from 43.79% in 2009 to 10.54% in 2014. Hospitalization due to rotavirus diarrhea was reduced by 75.93%. Vaccine coverage increased from 23% in 2012 to 72% in 2014. Also, the results showed that the most predominant genotypes in prevaccination period were G2P[4] (55.0%), followed by G1P[8] (15.0%), while in postvaccination period G1P[8] (31%) was the predominant genotype, followed by G9P[8] (27.5%). In conclusion, rotavirus vaccination in Yemen resulted in sharp reduction in diarrheal hospitalization. A successful rotavirus vaccination program in Yemen will rely upon efficient vaccine delivery systems and sustained vaccine efficacy against diverse and evolving rotavirus strains.

In-season and out-of-season variation of rotavirus genotype distribution and age of infection across 12 European countries before the introduction of routine vaccination, 2007/08 to 2012/13

The EuroRotaNet surveillance network has conducted rotavirus genotype surveillance since 2007 in 16 European countries. Using epidemiological and microbiological data from 39,786 genotyped rotavirus-positive specimens collected between September 2007 and August 2013, we assessed genotype distribution and age distribution of rotavirus gastroenteritis (RVGE) cases in and out of peak season in 12 countries which were yet to implement routine rotavirus vaccination. In multinomial multivariate logistic regression, adjusting for year, country and age, the odds of infection caused by genotype-constellation 2 DS-1-like stains (adjusted multinomial odds ratio (aM-OR) = 1.25; 95% confidence interval (CI): 1.13-1.37; p < 0.001), mixed or untypable genotypes (aM-OR = 1.55; 95% CI: 1.40-1.72; p < 0.001) and less common genotypes (aM-OR = 2.11; 95% CI:1.78-2.51; p < 0.001) increased out of season relative to G1P[8]. Age varied significantly between seasons; the proportion of RVGE cases younger than 12 months in the United Kingdom increased from 34% in season to 39% out of season (aM-OR = 1.66; 95% CI: 1.20-2.30), and the proportion five years and older increased from 9% in season to 17% out of season (aM-OR = 2.53; 95% CI: 1.67-3.82). This study provides further understanding of the rotavirus ecology before vaccine introduction, which will help interpret epidemiological changes in countries introducing or expanding rotavirus vaccination programmes.

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.

Improvement in hospital Quality of Care (QoC) after the introduction of rotavirus vaccination: An evaluation study in Belgium

During each winter period hospital emergency rooms and pediatric wards are often overwhelmed by high patient influx with infectious diseases leading to chaotic conditions with poor quality of care (QoC) delivery as a consequence. The conditions could be improved if we were able to better control the influx by introducing for instance better prevention strategies against some of the most frequent infectious diseases. New prevention strategies using vaccination against rotavirus infection were introduced in Belgium in November 2006. We developed a measure of hospital QoC suitable for assessing the impact of pediatric rotavirus vaccination. The study is retrospective collecting routine data on bed and staff management in one pediatric hospital in Belgium. The data were divided in pre- and post-vaccination periods during rotavirus-epidemic and non-epidemic periods. The scores were constructed using Explanatory Factor Analysis (EFA). All patients enrolled were admitted to the pediatric ward over the period from 1 January 2004 to 31 December 2009. The results of the epidemic period indicated that bed-day occupancy, bed-day turnover and unplanned readmissions for acute gastroenteritis were lower in the post-vaccination compared with the pre-vaccination periods. The QoC scores were therefore significantly lower (indicating improved QoC) after the introduction of rotavirus vaccination, compared with pre-vaccination. The data suggests that the reduction in the winter peak of rotavirus-related hospitalizations after the introduction of the vaccine reduces pressure on hospital resources and improves the quality of hospital care. The findings should be further tested in similar settings.

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.

