Intussusception, rotavirus, and oral vaccines: summary of a workshop

Evaluation of Intussusception Following Pentavalent Rotavirus Vaccine (RotaTeq) Administration in 5 African Countries

BACKGROUND

A low-level risk of intussusception following rotavirus vaccination has been observed in some settings and may vary by vaccine type. We examined the association between RotaTeq vaccination and intussusception in low-income settings in a pooled analysis from 5 African countries that introduced RotaTeq into their national immunization program.

METHODS

Active surveillance was conducted at 20 hospitals to identify intussusception cases. A standard case report form was completed for each enrolled child, and vaccination status was determined by review of the child's vaccination card. The pseudo-likelihood adaptation of self-controlled case-series method was used to assess the association between RotaTeq administration and intussusception in the 1-7, 8-21, and 1-21 day periods after each vaccine dose in infants aged 28-245 days.

RESULTS

Data from 318 infants with confirmed rotavirus vaccination status were analyzed. No clustering of cases occurred in any of the risk windows after any of the vaccine doses. Compared with the background risk of naturally occurring intussusception, no increased risk was observed after dose 1 in the 1-7 day (relative incidence = 2.71; 95% confidence interval [CI] = 0.47-8.03) or the 8-21 day window (relative incidence = 0.77; 95%CI = 0.0-2.69). Similarly, no increased risk of intussusception was observed in any risk window after dose 2 or 3.

CONCLUSIONS

RotaTeq vaccination was not associated with increased risk of intussusception in this analysis from 5 African countries. This finding mirrors results from similar analyses with other rotavirus vaccines in low-income settings and highlights the need for vaccine-specific and setting-specific risk monitoring.

Characteristics of intussusception among children in Hokkaido, Japan, during the pre- and post-rotavirus vaccine eras (2007-2016)

AIM

To analyse the epidemiology of intussusception in Hokkaido Prefecture, Japan during a 10-year period spanning the introduction of the rotavirus (RV) vaccine (2007-2016).

METHODS

Using a standard questionnaire, a retrospective surveillance was conducted across 17 hospitals with paediatric beds in Hokkaido Prefecture. We compared the data between the pre-vaccine era (2007-2011) and post-vaccine era (2012-2016).

RESULTS

In total, 208 and 110 intussusception cases were in the pre- and post-vaccine eras, respectively. A significant reduction of the intussusception incidence in children aged <1 year was observed from the pre- to the post-vaccine era (102.4-56.5 per 100 000 infants; incidence rate ratio, 0.55; p = 0.004). There was a relatively high-positive RV antigen detection rate (29.4%, 5/17) during the RV epidemic period in Japan (March-May) in the pre-vaccine era. None of the intussusception cases in the 31 patients with a history of RV vaccination occurred within 1 month after the administration of an RV vaccine dose.

CONCLUSIONS

The incidence of intussusception in children aged <1 year decreased significantly after RV vaccine introduction in Japan. Another survey is needed to determine how the incidence of intussusception has changed further since the introduction of routine RV vaccination in 2020.

Review of Over 15 Years Postmarketing Safety Surveillance Spontaneous Data for the Human Rotavirus Vaccine (Rotarix) on Intussusception

Introduction

Rotavirus (RV) is the most common cause of acute gastroenteritis in children <5 years of age worldwide, and vaccination reduces the disease burden. Evidence from postmarketing surveillance studies suggested an increased risk of intussusception (IS) in infants post-RV vaccination. An overall positive benefit–risk balance for the human RV vaccine (HRV) Rotarix (GlaxoSmithKline [GSK], Belgium) has been established and recent findings indicate an indirect effect of reduced IS over the long term.

Objective

The aim of this study was to discuss spontaneous data from the GSK worldwide safety database on IS post-Rotarix administration.

Methods

The database was reviewed for all spontaneous IS cases from 2004 to 2020. Additionally, an observed versus expected (O/E) analysis was done for adverse events attributed to IS. Data were reviewed as overall worldwide and stratified by region (Europe/USA/Japan) and dose.

Results

A male predominance of IS patients was observed, consistent with earlier reports. The most frequently reported events in confirmed IS cases (Brighton Collaboration Working Group [BCWG] level 1) with time to onset ≤ 30 days post-vaccination were vomiting (55.8%), haematochezia (47.2%), and crying (21.1%). The observations from the IS spontaneous cases review and results of the O/E analysis are consistent with the known IS safety profile of RV vaccines: a transient increased incidence of IS post-vaccination (primarily in Europe/Japan/worldwide), mostly within 7 days postdose 1.

Conclusion

Since the outcomes of early IS management are favourable over delayed management, healthcare professionals should inform parents about the importance of seeking immediate medical advice in case of unusual behaviour of the vaccinated infant. GSK continues to monitor the IS risk post-Rotarix administration through routine pharmacovigilance activities.

Graphic abstract

Supplementary Information

The online version contains supplementary material available at 10.1007/s40264-021-01141-4.

Rotavirus (RV) is the most common cause of acute gastroenteritis and a major cause of death in young children worldwide. Vaccination has been instrumental in reducing the impact of RV disease. Real-world evidence suggests an increased risk of intussusception (an infrequent type of bowel obstruction) in infants following RV vaccination. We reviewed IS cases reported spontaneously worldwide in children following a two-dose vaccination with the human RV vaccine (Rotarix, GlaxoSmithKline [GSK]) since its launch in 2004. We observed that (1) IS occurred more frequently 7 days after the first dose and, to a lesser extent, after the second dose; (2) boys were more frequently affected than girls (56.3%); (3) of 862 confirmed reported cases, 557 required hospitalisation; and (4) surgical intervention was required for 294 of 557 hospitalised cases. We used statistical analysis to assess whether the number of cases observed would be higher or lower than the natural occurrence of IS (irrespective of vaccination). These results were in line with the known RV vaccine safety profile. It is important to constantly monitor the real-world safety profile of RV vaccines in the postmarketing setting. Since the outcomes of early management of IS are favourable compared with delayed management, healthcare professionals should inform parents to seek immediate medical advice if they observe unusual behaviour in their vaccinated child. In conclusion, our analyses on data of a large patient pool for this rare event reinforce the favourable safety profile of human RV vaccine and the benefits of vaccination in young children.

Acute intestinal intussusception among children under five years of age admitted in an Ouagadougou hospital, Burkina Faso, 2008-2013: epidemiological, clinical and therapeutic aspects

Introduction

acute intestinal intussusception is a life-threatening surgical condition. In some settings, rotavirus vaccines have been associated with a low-level increased risk of intussusception. We describe the epidemiology, clinical manifestations and management of intussusception in a tertiary referral hospital in Burkina Faso prior to the introduction of rotavirus vaccine in October 2013.

