Intussusception and Monovalent Rotavirus Vaccination in Singapore: Self-Controlled Case Series and Risk-Benefit Study

A broad assessment of rotavirus vaccine safety in infants in Korea: Insights from a data-driven signal detection approach

In light of the widespread use of rotavirus vaccines, there is a pressing need to perform thorough, large-scale surveillance to actively monitor safety. This study aimed to identify potential adverse events following rotavirus vaccination in infants. Using a nationwide linked database of the national immunization registry and health insurance claims data, we identified infants vaccinated with the first dose of rotavirus vaccine between January 2016 and October 2022. The self-controlled tree-temporal scan statistics method analyzed all incident diagnoses recorded within 56 days post-vaccination and evaluated all temporal risk windows. Among 1,720,778 rotavirus vaccine recipients 64,752 infants contributed to the analysis, yielding 72,970 incident diagnoses. Of these, 28 clusters were categorized as known adverse drug reactions (ADRs), including infection following immunization (Days 1-2, p<.001), viral infection (Days 1-5, p<.001), urticaria and erythema (Days 3-9, p<.001), acute upper respiratory infections (Days 28-42, p<.001), and pneumonia (Days 9-19 or 28-42, p<.001). Seventeen clusters were classified as ADR-related events, such as the ones clinically related to ADR or lower-level diagnostic codes of ADR. The remaining 26 clusters were classified as signals, including sepsis (Days 1-20, p<.001), meningitis (Days 1-23, p<.001), liver disease (Days 4-11, p<.001), and tubulo-interstitial nephritis (Days 11-38, p<.001). A cluster of intussusceptions was only found in monovalent vaccine-stratified analysis (Days 5-8, p  = 0.005). This study confirmed known ADRs following rotavirus vaccination, while identifying potential safety signals requiring further investigation. These findings emphasize the importance of active vaccine surveillance and underscore the need for epidemiological studies with validated outcome definitions to confirm causal relationships between rotavirus vaccination and the detected outcomes.

Australia's rotavirus immunisation program: Impact on acute gastroenteritis and intussusception hospitalisations over 13 years

BACKGROUND

Australia was one of the first countries to include rotavirus vaccines in its National Immunisation Program, in 2007. We compared trends in acute gastroenteritis (AGE) and intussusception-coded hospitalisations over 13-year post-vaccine period against five-year pre-vaccine baseline.

METHODS

In a descriptive before-after study, incidence of hospitalisations with ICD-code of rotavirus AGE (A08.0), other AGE (K52, A01-A09 excluding A08.0) or intussusception (K56.1) between 2002 and 2020 was calculated using population denominators by age and Indigenous status. We used 2002-2006 as pre-vaccine baseline and calculated Incidence Rate Ratios [IRRs] for 2008-2019 and 2020.

FINDINGS

In children aged <5 years, mean annual hospitalisation rate/100,000 decreased by 85% for rotavirus-coded AGE, from 248.3 in 2002-2006 to 37.6 (IRR 0.15; 95% CI 0.15-0.16) in 2008-2019 (61.4% for Indigenous children, from 680.2 to 262.2), and 46% for other AGE, from 1274.5 to 689.1 (IRR 0.54; CI 0.54-0.55), decreasing further in 2020 to 6.3 (rotavirus-coded) and 445.0 (other AGE). Rates for rotavirus-coded and other AGE declined in 2008-2019 in those aged 5-<20 years (IRR 0.52; CI 0.49-0.56 and 0.86; CI 0.85-0.87, respectively), but increased in 20-<65 years (IRR 2.38; CI 2.01-2.83 and 1.15; CI 1.15-1.16) and ≥65 years (IRR 2.24; CI 1.91-2.62 and 1.24; CI 1.23-1.25). Average annual hospitalisation rate for intussusception in infants was similar in pre-vaccine and post-vaccine periods (IRR 0.97; CI 0.90-1.04).

CONCLUSION

Over a 13-year period post-rotavirus vaccine introduction we document major sustained declines in hospitalisations coded as rotavirus and other AGE in age groups <20 years, with no change in intussusception hospitalisation rates in infants. Despite small increases in AGE hospitalisations in adults, likely due to increased PCR testing, our findings are consistent with highly favourable risk benefit ratio at whole-of-population level in Australia.

A Viral Protein 4-Based Trivalent Nanoparticle Vaccine Elicited High and Broad Immune Responses and Protective Immunity against the Predominant Rotaviruses

The current live rotavirus (RV) vaccines show reduced effectiveness in developing countries, calling for vaccine strategies with improved efficacy and safety. We generated pseudovirus nanoparticles (PVNPs) that display multiple ectodomains of RV viral protein 4 (VP4), named S-VP4e, as a nonreplicating RV vaccine candidate. The RV spike protein VP4s that bind host receptors and facilitate viral entry are excellent targets for vaccination. In this study, we developed scalable methods to produce three S-VP4e PVNPs, each displaying the VP4e antigens from one of the three predominant P[8], P[4], and P[6] human RVs (HRVs). These PVNPs were recognized by selected neutralizing VP4-specific monoclonal antibodies, bound glycan receptors, attached to permissive HT-29 cells, and underwent cleavage by trypsin between VP8* and VP5*. 3D PVNP models were constructed to understand their structural features. A trivalent PVNP vaccine containing the three S-VP4e PVNPs elicited high and well-balanced VP4e-specific antibody titers in mice directed against the three predominant HRV P types. The resulting antisera neutralized the three HRV prototypes at high titers; greater than 4-fold higher than the neutralizing responses induced by a trivalent vaccine consisting of the S60-VP8* PVNPs. Finally, the trivalent S-VP4e PVNP vaccine provided 90-100% protection against diarrhea caused by HRV challenge. Our data supports the trivalent S-VP4e PVNPs as a promising nonreplicating HRV vaccine candidate for parenteral delivery to circumvent the suboptimal immunization issues of all present live HRV vaccines. The established PVNP-permissive cell and PVNP-glycan binding assays will be instrumental for further investigating HRV-host cell interactions and neutralizing effects of VP4-specific antibodies and antivirals.

Intussusception and Other Adverse Event Surveillance after Pilot Introduction of Rotavirus Vaccine in Nam Dinh and Thua Thien Hue Provinces-Vietnam, 2017-2021

Rotavin-M1 (POLYVAC) was licensed in Vietnam in 2012. The association of Rotavin-M1 with intussusception, a rare adverse event associated with rotavirus vaccines, and with adverse events following immunization (AEFI) have not been evaluated and monitored under conditions of routine use. From February 2017 to May 2021, we conducted a pilot introduction of Rotavin-M1 into the routine vaccination program in two provinces. Surveillance for intussusception was conducted at six sentinel hospitals. AEFI reports at 30 min and 7 days after vaccination were recorded. Among 443 children <12 months of age admitted for intussusception, most (92.3%) were children ≥ 6 months. Of the 388 children who were age-eligible to receive Rotavin-M1, 116 (29.9%) had received ≥1 dose. No intussusception cases occurred in the 1-21 days after dose 1 and one case occurred on day 21 after dose 2. Among the 45,367 children who received ≥1 dose of Rotavin-M1, 9.5% of children reported at least one AEFI after dose 1 and 7.3% after dose 2. Significantly higher AEFI rates occurred among children given Rotavin-M1 with pentavalent vaccines (Quinvaxem®, ComBE Five®) compared to Rotavin-M1 without pentavalent vaccines. There was no association between intussusception and Rotavin-M1. The vaccine was generally safe when administered alone and when co-administered with other vaccines.

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.

Self-controlled risk interval study of rotavirus vaccine safety: Findings and implications

BACKGROUND

The self-controlled case series (SCCS) is often used to monitor vaccine safety. The evaluation of intussusception after the rotavirus vaccine is complicated because the baseline rate varies with age. Time-varying baseline risk adjustments with data from unexposed cohorts are utilised. Self-controlled risk interval (SCRI), with a shorter observation period, can also mitigate the problem by studying a control period close to the risk period.

OBJECTIVE

An Indian rotavirus vaccine has previously been studied using SCCS. The risk of intussusception in the high-risk windows (21 days after vaccination) was comparable to the background risk. The aim was to re-analyse data of an existing SCCS study using alternate statistical methods to examine vaccine safety.

METHODS

We examined the mean age of intussusception in the vaccinated and the unvaccinated. We performed an SCRI analysis of the surveillance data from the SCCS study, limiting the observation period to 180 days. We analysed the time-to-intussusception from the last vaccination. Finally, we performed an SCCS analysis, excluding unvaccinated cases from the analysis.

