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.

Post-marketing surveillance of intussusception after Rotarix administration in Afghanistan, 2018-2022.

BACKGROUND: In January 2018, Afghanistan introduced the monovalent oral rotavirus vaccine (Rotarix) nationwide, administered as a 2-dose series at six and ten weeks of age. We describe characteristics of intussusception cases and assess potential intussusception risk associated with Rotarix vaccination in Afghan infants. METHODS: Multi-center prospective active hospital-based surveillance for intussusception was conducted from May 2018 to March 2022 in four sentinel sites in Afghanistan. We applied the Brighton Level 1 criteria for intussusception and verified vaccination status by reviewing vaccine cards. We used the self-controlled case series (SCCS) methodology to compare intussusception incidence in the 1 to 21 days after each dose of Rotarix vaccination against non-risk periods. RESULTS: A total of 468 intussusception cases were identified in infants under 12 months, with 264 cases aged between 28 and 245 days having confirmed vaccination status contributing to the SCCS analysis. Most case-patients (98 %) required surgery for treatment, and over half (59 %) of those who underwent surgery required intestinal resection. Nineteen (7 %) case-patients died. Eighty-six percent of case-patients received the first dose of Rotarix, and 69 % received the second dose before intussusception symptom onset. There was no increased risk of intussusception in the 1-7 days (relative incidence: 0.9, 95 % CI: 0.1, 7.5), 8-21 days (1.3, 95 % CI: 0.4, 4.2), or 1-21 days (1.1, 95 % CI: 0.4, 3.4) following receipt of the first dose or in the 1-7 days (0.2, 95 % CI: 0.3, 1.8), 8-21 days (0.7, 95 % CI: 0.3, 1.5), or 1-21 days (0.6, 95 % CI: 0.3, 1.2) following the second dose. CONCLUSION: Rotarix vaccination was not associated with an increased intussusception risk, supporting its continued use in Afghanistan's immunization program. However, there was a high level of death and resection due to intussusception among Afghan infants.

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.

No increased risk of intussusception after pentavalent rotavirus vaccination in China: a retrospective birth cohort using electronic health records of Ningbo city.

Some post-licensure studies have shown a potential increased risk of intussusception following vaccination with rotavirus vaccines. This is the first study that aimed to assess the incidence and risk of intussusception within 90 days after vaccination with RotaTeq in Chinese infants. A population-based birth cohort from 27th November 2018 to 30th June 2021 included all newborns in Ningbo city. The records of intussusception were identified through the ICD-10 code K56.1 or Chinese keywords "Chang Tao" from all hospital discharge records. Each episode was confirmed in line with the Brighton criteria, and only Brighton level 1 cases were included. The association of RotaTeq vaccination and intussusception was evaluated using the Poisson regression. A total of 108,405 eligible subjects from birth cohort were eligible, with 52.30% males. Among them, 26, 847 (24.77%) infants received at least one dose of RotaTeq, and 95.52% of them were fully vaccinated, with 76, 934 doses in total. After adjudication, none of the cases occurred post first, or second dose, the cumulative number of cases that occurred 1-7, 1-14, 1-21, 1-42, and 1-90 days post third dose was 0, 1, 1, 3, and 7, respectively. Adjusting for age, sex, birth year, birth season and location, the incidence rate ratio of intussusception after RotaTeq vaccination was 0.90 (90% two-sided CI: 0.46, 1.75). Increasing age and male gender were associated with higher risk of intussusception. In summary, no increased risk of IS was observed following 3 months of RotaTeq vaccination in this study.

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.

Impact of polio vaccines (oral polio vaccine - OPV or inactivated polio vaccine - IPV) on rotavirus vaccine-associated intussusception.