The cost effectiveness of rotavirus vaccination in Iran

Rotavirus is the most common cause of severe diarrhea leading to hospitalization or disease-specific death among young children. Effective vaccines have recently been approved and successful vaccination program implemented. The aim of this study was to evaluate the cost effectiveness of mass rotavirus vaccination program in Iran. We developed a Markov model that reflects key features of rotavirus natural history. Parameters of the model were assessed by field study or developed through literature search and published data. We applied the model to the 2009 Iranian birth cohort and evaluated the cost-effectiveness of including the rotavirus vaccine (Rotarix®) into Iranian expanded immunization program (EPI). With an estimated hospitalization rate of 0.05 and outpatient rate of 0.23 cases per person-year, vaccinating cohort of 1231735 infants in Iran with 2 doses of (Rotarix®), would prevent 32092 hospitalizations, 158750 outpatient visits, and 1591 deaths during 5 y of follow-up. Under base-case assumption of $10 cost per course of vaccine, the vaccination would incur an extra cost of $1,019,192 from health care perspective and would avert 54680 DALYs. From societal perspective, there would be $15,192,568 saving for the society with the same averted DALYs. The incremental cost effectiveness ratio showed a cost of $19 US dollars per averted DALY from health care perspective and a saving of $278 US dollars for each averted DALY from societal perspective. Introducing rotavirus vaccine into EPI program would be highly cost-effective public health intervention in Iran.

Temporal trends in hospitalization for rotavirus gastroenteritis: A nationwide study in Italy, 2005-2012

AGE severity is linked to etiology, and Rotavirus (RV) accounts for most of severe cases. In 2009 the World Health Organization recommended RV vaccination for all children. Worldwide a number of Countries implemented RV vaccination in their pediatric immunisation programmes, but only a limited number in Europe. This study was designed to estimate the proportion of RVGE among children aged <6 y who were diagnosed with AGE and admitted to hospitals in Italy during the years 2005-2012. A total of 334,982 hospital discharge forms were collected, being 79,344 hospitalizations associated with RV. The average hospitalization rate (HR) was 146/100,000 children for RVGE in primary diagnosis (PD) and 150/100,000 children for RVGE in secondary diagnosis (SD). Since 2008 the RVGE hospitalization figures and rates (HRs) in SD exceed those in PD. The majority of RVGE hospitalizations (33.67%) were reported among children aged ≤ 2 years. Despite some limitations due to the hospital discharge database (HDD) synthetic contents and low potential for clinical interpretation, the analysis of national HDD, including PD and SD, documents that RV still represents a consistent cause of pediatric hospitalizations in Italy.

Rotavirus Infection: A Disease of the Past?

Rotavirus infection is the most common cause of severe diarrhea disease in infants and young children worldwide. Vaccination is the only control measure likely to have a significant impact on the incidence of severe disease. Rotavirus vaccines have reduced the burden of disease in the United States and Europe and vaccine programs are being introduced in Asia and Africa where it is hoped that vaccine will have significant impact on severe infection. Long-term monitoring and strain surveillance are needed to assess the effects of rotavirus immunization programs and to determine whether changes in strain ecology will affect rotavirus vaccine effectiveness.

Genome-Wide Evolutionary Analyses of G1P[8] Strains Isolated Before and After Rotavirus Vaccine Introduction

Rotaviruses are the most important etiological agent of acute gastroenteritis in young children worldwide. Among the first countries to introduce rotavirus vaccines into their national immunization programs were Belgium (November 2006) and Australia (July 2007). Surveillance programs in Belgium (since 1999) and Australia (since 1989) offer the opportunity to perform a detailed comparison of rotavirus strains circulating pre- and postvaccine introduction. G1P[8] rotaviruses are the most prominent genotype in humans, and a total of 157 G1P[8] rotaviruses isolated between 1999 and 2011 were selected from Belgium and Australia and their complete genomes were sequenced. Phylogenetic analysis showed evidence of frequent reassortment among Belgian and Australian G1P[8] rotaviruses. Although many different phylogenetic subclusters were present before and after vaccine introduction, some unique clusters were only identified after vaccine introduction, which could be due to natural fluctuation or the first signs of vaccine-driven evolution. The times to the most recent common ancestors for the Belgian and Australian G1P[8] rotaviruses ranged from 1846 to 1955 depending on the gene segment, with VP7 and NSP4 resulting in the most recent estimates. We found no evidence that rotavirus population size was affected after vaccine introduction and only six amino acid sites in VP2, VP3, VP7, and NSP1 were identified to be under positive selective pressure. Continued surveillance of G1P[8] strains is needed to determine long-term effects of vaccine introductions, particularly now rotavirus vaccines are implemented in the national immunization programs of an increasing number of countries worldwide.