RESULTS

We found that the mean age of intussusception was significantly lower in the vaccinated (205 days) compared to the unvaccinated (223 days) (p-value 0.0026). The Incident Risk Ratio (IRR) on SCRI analysis was 1.62 (95% CI 1.07-2.44). There were significantly more intussusceptions in the first 30 days after vaccination compared to the next 30-day window. (92 vs 63 p-value = 0.009). We found that excluding unvaccinated infants from the SCCS analysis demonstrated significantly increased risk for the risk period 1-21 days after the 3rd dose (IRR 2.47, 95% CI 1.70-3.59). The risks of intussusception were missed in traditional SCCS analysis using unvaccinated infants as controls.

CONCLUSION

Traditional risk adjustments using data from unexposed cohorts in SCCS may not be appropriate for investigating the risk of intussusception where vaccination lowers the mean age of intussusception.

Intussusception risk following oral monovalent rotavirus vaccination in 3 Asian countries: A self-control case series evaluation

Rotavirus vaccines have substantially decreased rotavirus hospitalizations in countries where they have been implemented. In some high- and middle-income countries, a low-level of increased risk of intussusception, a type of acute bowel obstruction, has been detected following rotavirus vaccination. However, no increased risk of intussusception was found in India, South Africa, or a network of 7 other African countries. We assessed the association between a 2-dose monovalent rotavirus vaccine (Rotarix) and intussusception in 3 early-adopter low-income Asian countries -- Afghanistan, Myanmar, and Pakistan. Children <12 months of age admitted to a sentinel surveillance hospital with Brighton level 1 intussusception were eligible for enrollment. We collected information about each child's vaccination status and used the self-controlled case series method to calculate the relative incidence of intussusception 1-7 days, 8-21 days, and 1-21 days following each dose of vaccine and derived confidence intervals with bootstrapping. Of the 585 children meeting the analytic criteria, the median age at intussusception symptom onset was 24 weeks (IQR: 19-29). Overall, 494 (84 %) children received the first Rotarix dose and 398 (68 %) received the second dose. There was no increased intussusception risk during any of the risk periods following the first (1-7 days: 1.01 (95 %CI: 0.39, 2.60); 8-21 days: 1.37 (95 %CI: 0.81, 2.32); 1-21 days: 1.28 (95 %CI: 0.78, 2.11)) or second (1-7 days: 0.81 (95 %CI: 0.42, 1.54); 8-21 days: 0.77 (95 %CI: 0.53, 1.16); 1-21 days: 0.78 (95 %CI: 0.53, 1.16)) rotavirus vaccine dose. Our findings are consistent with other data showing no increased intussusception risk with rotavirus vaccination in low-income countries and add to the growing body of evidence demonstrating safety of rotavirus vaccines.

Rotavirus vaccine clinical trials: a cross-sectional analysis of clinical trials registries

Background

Rotavirus is a primary infectious virus causing childhood diarrhoea and is associated with significant mortality in children. Three African countries (Nigeria, the Democratic Republic of Congo, and Angola) are among the five countries that account for 50% of all diarrheal-related deaths worldwide. This indicates that much needs to be done to reduce this burden. The World Health Organization International Clinical Trial Registry Platform (WHO ICTRP) is a global repository for primary registries reporting on clinical trials. This study aimed to identify and describe planned, ongoing, and completed rotavirus vaccine trials conducted globally.

Methods

We searched WHO-ICTRP on 17 June 2021 and conducted a cross-sectional analysis of rotavirus studies listed in the database. Data extraction included trial location, participant age, source of the trial record, trial phase, sponsor, and availability of results. We used the Microsoft Excel 365 package to generate descriptive summary statistics.

Results

We identified 242 rotavirus vaccine trials registered from 2004 to 2020. Most of these trials were registered retrospectively, with only 26% of the rotavirus vaccine trials reporting the availability of results in their registries. Most of the trials are studying children aged less than 5 years. The recruitment status for these trials is currently shown in the WHO-ICTRP as “not recruiting” for 80.17% of trials, “recruiting” for 11.57% of trials recruiting, and unknown for 6.61% of trials. The continents in which these rotavirus vaccine trials have recruitment sites in Asia (41%) and North America (20%), with the maximum number of trials in the clinical trial registries coming from India (21%) and the USA (11%) with most being sponsored by the pharmaceutical industry. Our analysis shows that only 26% of the rotavirus vaccine trials report the availability of results in their registries.

Conclusions

Mapping rotavirus vaccine clinical trial activity using data from the WHO ICTRP beneficial provides valuable information on planned, ongoing, or completed trials for researchers, funders, and healthcare decision-makers. Despite the high rotavirus disease burden in low- and middle-income countries, including Africa, there is minimal clinical trial activity related to the condition on the continent. The clinical trial registries as a valuable tool to share interim results of the trials.

A Pseudovirus Nanoparticle-Based Trivalent Rotavirus Vaccine Candidate Elicits High and Cross P Type Immune Response

Rotavirus infection continues to cause significant morbidity and mortality globally. In this study, we further developed the S60-VP8* pseudovirus nanoparticles (PVNPs) displaying the glycan receptor binding VP8* domains of rotavirus spike proteins as a parenteral vaccine candidate. First, we established a scalable method for the large production of tag-free S60-VP8* PVNPs representing four rotavirus P types, P[8], P[4], P[6], and P[11]. The approach consists of two major steps: selective precipitation of the S-VP8* proteins from bacterial lysates using ammonium sulfate, followed by anion exchange chromatography to further purify the target proteins to a high purity. The purified soluble proteins self-assembled into S60-VP8* PVNPs. Importantly, after intramuscular injections, the trivalent vaccine consisting of three PVNPs covering VP8* antigens of P[8], P[4], and P[6] rotaviruses elicited high and broad immunogenicity in mice toward the three predominant P-type rotaviruses. Specifically, the trivalent vaccine-immunized mouse sera showed (1) high and balanced IgG and IgA antibody titers toward all three VP8* types, (2) high blocking titer against the VP8*-glycan receptor interaction, and (3) high and broad neutralizing titers against replications of all P[8], P[4], and P[6] rotaviruses. Therefore, trivalent S60-VP8* PVNPs are a promising non-replicating, parenteral vaccine candidate against the most prevalent rotaviruses worldwide.

Self-controlled case series design in vaccine safety: a systematic review

BACKGROUND

: An increasing number of vaccine safety studies using the self-controlled case-series (SCCS) design have been conducted in the last decade. However, there has been no comprehensive evaluation of the methodology and reporting quality of these observational studies. The purpose of this paper is to document the methodological features of studies that focused on vaccine safety using the SCCS design, and to evaluate the reporting quality of these studies to suggest future improvements on appropriate design and transparent reporting.

METHODS

: Databases including Medline, Embase, Web of Science, Scopus and Chinese databases were searched from inception to May 31, 2021. All observational studies regarding vaccine safety using a SCCS design were selected. Information regarding methodological elements were extracted. In addition, reporting quality was assessed using the REporting of studies Conducted using Observational Routinely collected health Data statement for PharmacoEpidemiology (RECORD-PE).

RESULTS

: Of the 105 studies identified, administrative databases were the main data source for vaccination records and adverse events following immunization (AEFI). 28 articles (27%) used multiple designs to verify the association, and the results obtained with the SCCS design were robust. The top three AEFI studied were intussusception, Guillain-Barré syndrome, and convulsions. Only 21 studies (20%) reported the approach for case validation by chart review. The healthy vaccinee effect was considered by 51studies (49%), with 16 of them (31%) using extended SCCS models to alleviate this effect. Overall, the reporting quality of included studies could be improved.

CONCLUSIONS

: This study systematically reviewed the methodology of studies regarding vaccine safety using a SCCS design and critically assessed their respective reporting quality. Case validation, the validity of assumptions for standard SCCS, and quality of reporting should be given more importance in future research projects.

Epidemiology of intussusception in infants less than one year of age in Ghana, 2012-2016

Introduction

we examined the epidemiology, clinical and demographic characteristics of intussusception in Ghanaian infants.

Methods

active sentinel surveillance for pediatric intussusception was conducted at Komfo Anokye Teaching Hospital in Kumasi and Korle Bu Teaching Hospital in Accra. From March 2012 to December 2016, infants < 1 year of age who met the Brighton Collaboration level 1 diagnostic criteria for intussusception were enrolled. Data were collected through parental interviews and medical records abstraction.