Although safe, rotavirus vaccines have been associated with increased intussusception risk. In Brazil, after the oral human rotavirus vaccine (OHRV) introduction in the childhood immunization, in 2006, increased intussusception risk was identified after the second OHRV dose, whereas in other countries, higher risk was associated to the first vaccine dose. It was hypothesized that the concomitant use of oral poliovirus vaccine (OPV) in Brazil might explain this difference. In 2012, the inactivated polio vaccine (IPV) was adopted in the first two doses of Brazilian childhood immunization schedule, creating an opportunity to study the subject. Our objective was analyzing the impact of polio vaccines on rotavirus-associated intussusception. We used surveillance data on intussusception in infants living in São Paulo State. Two periods were considered: an OPV-period (March 2006 to June 2012) and an IPV-period (October 2012 to December 2017). The period from June to September 2012 were considered as transition. Self-controlled case series analysis with event-dependent exposure was performed, considering two risk periods (7 and 21 days post-vaccination). We identified 325 intussusception cases in infants reported to the surveillance systems during the study period. The statistical analysis included 221 cases that occurred within 60 days after vaccination. Overall, a higher intussusception risk was observed in the first week after vaccination for both the first (Relative Incidence [RI] = 4.3, 95%CI 2.8-6.5, p < .001) and second vaccine doses (RI = 4.2, 95%CI 2.7-6.4; p < .001). There were no statistically significant differences in intussusception risk according to the rotavirus vaccine dose and the polio vaccine (OPV or IPV) administered concomitantly.

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.

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.

Intussusception and Chronic Marijuana Use in a Young Adult.

BACKGROUND Intussusception is a common phenomenon in children, but it is rare in adults. In the pediatric population, the presentation is commonly primary, without a lead point. However, up to 90% of intussusception cases arise due to a secondary cause - a pathological lead point - which the most common etiology in adults being malignancy. Herein, we present a case report of adult intussusception without a known cause. CASE REPORT A 26-year-old woman presented to the hospital with severe abdominal pain. She admitted to not passing stool or gas for 2 days. The patient's social history was significant for chronic marijuana use. A computed tomography (CT) scan of the abdomen revealed a 6-cm in length intussuscepted segment of bowel in the descending colon distal to the splenic flexure with no obvious inciting mass. The patient was sent for emergent open abdominal surgery. Upon surgical exploration, the surgeons discovered that the intussusception had self-resolved. Aside from a small ball of stool, an intraoperative colonoscopy revealed no masses or polyps. CONCLUSIONS Marijuana use is known to disrupt gastrointestinal (GI) mobility through receptors in the GI tract nerve plexuses. The incidence of chronic marijuana use and adult intussusception is documented in the literature. Conservative management with bowel rest is confirmed to be a suitable treatment option with a favorable outcome. Therefore, we present this case to increase awareness of the potential adverse effects of chronic marijuana use, and to prevent invasive treatment.

Implementation of the World Health Organization recommendation on the use of rotavirus vaccine without age restriction by African countries.

The World Health Organization (WHO) recommended the worldwide use of rotavirus vaccines initially in 2007 and 2009 applying a strict age restriction criterion due to the potential for age-related association with increased risk of intussusception in infants. The restriction was relaxed in the 2013 after detailed review of robust safety data generated in post-marketing surveillance studies. We assessed the status of the implementation of the 2013 recommendation to remove age restriction in the WHO African region (AFR). Of the approximately 75% (35/47) of countries that had introduced the vaccine by 2018, only 43% (15/35) removed age restriction, exclusively from South and East sub-region (78%, 14/18). Avoiding confusion at the health facilities and financial constraints particularly resources required for re-training the health workers, use of vaccine off-label were cited as the main reasons for not implementing the 2013 WHO recommendation on age restriction removal. The 2013 WHO recommendation has not been fully implemented by African countries, suggesting the need for technical advisory bodies to further guide the countries, continue monitoring the implementation status and impact on the rotavirus vaccine coverage and intussusception in the Africa region.

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.

Rotavirus vaccination and intussusception: a paradigm shift?

Rotavirus (RV) is one of the leading causes of severe childhood gastroenteritis in children <5 years of age. Several countries have successfully implemented vaccination against RV disease; however, hesitancy to include RV vaccination in the national immunization program exists and relates, among other reasons, to the results of international post-licensure studies of RV vaccines that established an increased risk of intussusception (IS) in infants following immunization. IS is one of the major causes of bowel obstruction in infants between 4 and 10 months of age. Some studies have investigated the etiology of IS, including the role of natural RV infection and available evidence suggests that RV disease may be an independent risk factor for IS. In this regard, the benefit-risk profile of RV vaccination, which is recognized as positive, could potentially turn out to be even more favorable in preventing IS cases triggered by RV disease. However, further research is prompted to quantify the IS risk attributable to RV disease.

Safety profile of rotavirus vaccines among individuals aged ≥8 months of age, United States, vaccine adverse event reporting system (VAERS), 2006-2019.