Burden and genotyping of rotavirus disease in the United Arab Emirates: a multicenter hospital-based surveillance

Rotavirus (RV) is the most common etiological agent causing acute gastroenteritis (GE) in children aged <5 years. This cross-sectional, hospital-based surveillance study (NCT01201252) was designed to investigate RVGE disease burden. It was conducted from July 2009-July 2010 at 3 referral hospitals in the United Arab Emirates (UAE). Children who had been hospitalized for acute GE were enrolled with informed consent. Stool samples were tested for RV using enzyme immunoassay and RV-positive samples were further typed using reverse transcriptase-polymerase chain reaction and reverse hybridization to determine the G and P types. GE data were collected from medical charts and GE severity was assessed through clinical examination. Treatment and outcome were prospectively recorded. Among 6323 children hospitalized due to any reason, 771 (12.2%) presented acute GE and were enrolled, of whom 758 (98.3%) were included in the final analysis. Acute GE and RVGE accounted for 12.0% (758/6323) and 6.0% (381/6323) of all hospitalizations, respectively. RVGE accounted for 50.3% (381/758) of GE hospitalizations and predominantly affected, children younger than 2 years (66.1%; 252/381). The severity of GE before hospitalization was significantly associated with RV-positive status (P = 0.0031). The majority (>95%) of children received intravenous hydration during hospitalization. RVGE occurred throughout the year, with a subtle winter peak in February 2010 (63.6%; 56/88). G1WTP[8]WT was the most commonly detected RV strain (56.3%) in 268 analyzed samples. RV was a major cause of GE-hospitalizations in children under 5 years in the UAE; the highest number of RVGE cases was observed in children younger than 2 years.

Insights from global data for use of rotavirus vaccines in India

Rotavirus vaccines are being introduced in several low- and middle-income countries across the world with and without support from the GAVI Alliance. India has the highest disease burden of rotavirus based on morbidity and mortality estimates and several indigenous vaccine manufacturers are developing rotavirus vaccines. One candidate has undergone phase III testing and others have completed evaluation in phase II. Global data on licensed vaccine performance in terms of impact on disease, strain diversity, safety and cost-effectiveness has been reviewed to provide a framework for decision making in India.

Viral gastroenteritis in rotavirus negative hospitalized children <5 years of age from the independent states of the former Soviet Union

PURPOSE

Rotavirus causes nearly 40% of all hospitalizations for AGE among children <5 years of age in the NIS of the former Soviet Union. The etiologic role of other established gastroenteritis viruses in this age group is unknown.

METHODS

Laboratory-confirmed rotavirus negative fecal specimens (N=495) collected between January and December 2009 from children in 6 NIS (Armenia, Azerbaijan, Belarus, Georgia, Republic of Moldova and Ukraine) were tested for norovirus, sapovirus, enteric adenovirus and astrovirus by real-time RT-PCR. Genotyping was carried out by sequencing and phylogenetic analysis.

RESULTS

Norovirus, enteric adenovirus, sapovirus and astrovirus were detected in 21.8%, 4.0%, 3.2%, and 1.4% of the rotavirus negative specimens, respectively. Mixed infections were identified in 4.1% of the specimens. Phylogenetic analysis showed co-circulation of several different genotypes with GII.4 Den Haag (2006b) norovirus, GI.2 sapovirus, adenovirus type 41, and astrovirus type 1 causing majority of the infections.

