Rotavirus Hospitalizations Research Articles

Early impact of rotavirus vaccine in under 5 year old children hospitalized due to diarrhea, Swaziland

BackgroundSwaziland introduced rotavirus vaccine in the National Immunization Program, in May 2015, with the objective of reducing the burden of rotavirus diarrheal disease. We monitored the early impact of the vaccine in reducing rotavirus diarrhea. MethodsWe conducted sentinel rotavirus surveillance from January 2013 to December 2016 in children under five years of age admitted due to diarrhea attending Mbabane Government Referral Hospital in the Hhohho Region and Raleigh Fitkin Memorial Hospital in the Manzini Region. All cases had stool samples collected and tested for rotavirus antigen by enzyme immunoassay. ResultsBetween 2013 and 2016, 596 samples were collected and tested. Rotavirus positivity reduced from average of 50.8% (172/338) (in 2013–2014 (pre vaccine period)) to 29% (24/82) in 2016, post-vaccine introduction. The median age of children with rotavirus infection increased from average of 10months in 2013–2014 to 13.7months in 2016. The peak season for all-cause diarrhea and rotavirus-specific hospitalizations among children under five years of age was June–August in all years with a blunting of the peak season in 2016. Rotavirus positivity among children 0–11months reduced from an average of 49% in 2013–2014 (116/236) to 33% (15/45) in 2016, a 33% reduction following rotavirus vaccine introduction. ConclusionThere has been a rapid reduction of all-cause diarrhea and rotavirus hospitalizations in Swaziland, particularly in young children and during the rotavirus season, after the introduction rotavirus vaccine. Continued surveillance is needed to monitor the long-term impact of rotavirus vaccine introduction.

Hospitalised rotavirus gastroenteritis in New Zealand: The laboratory database is a valuable tool for assessing the impact of rotavirus vaccination.

To assess the impact of the introduction of rotavirus vaccination in New Zealand at a regional and national level, underlining the utility of a passively collected laboratory dataset. Retrospective laboratory data for rotavirus testing from Wellington and Hutt Hospitals from 1 January 2010 to 31 December 2016, matched with hospital admissions data of children under 5years of age with gastroenteritis primary and secondary coded admissions. The second part of the study examined the national dataset of primary coded hospital gastroenteritis admissions from the same period. Rotavirus testing was performed in 1054 (64.1%) of the 1645 gastroenteritis admissions to Wellington and Hutt Hospitals. Four hundred and nine of these tests (38.8%) were positive. Children who were not given a primary code of gastroenteritis accounted for 5.7% of rotavirus admissions. The estimated annual rotavirus hospitalisation rate in the Hutt and Wellington regions for children under 5years during the pre-vaccination period was 427.1 per 100,000. In the post-vaccination period (2015-2016), there was a 94.6% reduction in confirmed rotavirus gastroenteritis hospitalisations with only 8 confirmed cases. The total number of gastroenteritis admissions declined by 51.4%. On a national scale, there was a decline of 34.4% in the average annual number of gastroenteritis admissions and the number of coded rotavirus admissions was 87.1% lower than the pre-vaccination average. The non-restrictive continuous approach to rotavirus testing has provided a detailed description of the epidemiology of rotavirus gastroenteritis hospitalisations in the Wellington and Hutt regions. Rotavirus vaccination introduced on the crest of a peak in rotavirus cases has lead to a marked reduction in the number of admissions with gastroenteritis in New Zealand in the two years following vaccine introduction. The national figures likely underestimate the impact of the vaccine.