Results

a total of 378 children < 1 year of age were enrolled. Median age at onset of intussusception was 27 weeks; only 12 cases (1%) occurred in infants < 12 weeks while most occurred in infants aged 22-34 weeks. Median time from symptom onset until referral to a tertiary hospital was 2 days (IQR: 1-4 days). Overall, 35% of infants were treated by enema, 33% had surgical reduction and 32% required surgical reduction and bowel resection. Median length of hospital stay was 5 days (IQR: 3-8 days) with most patients (95%) discharged home. Eleven (3%) infants died. Infants undergoing enema reduction were more likely than those treated surgically to present for treatment sooner after symptom onset (median 1 vs 3 days; p < 0.0001) and have shorter hospital stays (median 3 vs 7 days; p < 0.001).

Conclusion

Ghanaian infants had a relatively low case fatality rate due to intussusception, with a substantial proportion of cases treated non-surgically. Early presentation for treatment, possibly enhanced by community-based health education programs and health information from various media platforms during the study period might contribute to both the low fatality rate and high number of successful non-surgical treatments in this population.

Epidemiology of intussusception in sub-Saharan Africa

This supplement contains the findings from intussusception surveillance conducted in 9 countries. These articles provide information on the age distribution of intussusception in the first year of life with cases peaking at 4-6 months of age, highlight the high proportion of cases in most, but not all, countries that undergo surgery and often require bowel resection for the treatment of intussusception, and show the variability of treatment outcomes in different countries. These data will be important for improving diagnosis and treatment of intussusception in young children in sub-Saharan Africa.

Benefit-Risk Assessment of Vaccines. Part I: A Systematic Review to Identify and Describe Studies About Quantitative Benefit-Risk Models Applied to Vaccines

Introduction

Understanding the balance between the benefits and risks of vaccination is essential to ensure informed and adequate public health decision making. Quantitative benefit–risk models (qBRm) represent useful tools to help decision makers with supporting benefit–risk assessment throughout the lifecycle of a medical product. However, few initiatives have been launched to harmonise qBRm approaches, specifically for vaccines.

Objectives

The aim of this paper was to identify publications about qBRm applied to vaccines through a systematic literature review, and to describe their characteristics.

Methods

Medline, Scopus and Institute for Scientific Information Web of Knowledge databases were searched to identify articles in English, published from database inceptions up to December 2019. The search strategy included the combination of three key concepts: ‘benefit–risk’, ‘modelling’ and ‘vaccines’. Data extracted included the modelling context and the methodological approaches used.

Results

Of 3172 publications screened, 48 original publications were included. Most of the selected studies were published over the past decade and focused on rotavirus (15), dengue (10) and influenza (6) vaccines. The majority (30) of studies reported analyses related to high-income countries. The methodology of the studies differed, particularly in modelling techniques, benefit–risk measures, and sensitivity analyses. The present work also pointed out a high level of variability in the quality of reporting across studies, with particular regard to input parameters and methodological approaches.

Conclusions

This review provides an extensive list of qBRm applied to vaccines. Discrepancies across studies were identified during our review. While the number of published qBRm studies is increasing, no reporting guidance for qBRm applied to vaccines is currently available. This may affect decision makers’ confidence in the results and their benefit–risk assessment(s); therefore, the development of such reporting guidance is highly needed.

Electronic supplementary material

The online version of this article (10.1007/s40264-020-00984-7) contains supplementary material, which is available to authorized users.

Global Experience with Rotavirus Vaccines

Rotavirus is a major cause of severe pediatric diarrhea worldwide. In 2006, two live, oral rotavirus vaccines, Rotarix and RotaTeq, were licensed for use in infants and were rapidly adopted in many high- and middle-income settings where efficacy had been demonstrated in clinical trials. Following completion of additional successful trials in low-income settings, the World Health Organization (WHO) recommended rotavirus vaccination for all infants globally in 2009. In 2018, two new rotavirus vaccines, Rotasiil and Rotavac, were prequalified by WHO, further expanding global availability. As of March 2021, rotavirus vaccines have been introduced nationally in 106 countries. Since introduction, rotavirus vaccines have demonstrated effectiveness against severe disease and mortality, even among age groups not eligible for vaccination. Cross-genotypic protection has also been demonstrated, and the favorable benefit-risk profile of these vaccines continues to be confirmed via post-marketing surveillance. Ongoing research seeks to better understand reasons for the lower effectiveness observed in lower-resource settings, and to use these findings to optimize vaccine strategies worldwide.

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.

A review of rotavirus vaccine use in Asia and the Pacific regions: challenges and future prospects

Introduction: Rotavirus infection causes a significant proportion of diarrhea disease burden in children <5 years of age in Asia and the Pacific regions. The World Health Organization recommends that rotavirus vaccination should be included in national immunization programs to prevent rotavirus gastroenteritis (RVGE).Areas covered: A literature review was performed to identify and summarize published evidence on RVGE epidemiology and status of rotavirus vaccine use, including the impact and cost-effectiveness of rotavirus vaccination programs in Asia and the Pacific regions (49 countries) during the period 2000-2018.Expert opinion: Rotavirus vaccination programs have successfully reduced the burden of RVGE in many countries. However, such programs still do not exist in most Asia-Pacific countries, and therefore the burden of RVGE remains high in children <5 years of age. Challenges to vaccine implementation include a lack of surveillance data; safety concerns around intussusception; a general lack of awareness about RVGE disease epidemiology and vaccines among physicians, policy-makers, and parents; insufficient cost-effectiveness analyses; and potential issues with vaccine affordability including vaccination costs and lack of political will. Recommendations to overcome these challenges include developing cost-effectiveness analyses for more diverse national and regional settings, providing non-governmental support for low-income countries, and improving advocacy efforts.Plain language summaryWhat is the context?• Rotavirus (RV) infection causes acute gastroenteritis (GE) in children under 5 years of age.• Rotavirus vaccination (RVV) implementation has been slow in Asia and the Pacific (AP) regions, which could be responsible for the region falling behind in their fight against RVGE.What is new?• RVV via national immunization programs (NIPs) is available in 8/49 countries and through the private market or non-governmental support in other countries. Coverage rates vary between countries, possibly driven by the mechanism through which RVV is available.• A substantial positive impact of RVV on RVGE disease burden with a very low risk of intestinal intussusception for up to 7 days after RVV has been documented in the AP regions.• Economic evaluation studies, mainly cost-effectiveness analyses, predict a significant reduction in treatment costs related to RVGE and its complications showing that RVV is good value for money.What is the impact?• The prospect of continued safe and effective use of RVV in the AP regions is promising.• Challenges to RVV implementation include establishing evidence of burden of disease, poor awareness of rotavirus vaccines, limited evidence from cost-effectiveness analyses from several countries, issues of affordability of the vaccine and a lack of political will.• Recommendations for RVV implementation into the NIPs include conducting clinical and cost-effectiveness studies in countries where these are not available, establishing reliable surveillance mechanisms, providing non-governmental support for low-income countries and improving advocacy efforts.• Maintenance of high vaccination coverage is needed in countries that have implemented national RVV programs.Graphical abstract[Formula: see text].

Suitability of databases in the Asia-Pacific for collaborative monitoring of vaccine safety

INTRODUCTION

Information regarding availability of electronic healthcare databases in the Asia-Pacific region is critical for planning vaccine safety assessments particularly, as COVID-19 vaccines are introduced. This study aimed to identify data sources in the region, potentially suitable for vaccine safety surveillance. This manuscript is endorsed by the International Society for Pharmacoepidemiology (ISPE).

METHODS

Nineteen countries targeted for database reporting were identified using published country lists and review articles. Surveillance capacity was assessed using two surveys: a 9-item introductory survey and a 51-item full survey. Survey questions related to database characteristics, covariate and health outcome variables, vaccine exposure characteristics, access and governance, and dataset linkage capability. Other questions collated research/regulatory applications of the data and local publications detailing database use for research.

RESULTS

Eleven databases containing vaccine-specific information were identified across 8 countries. Databases were largely national in coverage (8/11, 73%), encompassed all ages (9/11, 82%) with population size from 1.4 to 52 million persons. Vaccine exposure information varied particularly for standardized vaccine codes (5/11, 46%), brand (7/11, 64%) and manufacturer (5/11, 46%). Outcome data were integrated with vaccine data in 6 (55%) databases and available via linkage in 5 (46%) databases. Data approval processes varied, impacting on timeliness of data access.