CONCLUSION

Norovirus, enteric adenovirus, sapovirus and astrovirus account for a significant proportion (30.5%) of AGE in hospitalized children <5 years of age in 6 NIS.

Cost effectiveness of a pentavalent rotavirus vaccine in Oman

BACKGROUND

Rotavirus gastroenteritis (RGE) is the leading cause of diarrhea in young children in Oman, incurring substantial healthcare and economic burden. We propose to formally assess the potential cost effectiveness of implementing universal vaccination with a pentavalent rotavirus vaccine (RV5) on reducing the health care burden and costs associated with rotavirus gastroenteritis (RGE) in Oman

METHODS

A Markov model was used to compare two birth cohorts, including children who were administered the RV5 vaccination versus those who were not, in a hypothetical group of 65,500 children followed for their first 5 years of life in Oman. The efficacy of the vaccine in reducing RGE-related hospitalizations, emergency department (ED) and office visits, and days of parental work loss for children receiving the vaccine was based on the results of the Rotavirus Efficacy and Safety Trial (REST). The outcome of interest was cost per quality-adjusted life year (QALY) gained from health care system and societal perspectives.

RESULTS

A universal RV5 vaccination program is projected to reduce, hospitalizations, ED visits, outpatient visits and parental work days lost due to rotavirus infections by 89%, 80%, 67% and 74%, respectively. In the absence of RV5 vaccination, RGE-related societal costs are projected to be 2,023,038 Omani Rial (OMR) (5,259,899 United States dollars [USD]), including 1,338,977 OMR (3,481,340 USD) in direct medical costs. However, with the introduction of RV5, direct medical costs are projected to be 216,646 OMR (563,280 USD). Costs per QALY saved would be 1,140 OMR (2,964 USD) from the health care payer perspective. An RV5 vaccination program would be considered cost saving, from the societal perspective.

CONCLUSIONS

Universal RV5 vaccination in Oman is likely to significantly reduce the health care burden and costs associated with rotavirus gastroenteritis and may be cost-effective from the payer perspective and cost saving from the societal perspective.

Rotavirus vaccination in Europe: drivers and barriers

Rotavirus gastroenteritis is a vaccine-preventable disease that confers a high medical and economic burden in more developed countries and can be fatal in less developed countries. Two vaccines with high efficacy and good safety profiles were approved and made available in Europe in 2006. We present an overview of the status of rotavirus vaccination in Europe. We discuss the drivers (including high effectiveness and effect of universal rotavirus vaccination) and barriers (including low awareness of disease burden, perception of unfavourable cost-effectiveness, and potential safety concerns) to the implementation of universal rotavirus vaccination in Europe. By February, 2014, national universal rotavirus vaccination had been implemented in Belgium, Luxembourg, Austria, Finland, Greece, Luxembourg, Norway, and the UK. Four other German states have issued recommendations and reimbursement is provided by sickness funds. Other countries were at various stages of recommending or implementing universal rotavirus vaccination.

Hospital-based surveillance and analysis of genotype variation in Nicaragua after the introduction of the pentavalent rotavirus vaccine

BACKGROUND

A live, attenuated, pentavalent rotavirus vaccine (RV5) was introduced in Nicaragua in 2006 through a 3-year partnership between Merck & Co, Inc., and the Nicaraguan Ministry of Health. Nicaragua was the first developing nation to include rotavirus vaccine in its national childhood vaccine program. To monitor the possibility of changing circulating rotavirus strains after the introduction of RV5, we determined the genotypes responsible for rotavirus gastroenteritis-related hospitalization during the first 3 postvaccine years.

METHODS

Stool samples were collected from children with acute gastroenteritis who presented to any of 6 participating hospitals within 7-14 days of symptom onset. Samples positive for rotavirus antigen were analyzed for P and G genotypes using a reverse transcription polymerase chain reaction method.