Methods

we retrospectively reviewed medical records of all children under 5 years of age treated at the Charles de Gaulle Pediatric Hospital for intussusception meeting the Brighton level 1 diagnostic criteria, from October 31st, 2008 to October 30th, 2013. We report the incidence of intussusception as well as descriptive characteristics of these cases.

Results

a total of 107 Brighton level 1 intussusception cases were identified, representing a hospital incidence of 21.4 cases / year. There were 69 males and 38 females (sex ratio of 1.8), with a median age of 8 months (range 2 months to 4 years). Sixty-two percent of intussusception cases occurred among infants (n = 67 cases). The average time from symptom onset to seeking medical consultation was 3.8 days +/- 2.7 (range 0 to 14 days). Treatment was mainly surgical (105 patients, 98.1%) with 35 patients (32.7%) undergoing intestinal resection. Thirty-seven patients (35.5%) experienced post-operative complications. The mortality rate was 9.3%. Intestinal resection was a risk factor for death from intussusception.

Conclusion

in this review of intussusception hospitalizations prior to rotavirus vaccine introduction in Burkina Faso, delays in seeking care were common and were associated with mortality.

Intussusception in children under five years of age in Enugu, Nigeria

Introduction

intussusception is the invagination of a segment of the bowel into a distal segment. It occurs predominantly in infants worldwide. Following documentation of increased incidence after introduction of the first rotavirus vaccine (Rotashield, Wyeth-Lederle), it has become a standard recommendation to maintain surveillance for intussusception as newer rotavirus vaccines are introduced into EPI. Nigeria plans to introduce rotavirus vaccine in 2020. Pre-vaccine introduction surveillance will serve as a baseline to understand the epidemiology of intussusception in Nigeria.

Methods

from 2013 to 2017, prospective enrolment of under five children with intussusception was done following the WHO protocol and using the WHO case report form. Only children who met the Pan American Health Organization/World Health Organization (PAHO/WHO) protocol case definition for intussusception were enrolled. These children were monitored until discharge or death. Clinical features and outcome were recorded in the case report form.

Results

a total of 63 cases were enrolled, with age range of 3 to 42 months (median: 6 months, IQR: 5-9 months). Majority were within 4-6 months and 96% were < 12 months old. There were 41 males and 22 females (male to female ratio of 1.9:1). Duration of symptoms before presentation ranged from 2 hours to 15 days (median: 72 hours). Fifty-seven patients had abdominal ultrasound and 52 patients (83%) had surgery. Case fatality rate was 9% and duration of hospitalization ranged from 1 to 30 days (median 10 days, IQR 8-15 days).

Conclusion

intussusception occurred most commonly in infants but well beyond the proposed age for rotavirus vaccination in the population studied. Late presentation and surgical intervention were common. This data provides a good baseline description of the epidemiology of intussusception.

Novel vaccine safety issues and areas that would benefit from further research

Vaccine licensure requires a very high safety standard and vaccines routinely used are very safe. Vaccine safety monitoring prelicensure and postlicensure enables continual assessment to ensure the benefits outweigh the risks and, when safety problems arise, they are quickly identified, characterised and further problems prevented when possible. We review five vaccine safety case studies: (1) dengue vaccine and enhanced dengue disease, (2) pandemic influenza vaccine and narcolepsy, (3) rotavirus vaccine and intussusception, (4) human papillomavirus vaccine and postural orthostatic tachycardia syndrome and complex regional pain syndrome, and (5) RTS,S/adjuvant system 01 malaria vaccine and meningitis, cerebral malaria, female mortality and rebound severe malaria. These case studies were selected because they are recent and varied in the vaccine safety challenges they elucidate. Bringing these case studies together, we develop lessons learned that can be useful for addressing some of the potential safety issues that will inevitably arise with new vaccines.

Retrospective Case-Control Study of 2017 G2P[4] Rotavirus Epidemic in Rural and Remote Australia

Background: A widespread G2P[4] rotavirus epidemic in rural and remote Australia provided an opportunity to evaluate the performance of Rotarix and RotaTeq rotavirus vaccines, ten years after their incorporation into Australia’s National Immunisation Program. Methods: We conducted a retrospective case-control analysis. Vaccine-eligible children with laboratory-confirmed rotavirus infection were identified from jurisdictional notifiable infectious disease databases and individually matched to controls from the national immunisation register, based on date of birth, Aboriginal status and location of residence. Results: 171 cases met the inclusion criteria; most were Aboriginal and/or Torres Strait Islander (80%) and the median age was 19 months. Of these cases, 65% and 25% were fully or partially vaccinated, compared to 71% and 21% of controls. Evidence that cases were less likely than controls to have received a rotavirus vaccine dose was weak, OR 0.79 (95% CI, 0.46–1.34). On pre-specified subgroup analysis, there was some evidence of protection among children <12 months (OR 0.48 [95% CI, 0.22–1.02]), and among fully vs. partially vaccinated children (OR 0.65 [95% CI, 0.42–1.01]). Conclusion: Despite the known effectiveness of rotavirus vaccination, a protective effect of either rotavirus vaccine during a G2P[4] outbreak in these settings among predominantly Aboriginal children was weak, highlighting the ongoing need for a more effective rotavirus vaccine and public health strategies to better protect Aboriginal children.

The control of diarrhea, the case of a rotavirus vaccine

[No disponible]

Intussusception among Norwegian children: What to expect after introduction of rotavirus vaccination?

BACKGROUND

To reduce the risk of vaccine-associated intussusception, rotavirus vaccination in Norway was implemented under strict age limits (the first dose given by 12 weeks of age and the second dose by 16 weeks of age) in 2014. We estimated the incidence of intussusception in children <2 years old before vaccine introduction and the number of vaccine-associated cases under current and extended age limits for vaccine administration in Norway.

METHODS

To estimate the baseline incidence, we validated all diagnoses in children <2 years old registered in the national hospital registry during the pre-vaccine period of 2008-2013. Using national vaccine coverage data and international estimates of intussusception risk after rotavirus vaccination, we calculated the numbers of expected vaccine-associated intussusception cases to compare with the estimated numbers of averted rotavirus cases. Uncertainty was accounted for by several scenario analyses using current and extended age limits for vaccine administration.