CONCLUSIONS

Variation in vaccine data availability, complexities in data access including, governance and data release approval procedures, together with requirement for data linkage for outcome information, all contribute to the challenges in building a distributed network for vaccine safety assessment in the Asia-Pacific and globally. Common data models (CDMs) may help expedite vaccine safety research across the region.

Effects of rotavirus NSP4 protein on the immune response and protection of the SR69A-VP8* nanoparticle rotavirus vaccine

Rotavirus causes severe diarrhea and dehydration in young children. Even with the implementation of the current live vaccines, rotavirus infections still cause significant mortality and morbidity, indicating a need for new rotavirus vaccines with improved efficacy. To this end, we have developed an SR69A-VP8*/S60-VP8* nanoparticle rotavirus vaccine candidate that will be delivered parenterally with Alum adjuvant. In this study, as parts of our further development of this nanoparticle vaccine, we evaluated 1) roles of rotavirus nonstructural protein 4 (NSP4) that is the rotavirus enterotoxin, a possible vaccine target, and an immune stimulator, and 2) effects of CpG adjuvant that is a toll-like receptor 9 (TLR9) ligand and agonist on the immune response and protection of our SR69A-VP8*/S60-VP8* nanoparticle vaccine. The resulted vaccine candidates were examined for their IgG responses in mice. In addition, the resulted mouse sera were assessed for i) blocking titers against interactions of rotavirus VP8* proteins with their glycan ligands, ii) neutralization titers against rotavirus replication in cell culture, and iii) passive protection against rotavirus challenge with diarrhea in suckling mice. Our data showed that the Alum adjuvant appeared to work better with the SR69A-VP8*/S60-VP8* nanoparticles than the CpG adjuvant, while an addition of the NSP4 antigen to the SR69A-VP8*/S60-VP8* vaccine may not help to further increase the immune response and protection of the resulted vaccine.

A Nanoparticle-Based Trivalent Vaccine Targeting the Glycan Binding VP8* Domains of Rotaviruses

Rotavirus causes severe gastroenteritis in children. Although vaccines are implemented, rotavirus-related diarrhea still claims ~200,000 lives annually worldwide, mainly in low-income settings, pointing to a need for improved vaccine tactics. To meet such a public health need, a P24-VP8* nanoparticle displaying the glycan-binding VP8* domains, the major neutralizing antigens of rotavirus, was generated as a new type of rotavirus vaccine. We reported here our development of a P24-VP8* nanoparticle-based trivalent vaccine. First, we established a method to produce tag-free P24-VP8* nanoparticles presenting the VP8*s of P[8], P[4], and P[6] rotaviruses, respectively, which are the three predominantly circulating rotavirus P types globally. This approach consists of a chemical-based protein precipitation and an ion exchange purification, which may be scaled up for large vaccine production. All three P24-VP8* nanoparticle types self-assembled efficiently with authentic VP8*-glycan receptor binding function. After they were mixed as a trivalent vaccine, we showed that intramuscular immunization of the vaccine elicited high IgG titers specific to the three homologous VP8* types in mice. The resulted mouse sera strongly neutralized replication of all three rotavirus P types in cell culture. Thus, the trivalent P24-VP8* nanoparticles are a promising vaccine candidate for parenteral use against multiple P types of predominant rotaviruses.

Economic evaluation of the introduction of rotavirus vaccine in Hong Kong

BACKGROUND

Rotavirus is a common cause of severe gastroenteritis in young children in Hong Kong (HK) with a high economic burden. This study aimed to evaluate the cost-effectiveness of introducing rotavirus vaccination into the HK Government's Childhood Immunisation Programme (CIP) and to include the potential protective effect of the vaccine against seizures.

METHODS

A decision-support model was customised to estimate the potential impact, cost-effectiveness and benefit-risk of rotavirus vaccination in children below 5 years over the period 2020-2029 in HK. Two doses of Rotarix® and three doses of RotaTeq® were each compared to no vaccination. Rotavirus treatment costs were calculated from a governmental health sector perspective (i.e., costs of public sector treatment) and an overall health sector perspective (both governmental and patient, i.e., costs of public sector treatment, private sector treatment, transport and diapers). We ran probabilistic and deterministic uncertainty analyses.

RESULTS

Introduction of rotavirus vaccination in HK could prevent 49,000 (95% uncertainty interval: ~44,000-54,000) hospitalisations of rotavirus gastroenteritis and seizures and result in ~50 (95% uncertainty interval: ~25-85) intussusception hospitalisations, over the period 2020-2029 (a benefit-risk ratio of ~1000:1), compared to a scenario with no public or private sector vaccine use. The discounted vaccination cost would be US$51-57 million over the period 2020-2029 based on per-course prices of US$72 (Rotarix®) or US$78 (RotaTeq®), but this would be offset by discounted treatment cost savings of US$70 million (government) and US$127 million (governmental and patient health sector). There was a greater than 94% probability that the vaccine could be cost-saving irrespective of the vaccine product or perspective considered. All deterministic 'what-if' scenarios were cost-saving from an overall health sector perspective (governmental and patient).

CONCLUSIONS

Rotavirus vaccination is likely to be cost-saving and have a favourable benefit-risk profile in HK. Based on the assumptions made, our analysis supports its introduction into CIP.

Intussusception after Rotavirus Vaccine Introduction in India

BACKGROUND

A three-dose, oral rotavirus vaccine (Rotavac) was introduced in the universal immunization program in India in 2016. A prelicensure trial involving 6799 infants was not large enough to detect a small increased risk of intussusception. Postmarketing surveillance data would be useful in assessing whether the risk of intussusception would be similar to the risk seen with different rotavirus vaccines used in other countries.

METHODS

We conducted a multicenter, hospital-based, active surveillance study at 27 hospitals in India. Infants meeting the Brighton level 1 criteria of radiologic or surgical confirmation of intussusception were enrolled, and rotavirus vaccination was ascertained by means of vaccination records. The relative incidence (incidence during the risk window vs. all other times) of intussusception among infants 28 to 365 days of age within risk windows of 1 to 7 days, 8 to 21 days, and 1 to 21 days after vaccination was evaluated by means of a self-controlled case-series analysis. For a subgroup of patients, a matched case-control analysis was performed, with matching for age, sex, and location.

RESULTS

From April 2016 through June 2019, a total of 970 infants with intussusception were enrolled, and 589 infants who were 28 to 365 days of age were included in the self-controlled case-series analysis. The relative incidence of intussusception after the first dose was 0.83 (95% confidence interval [CI], 0.00 to 3.00) in the 1-to-7-day risk window and 0.35 (95% CI, 0.00 to 1.09) in the 8-to-21-day risk window. Similar results were observed after the second dose (relative incidence, 0.86 [95% CI, 0.20 to 2.15] and 1.23 [95% CI, 0.60 to 2.10] in the respective risk windows) and after the third dose (relative incidence, 1.65 [95% CI, 0.82 to 2.64] and 1.08 [95% CI, 0.69 to 1.73], respectively). No increase in intussusception risk was found in the case-control analysis.

CONCLUSIONS

The rotavirus vaccine produced in India that we evaluated was not associated with intussusception in Indian infants. (Funded by the Bill and Melinda Gates Foundation and others.).

Risk of intussusception after monovalent rotavirus vaccine (Rotavac) in Indian infants: A self-controlled case series analysis

Background

An association between rotavirus vaccination and intussusception has been documented in post-licensure studies in some countries. We evaluated the risk of intussusception associated with monovalent rotavirus vaccine (Rotavac) administered at 6, 10 and 14 weeks of age in India.

Methods

Active prospective surveillance for intussusception was conducted at 22 hospitals across 16 states from April 2016 through September 2017. Data on demography, clinical features and vaccination were documented. Age-adjusted relative incidence for 1–7, 8–21, and 1–21 days after rotavirus vaccination in children aged 28–364 days at intussusception onset was estimated using the self-controlled case-series (SCCS) method. Only Brighton Collaboration level 1 cases were included.

Results

Out of 670 children aged 2–23 months with intussusception, 311 (46.4%) children were aged 28–364 days with confirmed vaccination status. Out of these, 52 intussusception cases with confirmed receipt of RVV were included in the SCCS analysis. No intussusception case was observed within 21 days of dose 1. Only one case occurred during 8–21 days after the dose 2. Post-dose 3, two cases in 1–7 days and 7 cases during 8–21 days period were observed. There was no increased risk of intussusception during 1–7 days after the doses 1 and 2 (zero cases observed) or dose 3 (relative incidence [RI], 1.71 [95% confidence interval {CI} 0.0–5.11]). Similarly, no increased risk during 8–21 days after the dose 1 (zero cases observed), dose 2 (RI, 0.71 [95% CI, 0.0–3.28]) or dose 3 (RI, 2.52 [95% CI, 0.78–5.61]). The results were similar for 1–21 day periods after the doses separately or pooled.