INTRODUCTION: In 2006 and 2008, two live, oral rotavirus vaccines, RotaTeq (RV5) and Rotarix (RV1), were introduced into the routine immunization program in the United States. A previous rotavirus vaccine, RotaShield, was associated with an increased risk of intussusception, with data suggesting an age-dependent variation in risk. Advisory Committee on Immunization Practices (ACIP) currently recommends that RV5 or RV1 immunization be initiated by age 14 weeks and 6 days and completed by 8 months 0 days. METHODS: We searched for U.S. VAERS reports of RV5, RV1, or unknown rotavirus vaccine brand among individuals aged ≥8 months. We analyzed reports by 2 age groups (individuals aged ≥8 months-≤5 years and ≥6 years), vaccine brand name, adverse event (AE) reported, classification of seriousness (death, non-death serious, and non-serious) and mode of exposure (direct vs. indirect exposure). For serious reports we reviewed available medical records and assigned a primary diagnosis. RESULTS: VAERS received a total of 344 U.S. reports following rotavirus vaccination among individuals ≥8 months of age, 32 (9.3%) were serious. In the younger age-group, 307 (99%) of 309 reports followed direct vaccination of the child. In contrast, in individuals aged ≥6 years, 21 (60%) of 35 reports were via potential indirect exposure to a vaccinated child. The frequently reported AEs in the younger age-group were inappropriate schedule of drug administration 104 (34%) and drug administered to patient of inappropriate age 45 (15%); in the older group these were accidental exposure 9 (26%) and eye irritation 7 (20%). No difference in the safety profile was observed between RV1 and RV5. CONCLUSIONS: We did not identify any unexpected AEs for RV vaccines among individuals aged ≥8 months. Health care providers should adhere to the ACIP recommended schedule and older individuals should apply necessary precautions to prevent potential secondary exposure from vaccinated children.

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.

Impact of rotavirus vaccination on intussusception hospital admissions in England.

BACKGROUND: An increased risk of intussusception has been reported following rotavirus vaccination. We sought to determine whether introduction of rotavirus vaccination in England in July 2013 was associated with a change in the burden of total and age group-specific childhood hospital admissions for intussusception. METHODS: We identified all children aged 0-36 months admitted to hospitals in England with intussusception using the Hospital Episode Statistics dataset. We performed a retrospective ecological analysis comparing hospital admission rates for intussusception during the periods before (2008/2009-2012/2013) and after (2014/2015-2017/2018) introduction of rotavirus vaccination using modified Poisson regression and interrupted time series analysis. Length of hospital stay and clinical outcomes were also examined. RESULTS: The mean annual admission rate for intussusception in infants over the ten-year study period was 31.5 per 100,000 person-years. An increase in the admission rate in the 8-16 weeks age group (RR 1.46, 95% CI 1.12-1.91), those receiving vaccination, was compensated for by decreases in the 17-24 weeks (RR 0.77, 0.63-0.94), 25-32 weeks (RR 0.71, 0.59-0.86) and 41-52 weeks (RR 0.80, 0.66-0.98) age groups. Using interrupted time series analysis, we observed a significant decrease in incidence in the 0-12 months age group (RR 0.80, 0.67-0.96), but not in the overall 0-36 months age group (RR 1.09, 0.98-1.20). There was no significant change in the proportion of children requiring surgical intervention or with major complications of intussusception. Length of hospital stay decreased among infants receiving surgery for intussusception. CONCLUSIONS: Our results suggest that introduction of rotavirus vaccination in England has resulted in a downward shift in the age at which intussusception occurs in infants, with no overall increase in hospital admission rate or disease severity. These findings support the view that the benefits of rotavirus vaccination outweigh the small increased risk of intussusception in the early post-vaccination period.

Assessment of risk of intussusception after pilot rollout of rotavirus vaccine in the Indian public health system.