RESULTS

Overall, the predominant strains were G2P[4] (41.5%), G1P[8] (40.6%), G4P[8] (5.1%) and G3P[8] (4.7%). Strain predominance varied by season. During the 2007 season, G4P[8] (53.2%) and G2P[4] (40.5%) predominated. In the 2008 season, G2P[4] (77.9%) and G1P[8] (12.6%) were predominant, while in the 2009 season, G1P[8] (79.3%) and G3P[8] (7.8%) were predominant.

CONCLUSION

No new or unexpected strains were predominant in the years immediately following the introduction of RV5 into Nicaragua. RV5 does not appear to have substantially altered the historical pattern of seasonal fluctuation in rotavirus genotypes.

Pharmacoeconomic spotlight on rotavirus vaccine RIX4414 (Rotarix™) in developed countries

The most common cause of severe diarrhea in infants and young children is rotavirus gastroenteritis (RVGE), which is associated with significant morbidity, healthcare resource use, and direct and indirect costs in industrialized nations. The monovalent rotavirus vaccine RIX4414 (Rotarix™) is administered as a two-dose oral series in infants and has demonstrated protective efficacy against RVGE in clinical trials conducted in developed countries. In addition, various naturalistic studies have demonstrated ‘real-world’ effectiveness after the introduction of widespread rotavirus vaccination programs in the community setting.

Numerous cost-effectiveness analyses have been conducted in developed countries in which a universal rotavirus vaccination program using RIX4414 was compared with no universal rotavirus vaccination program. There was a high degree of variability in base-case results across studies even when the studies were conducted in the same country, often reflecting differences in the selection of data sources or assumptions used to populate the models. In addition, results were sensitive to plausible changes in a number of key input parameters. As such, it is not possible to definitively state whether a universal rotavirus vaccination program with RIX4414 is cost effective in developed countries, although results of some analyses in some countries suggest this is the case. In addition, international guidelines advocate universal vaccination of infants and children against rotavirus. It is also difficult to draw conclusions regarding the cost effectiveness of rotavirus vaccine RIX4414 relative to that of the pentavalent rotavirus vaccine, which is administered as a three-dose oral series. Although indirect comparisons in cost-effectiveness analyses indicate that RIX4414 provided more favorable incremental cost-effectiveness ratios when each vaccine was compared with no universal rotavirus vaccination program, results were generally sensitive to vaccine costs. Actual tender prices of a full vaccination course for each vaccine were not known at the time of the analyses and therefore had to be estimated.

Genetic diversity of G1P[8] rotavirus VP7 and VP8* antigens in Finland over a 20-year period: No evidence for selection pressure by universal mass vaccination with RotaTeq® vaccine

Two live-attenuated oral vaccines (Rotarix™ and Rotateq®) against rotavirus gastroenteritis were licensed in 2006 and have been introduced into National Immunization Programs (NIPs) of several countries. Large scale use of rotavirus vaccines might cause antigenic pressure on circulating rotavirus types or lead to selection of new rotaviruses thus decreasing vaccine efficacy. We examined the nucleotide and amino acid sequences of the surface proteins VP7 and VP4 (cleaved to VP8(*) and VP5(*)) of a total of 108 G1P[8] rotavirus strains collected over a 20-year period from 1992, including the years 2006-2009 when rotavirus vaccine (mainly Rotarix™) was available, and the years 2009-2012 after implementation of RotaTeq® vaccine into the NIP of Finland. In G1 VP7 no changes at amino acid level were observed. In VP8(*) periodical fluctuation of the sublineage over the study period was found with multiple changes both at nucleotide and amino acid levels. Most amino acid changes were in the dominant antigenic epitopes of VP8(*). A change in VP8(*) sublineage occurred between 2008 and 2009, with a temporal correlation to the use of Rotarix™ up to 30% coverage in the period. In contrast, no antigenic changes in the VP8(*) protein appeared to be correlated to the exclusive use of RotaTeq® vaccine after 2009. Nevertheless, long-term surveillance of antigenic changes in VP4 and also VP7 proteins in wild-type rotavirus strains is warranted in countries with large scale use of the currently licensed live oral rotavirus vaccines.