Conclusions

The risk of intussusception during the first 21 days after any dose of rotavirus vaccine (Rotavac) was not higher among the Indian infants than the background risk, based on limited SCCS analysis of 52 children.

Benefit-Risk Assessment of Vaccines. Part II: Proposal Towards Consolidated Standards of Reporting Quantitative Benefit-Risk Models Applied to Vaccines (BRIVAC)

INTRODUCTION

Quantitative benefit-risk models (qBRm) applied to vaccines are increasingly used by public health authorities and pharmaceutical companies as an important tool to help decision makers with supporting benefit-risk assessment (BRA). However, many publications on vaccine qBRm provide insufficient details on the methodological approaches used. Incomplete and/or inadequate qBRm reporting may affect result interpretation and confidence in BRA, highlighting a need for the development of standard reporting guidance.

OBJECTIVES

Our objective was to provide an operational checklist for improved reporting of vaccine qBRm.

METHODS

The consolidated standards of reporting quantitative Benefit-RIsk models applied to VACcines (BRIVAC) were designed as a checklist of key information to report in qBRm scientific publications regarding the assessed vaccines, the methodological considerations and the results and their interpretation.

RESULTS

In total, 22 items and accompanying definitions, recommendations, explanations and examples were provided and divided into six main sections corresponding to the classic subdivisions of a scientific publication: title and abstract (items 1-2), introduction (items 3-4), methods (items 5-15), results (items 16-17), discussion (items 18-20) and other (items 21-22).

CONCLUSIONS

The BRIVAC checklist is the first initiative providing an operational checklist for improved reporting of qBRm applied to vaccines in scientific articles. It is intended to assist authors, peer-reviewers, editors and readers in their critical appraisal. Future initiatives are needed to provide methodological guidance to perform qBRm while taking into account the vaccine specificities.

Prospective surveillance for intussusception in Indian children aged under two years at nineteen tertiary care hospitals

Background

India introduced rotavirus vaccines (RVV, monovalent, Rotavac™ and pentavalent, Rotasiil™) in April 2016 with 6, 10 and 14 weeks schedule and expanded countrywide in phases. We describe the epidemiology of intussusception among children aged 2–23 months in India.

Methods

The prospective surveillance at 19 nationally representative sentinel hospitals from four regions recruited children with intussusception from April 2016 to September 2017. Data on sociodemography, immunization, clinical, treatment and outcome were collected. Along with descriptive analysis, key parameters between four regions were compared using Chi-Square/Fisher’s exact/Mann–Whitney U/Kruskal-Wallis tests. The pre- and post-RVV periods were compared to estimate the risk ratios.

Results

Six hundred twenty-one children with intussusception from South (n = 262), East (n = 190), North (n = 136) and West (n = 33) regions were recruited. Majority (n = 465, 74.8%) were infants (40.0% aged 4–7 months) with median age 8 months (IQR 5, 13 months), predominantly males (n = 408, 65.7%) and half (n = 311, 50.0%) occurred during March–June months. A shorter interval between weaning and intussusception was observed for ragi based food (median 1 month, IQR 0–4.2 months) compared to rice (median 4 months, IQR 1–9 months) and wheat (median 3 months, IQR 1–7 months) based food (p < 0.01). Abdominal pain or excessive crying (82.8%), vomiting (72.6%), and bloody stool (58.1%) were the leading symptoms. Classical triad (abdominal pain, vomiting and bloody stool) was observed in 34.8% cases (24.4 to 45.8% across regions). 95.3% of the cases were diagnosed by ultrasound. 49.3% (10.5 to 82.4% across regions) cases were managed by reduction, 39.5% (11.5 to 71.1% across regions) cases underwent surgery and 11.1% spontaneously resolved. Eleven (1.8%) cases died. 89.1% cases met Brighton criteria level 1 and 7.6% met Level 2. RVV was received by 12 cases within 1–21 days prior to intussusception. No increase in case load (RR = 0.44; 95% CI 0.22–1.18) or case ratio (RR = 0.5; 95% CI 0.3–1.2) was observed after RVV introduction in select sites.

Conclusions

Intussusception cases were observed across all sites, although there were variations in cases, presentation and mode of management. The high case load age coincided with age of the RVV third dose. The association with ragi based weaning food in intussusception needs further evaluation.

Current and new rotavirus vaccines

As of 2019, four rotavirus vaccines have been prequalified by the WHO for use worldwide. This review highlights current knowledge regarding rotavirus vaccines available, and provides a brief summary of the rotavirus vaccine pipeline.

Intussusception and Kawasaki disease after rotavirus vaccination in Taiwanese infants

BACKGROUND

Since 2006, two rotavirus vaccines have been licensed in Taiwan, either as a 2- (RV1) or 3-dose (RV5) schedule administered at ages 2, 4, and 6 months. This study assessed the risk of intussusception and Kawasaki disease (KD) associated with rotavirus vaccines among infants.

METHODS

Cases of intussusception and KD in infants aged less than 365 days were identified from the National Health Insurance databases, from 1 January 2007 through 31 December 2014, using the first-ever ICD-9-CM diagnosis codes. Histories of rotavirus vaccination were obtained from the National Immunization Information System. The modified self-controlled case series design included vaccinated cases, and compared incidence rate ratios (IRRs) between the risk period (postvaccination days 1-21 [intussusception] or days 1-28 [KD]) and control period (ages 0-364 days outside the -14 to +21 [intussusception] or +28 [KD] days of vaccination) by each type and dose of vaccine. Conditional Poisson regression models were adjusted for age using age-in-week (7-day) categorization.

RESULTS

Overall 2064 intussusception cases and 2079 KD cases were diagnosed in 567,726 recipients (5313 [0.9%] received both RV5 and RV1). An increase in intussusception risk was observed in the 1-7 days (IRR 12.59, 95% confidence interval [CI] 8.07-19.66) and 8-21 days (IRR 1.78, 95% CI 1.00-3.16) post dose 1 of RV1, but not RV5. Risk of KD was higher during the third week post dose 2 of RV5 (IRR 2.33, 95% CI 1.35-4.00), and fourth week post dose 1 of RV1 (IRR 1.98, 95% CI 1.16-3.40).

CONCLUSION

Our finding of an increased risk of intussusception associated with RV1 in the first week after dose 1 is consistent with results of previous postlicensure studies. Further research should verify a potentially delayed risk of KD after rotavirus vaccination.

Overview of the Development, Impacts, and Challenges of Live-Attenuated Oral Rotavirus Vaccines

Safety, efficacy, and cost-effectiveness are paramount to vaccine development. Following the isolation of rotavirus particles in 1969 and its evidence as an aetiology of severe dehydrating diarrhoea in infants and young children worldwide, the quest to find not only an acceptable and reliable but cost-effective vaccine has continued until now. Four live-attenuated oral rotavirus vaccines (LAORoVs) (Rotarix^®, RotaTeq^®, Rotavac^®, and RotaSIIL^®) have been developed and licensed to be used against all forms of rotavirus-associated infection. The efficacy of these vaccines is more obvious in the high-income countries (HIC) compared with the low- to middle-income countries (LMICs); however, the impact is far exceeding in the low-income countries (LICs). Despite the rotavirus vaccine efficacy and effectiveness, more than 90 countries (mostly Asia, America, and Europe) are yet to implement any of these vaccines. Implementation of these vaccines has continued to suffer a setback in these countries due to the vaccine cost, policy, discharging of strategic preventive measures, and infrastructures. This review reappraises the impacts and effectiveness of the current live-attenuated oral rotavirus vaccines from many representative countries of the globe. It examines the problems associated with the low efficacy of these vaccines and the way forward. Lastly, forefront efforts put forward to develop initial procedures for oral rotavirus vaccines were examined and re-connected to today vaccines.

Mortality reduction benefits and intussusception risks of rotavirus vaccination in 135 low-income and middle-income countries: a modelling analysis of current and alternative schedules

Background

Infant rotavirus vaccines have led to substantial reductions in hospital admissions and deaths due to gastroenteritis, but some studies have reported an elevated risk of intussusception, a rare bowel disorder. This analysis aimed to provide evidence on the potential mortality reduction benefits and intussusception risks of current rotavirus vaccination schedules, and to explore whether alternative schedules could have advantages.