Effectiveness of rotavirus vaccines against hospitalisations in Japan

BackgroundIn Japan, rotavirus hospitalisation occurs at a rate from 2.8 to 13.7 per 1000 child-years among children age less than 5 years, and it imposes a substantial burden to the healthcare system in the country. While both monovalent (RV1) and pentavalent (RV5) rotavirus vaccines are licensed in Japan, neither has been incorporated in the national infant immunization programme. In this study, we estimated vaccine effectiveness (VE) in Japan.MethodsThis study was conducted in Yuri-Kumiai General Hospital located in a city in the north-western part of Japan. Age-eligible children for rotavirus vaccination were enrolled if they were hospitalized for rotavirus gastroenteritis between September 2013 and August 2016. Rotavirus gastroenteritis was defined by the detection of rotavirus antigen by immunochromatography. “Vaccinated” was defined as infant inoculated with at least one dose of either RV1 or RV5. A conditional logistic regression analysis was performed by modelling the year of birth, year of admission, residence of the children and vaccination status, and by matching the age of cases with that of test-negative controls. The adjusted odds ratio of the vaccinated over unvaccinated was then used to calculate VE in the formula of (1 – adjusted odds ratio) × 100.ResultsOut of the 244 patients enrolled, rotavirus antigen was detected in 55 (22.5%) of whom 10 (18.2%) were vaccinated, whereas 94 (49.7%) of 189 test-negative controls were vaccinated. During the study period, the vaccine uptake rate in the controls increased from 36.2% to 61.8%. On the other hand, the vaccination coverage over the three years was 64.2% in Yuri-Honjo city (three quarters of the catchment), and 91.4% in Nikaho city (one quarter of the catchment). The VE was calculated to be 70.4% (95% confidence interval: 36.0–86.4%, P = 0.002). The point estimate of the VE was lower but its 95% confidence interval overlaps those of the efficacies obtained from clinical trials in Japan.ConclusionThe rotavirus vaccine was effective in the real-world setting in Japan as in the clinical trials, and the introduction of rotavirus vaccine in the national infant immunization schedule will substantially reduce the number of rotavirus gastroenteritis hospitalisation in Japan.

Impact of self-financed rotavirus vaccines on hospital stays and costs in Spain after a 3-year introductory period.

Vaccination has reduced rotavirus hospitalizations by 25% in European regions with low-moderate vaccine availability. We aimed to quantify the reduction in hospital costs after the longest period in which Rotarix® and Rotateq® were simultaneously commercially available in Spain. Cases, length of stay (LOS), and diagnosis-related groups (DRGs) were retrieved from the Minimum Basic Data Set. Healthcare expenditure was estimated through the cost accounting system Gescot®. DRGs were clustered: I, non-bacterial gastroenteritis with complications; II, without complications; III, requiring surgical/other procedures or neonatal cases (highest DRG weights). Comparisons between pre (2003-2005)- and post-vaccine (2007-2009) hospital stays and costs by DRG group were made. Rotaviruses were the most common agents of specific-coded gastroenteritis (N = 1657/5012). LOS and extended LOS of rotaviruses fell significantly in 2007-2009 (β-coefficient = -0·43, 95% confidence intervals (95% CI) -0·68 to -0·17; and odds ratio 0·62, 95% CI 0·50-0·76, respectively). Overall, costs attributable to rotavirus hospitalizations fell approximately €244 per patient (95% CI -365 to -123); the decrease in DRG group III was €2269 per patient (95% CI -4098 to -380). We concluded modest savings in hospital costs, largely attributable to cases with higher DRG weights, and a faster recovery. A universal rotavirus vaccination program deserves being re-evaluated, regarding its potential high impact on both at-risk children and societal costs.

Efficacy, safety and effectiveness of licensed rotavirus vaccines: a systematic review and meta-analysis for Latin America and the Caribbean.

BackgroundRotaTeq™ (RV5; Merck & Co. Inc., USA) and Rotarix™ (RV1, GlaxoSmithKline, Belgium) vaccines, developed to prevent rotavirus diarrhea in children under five years old, were both introduced into national immunization programs in 2006. As many countries in Latin America and the Caribbean have included either RV5 or RV1 in their routine childhood vaccination programs, we conducted a systematic review and meta-analysis to analyze efficacy, safety and effectiveness data from the region.MethodsWe conducted a systematic search in PubMed, EMBASE, Scielo, Lilacs and the Cochrane Central Register, for controlled efficacy, safety and effectiveness studies published between January 2000 until December 2011, on RV5 and RV1 across Latin America (where both vaccines are available since 2006). The primary outcome measures were: rotavirus-related gastroenteritis of any severity; rotavirus emergency department visits and hospitalization; and severe adverse events.ResultsThe results of the meta-analysis for efficacy show that RV1 reduced the risk of any-severity rotavirus-related gastroenteritis by 65% (relative risk (RR) 0.35, 95% confidence interval (CI) 0.25; 0.50), and of severe gastroenteritis by 82% (RR 0.18, 95%CI 0.12; 0.26) versus placebo. In trials, both vaccines significantly reduced the risk of hospitalization and emergency visits by 85% (RR 0.15, 95%CI 0.09; 0.25) for RV1 and by 90% (RR 0.099, 95%CI 0.012; 0.77) for RV5. Vaccination with RV5 or RV1 did not increase the risk of death, intussusception, or other severe adverse events which were previously associated with the first licensed rotavirus vaccine. Real-world effectiveness studies showed that both vaccines reduced rotavirus hospitalization in the region by around 45–50% for RV5 (for 1 to 3 doses, respectively), and, by around 50–80% for RV1 (for 1 to 2 doses, respectively). For RV1, effectiveness against hospitalization was highest (around 80–96%) for children vaccinated before 12 months of age, compared with 5–60% effectiveness in older children. Both vaccines were most effective in preventing more severe gastroenteritis (70% for RV5 and 80–90% for RV1) and severe gastroenteritis (50% for RV5 and 70–80% for RV1).ConclusionThis systematic literature review confirms rotavirus vaccination has been proven effective and well tolerated in protecting children in Latin America and the Caribbean.