RESULTS

The pre-vaccine incidence of intussusception was 26.7 (95% CI 23.1-30.6) cases/year per 100,000 children <2 years old and 37.1 (95% CI 31.2-43.8) cases/year per 100,000 children <1 year old. In the 2016 birth cohort (approx. 60,000) vaccinated under the current age limits, 1.3 (95% CI 0.7-2.0) vaccine-associated intussusception cases were expected to occur. If age limits were extended to 16 weeks for the first vaccine dose and 24 weeks for the second dose, leading to more children vaccinated at an older age, 2.2 (95% CI 1.2-3.5) excess cases would be expected in the same cohort. Simultaneously, an estimated 1768 rotavirus hospitalizations/year in children <5 years old would be averted under current age limits, with 98 additional rotavirus hospitalizations averted under extended age limits.

CONCLUSIONS

Administering rotavirus vaccines beyond current age limits in Norway would lead to a marginal increase in the number of intussusception cases, which would be offset by the benefits of vaccination.

The National Vaccine Advisory Committee at 30: Impact and opportunity

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NVAC activities improved the U.S. immunization enterprise over the past 30 years.

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NVAC focused on the implementation of immunization across the lifespan and system.

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Tracking the implementation of NVAC recommendations remains difficult.

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Standards for practicesacross the lifespan continue to help practitioners immunize.

Thirty years after passage of legislation that created the National Vaccine Advisory Committee (NVAC) “to achieve optimal prevention of human infectious diseases through immunization and to achieve optimal prevention against adverse reactions to vaccines,” this review reflects NVAC’s role and impact on the U.S. vaccine and immunization enterprise as an external advisor to the Department of Health and Human Services. We reviewed the history of NVAC in the context of the principles of its establishment, with a focus on its reports and recommendations. We performed a systematic literature review to identify NVAC reports published in widely-accessible public health journals, and we reviewed the available archives to identify other reports and resolutions approved by the committee not published in journals. We characterized key issues considered by NVAC according to the five goals of the 2010 National Vaccine Plan. The predominance of NVAC activities to date related to the implementation of immunization across the lifespan and the many aspects of the system needed to foster the goal of full immunization. Reflecting on the impacts of NVAC to date, this review identified 30 NVAC approved reports published in journals, 22 stand-alone resolutions, and 26 unique unpublished reports. The development of new and improved vaccines continues to represent a significant priority for NVAC, and we identified several challenges related to future vaccine innovation. Given the many factors that impact on policy changes in the vaccine and immunization enterprise, we encountered challenges associated with demonstrating attribution of specific policy changes to NVAC recommendations. Although difficult to quantify, this review suggests that NVAC played an important role in the improvements in the U.S. immunization enterprise over the past 30 years and that NVAC can and will continue to play an important role supporting U.S. immunization going forward.

Rotavirus Vaccines: Effectiveness, Safety, and Future Directions

Rotavirus is the leading cause of diarrheal death among children < 5 years old worldwide, estimated to have caused ~ 215,000 deaths in 2013. Prior to rotavirus vaccine implementation, > 65% of children had at least one rotavirus diarrhea illness by 5 years of age and rotavirus accounted for > 40% of all-cause diarrhea hospitalizations globally. Two live, oral rotavirus vaccines have been implemented nationally in > 100 countries since 2006 and their use has substantially reduced the burden of severe diarrheal illness in all settings. Vaccine efficacy and effectiveness estimates suggest there is a gradient in vaccine performance between low child-mortality countries (> 90%) and medium and high child-mortality countries (57-75%). Additionally, an increased risk of intussusception (~ 1-6 per 100,000 vaccinated infants) following vaccination has been documented in some countries, but this is outweighed by the large benefits of vaccination. Two additional live, oral rotavirus vaccines were recently licensed and these have improved on some programmatic limitations of earlier vaccines, such as heat stability, cost, and cold-chain footprint. Non-replicating rotavirus vaccines that are parenterally administered are in clinical testing, and these have the potential to reduce the performance differential and safety concerns associated with live oral rotavirus vaccines.

Evaluation of Intussusception after Monovalent Rotavirus Vaccination in Africa

BACKGROUND

Postlicensure evaluations have identified an association between rotavirus vaccination and intussusception in several high- and middle-income countries. We assessed the association between monovalent human rotavirus vaccine and intussusception in lower-income sub-Saharan African countries.

METHODS

Using active surveillance, we enrolled patients from seven countries (Ethiopia, Ghana, Kenya, Malawi, Tanzania, Zambia, and Zimbabwe) who had intussusception that met international (Brighton Collaboration level 1) criteria. Rotavirus vaccination status was confirmed by review of the vaccine card or clinic records. The risk of intussusception within 1 to 7 days and 8 to 21 days after vaccination among infants 28 to 245 days of age was assessed by means of the self-controlled case-series method.

RESULTS

Data on 717 infants who had intussusception and confirmed vaccination status were analyzed. One case occurred in the 1 to 7 days after dose 1, and 6 cases occurred in the 8 to 21 days after dose 1. Five cases and 16 cases occurred in the 1 to 7 days and 8 to 21 days, respectively, after dose 2. The risk of intussusception in the 1 to 7 days after dose 1 was not higher than the background risk of intussusception (relative incidence [i.e., the incidence during the risk window vs. all other times], 0.25; 95% confidence interval [CI], <0.001 to 1.16); findings were similar for the 1 to 7 days after dose 2 (relative incidence, 0.76; 95% CI, 0.16 to 1.87). In addition, the risk of intussusception in the 8 to 21 days or 1 to 21 days after either dose was not found to be higher than the background risk.

CONCLUSIONS

The risk of intussusception after administration of monovalent human rotavirus vaccine was not higher than the background risk of intussusception in seven lower-income sub-Saharan African countries. (Funded by the GAVI Alliance through the CDC Foundation.).

Preparing for rotavirus vaccine introduction - A retrospective assessment of the epidemiology of intussusception in children below 2 years of age in Nepal

BACKGROUND

Rotavirus is the most common cause of severe diarrhea in Nepali children, accounting for 25-33% of childhood diarrhea hospitalizations. Two rotavirus vaccines recommended for inclusion in national immunization programs have been associated with a low risk of intussusception in post-marketing studies conducted in several countries. Data on the epidemiology of intussusception hospitalizations are lacking in Nepal. Thus, we aimed to describe the epidemiology of intussusception-associated hospitalizations among Nepali children in preparation for rotavirus vaccine introduction.

METHODS

A retrospective review of intussusception hospitalizations for a three year period was conducted at two major pediatric hospitals in Kathmandu, Nepal. Possible intussusception cases were identified through admission, discharge, and operation theater logs and ultrasound registers. Cases with a diagnosis of possible intussusception were selected for medical record review and classified as confirmed if they met the Brighton Collaboration level 1 criteria of diagnostic certainty and the child was aged < 24 months. Data on demographics, clinical course, and outcome were abstracted and analyzed.