Methods

All 135 low-income and middle-income countries, defined by gross national income per capita of less than US$12 236 in the 2018 fiscal year, were included in the model. Mortality reduction benefits and intussusception risks of rotavirus vaccination were modelled by use of an Excel-based static cohort model with a finely disaggregated age structure. Numbers of rotavirus gastroenteritis deaths and intussusception deaths in each week of age were calculated for all infants born in the year 2015 between birth and age 5·0 years, with and without restrictions on age at administration. Benefit–risk ratios (rotavirus gastroenteritis deaths prevented per excess intussusception death) and other indicators were calculated for two vaccination schedules currently recommended by WHO and 16 alternative schedules. Of these schedules, it was assumed that between one and three doses would be given; the first dose of the rotavirus vaccine would be co-administered with either BCG or diphtheria–tetanus–pertussis (DTP)1; and the second or third dose would be co-administered with either DTP1, DTP2, DTP3, or measles (Meas)1.

Findings

A three-dose schedule co-administered with DTP (without age restrictions) could prevent about 74 000 (95% uncertainty interval 59 000–100 000) rotavirus gastroenteritis deaths (38% reduction) and could lead to 201 (77–550) excess intussusception deaths (1·4% increase) compared with no vaccination, resulting in a benefit–risk ratio of 369:1 (160:1–895:1). The benefit–risk ratio was most favourable when the relative risk of intussusception was assumed to decline with the national under-5 mortality rate (2386:1) and least favourable with pessimistic assumptions about access to hospital for intussusception treatment (168:1). Schedules that involve giving the first dose with BCG and the second with DTP1 had the fewest excess intussusception deaths and most favourable benefit–risk ratios.

Interpretation

Rotavirus vaccines have a favourable benefit–risk profile in LMICs. Neonatal schedules have the potential to prevent more rotavirus gastroenteritis deaths and cause fewer excess intussusception deaths than the schedules currently recommended by WHO, but more efficacious rotavirus vaccines would be needed to achieve more substantial mortality reduction benefits.

Funding

Bill & Melinda Gates Foundation.

Rotavirus infection in children in Southeast Asia 2008-2018: disease burden, genotype distribution, seasonality, and vaccination

BACKGROUND

Rotaviruses (RVs) are recognized as a major cause of acute gastroenteritis (AGE) in infants and young children worldwide. Here we summarize the virology, disease burden, prevalence, distribution of genotypes and seasonality of RVs, and the current status of RV vaccination in Southeast Asia (Cambodia, Indonesia, Lao People's Democratic Republic, Malaysia, Myanmar, Philippines, Singapore, Thailand, and Vietnam) from 2008 to 2018.

METHODS

Rotavirus infection in Children in Southeast Asia countries was assessed using data from Pubmed and Google Scholars. Most countries in Southeast Asia have not yet introduced national RV vaccination programs. We exclude Brunei Darussalam, and Timor Leste because there were no eligible studies identified during that time.

RESULTS

According to the 2008-2018 RV surveillance data for Southeast Asia, 40.78% of all diarrheal disease in children were caused by RV infection, which is still a major cause of morbidity and mortality in children under 5 years old in Southeast Asia. Mortality was inversely related to socioeconomic status. The most predominant genotype distribution of RV changed from G1P[8] and G2P[4] into the rare and unusual genotypes G3P[8], G8P[8], and G9P[8]. Although the predominat strain has changed, but the seasonality of RV infection remains unchanged. One of the best strategies for decreasing the global burden of the disease is the development and implementation of effective vaccines.

CONCLUSIONS

The most predominant genotype distribution of RV was changed time by time. Rotavirus vaccine is highly cost effective in Southeast Asian countries because the ratio between cost per disability-adjusted life years (DALY) averted and gross domestic product (GDP) per capita is less than one. These data are important for healthcare practitioners and officials to make appropriate policies and recommendations about RV vaccination.

Incidence of intussusception in children less than five years of age: a pre-rotavirus vaccine survey from Iran, 2010-2015

Background: The aim of this study was to determine the baseline statistics of intussusception in the under-five- year age group in Iran to facilitate the monitoring of potential side effects after administration of rotavirus vaccine. Methods: This hospital-based historical cohort study reviewed children under 60 months of age with the final diagnosis of intussusception, ICD-10 code K56.1, using census in all hospitals of Tehran, Iran from March 2010-2015. Demographic (sex, age, hospital stay duration), clinical manifestations (such as currant jelly stool, abdominal pain, vomiting, and fever),diagnostic and treatment methods (contrast enema, ultrasonography, laparotomy, and laparoscopy), and outcome data of patients aged less than 5 years with the diagnosis of intussusception were collected and analyzed using SPSS Version 16.0 (SPSS Inc., Chicago, IL, USA) Results: In this study, 759 patients were diagnosed with intussusception; 309 (40.7%) cases were less than 12 months old. The annual incidence of intussusception was 66.54 cases per 100.000 in children less than one-year-old and 31.61 cases per 100.000 in children less than five years old. The most common symptoms and signs were abdominal pain/irritability (94.2%) and tenderness (24.2%), respectively. The diagnostic method was ultrasound in 75.9% of cases. The most frequent anatomic location was the ileocolic region (87.87%) and the most common treatment method was barium enema. Conclusion: This research has provided a baseline statistic for childhood intussusception in Tehran prior to the administration of the rotavirus vaccine to provide a better comparison with post-introduction data.

Quantitative Benefit-Risk Models Used for Rotavirus Vaccination: A Systematic Review

Background

Although rotavirus vaccines have proven to prevent the risk of rotavirus gastroenteritis (RVGE) in children under 5 years old, they are also associated with an increased transient risk of intussusception (IS). Several quantitative benefit-risk models (qBRm) are performed to measure this balance in hospitalizations and deaths prevented versus the ones induced.

Method

In this study, our objective was to provide a complete overview of qBRm used for rotavirus vaccination. We systematically searched 3 medical literature databases to identify relevant articles, in English, that were published between 2006 and 2019.

Results

Of the 276 publications screened, 14 studies using qBRm for rotavirus vaccination were retained, based on preselected criteria. Four were performed in low- and middle-income countries. Almost all (13 of 14) displayed the following characteristics: force of infection assumed to be constant over time (static model), indirect effect of rotavirus vaccination (herd effect) not considered, closed model (individuals not allowed to enter and/or exit the model over time), and aggregated level (no tracking of individual's behavior). Most of the models were probabilistic (9 of 14) and reported sensitivity and/or scenario analyses (12 of 14). Input parameter values varied across studies. Selected studies suggest that, depending on the models used, for every IS hospitalization and death induced, vaccination would prevent, respectively, 190-1624 and 71-743 RVGE-related hospitalizations and deaths.

Conclusions

The benefits of rotavirus vaccination were shown to largely exceed the increased risk of IS, across all studies. Future research aiming to harmonize qBRm for rotavirus vaccination should ensure the comparability of studies and provide additional information for regulatory authorities, physicians, and patients.

The control of diarrhea, the case of a rotavirus vaccine

[No disponible]

Kawasaki Disease following administration of 13-valent pneumococcal conjugate vaccine in young children

Kawasaki disease (KD) is a systemic vasculitis mainly affecting young children and the leading cause of acquired heart disease in developed countries. We performed a self-controlled case series analysis to investigate the association between PCV13 and KD. All hospitalized KD cases <2 y old from our hospital in Singapore from 2010 to 2014 were included. Complete KD cases were classified based on the definitions of the American Heart Association. During the study period, 288 KD cases were identified. A total of 21 KD cases (12 were classified as Complete KD) had date of onset within the risk interval of day 1 to day 28 post PCV13. The age-adjusted Relative Incidence (RI) for KD following PCV13 dose 1, dose 2 and dose 3 were 1.40 (95%CI, 0.72 to 2.71), 1.23 (95% CI, 0.62 to 2.44) and 0.34 (95% CI, 0.08 to 1.40) respectively. There were seven Complete KD cases with onset during the risk interval after dose 1 of PCV13 (age-adjusted RI 2.59, 95%confidence interval (CI), 1.16 to 5.81). We did not detect a significant increased risk for overall KD among PCV13 recipients. However, a significant association between PCV13 and Complete KD was noted following receipt of the first dose of PCV13.

Association Between Rotavirus Vaccination and Risk of Intussusception Among Neonates and Infants: A Systematic Review and Meta-analysis

IMPORTANCE

The conclusions from the multiple randomized clinical trials exploring the relationship between development of intussusception and rotavirus vaccination among neonates and infants have been controversial.