Evaluating the first introduction of rotavirus vaccine in Thailand: Moving from evidence to policy

BackgroundWe assessed the effectiveness and possible impact of introducing rotavirus vaccine into the routine immunization program. MethodsTwo provinces were selected for an observational study, one where vaccine was introduced and another where vaccine was not available. In these areas, two sub-studies were linked. The prospective cohort study enrolled children 2month old and followed them to the age of 18months to detect all diarrhea episodes. The hospital surveillance study enrolled all children up to age 5 hospitalized with diarrhea whose fecal samples were tested for rotavirus. Rates of rotavirus hospitalizations in older children who had not been vaccinated in both settings provided data to determine whether immunization had an indirect herd effect. The key endpoints for the study were both vaccine effectiveness (VE) based upon hospitalized rotavirus diarrhea and herd protection. FindingsFrom the cohort study, the overall VE for hospitalized rotavirus diarrhea was 88% (95%CI 76–94). Data from hospital surveillance indicated that for 2 consecutive years, the seasonal peak of rotavirus admissions was no longer present in the vaccinated area. Herd protection was observed among older children born before the rotavirus vaccine program was introduced, who experienced a 40–69% reduction in admission for rotavirus. ConclusionsRotavirus vaccine was highly effective in preventing diarrheal hospitalizations and in conferring herd protection among older children who had not been vaccinated.

Monovalent Rotavirus Vaccine Effectiveness and Impact on Rotavirus Hospitalizations in Zanzibar, Tanzania: Data From the First 3 Years After Introduction.

Low-income settings challenge the level of protection provided by live attenuated oral rotavirus vaccines. Rotarix (RV1) was introduced in the United Republic of Tanzania in early 2013, with 2 doses given at the World Health Organization-recommended schedule of ages 6 and 10 weeks, along with oral poliovirus vaccine. We performed active surveillance for rotavirus hospitalizations at the largest hospital in Zanzibar, Tanzania, from 2010 through 2015. Using a case-test-negative control design, we estimated the vaccine effectiveness (VE) of 2 RV1 doses in preventing rotavirus hospitalizations. Based on 204 rotavirus case patients and 601 test-negative controls aged 5-23 months, the VE of 2 RV1 doses against hospitalization for rotavirus diarrhea was 57% (95% confidence interval, 14%-78%). VE tended to increase against hospitalizations with higher severity, reaching 69% (95% confidence interval, 15%-88%) against the severity score for the top quarter of case patients. Compared with the prevaccine period, there were estimated reductions of 40%, 46%, and 69% in the number of rotavirus hospitalizations among infants in 2013, 2014, and 2015, respectively, and reductions of 36%, 26%, and 64%, respectively, among children aged <5 years. With data encompassing 3 years before and 3 years after vaccine introduction, our results indicate that successful delivery of RV1 on the current World Health Organization schedule can provide substantial health benefits in a resource-limited setting.