RESULTS

Eight-five confirmed intussusception cases were identified; most (96%) were confirmed at surgery. The number of intussusception cases peaked between ages 4-7 months; no cases occurred in children 0-2 months. Fifty-nine (64%) case-patients were male. The median duration of symptoms before admission was 2 days (range: 0-14). Abdominal pain, bloody stool, and vomiting were the most common clinical features. All cases underwent surgical treatment; there was only one death.

CONCLUSIONS

This is the first study to evaluate the epidemiology of intussusception hospitalizations among children aged < 24 months in Nepal. Because the public health impact of rotavirus vaccination could be substantial in Nepal, where childhood diarrhea-related morbidity and mortality are high, this baseline knowledge of intussusception prior to introduction of rotavirus vaccine in the national immunization schedule will provide useful information for post-vaccine introduction safety monitoring.

Intussusception-related Hospitalizations Among Infants Before and After Private Market Licensure of Rotavirus Vaccines in Taiwan, 2001-2013

INTRODUCTION

Rotavirus is a leading cause of acute gastroenteritis among Taiwanese children. Two globally licensed rotavirus vaccines recommended for inclusion in routine immunization programs that have been available for private market use in Taiwan since 2006 have been associated with a low risk of intussusception in postmarketing studies conducted in several countries. Our objective was to examine trends and characteristics of intussusception hospitalizations in Taiwan among children <12 months of age before and after rotavirus vaccine licensure to provide updated baseline and early postlicensure data.

METHODS

We extracted data on intussusception-related hospitalizations among children <12 months of age during 2001-2013 from the National Health Insurance Research Database. We examined patient demographics, clinical outcome and hospitalization trends, focusing on recommended ages for rotavirus vaccination (6-14, 15-24 and 25-34 weeks). We compared mean hospitalization rates for prevaccine licensure years 2001-2005 with those for postvaccine licensure years 2007-2013 using Poisson regression analysis.

RESULTS

During 2001-2013, 1998 intussusceptions hospitalizations were recorded. The mean age of hospitalization was 33 weeks. Almost all children recovered; 3 deaths occurred. The overall intussusception hospitalization rate was 75.1 per 100,000; seasonality was not evident. Hospitalization rates were greatest in children ≥25 weeks of age and occurred more frequently in boys. Prevaccine and postvaccine licensure trends in annual hospitalization rates did not significantly differ. However, mean hospitalization rates were lower during the postvaccine licensure period for children <12 months of age (rate ratio: 0.84, 95% confidence interval: 0.76-0.92) with the greatest decline among children 25-34 weeks of age (rate ratio: 0.66, 95% confidence interval: 0.55-0.78).

CONCLUSIONS

Infant intussusception in Taiwan occurs at a rate within the range of other Asian countries is rare among children <3 months of age, has a male predominance and does not have a clear seasonality pattern. We did not observe a postlicensure increase in intussusception hospitalization rates in children 6-14 weeks of age.

Management for intussusception in children

BACKGROUND

Intussusception is a common abdominal emergency in children with significant morbidity. Prompt diagnosis and management reduces associated risks and the need for surgical intervention. Despite widespread agreement on the use of contrast enema as opposed to surgery for initial management in most cases, debate persists on the appropriate contrast medium, imaging modality, pharmacological adjuvant, and protocol for delayed repeat enema, and on the best approach for surgical management for intussusception in children.

OBJECTIVES

To assess the safety and effectiveness of non-surgical and surgical approaches in the management of intussusception in children.

SEARCH METHODS

We searched the following electronic databases: Cochrane Central Register of Controlled Trials (CENTRAL; 2016, Issue 8) in the Cochrane Library; Ovid MEDLINE (1950 to September 2016); Ovid Embase (1974 to September 2016); Science Citation Index Expanded (via Web of Science) (1900 to September 2016); and BIOSIS Previews (1969 to September 2016).We examined the reference lists of all eligible trials to identify additional studies. To locate unpublished studies, we contacted content experts, searched the World Health Organization International Clinical Trials Registry Platform (ICTRP) and ClinicalTrials.gov (September 2016), and explored proceedings from meetings of the British Association of Paedatric Surgeons (BAPS), the American Soceity of Pediatric Surgery, and the World Congress of Pediatric Surgery.

SELECTION CRITERIA

We included all randomised controlled trials comparing contrast media, imaging modalities, pharmacological adjuvants, protocols for delayed repeat enema, and/or surgical approaches for the management of intussusception in children. We applied no language, publication date, or publication status restrictions.

DATA COLLECTION AND ANALYSIS

Two review authors independently conducted study selection and data extraction and assessed risk of bias using a standardised form. We resolved disagreements by consensus with a third review author when necessary. We reported dichotomous outcomes as risk ratios (RRs) with 95% confidence intervals (CIs). We analysed data on an intention-to-treat basis and evaluated the overall quality of evidence supporting the outcomes by using GRADE criteria.

MAIN RESULTS

We included six randomised controlled trials (RCTs) with a total of 822 participants. Two trials compared liquid enema reduction plus glucagon versus liquid enema alone. One trial compared liquid enema plus dexamethasone versus liquid enema alone. Another trial compared air enema plus dexamethasone versus air enema alone, and two trials compared use of liquid enema versus air enema. We identified three ongoing trials.We judged all included trials to be at risk of bias owing to omissions in reported methods. We judged five of six trials as having high risk of bias in at least one domain. Therefore, the quality of the evidence (GRADE) for outcomes was low. Interventions and data presentation varied greatly across trials; therefore meta-analysis was not possible for most review outcomes. Enema plus glucagon versus enema alone It is uncertain whether use of glucagon improves the rate of successful reduction of intussusception when compared with enema alone (reported in two trials, 218 participants; RR 1.09, 95% CI 0.94 to 1.26;low quality of evidence). No trials in this comparison reported on the number of children with bowel perforation(s) nor on the number of children with recurrent intussusception. Enema plus dexamethasone versus enema alone Use of the adjunct, dexamethasone, may be beneficial in reducing intussusception recurrence with liquid or air enema (two trials, 299 participants; RR 0.14, 95% CI 0.03 to 0.60; low quality of evidence). This equates to a number needed to treat for an additional beneficial outcome of 13 (95% CI 8 to 37). It is uncertain whether use of the adjunct, dexamethasone, improves the rate of successful reduction of intussusception when compared with enema alone (reported in two trials, 356 participants; RR 1.01, 95% CI 0.92 to 1.10;low quality of evidence). Air enema versus liquid enema Air enema may be more successful than liquid enema for reducing intussusception (two trials, 199 participants; RR 1.28, 95% CI 1.10 to 1.49; low quality of evidence). This equates to a number needed to treat for an additional beneficial outcome of 6 (95% CI 4 to 19). No trials in this comparison reported on the number of children with bowel perforation(s) or on the number of children with recurrent intussusception nor any intraoperative complications, such as bowel perforation, or other adverse effects. Only one trial reported postoperative complications, but owing to the method of reporting used, a quantitative analysis was not possible. We identified no studies that exclusively evaluated surgical interventions for management of intussusception.