OBJECTIVE

To evaluate the association between rotavirus vaccination and risk of intussusception.

DATA SOURCES

For this systematic review and meta-analysis, PubMed, Web of Science, Cochrane library, and Embase databases were searched from January 1, 1999, through December 31, 2018, using no language restrictions. The search terms were rotavirus or RV (rotavirus vaccine) or HRV (human rotavirus vaccine), vaccin*, and intussusception.

STUDY SELECTION

Randomized clinical trials of neonates and infants that compared the risk of intussusception after the vaccination with a placebo group were included.

DATA EXTRACTION AND SYNTHESIS

A fixed-effects model was used to pool the data. Statistical heterogeneity was assessed with Q test and I2 statistic; relative risk (RR), risk difference (RD), and 95% CIs were calculated using the Mantel-Haenszel method.

MAIN OUTCOMES AND MEASURES

The main outcome was the diagnosis of intussusception in the analysis. The pooled and subtotal results of RR, RD, and 95% CI for the risk of intussusception were estimated at 31 days, 1 year, and 2 years after vaccination.

RESULTS

A total of 25 randomized clinical trials including 200 594 participants (104 647 receiving vaccine and 95 947 receiving placebo) in 33 countries from 4 continents were included in this meta-analysis. Twenty cases of definite intussusception were diagnosed within 31 days after rotavirus vaccination, with 11 cases (55%) in the vaccine group and 9 cases (45%) in the placebo group (RD, 0.17 per 10 000 infants [95% CI, -1.16 to 1.50 per 10 000 infants], P = .80; RR, 1.14 [95% CI, 0.49 to 2.64], P = .77). Seventy-four cases were reported within 1 year, with 37 cases (50%) in the vaccine group and 37 cases (50%) in the placebo group (RD, -0.65 per 10 000 infants [95% CI, -2.68 to 1.39 per 10 000 infants], P = .53; RR, 0.84 [95% CI, 0.53 to 1.32], P = .45). Fifty-nine cases were reported within 2 years, with 29 cases (49%) in the vaccine group and 30 cases (51%) in the placebo group (RD, -0.48 per 10 000 infants [95% CI, -3.64 to 2.69 per 10 000 infants], P = .77; RR, 0.91 [95% CI, 0.55 to 1.52], P = .73).

CONCLUSIONS AND RELEVANCE

Results of this systematic review and meta-analysis suggest that monovalent, pentavalent, monovalent human-bovine, oral bovine pentavalent, and human neonatal rotavirus vaccination was not associated with an elevated risk of intussusception among neonates or infants.

Immune response and protective efficacy of the S particle presented rotavirus VP8* vaccine in mice

Rotaviruses cause severe diarrhea in infants and young children, leading to significant morbidity and mortality. Despite implementation of current rotavirus vaccines, severe diarrhea caused by rotaviruses still claims ∼200,000 lives of children with great economic loss worldwide each year. Thus, new prevention strategies with high efficacy are highly demanded. Recently, we have developed a polyvalent protein nanoparticle derived from norovirus VP1, the S particle, and applied it to display rotavirus neutralizing antigen VP8* as a vaccine candidate (S-VP8*) against rotavirus, which showed promise as a vaccine based on mouse immunization and in vitro neutralization studies. Here we further evaluated this S-VP8* nanoparticle vaccine in a mouse rotavirus challenge model. S-VP8* vaccines containing the murine rotavirus (EDIM strain) VP8* antigens (S-mVP8*) were constructed and immunized mice, resulting in high titers of anti-EDIM VP8* IgG. The S-mVP8* nanoparticle vaccine protected immunized mice against challenge of the homologous murine EDIM rotavirus at a high efficacy of 97% based on virus shedding reduction in stools compared with unimmunized controls. Our study further supports the polyvalent S-VP8* nanoparticles as a promising vaccine candidate against rotavirus and warrants further development.

Benefit Versus Risk Assessment of Rotavirus Vaccination in France: A Simulation and Modeling Analysis

Introduction

Two vaccines against rotavirus gastroenteritis (RVGE) in young children, Rotarix and RotaTeq, have been available in Europe since 2006. Vaccination against rotaviruses significantly reduces the burden of RVGE, but it is also associated with a very small increased risk of intussusception. In a benefit–risk analysis, the prevented RVGE burden is weighed against the possible excess of intussusception.

Purpose

The aim was to compare the estimated benefits and risks of Rotarix vaccination in France.

Methods

We estimated the benefits (vaccine-preventable RVGE hospitalizations and deaths) and risks (vaccine-caused intussusception hospitalizations and deaths) following two doses of Rotarix in a birth cohort of 791,183 followed for 3–5 years in France. We used data from peer-reviewed clinical and epidemiological studies or publications, and government statistics.

Results

Within the total number of French children below 5 years of age, we estimate vaccination could prevent a median 11,132 [95% credible interval (CI) 7842–14,408] RVGE hospitalizations and 7.43 (95% CI 3.27–14.68) RVGE deaths. At the same time, vaccination could cause an average of 6.86 (95% CI 2.25–38.37) intussusception hospitalizations and 0.0099 (95% CI 0.0024–0.060) intussusception deaths in the entire French birth cohort of infants below 1 year of age. Therefore, for every intussusception hospitalization and every intussusception death caused by vaccination, 1624 (95% CI 240–5243) RVGE hospitalizations and 743 (95% CI 93–3723) RVGE deaths are prevented, respectively, by vaccination.

Conclusions

The vaccine-prevented RVGE hospitalizations and deaths (benefit) greatly outweigh the excess potentially vaccination-related cases of intussusception (risk), indicating a favorable benefit–risk balance for Rotarix in France.

Electronic supplementary material

The online version of this article (10.1007/s40259-018-0273-6) contains supplementary material, which is available to authorized users.

Epidemiology of intussusception before and after rotavirus vaccine introduction in Fiji

In 2012, Fiji introduced rotavirus vaccine (Rotarix, GSK) into the national immunisation schedule. We describe the intussusception epidemiology prior to rotavirus vaccine, temporal association of intussusception cases to administration of rotavirus vaccine, and estimate the additional number of intussusception cases that may be associated with rotavirus vaccine. A retrospective review of intussusception cases for children aged <24 months old was undertaken between January 2007 and October 2012 pre-vaccine. All admissions and deaths with a discharge diagnosis of intussusception, bowel obstruction, paralytic ileus, or intussusception ICD10-AM codes were extracted from national databases and hospital records. Nationwide active intussusception surveillance was established for three years post-vaccine (2013–2015). There were 24 definite intussusception cases in the pre-rotavirus vaccine period, 96% were confirmed by surgery. The median age was 6.5 months. The incidence rate was 22.2 (95% CI: 13.9–33.7) per 100,000 infants. There were no deaths. Active surveillance identified 25 definite intussusception cases, 96% of which were among children who were age-eligible for rotavirus vaccine. None were potentially vaccine related. We estimated one to five additional  cases of intussusception every five years. The incidence of intussusception pre-rotavirus vaccine in Fiji is low. Intussusception associated with rotavirus vaccine is likely a rare event in Fiji.

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.).

Safety study of live, oral human rotavirus vaccine: A cohort study in United States health insurance plans

As part of a regulatory commitment for post-licensure safety monitoring of live, oral human rotavirus vaccine (RV1), this study compared the incidence rates (IR) of intussusception, acute lower respiratory tract infection (LRTI) hospitalization, Kawasaki disease, convulsion, and mortality in RV1 recipients versus inactivated poliovirus vaccine (IPV) recipients in concurrent (cIPV) and recent historical (hIPV) comparison cohorts. Vaccine recipients were identified in 2 claims databases from August 2008 – June 2013 (RV1 and cIPV) and January 2004 – July 2008 (hIPV). Outcomes were identified in the 0–59 days following the first 2 vaccine doses. Intussusception, Kawasaki disease, and convulsion were confirmed via medical record review. Outcome IRs were estimated. Incidence rate ratios (IRRs) were obtained from Poisson regression models. A post-hoc self-controlled case series (SCCS) analysis compared convulsion IRs in a 0–7 day post-vaccination period to a 15–30 day post-vaccination period. We identified 57,931 RV1, 173,384 cIPV, and 159,344 hIPV recipients. No increased risks for intussusception, LRTI, Kawasaki disease, or mortality were observed. The convulsion IRRs were elevated following RV1 Dose 1 (cIPV: 2.07, 95% confidence interval [CI]: 1.27 – 3.38; hIPV: 2.05, 95% CI: 1.24 – 3.38), a finding which is inconclusive as it was observed in only one of the claims databases. The IRR following RV1 Dose 1 in the SCCS analysis lacked precision (2.40, 95% CI: 0.73 – 7.86). No increased convulsion risk was observed following RV1 Dose 2. Overall, this study supports the favorable safety profile of RV1. Continued monitoring for safety signals through routine surveillance is needed to ensure vaccine safety.