Rotavirus vaccine effectiveness in Hong Kong children

BackgroundRotavirus is a common infectious cause of childhood hospitalisation in Hong Kong. Rotavirus vaccines have been used in the private sector since licensure in 2006 but have not been incorporated in the government’s universal Childhood Immunisation Programme. This study aimed to evaluate rotavirus vaccine effectiveness against hospitalisation. MethodsThis case-control study was conducted in the 2014/2015 rotavirus season in six public hospitals. Hospitalised acute gastroenteritis patients meeting inclusion criteria were recruited and copies of their immunisation records were collected. Case-patients were defined as enrolled subjects with stool specimens obtained in the first 48h of hospitalisation that tested positive for rotavirus, whereas control-patients were those with stool specimens obtained in the first 48h of hospitalisation testing negative for rotavirus. Vaccine effectiveness for administration of at least one dose of either Rotarix® (GlaxoSmithKline Biologicals) or RotaTeq® (Merck Research Laboratories) was calculated as 1 minus the odds ratio for rotavirus vaccination history for case-patients versus control-patients. ResultsAmong the 525 eligible subjects recruited, immunisation records were seen in 404 (77%) subjects. 31% (162/525 and 126/404) tested positive for rotavirus. In the 404 subjects assessed for vaccine effectiveness, 2.4% and 24% received at least 1 dose of either rotavirus vaccine in case- and control-patients respectively. The unmatched vaccine effectiveness against hospitalisation for administration of at least one dose of either rotavirus vaccines was 92% (95% confidence interval [CI]: 75%, 98%). The matched analyses by age only and both age and admission date showed 96% (95% CI: 72%, 100%) and 89% (95% CI: 51%, 97%) protection against rotavirus hospitalisation respectively. ConclusionsRotavirus vaccine is highly effective in preventing hospitalisation from rotavirus disease in young Hong Kong children.

How Rainfall Matters? The Association between Rainfall and Rotavirus and Norovirus infection in Hong Kong

Introduction The association between temperature and infectious diseases has been well documented. However, the influence of change in the precipitation pattern is less known. This study aims to quantify the impact of precipitation on the hospitalizations due to norovirus and rotavirus infection in Hong Kong. Methods Daily counts of all Hong Kong public hospital admissions for norovirus and rotavirus infection from January 1st 2002 to December 31st 2011 were obtained. Generalized additive regression models were constructed for time-series analysis with hospitalizations as the outcome and meteorological variables, including rainfall, as predictors. Different lag effects of rainfall during the hot season and cool season were evaluated by distributed lag non-linear models. Results Less rainfall was associated with more admissions for rotavirus. Specifically, compared to 99th percentile of rainfall (128mm) in summer, no daily rainfall, about 34% of all days0, was found to be associated with a cumulative (0-13 days) 260% (95%CI 1.16-11.19) increase in the risk of rotavirus hospitalization. However, heavy precipitation was associated with more norovirus hospitalizations. The association was apparent at lags 0-3 in summer and 0-28 days in winter. Extreme rainfall (99th percentile) was associated with 1.18 (95%CI 1.01-1.39) times the risk of norovirus infection relative to no rainfall in summer. Norovirus hospitalizations were approximately linearly associated with precipitation in winter, with 10.17 (95%CI 3.07-33.64) times the cumulative risk of extreme rainfall (34mm) relative to no rainfall. Conclusions Rainfall has a strong short-term association with both norovirus and rotavirus hospitalizations in Hong Kong, which go in opposite directions. Climate change, which has been causing alterations of precipitation pattern worldwide, will also likely change norovirus and rotavirus infection patterns in subtropical Asian cities without further interventions.

Effectiveness of rotavirus vaccines against rotavirus infection and hospitalization in Latin America: systematic review and meta-analysis.