A critical literature review of health economic evaluations of rotavirus vaccination

Two licensed vaccines are available to prevent RVGE in infants. A worldwide critical review of economic evaluations of these vaccines was conducted. The objective was to describe differences in methodologies, assumptions and inputs and determine the key factors driving differences in conclusions. 68 economic evaluations were reviewed. RV vaccination was found to be cost-effective in developing countries, while conclusions varied between studies in developed countries. Many studies found that vaccination was likely to be cost-effective under some scenarios, such as lower prices scenarios, inclusion of herd protection, and/or adoption of a societal perspective. Other reasons for variability included uncertainty around healthcare visits incidence and lack of consensus on quality of life (QoL) valuation for infants and caregivers. New evidence on the vaccination effectiveness in real-world, new ways of modeling herd protection and assessments of QoL in children could help more precisely define the conditions under which RV vaccination would be cost-effective in developed countries.

Major reduction of rotavirus, but not norovirus, gastroenteritis in children seen in hospital after the introduction of RotaTeq vaccine into the National Immunization Programme in Finland

Universal rotavirus (RV) vaccination is expected to reduce hospitalizations for acute gastroenteritis (GE) of children by eliminating most of severe RVGE, but it does not have any effect on norovirus (NV), the second most common causative agent of GE in children. After the introduction of the RV vaccine into the National Immunization Programme (NIP) of Finland in 2009, we conducted a prospective 2-year survey of GE in children seen in Tampere University Hospital either as outpatients or inpatients and compared the results with a similar 2-year survey conducted prior to NIP in the years 2006-2008. Compared with the pre-NIP 2-year period, in 2009-2011, hospitalizations for RVGE were reduced by 76 % and outpatient clinic visits were reduced by 81 %. NVGE showed a slight decreasing trend and accounted for 34 % of all cases of GE seen in hospital in pursuance of RVGE having decreased to 26 % (down from 52 %). In cases admitted to the hospital ward, RV accounted for 28 % and NV accounted for 37 %.The impact of RV vaccination was reflected as a 57 % decrease in all hospital admissions and 62 % decrease in all outpatient clinic visits for GE of any cause.

CONCLUSION

RV vaccination in NIP has led to a major reduction of hospital admissions and clinic visits due to RVGE, but has had no effect on NVGE. After 2 years of NIP, NV has become the leading cause of acute GE in children seen in hospital.

The evolving epidemiology of rotavirus gastroenteritis in central Portugal with modest vaccine coverage

BACKGROUND

Rotavirus (RV) vaccines have been available on the private market in Portugal since 2006, with an estimated coverage rising from 16 to 42% between 2007 and 2010.

OBJECTIVES

To assess trends, surveillance of children presenting with acute gastroenteritis (AG) to a large paediatric emergency service (ES) in the central region of Portugal was conducted yearly during the winter-spring seasons.

STUDY DESIGN

Stool samples, collected throughout five epidemic seasons (January-June, 2006 to 2010) from children ≤ 36 months of age attending the ES with AG, were tested for RV by immunochromatographic rapid test and positive samples were genotyped.

RESULTS

A total of 6145 AG cases were identified: 1956 (32%) provided a stool sample (range: 28% in 2008-37% in 2009). The proportion of AG subjects who tested positive for RV fluctuated over the five surveillance seasons (49%, 39%, 25%, 26% and 39%, respectively) as did the distribution of co-circulating RV genotypes. There were no consistent changes in seasonality or age distribution and the proportion of admitted AG subjects who tested RV-positive did not show progressive trends over time.

CONCLUSIONS

Our results demonstrate fluctuations in RVAG incidence with no clear progressive trends or seasonal RV shifts among our surveillance subjects over five years, in the context of limited rotavirus vaccine coverage. Significant annual changes in genotype distributions were detected. Higher vaccine coverage may be necessary than at present for consistent impact on disease.