Incidence and epidemiology of intussusception among children under 2 years of age in Chenzhou and Kaifeng, China, 2009-2013

INTRODUCTION

In China, rotavirus is the leading cause of diarrhea hospitalizations among children aged <5 years. A locally manufactured rotavirus vaccine is available for private market use, but little is known about its coverage. Given the impending availability of newer rotavirus vaccines, we evaluated intussusception rates among children aged <2 years to better understand intussusception epidemiology for future vaccine safety monitoring.

METHODS

We conducted a retrospective review at 4 hospitals in Chenzhou City of Hunan Province and Kaifeng City of Henan Province. We identified intussusception cases admitted during 2009-2013 by reviewing medical records with the ICD-10 discharge code for intussusception and extracting demographic and clinical information from the electronic clinical record systems.

RESULTS

During 2009-2013, 1715 intussusception hospitalizations among 1,487,215 children aged <2 years occurred in both cities. The average annual intussusception hospitalization incidence was 112.9 per 100,000 children aged <2 years (181.8 per 100,000 children <1 year; 56 per 100,000 children 1 to <2 years). Intussusception incidence was low among infants aged <3 months and peaked at age 6-8 months. No clear seasonality was observed. Ultrasound was used to diagnose 95.9% of cases. Enema reduction was performed in 80% cases; 25% of cases in Chenzhou and 16% in Kaifeng required surgical intervention. No deaths were reported. The median time between symptom onset and admission was 1 day.

CONCLUSIONS

This study provides information on intussusception incidence and epidemiology in two cities of China during 2009-2013. Monitoring intussusception rates in this population will be important in the post-rotavirus vaccine era.

Age at First Rotavirus Vaccination and Risk of Intussusception in Infants: A Public Health Modeling Analysis

INTRODUCTION

The epidemiology of naturally occurring intussusception is known to increase significantly between the ages of 3 and 8 months. Post-licensure studies have reported a fivefold and twofold increase in intussusception in the first week after the first dose and second dose, respectively, of current rotavirus vaccines (RVs).

PURPOSE

We carried out a public health risk analysis to model the impact of age at first vaccination in relation to rotavirus vaccination and risk of intussusception in infants.

METHOD

We created a static model for a birth cohort followed until 1 year old to estimate the number of excess intussusception hospitalizations which could be caused by three different infant rotavirus vaccination schedules. A relative risk of 5.45 in the first 7 days after the first dose and 1.75 in the first 7 days after the second dose was used in the model.

RESULT

We estimated that the risk of intussusception would be the lowest at about 1 in 49,000 if both first and second dose RVs were given at <3 months of age followed by 1 in 41,000 if first dose RVs were given at <3 months and second dose RVs were given at 3-5 months. It would be highest at about 1 in 11,000 if infants received both doses when >3 months old.

CONCLUSION

Our epidemiological example illustrates the importance of ensuring that the first two doses of RVs are administered in infants <3 months old whenever possible to minimize the risk of intussusception as an adverse event following rotavirus vaccination.

Epidemiology of childhood intussusception in Bangladesh: Findings from an active national hospital based surveillance system, 2012-2016

INTRODUCTION

Rotavirus vaccines have significantly decreased the burden of diarrheal diseases in countries that have introduced them into their immunization programs. In some studies, there has been a small association between rotavirus vaccines and intussusception in post-marketing surveillance, highlighting the importance of tracking incidence before and after vaccine introduction. The objective of this study was to describe the epidemiology of intussusception among Bangladeshi children pre-vaccine introduction.

METHODS

We conducted active, hospital-based surveillance for intussusception at 7 tertiary care hospitals with pediatric surgical facilities during July 2012 to September 2016. Hospitalized children under 2years of age were identified according to Brighton Collaboration level 1 criteria for intussusception. The frequency and proportion of intussusception among overall surgical admissions, as well as the demographic and clinical information of the cases is described.

RESULTS

Overall 153 cases of intussusception among children <2years-old were identified at participating sites over the enrolment period, confirmed by Level 1 Brighton criteria. These cases represented 2% of all surgical admissions under 2years of age. One hundred twelve cases (73%) were male; the median age was 7months; and the median duration of hospitalization was 7days. One hundred forty-six (95%) children with intussusception required surgery, and 11 (7%) died.

CONCLUSIONS

Confirmed cases of intussusception represented nearly 2% of pediatric surgical admissions at tertiary referral centers in Bangladesh during the study period and 7% of children with intussusception died. Given the high burden of rotavirus disease in Bangladesh, vaccine introduction is warranted, however, further studies after introduction of rotavirus vaccine are necessary to determine any association between vaccine and intussusception in this setting.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Oral Administration of a Seed-based Bivalent Rotavirus Vaccine Containing VP6 and NSP4 Induces Specific Immune Responses in Mice

Rotavirus is the leading cause of severe diarrheal disease among newborns. Plant-based rotavirus vaccines have been developed in recent years and have been proven to be effective in animal models. In the present study, we report a bivalent vaccine candidate expressing rotavirus subunits VP6 and NSP4 fused with the adjuvant subunit B of E. coli heat-labile enterotoxin (LTB) in maize seeds. The RT-PCR and Western blot results showed that VP6 and LTB-NSP4 antigens were expressed and accumulated in maize seeds. The expression levels were as high as 0.35 and 0.20% of the total soluble protein for VP6 and LTB-NSP4, respectively. Oral administration of transgenic maize seeds successfully stimulated systemic and mucosal responses, with high titers of serum IgG and mucosal IgA antibodies, even after long-term storage. This study is the first to use maize seeds as efficient generators for the development of a bivalent vaccine against rotavirus.

Risk of Intussusception After Rotavirus Vaccination

BACKGROUND

In 2013, the German Standing Committee on Vaccination (Ständige Impfkommission, STIKO) recommended rotavirus (RV) vaccination for all infants while stating that this mildly increased the risk of intussusception, a potentially life-threatening event. Since this recommendation was issued, multiple observational studies on this topic designed as self-controlled case series (SCCS) have been published. The SCCS design is particularly suitable for the study of rare adverse effects of medications.

METHODS

We systematically searched the literature for SCCS studies on the risk of intussusception after RV vaccination. Relative risks (RR) corresponding to different doses of vaccine were summarized in a meta-analysis, and attributable risks (AR) were calculated.

RESULTS

Of the 16 initially identified studies, 10 with a predominantly low risk of bias were considered in the analysis. The RR for intussusception was 5.71 (95% confidence interval [4.50; 7.25]) 1-7 days after the first dose, 1.69 [1.33; 2.14] after the second, and 1.14 [0.75; 1.74] after the third. The AR for children of the age at which RV vaccination is recommended was 1.7 [1.1; 2.7] additional intussusceptions per 100 000 vaccinated children after the first dose and 0.25 [0.16; 0.40] after the second. If >3-month-old infants are vaccinated, the AR is higher: 5.6 [4.3; 7.2] per 100 000 after the first dose and 0.81 [0.63; 1.06] per 100 000 after the second.

CONCLUSION

RV vaccination is associated with a markedly elevated RR and a mildly elevated AR for intussusception 1-7 days after the first dose. Physicians should begin the series of vaccinations at age 6-12 weeks, as recommended by the STIKO, because the risk of intussusception is higher afterward. Current health insurance company claim data indicate that 11.2% of infants are still receiving the first dose of the vaccine at ages above 3 months. The parents of vaccinated children should be informed about the possible signs of intussusception (colicky pain, bilious vomiting, and red "currant jelly" stool).

Rectal Bleeding and Abdominal Pain Following Vaccination in a 4-Month-Old Infant

Intussusception is one of the most frequent causes of intestinal obstruction in infants. Rotavirus vaccination has been associated with intussusception in the medical literature. We report a case of a 4-month-old female with intussusception requiring hemicolectomy one week following rotavirus vaccination. We review the pathophysiology, presentation, and management of intussusception with a distinct focus on the history of rotavirus vaccination and risks of intussusception associated with timing of rotavirus vaccine administration. The discussion makes a strong case for rotavirus vaccine counseling regarding signs of intestinal obstruction and the importance of early recognition.