BackgroundRotavirus was the leading cause of childhood diarrhoea-related hospitalisations and death before the introduction of rotavirus vaccines.MethodsWe describe the effectiveness of rotavirus vaccines to prevent rotavirus infections and hospitalizations and the main rotavirus strains circulating before and after vaccine introduction through a systematic review and meta-analysis of studies published between 1990 and 2014. 203 studies were included to estimate the proportion of infections due to rotavirus and 10 to assess the impact of the vaccines. 41 of 46 studies in the post-vaccination period were used for meta-analysis of genotypes, 20 to calculate VE against infection, eight for VE against hospitalisation and seven for VE against severe rotavirus-diarrhoea.Results24.3 % (95 % CI 22.1–26.5) and 16.1 % (95 % CI 13.2–19.3) of cases of diarrhoea were due to rotavirus before and after vaccine introduction, respectively. The most prevalent G types after vaccine introduction were G2 (51.6 %, 95 % CI 38–65), G9 (14.5 %, 95 % CI 7–23) and G1 (14.2 %, 95 % CI 7–23); while the most prevalent P types were P[4] (54.1 %, 95 % CI 41–67) and P[8] (33 %, 95 % CI 22–46). G2P[4] was the most frequent genotype combination after vaccine introduction. Effectiveness was 53 % (95 % CI 46–60) against infection, 73 % (95 % CI, 66–78) against hospitalisation and 74 % (95 % CI, 68.0–78.0) against severe diarrhoea. Reductions in hospitalisations and mortality due to diarrhoea were observed in countries that adopted universal rotavirus vaccination.ConclusionsRotavirus vaccines are effective in preventing rotavirus-diarrhoea in children in Latin America. The vaccines were associated with changes in genotype distribution.Electronic supplementary materialThe online version of this article (doi:10.1186/s40249-016-0173-2) contains supplementary material, which is available to authorized users.

A Systematic Review of the Effect of Rotavirus Vaccination on Diarrhea Outcomes Among Children Younger Than 5 Years.

Rotavirus is the leading cause of vaccine-preventable diarrhea among children under 5 globally. Rotavirus vaccination has been shown to prevent severe rotavirus infections with varying efficacy and effectiveness by region. We sought to generate updated region-specific estimates of rotavirus vaccine efficacy and effectiveness. We systematically reviewed published vaccine efficacy and effectiveness studies to assess the region-specific effect of rotavirus vaccination on select diarrheal morbidity and mortality outcomes in children under 5 years of age. We employed meta-analytic methods to generate pooled effect sizes by Millennium Development Goal region. Rotavirus vaccination was both efficacious and effective in preventing rotavirus diarrhea, severe rotavirus diarrhea and rotavirus hospitalizations among children under 5 across all regions represented by the 48 included studies. Efficacy against severe rotavirus diarrhea ranged from 90.6% [95% confidence interval (CI): 82.3-95.0] in the developed region to 88.4% (95% CI: 67.1-95.9) in Eastern/Southeastern Asia, 79.6% (95% CI: 71.3-85.5) in Latin America and the Caribbean, 50.0% (95% CI: 34.4-61.9) in Southern Asia and 46.1% (95% CI: 29.1-59.1) in sub-Saharan Africa. Region-specific effectiveness followed a similar pattern. There was also evidence of vaccine efficacy against severe diarrhea and diarrheal hospitalizations. Our findings confirm the protective efficacy and effectiveness of rotavirus vaccination against rotavirus diarrheal outcomes among children under 5 globally.

Regional Variations in the Incidence of Rotavirus Hospitalization in Children Living in Defined Regions of Akita and Kyoto Prefectures, Japan.

Variable incidence rates of rotavirus gastroenteritis hospitalizations have been reported in Japan. However, it is not known whether the observed regional differences were due to the real difference in the occurrence of severe disease or other causes. This study aimed to determine the incidence rates of rotavirus hospitalization among children aged <5 years in the Yuri district in Akita prefecture and the Nantan district in Kyoto prefecture between March 2012 and February 2013. During this period, rotavirus vaccine uptake rates were equally low in both regions. All specimens were evaluated using the standardized case definition, severity scores, and the same assays. There were 44 rotavirus cases (44%) among 101 acute gastroenteritis-related hospitalizations in the Yuri district with a catchment population of 3,853, and 18 rotavirus cases (47%) among 38 acute gastroenteritis-related hospitalizations in the Nantan district with a catchment population of 5,128. While the severity score at the time of the hospitalizations was 11 in both hospitals, the incidence rates in Akita and Kyoto were 11.7 (95% confidence interval [CI]: 8.5-15.6) and 3.9 (95% CI: 2.1-5.5) per 1,000 child-years, respectively. Thus, there was a real difference in the occurrence rate of severe rotavirus infections between the 2 regions.