[Human rotavirus vaccine]

Since the presentation of the clinical trial reports showing the excellent efficacy and safety of the two human rotavirus vaccines (Rotarix and RotaTeq), the human rotavirus vaccines have received worldwide attention. The two vaccines have been approved in more than 100 countries, and were included in routine immunization schedule in about 30 countries. The effectiveness of the two vaccines exceeded our expectations, and severe rotavirus gastroenteritis cases have been greatly reduced. Also in Japan, administration of Rotarix started just last November, and RotaTeq will be also started soon. On this occasion, composition, characteristics, and effectiveness of these vaccines are described, and some points relating to the vaccination such as intussusception, cross protection, shedding and so on are also discussed.

First year experience of rotavirus immunisation programme in Finland

INTRODUCTION

This study aimed to estimate the impact of rotavirus (RV) immunisation programme on the total hospital treated acute gastroenteritis (AGE) burden, as well as, on severe RV disease burden in Finland during the first year after immunisation programme introduction. Such studies can also be considered as a vaccine-probe-study, where unspecific disease burden prevented by immunisation is assumed to be caused by the agent the vaccine is targeted against.

METHODS

The RV related outcome definitions were based on data registered in the National Hospital Discharge Register coded using ICD 10 codes. Incidences of hospitalised and hospital outpatient cases of AGE and RVGE were compared prior (1999-2005) and after (2010) the start of the programme among children under 5 years of age. ICD 10 codes utilised were A00-A09, R11 and K52.

RESULTS

The reductions in disease burden, when the post-introduction year was compared to pre-vaccine era, were 80.3% (95% CI 74.5-84.7) in hospital inpatient RVGE among toddlers less than 1 year of age and 53.9% (95% CI 49.8-57.7) when the total inpatient AGE burden was considered in the same age group. For the corresponding hospital outpatient cases the reductions were 78.8% (95% CI 48.4-91.3) and 12.5% (7.1-17.7). The overall vaccine impact against confirmed RVGE in age cohorts eligible for vaccination before the RV season 2010 was 97% (95% CI 90.7-99.0). If the total reductions, both in diagnosed RVGE, as well as in cases without definite microbial diagnosis, were expected to be RVGE, population based estimates for the total disease burden can be obtained: for inpatient RVGE in children less than 1 year of age the estimate is 10.5/1000 pyrs, while the diagnosed specific incidence was less than half of that, 4.9/1000 pyrs.

DISCUSSION

During the first post-vaccination year 2010, RV immunisation programme clearly managed to control the severe, hospital treated, forms of RVGE. The total disease burden is a more valuable end point than mere diagnosed cases as laboratory confirmation practises change after vaccine introduction. Our study is limited by the very short post-introduction follow up.

Impact of rotavirus vaccines on rotavirus disease

Rotaviruses are the most common cause of acute gastroenteritis in young children worldwide. Both licensed rotavirus vaccines (Rotarix™ [RV1] and RotaTeq™ [RV5]) are effective and safe. Studies from countries that have included RV1 or RV5 in the national immunization programs have demonstrated their safety and sustained efficacy under real-life circumstances. A significant decline in acute gastroenteritis-related deaths among Latin American children was observed after the introduction of RV1 and RV5 vaccines. Both vaccines were able to decrease the number of cases of rotavirus acute gastroenteritis and of severe rotavirus diseases. Vaccination was also associated with a dramatic reduction in hospitalizations and outpatient visits for all-cause acute gastroenteritis. Indirect protection after infant mass vaccination has been strongly suggested. Moreover, postlicensure safety studies assessed rare adverse events (rates <1 in 50,000), such as intussusception.

Fulfilling the promise of rotavirus vaccines: how far have we come since licensure?