AUTHORS' CONCLUSIONS

This review identified a small number of trials that assessed a variety of interventions. All included trials provided evidence of low quality and were subject to serious concerns about imprecision, high risk of bias, or both. Air enema may be superior to liquid enema for successfully reducing intussusception in children; however, this finding is based on a few studies including small numbers of participants. Dexamethasone as an adjuvant may be more effective in reducing intussusception recurrence rates following air enema or liquid enema, but these results are also based on a few studies of small numbers of participants. This review highlights several points that need to be addressed in future studies, including reducing the risk of bias and including relevant outcomes. Specifically, surgical trials are lacking, and future research is needed to address this evidence gap.

Review of Naturally Occurring Intussusception in Young Children in the WHO African Region prior to the Era of Rotavirus Vaccine Utilization in the Expanded Programme of Immunization

Rotavirus vaccines, Rotarix and RotaTeq, are increasingly being introduced in national immunization programmes in Africa to prevent severe dehydrating acute gastroenteritis. A low-level risk of intussusception has been associated with rotavirus vaccines. We reviewed published data on intussusception in children <2 years of age in Africa. PubMed electronic database search was used to retrieve papers published on intussusception. The search was further refined to identify surveillance reports and case series conducted from 1980 to 2014, with at least 25 cases. The initial search identified 34 studies, and the refined search yielded 16. Intussusception occurred naturally in infants 2-4 months and peaked around 5-8 months of age. Delayed presentation was common and required surgical intervention in 87% (1008 of 1158) of cases with a high CFR, 10-33.7%. In African children, intussusception has been reported infrequently at a young age when the first dose of rotavirus vaccine is administered.

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

BACKGROUND

RotaTeq™ (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.

METHODS

We 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.

RESULTS

The 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).

CONCLUSION

This systematic literature review confirms rotavirus vaccination has been proven effective and well tolerated in protecting children in Latin America and the Caribbean.

Rotavirus vaccination and intussusception - Science, surveillance, and safety: A review of evidence and recommendations for future research priorities in low and middle income countries

As of January 2016, 80 countries have introduced rotavirus vaccines into their national immunization programs. Many have documented significant declines in rotavirus-specific and all-cause diarrheal illnesses following vaccine introduction. Two globally licensed rotavirus vaccines have been associated with a low risk of intussusception in several studies. In July 2014, the Rotavirus Organization of Technical Allies Council convened a meeting of research and advocacy organizations, public health experts, funders, and vaccine manufacturers to discuss post-marketing intussusception surveillance and rotavirus vaccine impact data. Meeting objectives were to evaluate updated data, identify and prioritize research gaps, discuss best practices for intussusception monitoring in lower-income settings and risk communication, and provide insight to country-level stakeholders on best practices for intussusception monitoring and communication. Meeting participants agreed with statements from expert bodies that the benefits of vaccination with currently available rotavirus vaccines outweigh the low risk of vaccination-associated intussusception. However, further research is needed to better understand the relationship of intussusception to wild-type rotavirus and rotavirus vaccines and delineate potential etiologies and mechanisms of intussusception. Additionally, evidence from research and post-licensure evaluations should be presented with evidence of the benefits of vaccination to best inform policymakers deciding on vaccine introduction or vaccination program sustainability.

Rotavirus vaccines: current global impact and future perspectives

As of May 2016, 81 countries have introduced Rotarix or RotaTeq rotavirus vaccines into their national immunization program. Despite initially slow uptake in some countries and differences in vaccine effectiveness (VE) between high-, low- and middle-income countries, impact of the vaccines has been swift and striking in all settings, with good VE against vaccine-type and nonvaccine-type strains. Newly published research indicates poor nutrition is associated with decreased VE and breastfeeding at the time of vaccination does not affect vaccine response. Vaccines in development and proposed alternate schedules also promise to address limitations of the current vaccines and optimize rotavirus disease prevention.

Intussusception Rates Before and After the Introduction of Rotavirus Vaccine

BACKGROUND

Recent US studies have identified a small increased risk of intussusception after rotavirus vaccination, mainly after the first dose. We examined trends in intussusception hospitalizations before (2000-2005) and after (2007-2013) rotavirus vaccine introduction to assess whether this observed temporal risk translates into more hospitalized cases at the population level.

METHODS

Intussusception hospitalizations in children <12 months of age were abstracted from the State Inpatient Database maintained by the Healthcare Cost and Utilization Project for 26 states that provided data from 2000 to 2013. Rates were calculated using bridged-race postcensal population estimates. Trends were analyzed by age groups (6-14 weeks, 15-24 weeks, and 25-34 weeks) based on the recommended ages for vaccine administration as well as 8-11 weeks when the majority of first doses are given. Rate ratios were calculated by using Poisson regression.

RESULTS

No consistent change in intussusception hospitalization rates was observed among all children <12 months of age and among children 15 to 24 weeks and 25 to 34 weeks of age. The intussusception hospitalization rate for children aged 8 to 11 weeks was significantly elevated by 46% to 101% (range: 16.7-22.9 per 100 000) in all postvaccine years except 2011 and 2013 compared with the prevaccine baseline (11.7 per 100 000).

CONCLUSIONS

The increase in the intussusception hospitalization rate in children 8 to 11 weeks when the majority of first doses of vaccine are given is consistent with recent US postlicensure studies. Given the magnitude of declines in rotavirus disease compared with this small increase in intussusception, the benefits of rotavirus vaccination outweigh the increase risk of intussusception.