Decreases in Rotavirus Hospitalizations: Impact Data Pre- and 3 Years Post- First Publically Funded Programs

Abstract BACKGROUND: Since January 2012, almost all Canadian provinces have implemented publically funded rotavirus immunization programs. IMPACT had been doing routine active surveillance for rotavirus hospital-izations at pediatric hospitals in 7 provinces since 2005. OBJECTIVES: Determine changes in hospitalization for rotavirus infection pre and post vacination programs. DESIGN/METHODS: Active, surveillance of patients hospitalized for rotavirus infections was conducted by IMPACT from January 1 2010 to December 2015 at 12 paediatric hospitals. Rotavirus hospitalization data was compared for periods pre (2010-2011) and post (2012-2014) implementation of publically funded immunization programs. Six sites were located in jurisdictions that had publically funded programs as of January 2012. RESULTS: Initiation of rotavirus vaccine programs have resulted in a 43% overall reduction in hospitalizations for rotavirus infection in pediat-ric hospitals in Canada with the greatest decreases seen in provinces with programs that were established as of January 2012 where there was a 66% reduction in hospitalizations. Overall, the average yearly number of hospi-talizations for 2012-2014 was 279, compared to 490 in 2010-2011. Six sites with publically funded programs since 2012 had a yearly average of 121.3 cases identified in 2012-2014 compared to an average of 360 cases in 2010-2011. The average yearly number of hospital acquired cases decreased from 78 to 24.7 in sites with vaccine programs whereas sites without increased (26.5 to 33.7 average cases yearly). The proportion of cases occurring in children &amp;lt;2 years was significantly lower in sites with programs (51.6% vs. 72.5%; p&amp;lt;0.0001). In 2012-2014, 63.4% of children were &amp;lt;2 years compared to the period 2010-2011 where 67.7% were &amp;lt;2 years. The seasonal peak in infections has decreased over time, especially in the age groups 6-11 months and 12 to 24 months. CONCLUSION: Publically funded rotavirus vaccine programs have resulted in important reductions in hospitalizations due to community acquired and hospital acquired rotavirus infections in pediatric hospitals in Canada with the greatest decreases seen in provinces with programs that were established as of January 2012. The proportion of children &amp;lt; 2 years hospitalized with rotavirus infection is decreasing at sites with established programs. Given the &amp;gt;85% efficacy of rotavirus vaccine, increasing uptake and delivery throughout Canada could potentially decrease admissions further.

A multifactorial regression analysis of the features of community-acquired rotavirus requiring hospitalization in Spain as represented in the Minimum Basic Data Set.

Over 10% of acute rotavirus gastroenteritis (ARGE) requires hospitalization because of complications. The aggravating factors have been widely analysed, but in an isolated way. We aimed to explore the interrelationship between the clinical and epidemiological factors that characterize rotavirus hospitalizations in Spain using information from the Minimum Basic Data Set (MBDS). Using ICD-9-CM codes, we classified acute gastroenteritis (AGE) cases by principal diagnosis fields and then categorized their comorbidities, complications, and epidemiological features by secondary fields. A multivariable, logistic, step-wise regression model was then constructed. We identified 1657 ARGE cases from 17 415 cases of AGE. Rotavirus hospitalizations were associated with place of residence, age, and season (P < 0·0001), as well as with dehydration [odds ratio (OR) 12·44, 95% confidence interval (CI) 1·52-40·38], intravenous rehydration (OR 1·74, 95% CI 1·29-2·35), metabolic acidosis (OR 1·51, 95% CI 1·24-1·83), respiratory tract infections (RTIs) (OR 1·60, 95% CI 1·09-1·98), and concomitant AGE (OR 1·52, 95% CI 1·03-2·25). Dehydration was four times more likely in patients aged <5 years (OR 4·36, 95% CI 1·20-12·96) and was associated with acidosis when ARGE and RTI were present simultaneously (P < 0·0001). Specific co-infecting viruses may play a role in acute respiratory symptoms and aggravation of gastrointestinal manifestations of rotaviruses, thus leading to complications requiring hospitalization.

Impact and Effectiveness of Monovalent Rotavirus Vaccine Against Severe Rotavirus Diarrhea in Ghana.