Rotavirus is the most common cause of fatal and severe childhood diarrhoea worldwide. Two new rotavirus vaccines have shown efficacy against severe rotavirus disease in large clinical trials. Between 2006 and 2010, 27 countries introduced rotavirus vaccination into national immunisation programmes and, subsequently, the burden of severe rotavirus disease in these countries has decreased substantially in both vaccinated and unvaccinated children. Rotavirus vaccination has led to large, sustained declines in childhood deaths from diarrhoea in Brazil and Mexico, which supports estimates that rotavirus was the leading cause of diarrhoeal deaths in these countries. Studies after licensing have provided new insights into these vaccines, such as the duration of protection, relative effectiveness in poor populations, and strain evolution after vaccine introduction. The challenge for policy makers worldwide is to analyse the effect of vaccination in early adopter countries and to assess whether the benefits outweigh the costs and encourage wider dissemination of these vaccines.

Direct and indirect effects of rotavirus vaccination: comparing predictions from transmission dynamic models

Early observations from countries that have introduced rotavirus vaccination suggest that there may be indirect protection for unvaccinated individuals, but it is unclear whether these benefits will extend to the long term. Transmission dynamic models have attempted to quantify the indirect protection that might be expected from rotavirus vaccination in developed countries, but results have varied. To better understand the magnitude and sources of variability in model projections, we undertook a comparative analysis of transmission dynamic models for rotavirus. We fit five models to reported rotavirus gastroenteritis (RVGE) data from England and Wales, and evaluated outcomes for short- and long-term vaccination effects. All of our models reproduced the important features of rotavirus epidemics in England and Wales. Models predicted that during the initial year after vaccine introduction, incidence of severe RVGE would be reduced 1.8–2.9 times more than expected from the direct effects of the vaccine alone (28–50% at 90% coverage), but over a 5-year period following vaccine introduction severe RVGE would be reduced only by 1.1–1.7 times more than expected from the direct effects (54–90% at 90% coverage). Projections for the long-term reduction of severe RVGE ranged from a 55% reduction at full coverage to elimination with at least 80% coverage. Our models predicted short-term reductions in the incidence of RVGE that exceeded estimates of the direct effects, consistent with observations from the United States and other countries. Some of the models predicted that the short-term indirect benefits may be offset by a partial shifting of the burden of RVGE to older unvaccinated individuals. Nonetheless, even when such a shift occurs, the overall reduction in severe RVGE is considerable. Discrepancies among model predictions reflect uncertainties about age variation in the risk and reporting of RVGE, and the duration of natural and vaccine-induced immunity, highlighting important questions for future research.

Projected health and economic impact of rotavirus vaccination in GAVI-eligible countries: 2011-2030

Rotavirus is the leading cause of diarrheal disease in children under 5 years of age. It is responsible for more than 450,000 deaths each year, with more than 90% of these deaths occurring in low-resource countries eligible for support by the GAVI Alliance. Significant efforts made by the Alliance and its partners are providing countries with the opportunity to introduce rotavirus vaccines into their national immunization programs, to help prevent childhood illness and death. We projected the cost-effectiveness and health impact of rotavirus vaccines in GAVI-eligible countries, to assist decision makers in prioritizing resources to achieve the greatest health benefits for their populations. A decision-analytic model was used to project the health outcomes and direct costs of a birth cohort in the target population, with and without a rotavirus vaccine. Current data on disease burden, vaccine efficacy, immunization rates, and costs were used in the model. Vaccination in GAVI-eligible countries would prevent 2.46 million childhood deaths and 83 million disability-adjusted life years (DALYs) from 2011 to 2030, with annual reductions of 180,000 childhood deaths at peak vaccine uptake. The cost per DALY averted is $42 for all GAVI countries combined, over the entire period. Rotavirus vaccination would be considered very cost-effective for the entire cohort of GAVI countries, and in each country individually, as cost-effectiveness ratios are less than the gross domestic product (GDP) per capita. Vaccination is most cost-effective and has the greatest impact in regions with high rotavirus mortality. Rotavirus vaccination in GAVI-eligible countries is very cost-effective and is projected to substantially reduce childhood mortality in this population.