Health Impact of Rotavirus Vaccination in Developing Countries: Progress and Way Forward

Two rotavirus vaccines have been licensed in >100 countries worldwide since 2006. As of October 2105, these vaccines have been implemented in the national immunization programs of 79 countries, including 36 low-income countries that are eligible for support for vaccine purchase from Gavi, the Vaccine Alliance. Rotavirus vaccines were initially introduced in Australia and countries of the Americas and Europe after completion of successful clinical trials in these regions, and the impact of routine vaccination in reducing the health burden of severe childhood gastroenteritis in these regions has been well documented. Because of concerns around the performance of orally administered rotavirus vaccines in developing countries, vaccine implementation in these settings only began after additional clinical trials were completed and the World Health Organization issued a global recommendation for use of rotavirus vaccines in 2009. This supplementary issue of Clinical Infectious Diseases includes a collection of articles describing the impact and effectiveness of routine rotavirus vaccination in developing countries that were among the early adopters of rotavirus vaccine. The data highlight the benefits of vaccination and should provide valuable evidence to sustain vaccine use in these countries and encourage other countries to adopt routine rotavirus vaccination to reduce the health burden of severe childhood gastroenteritis.

Potential safety issues and other factors that may affect the introduction and uptake of rotavirus vaccines

Rotavirus vaccines have demonstrated significant impact in reducing the burden of morbidity and mortality from childhood diarrhoea in countries that have implemented routine vaccination to date. Despite this success, in many countries, rotavirus vaccine coverage remains lower than that of other routine childhood vaccines. Several issues may potentially affect vaccine uptake, namely safety concerns related to intussusception with consequent age restrictions on rotavirus vaccination, contamination with porcine circovirus, vaccine-derived reassortant strains and hospitalization in newborn nurseries at time of administration of live oral rotavirus vaccine. In addition to these safety concerns, other factors may also affect uptake, including lower vaccine efficacy in the developing world, potential emergence of strains escaping from vaccine protection resulting in lower overall impact of a vaccination programme and sustainable vaccine financing. Although further work is needed to address some of these concerns, global policy bodies have reaffirmed that the benefits of rotavirus vaccination outweigh the risks, and vaccine use is recommended globally.

Value of Post-Licensure Data on Benefits and Risks of Vaccination to Inform Vaccine Policy: The Example of Rotavirus Vaccines

In 1999, the first rhesus-human reassortant rotavirus vaccine licensed in the U.S. was withdrawn within a year of its introduction after it was linked with intussusception at a rate of ~1 excess case per 10,000 vaccinated infants. While clinical trials of 60,000-70,000 infants of each of the two current live oral rotavirus vaccines, RotaTeq (RV5) and Rotarix (RV1), did not find an association with intussusception, post-licensure studies have documented a risk in several high and middle income countries, at a rate of ~1-6 excess cases per 100,000 vaccinated infants. However, considering this low risk against the large health benefits of vaccination that have been observed in many countries, including in countries with a documented vaccine-associated intussusception risk, policy makers and health organizations around the world continue to support the routine use of RV1 and RV5 in national infant immunization programs. Because the risk and benefit data from affluent settings may not be directly applicable to developing countries, further characterization of any associated intussusception risk following rotavirus vaccination as well as the health benefits of vaccination is desirable for low income settings.

Current status of rotavirus vaccines

BACKGROUND

Rotaviruses remain the major cause of childhood diarrheal disease worldwide and of diarrheal deaths of infants and children in developing countries. The huge burden of childhood rotavirus-related diarrhea in the world continues to drive the remarkable pace of vaccine development.

DATA SOURCES

Research articles were searched using terms "rotavirus" and "rotavirus vaccine" in MEDLINE and PubMed. Articles not published in the English language, articles without abstracts, and opinion articles were excluded from the review. After preliminary screening, all articles were reviewed and synthesized to provide an overview of current vaccines and vaccination programs.

RESULTS

In this review of the global rotavirus vaccines and vaccination programs, the principles of rotavirus vaccine development and the efficacy of the currently licensed vaccines from both developed and developing countries were summarized.

CONCLUSIONS

Rotavirus is a common cause of diarrhea in children in both developed and developing countries. Rotavirus vaccination is a cost-effective measure to prevent rotavirus diarrhea.

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.

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.

Rotavirus vaccines in routine use

Vaccines are now available to combat rotavirus, the most common cause of severe diarrhea among children worldwide. We review clinical trial data for available rotavirus vaccines and summarize postlicensure data on effectiveness, impact, and safety from countries routinely using these vaccines in national programs. In these countries, rotavirus vaccines have reduced all-cause diarrhea and rotavirus hospitalizations by 17%-55% and 49%-92%, respectively, and all-cause diarrhea deaths by 22%-50% in some settings. Indirect protection of children who are age-ineligible for rotavirus vaccine has also been observed in some high and upper middle income countries. Experience with routine use of rotavirus vaccines in lower middle income countries has been limited to date, but vaccine introductions in such countries have been increasing in recent years. The risk-benefit analysis of rotavirus vaccines is extremely favorable but other strategies to improve the effectiveness of the vaccine, particularly in lower middle income settings, should be considered.

Safety of rotavirus vaccine in the NICU

BACKGROUND AND OBJECTIVE

Rotavirus vaccination is discouraged during hospitalization given concerns regarding live attenuated virus transmission, although recommended upon discharge. Infants should have vaccination initiated by 104 days of age or they become age-ineligible. Our institution believed the known risk of severe disease in unvaccinated infants outweighed the theoretical risk of transmission. We routinely administer RotaTeq (RV5) to age-eligible hospitalized infants on enteral feeds. The objective of this study was to determine the safety of RV5 vaccination among vaccinated (VI) and unvaccinated infants (UVI) within the NICU.

METHODS

A retrospective review identified VI between 2008 and 2010, and UVI geographically located near VI within 15 days of vaccination. We screened for gastrointestinal symptoms among UVI by using an electronic medical record query (trigger tool) to identify infants with orders for bowel rest, abdominal imaging, and antibiotics. Trigger-positive infants had full chart review.

RESULTS

Most VI (76%) were either asymptomatic (25% [24 of 96]) or symptomatic but unchanged from baseline (51% [49 of 96]) postvaccination. Although 24% of VI had clinical status changes postvaccination, none were directly attributed to RV5. Among 801 neighboring UVI, 10 (1.2%) had clinical status changes, none directly attributed to RV5, but mostly bacterial sepsis or preexisting gastrointestinal pathology. Two UVI underwent stool analysis; both negative for rotavirus.

CONCLUSIONS

RV5 was well tolerated in hospitalized infants, with most postvaccination symptoms attributed to preexisting symptoms. UVI seemed to have a low risk of symptomatic transmission. Inpatient administration ensures that age-eligible infants are vaccinated regardless of hospital duration. Prospective evaluation of safety and transmissibility is needed.