Ghana was among the first African nations to introduce monovalent rotavirus vaccine (RV1) into its childhood immunization schedule in April 2012. We aimed to assess the impact of vaccine introduction on rotavirus and acute gastroenteritis (AGE) hospitalizations and to estimate vaccine effectiveness (VE). Using data from 2 teaching hospitals, monthly AGE and rotavirus admissions by age were examined 40 months before and 31 months after RV1 introduction using interrupted time-series analyses. From January 2013, we enrolled children <2 years of age who were eligible for RV1 from a total of 7 sentinel sites across the country. To estimate VE, we fit unconditional logistic regression models to calculate odds ratios of vaccination by rotavirus case-patient status, controlling for potential confounders. Vaccine coverage ranged from 95% to 100% for dose 1 and 93% to 100% for dose 2. In the first 3 years after vaccine introduction, the percentage of hospital admissions positive for rotavirus fell from 48% in the prevaccine period to 28% (49% adjusted rate reduction; 95% confidence interval [CI], 32%-63%) postvaccination among <5-year-olds. With high vaccine coverage, it was not possible to arrive at robust VE estimates; any-dose VE against rotavirus hospitalization was estimated at 60% (95% CI, -2% to 84%;P= .056). Results from the first 3 years following RV1 introduction suggest substantial reductions of pediatric diarrheal disease as a result of vaccination. Our VE estimate is consistent with the observed rotavirus decrease and with efficacy estimates from elsewhere in sub-Saharan Africa.

Impact and Effectiveness of Monovalent Rotavirus Vaccine in Armenian Children.

The Republic of Armenia was 1 of the 2 earliest countries in the Newly Independent States to introduce rotavirus vaccine into its national immunization program to reduce the burden of rotavirus disease (documented to cause 38% of acute gastroenteritis hospitalizations [AGE] among children aged <5 years). In November 2012, RV1 (Rotarix) was introduced for Armenian infants at ages 6 and 12 weeks. The established active surveillance system at 2 hospitals in the capital, Yerevan, whereby children aged <5 years hospitalized for AGE have stool sample tested for rotavirus antigen, was used to assess trends in rotavirus hospitalizations. Immunization records on children enrolled after vaccine introduction were obtained from clinics, and vaccine effectiveness (VE) was estimated using children with AGE who test negative for rotavirus as controls for the rotavirus-positive cases. Among infants, rotavirus hospitalizations were reduced by 48% within the first year after introduction, and by ≥75% in years 2 and 3 following introduction. Reductions of ≥30% in other young children too old to have been vaccinated suggest additional benefit through indirect protection; overall in year 3, rotavirus hospitalizations were reduced by 69% among children aged <5 years. The overall VE of 2 RV1 doses in protecting against rotavirus hospitalization (any severity) was 62% (95% confidence interval [CI], 36%-77%) among children aged 6-23 months; 68% (95% CI, 24%-86%) among those aged 6-11 months, and 60% (95% CI, 20%-80%) in children aged 12-23 months. Against more severe rotavirus disease, VE was 79% (95% CI, 55%-90%) and similarly high in both age groups. RV1 is effective in young Armenian children and substantially reduced rotavirus hospitalizations shortly after introduction.

Impact of Rotavirus Vaccine Introduction and Vaccine Effectiveness in the Republic of Moldova.

The Republic of Moldova was the first low- to middle-income country in the World Health Organization European Region to introduce rotavirus vaccine (July 2012). We aimed to assess the impact of the rotavirus vaccine program and estimate vaccine effectiveness (VE). Surveillance for rotavirus gastroenteritis was conducted in 2 hospitals in the capital city of Chisinau starting in September 2009. Monthly rotavirus admissions by age were examined before and after introduction of rotavirus vaccination using interrupted time-series analyses. We performed a case-control study of VE by comparing rotavirus case patients with test-negative controls. Coverage with at least 1 dose of vaccine increased from 35% in year 1 to 55% in year 2 for children <1 year of age. The percentage of hospital admissions positive for rotavirus fell from 45% in the prevaccine period to 25% (rate reduction, 36%; 95% confidence interval [CI], 26%-44%) and 14% (rate reduction, 67%; 95% CI, 48%-88%) in the first and second years after vaccine introduction, respectively, among children aged <5 years. Reductions were most pronounced among those aged <1 year. Significant reductions among cohorts too old to be vaccinated suggest indirect benefits. Two-dose VE was 79% (95% CI, 62%-88%) against rotavirus hospitalization and 84% (95% CI, 64%-93%) against moderate to severe rotavirus. These results consistently point to profound direct and herd immunity impacts of the rotavirus vaccine program in young children in the Republic of Moldova. Vaccine coverage was modest in these early years following introduction, so there remains potential for further disease reductions.

Impact of Rotavirus Vaccination on Diarrheal Hospitalizations in Children Aged

Monovalent rotavirus vaccine was introduced in the routine public health immunization program in Lusaka, Zambia, in January 2012 and was rolled out countrywide in November 2013. We examined the effect of rotavirus vaccination on hospitalization for all-cause acute gastroenteritis (AGE) and rotavirus-specific AGE at a large referral hospital in Lusaka. Data were derived from ongoing hospital-based AGE surveillance from January 2009 to December 2014. Pre-rotavirus vaccine introduction (2009-2011) and post-rotavirus vaccine introduction (2013-2014) periods were compared for annual changes in hospitalizations for AGE and rotavirus; 2012 was excluded as a transition year. Hospital administrative discharge data were used to compare trends in all-cause diarrhea discharges and in-hospital diarrhea deaths captured by HIMS pre- and post-rotavirus vaccine introduction. Between January 2009 and December 2014, 5937 children <5 years of age presenting with AGE had their stools collected and tested for rotavirus by enzyme immunoassay. The rotavirus positivity rate declined from 40.1% (449/1121) in prevaccine years to 30.2% (250/828;P< .001) in 2013 and 24.7% (157/635;P< .001) in 2014. The greatest reduction was noted in infants, with the rotavirus positivity rate in this age group declining from 40.9% in prevaccine years to 34.0% (P= .009) in 2013 and 26.2% (P< .001) in 2014. Following rotavirus vaccine introduction, seasonal peaks of rotavirus and all-cause AGE were dwarfed. From HIMS data, compared to the prevaccine era, reductions of 18%-29% in all-cause diarrhea hospitalizations and 27%-33% in-hospital diarrhea deaths among children <1 year of age were observed in 2013 and 2014. We observed a significant reduction in AGE-associated in-hospital morbidity and mortality following rotavirus vaccine introduction. The greatest reduction was seen in infants <1 year who accounted for 84.4% of rotavirus hospitalizations prior to vaccine introduction.

Population Impact and Effectiveness of Monovalent Rotavirus Vaccination in Urban Malawian Children 3 Years After Vaccine Introduction: Ecological and Case-Control Analyses.

Background. Rotavirus vaccines have been introduced in many low-income African countries including Malawi in 2012. Despite early evidence of vaccine impact, determining persistence of protection beyond infancy, the utility of the vaccine against specific rotavirus genotypes, and effectiveness in vulnerable subgroups is important.Methods. We compared rotavirus prevalence in diarrheal stool and hospitalization incidence before and following rotavirus vaccine introduction in Malawi. Using case-control analysis, we derived vaccine effectiveness (VE) in the second year of life and for human immunodeficiency virus (HIV)–exposed and stunted children.Results. Rotavirus prevalence declined concurrent with increasing vaccine coverage, and in 2015 was 24% compared with prevaccine mean baseline in 1997–2011 of 32%. Since vaccine introduction, population rotavirus hospitalization incidence declined in infants by 54.2% (95% confidence interval [CI], 32.8–68.8), but did not fall in older children. Comparing 241 rotavirus cases with 692 test-negative controls, VE was 70.6% (95% CI, 33.6%–87.0%) and 31.7% (95% CI, −140.6% to 80.6%) in the first and second year of life, respectively, whereas mean age of rotavirus cases increased from 9.3 to 11.8 months. Despite higher VE against G1P[8] than against other genotypes, no resurgence of nonvaccine genotypes has occurred. VE did not differ significantly by nutritional status (78.1% [95% CI, 5.6%–94.9%] in 257 well-nourished and 27.8% [95% CI, −99.5% to 73.9%] in 205 stunted children; P = .12), or by HIV exposure (60.5% [95% CI, 13.3%–82.0%] in 745 HIV-unexposed and 42.2% [95% CI, −106.9% to 83.8%] in 174 exposed children; P = .91).Conclusions. Rotavirus vaccination in Malawi has resulted in reductions in disease burden in infants <12 months, but not in older children. Despite differences in genotype-specific VE, no genotype has emerged to suggest vaccine escape. VE was not demonstrably affected by HIV exposure or stunting.

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

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. 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. 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. 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.