A critical time for rotavirus vaccines: a review

Universal introduction of rotavirus vaccines into childhood immunization programs is expected to substantially reduce the mortality from rotavirus gastroenteritis in developing countries (currently estimated at 702,000 annual deaths among children less than 5 years of age). In addition, it is expected to virtually eliminate hospitalizations due to rotavirus gastroenteritis in developed countries. Two rotavirus vaccines, Rotarix (GlaxoSmithKline Biologicals, Belgium) and RotaTeq (Merck & Co., USA) have recently completed Phase III clinical trials, each involving more than 60,000 children. Both vaccines appear safe with respect to intussusception, and are highly efficacious in preventing severe gastroenteritis due to rotavirus strains carrying predominantly serotype G1. The monovalent human rotavirus vaccine Rotarix, possessing serotype P1A[8],G1, is being first introduced into developing countries, whereas the pentavalent bovine-human reassortant rotavirus vaccine RotaTeq, comprising G-types G1, G2, G3, G4 and P-type P1A[8], will be initially introduced into the USA and Europe. Current disease burden estimates and economic justification will be required wherever the vaccines are introduced. Confirmation of the safety of both vaccines will require extensive postlicensure evaluation in which it will be key to assure adherence to administration of the first dose of either vaccine before 3 months of age. Assessment of the ability of each vaccine to provide protection against an increasingly diverse population of rotavirus strains will crucially depend on continuous global strain surveillance. Finally, efforts to improve existing rotavirus vaccines and to develop alternative vaccines should continue, so as to ensure that the prerotavirus vaccine era is consigned to a historical context.

Rotavirus vaccination in Brazil: effectiveness and health impact seven years post-introduction

Before vaccine introduction in Brazil, rotavirus caused approximately 650,000 outpatient visits, 92,000 hospitalizations and 850 deaths annually among children aged <5 years. Brazil was one of the first countries to introduce rotavirus vaccination into the National Immunisation Program (NIP), in 2006, but estimated coverage (87.1%) for 2011 remained lower if compared with other routine immunizations (95%). Case-control studies reached effectiveness rates as high as 85%. Observational studies showed a significant reduction in gastroenteritis-related hospitalizations and deaths among children aged <1 year, at rates as high as 48 and 54%, respectively. There was a significant increase in the relative prevalence of G2P[4] genotype after vaccine introduction, reaching 100% of strains in some settings. A small increase in intussusception incidence was seen within 1 week following the second vaccine dose, but benefits far outweigh any potential risk. This article provides an in-depth review of postlicensure studies conducted in Brazil 7-year postintroduction.

Validation of diagnostic codes for intussusception and quantification of childhood intussusception incidence in Ontario, Canada: a population-based study

OBJECTIVES

To validate an algorithm to identify cases of intussusception using the health administrative data of Ontario, Canada, and to apply the algorithm to estimate provincial incidence of intussusception, preceding the introduction of the universal rotavirus vaccination program.

STUDY DESIGN

We determined the accuracy of various combinations of diagnostic, procedural, and billing codes using the chart-abstracted diagnoses of patients of the Children's Hospital of Eastern Ontario as the reference standard. We selected an algorithm that maximized positive predictive value while maintaining a high sensitivity and used it to ascertain annual incidence of intussusception for fiscal years 1995-2010. We explored temporal trends in incidence using Poisson regression.

RESULTS

The selected algorithm included only the International Classification of Diseases (ICD)-9 or ICD-10 code for intussusception in the hospitalization database and was sensitive (89.3%) and highly specific (>99.9%). The positive predictive value of the ICD code was 72.4%, and the negative predictive value was >99.9%. We observed the highest mean incidence (34 per 100000) in male children <1 year of age. Temporal trends in incidence varied by age group. There was a significant mean decrease in incidence of 4% per year in infants (<1 year) until 2004 and rates stabilized thereafter.

CONCLUSIONS

We have demonstrated that intussusception can be accurately identified within health administrative data using validated algorithms. We have described changes in temporal trends in intussusception incidence in Ontario and established a baseline to allow ongoing monitoring as part of vaccine safety surveillance.

Clinical features and role of viral isolates from stool samples of intussuception in children

PURPOSE

To detect major acute gastroenteritis virus (rotavirus, norovirus, astrovirus, and enteric adenovirus) and non-enteric type of adenovirus (AdV) in the stools of intussusception patients and to investigate the clinical role of detected viruses.

METHODS

From March 2012 to February 2013, major acute gastroenteritis virus and non-enteric type of AdV were isolated from stool samples that collected from 44 patients treated for intussusception in Chungnam National University Hospital. Patients were divided according to age and isolated virus.

RESULTS

Virus was detected in 28 (63%) stool specimens. The virus detection rate was significantly lower in patients aged under 12 months (p = 0.04). Twenty-two patients (78.6%) had non-enteric adenovirus, 4 (14.3%) had norovirus, 1 (3.6%) had sapovirus, and 1 (3.6%) had astrovirus. AdV subgroup C (AdV 1, 2, 5, and 6) comprised the majority with 20 cases (90.9%). A monthly increment-and-decrement pattern of intussusception was similar to that of viral detection in the stool samples. Enema reductions were successful in 39 patients and surgical manual reductions were performed in 5 patients. Virus was detected in 24 patients (61.5%) of enema reduction group and 4 patients (80.0%) of surgical manual reduction group. All of the detected viruses were non-enteric adenovirus subgroup C (AdV 1, 5, and 6) in surgical reduction patients.

CONCLUSIONS

The virus detection rate was high in the stools of intussusception patients. The pattern of seasonal intussusception occurrence rate was parallel with seasonal these viral detection rate in the stool samples. These findings suggest that viral infection plays an important role in the development of intussusception and further research is warranted.

A High Incidence of Intussusception Revealed by a Retrospective Hospital-Based Study in Nha Trang, Vietnam between 2009 and 2011

Rotavirus is a leading cause of severe diarrhea among children worldwide. Thus, the World Health Organization recommended including rotavirus vaccines in national immunization programs. One concern about rotavirus vaccine, however, is a possible association with intussusception. Thus, it is crucial to know the baseline incidence of intussusception in the first year of life. A study conducted in Hanoi, Vietnam showed that the incidence of intussusception was the highest in the world. This retrospective cross-sectional study was undertaken to determine the incidence of intussusception among children <5 years of age in Nha Trang, Vietnam. Hospital charts between 2009 and 2011 were reviewed in Khanh Hoa Provincial General Hospital where virtually all cases of intussusception occurring in the city were assumed to have been encountered. The incidence of intussusception among children <1 year of age was 296 per 100,000 person-years (95% confidence interval [CI]: 225–382), and that among children <5 years of age was 196 per 100,000 person-years (95% CI: 169–226), confirming the high incidence of intussusception in Vietnam. Nevertheless, there was no intussusception in the first three months of life. We therefore recommend that the first dose of any rotavirus vaccine be administered to infants between 6 and 12 weeks of age.

The first rotavirus vaccine and the politics of acceptable risk

Context

Vaccination in the United States is a frequent source of controversy, with critics alleging failures by public health officials to adequately identify, monitor, and respond to risks associated with vaccines. In response to these charges, the case of RotaShield, a vaccine withdrawn in 1999 following confirmation of a serious adverse event associated with its use, is regularly invoked as evidence of the effectiveness of current vaccine safety activities.

Methods

This article examines the history of RotaShield, with particular attention paid to decision making regarding its use in the United States and internationally. I reviewed and analyzed federal advisory committee meeting transcripts, international conference reports, government and scientific publications, media coverage, and other primary and secondary source materials. I also conducted six semistructured interviews with former senior officials and advisory committee members at the U.S. Centers for Disease Control and Prevention who participated in decisions regarding the vaccine.

Findings

Decision making regarding RotaShield, including the ultimate withdrawal of its recommendation for use, was shaped significantly by government health officials’ concern for preserving public confidence in overall U.S. vaccination efforts amid several unrelated vaccine risk controversies ongoing at that time. This attention to public perception and external pressures occurred in tandem with the evaluation of the quantitative evidence regarding the magnitude and severity of the risk associated with the vaccine. The decisions made in the United States resulted in foreseen but unintended consequences for international use of the vaccine, including in nations where the profile of risks and potential benefits was dramatically different.

Conclusions

As enthusiasm for evidence-based decision making grows throughout medicine and public health, greater explicit attention should be directed to the processes by which decision makers and their expert advisers evaluate such evidence and translate it into regulation and policy by means of qualitative judgments.

Retrospective hospital based surveillance of intussusception in children in a sentinel paediatric hospital: benefits and pitfalls for use in post-marketing surveillance of rotavirus vaccines

Evaluation of the safety of rotavirus vaccines, particularly with respect to the risk of intussusception, is recommended for countries planning to introduce rotavirus vaccines into the National Immunisation Program. However, as prospective studies are costly, require time to conduct and may be difficult to perform in some settings, retrospective hospital based surveillance at sentinel sites has been suggested as an option for surveillance for intussusception following introduction of rotavirus vaccines.

OBJECTIVE

To assess the value of retrospective hospital based surveillance to describe clinical and epidemiological features of intussusception in children aged <24 months and to investigate any temporal association between receipt of a rotavirus vaccine and intussusception.

METHODS

A retrospective chart review of all patients diagnosed with intussusception at Royal Children's Hospital, Melbourne, Australia over an 8-year period including before and after rotavirus vaccine introduction into the National Immunisation Program, was conducted using patients identified by a medical record database (ICD-10-CM 56.1). Patient profile, clinical presentation, treatment and outcome were analysed along with records of immunisation status obtained using the Australian Childhood Immunisation Register.

RESULTS

A 9% misclassification rate of discharge diagnosis of intussusception was identified on critical chart review. The incidence rate of intussusception at the Royal Children's Hospital over the study period was 1.91 per 10,000 infants <24 months (95% CI 1.65-2.20). Intestinal resection was required in 6.5% of infants (95% CI 3.6%, 11.0%). Intussusception occurred within 30 days after vaccination in 2 of 27 patients who had received at least 1 dose of a rotavirus vaccine.

CONCLUSIONS

Valuable data on the incidence, clinical presentation and treatment outcomes of intussusception can be obtained from data retrieved from hospital medical records in a sentinel paediatric hospital using standardised methodology. However, there are methodological limitations and the quality of the data is highly dependent on the accuracy and completeness of the patient information recorded, the system of coding and record retrieval.

Research priorities regarding rotavirus vaccine and intussusception: a meeting summary

Currently available rotavirus vaccines have been associated with a small increased risk of intussusception (~1-2 cases per 100,000 vaccinated infants) in some populations. In response to this newly emerging data on intussusception related to current rotavirus vaccines, a group of technical experts convened by the Program for Applied Technology in Health met to review the data, establish what gaps in knowledge exist, and identify what future research is needed. This manuscript outlines the evidence that is currently available and the research agenda that was generated during this meeting. It also highlights the need for countries that are using or considering introducing the rotavirus vaccine to evaluate both the benefits and risks of vaccination.

Remaining issues and challenges for rotavirus vaccine in preventing global childhood diarrheal morbidity and mortality

Rotavirus vaccines have had a dramatic impact on morbidity and mortality from diarrhea among children in high- and middle-income countries that have introduced the vaccine into their national immunization programs. Widespread introduction of rotavirus vaccine in developing countries is imminent and their full potential in reducing the global burden from severe childhood diarrhea may soon be realized. The objectives of this paper are to describe the remaining issues and challenges in ensuring the success of the global rotavirus vaccination program and to discuss further research needed to help address them.

Trends in intussusception hospitalizations among US infants before and after implementation of the rotavirus vaccination program, 2000-2009

BACKGROUND

Although US data have not documented an intussusception risk with current rotavirus vaccines, international data indicate a possible low risk, primarily after the first dose.

METHODS

Among infants in 26 US states comprising 75% of the birth cohort, we examined age-specific trends in population-level intussusception hospitalization rates before (2000-2005) and after (2007-2009) rotavirus vaccine introduction.

RESULTS

Compared with 2000-2005 (35.3 per 100,000), the rate was greater in 2007 (39.0 per 100,000; rate ratio [RR], 1.10; 95% confidence interval [CI], 1.04-1.18), similar in 2008 (33.4 per 100,000; RR, 0.95; 95% CI, .89-1.01), and lower in 2009 (32.9 per 100,000; RR, 0.93; 95% CI, .87-.99). Among infants aged 8-11 weeks, compared with 2000-2005 (6.9 per 100,000), a small, significant increase was observed in each of 2007 (11.4 per 100,000; RR, 1.64; 95% CI, 1.08-2.50), 2008 (12.2 per 100,000; RR, 1.76; 95% CI, 1.17-2.65), and 2009 (11.0 per 100,000; RR, 1.59; 95% CI, 1.04-2.44).

CONCLUSIONS

Following rotavirus vaccine introduction, a small increase in intussusception rates was seen among US infants aged 8-11 weeks, to whom most first doses of vaccine are given; no sustained population-level change in overall rates was observed.