BACKGROUND: Pre-licensure trials of ROTAVAC® were not adequately powered to assess risk of intussusception, a rare adverse event associated with other rotavirus vaccines in some settings. We examined the risk of intussusception after ROTAVAC® vaccination among Indian infants during pilot rollout of the vaccine in the public health system in three states - Himachal Pradesh, Maharashtra and Tamil Nadu. METHODS: Passive surveillance for intussusception was set up in 35 sentinel health facilities covering 26.3 million population in the three states under monitoring of an Interministerial-Interagency Steering Committee. Clinical and immunization data were collected by independent teams. An expert committee blinded to vaccination status, classified intussusception cases using Brighton criteria. The self-controlled case-series method was used to estimate risk of intussusception (Brighton Level 1) after ROTAVAC® vaccination. RESULTS: 151 intussusception cases were included in the analysis. The relative incidence (incidence during the risk period compared to the control period) 1-21 days after doses 1 and 2 combined was 1.56 (95% CI, 0.0-5.28) and that for three doses combined was 1.88 (95% CI, 0.76-4.30). Attributable risk 1-21 days after doses 1 and 2 combined was 0.11 (95% CI, 0.0-0.25) and that for 3 doses combined was 0.42 (95% CI, 0.0-0.70) per 100,000 doses. CONCLUSIONS: No increased risk of intussusception within 21 days of receipt of the first two doses combined or all 3 doses combined of ROTAVAC® was detected.

Letter to the editor concerning the article 'Association between rotavirus vaccination and risk of intussusception among neonates and infants: a systematic review and meta-analysis' (JAMA Netw Open. 2019;2(10):e1912458).

A recent meta-analysis investigating the association between intussusception (IS) and rotavirus (RV) vaccination demonstrated an absence of risk up to 2 years after vaccination. Meta-analyses including only randomized clinical trials are inadequate to identify a potential increased risk of rare adverse events such as IS. The study conducted failed to discuss relevant limitations. Additionally, the safety profiles of newer RV vaccines, evaluated in clinical studies with limited sample size, were considered comparable with that of the well-established and widely used RV vaccines, RotaTeq and Rotarix. We, therefore, re-emphasize that extensive and updated evidence from post-marketing surveillance indicates a slight increased risk of IS, mostly within 7 days of RV vaccination, with a benefit/risk profile assessment in favor of RV vaccination.

Evaluation of Intussusception After Oral Monovalent Rotavirus Vaccination in South Africa.

BACKGROUND: Postlicensure studies have shown an association between rotavirus vaccination and intussusception. We assessed the risk of intussusception associated with Rotarix (RV1) administration, at 6 and 14 weeks of age, in an upper-middle-income country, South Africa. METHODS: Active prospective surveillance for intussusception was conducted in 8 hospitals from September 2013 through December 2017. Retrospective case enrollment was done at 1 hospital from July 2012 through August 2013. Demographic characteristics, symptom onset, and rotavirus vaccine status were ascertained. Using the self-controlled case-series method, we estimated age-adjusted incidence rate ratios within 1-7, 8-21, and 1-21 days of rotavirus vaccination in children aged 28-275 days at onset of symptoms. In addition, age-matched controls were enrolled for a subset of cases (n = 169), and a secondary analysis was performed. RESULTS: Three hundred forty-six cases were included in the case-series analysis. Post-dose 1, there were zero intussusception cases within 1-7 days, and 5 cases within 8-21 days of vaccination. Post-dose 2, 15 cases occurred within 1-7 days, and 18 cases within 8-21 days of vaccination. There was no increased risk of intussusception 1-7 days after dose 1 (no cases observed) or dose 2 (relative incidence [RI], 1.71 [95% confidence interval {CI} .83-3.01]). Similarly, there was no increased risk 8-21 days after the first (RI, 4.01 [95% CI, .87-10.56]) or second dose (RI, .96 [95% CI, .52-1.60]). Results were similar for the case-control analysis. CONCLUSIONS: The risk of intussusception in the 21 days after the first or second dose of RV1 was not higher than the background risk among South Africa infants. CLINICAL TRIALS REGISTRATION: South African National Clinical Trial Register (DOH-27-0913-4183).

Adverse events in patients with ulcerative colitis treated with indigo naturalis: a Japanese nationwide survey.

BACKGROUND: Although indigo naturalis (IN) is effective for patients with active ulcerative colitis (UC), IN was associated with adverse events (AEs), including pulmonary arterial hypertension (PAH). Our aim was to evaluate the occurrence of IN-associated AEs and to evaluate any IN dose-effect on AEs. METHODS: A nationwide survey, using questionnaires, was conducted by conducted by the research group funded by the Ministry of Health, Labour and Welfare of Japan, between June 2017 and September 2018. A first questionnaire determined the occurrence of AEs associated with the therapeutic use of IN or herbal medicines containing IN in patients with UC. A second survey identified the clinical characteristics of patients who developed IN-associated critical AEs, namely, liver dysfunction, PAH, and intussusception. RESULTS: Across 337 participating institutions, 49,320 patients with UC were identified, with IN used in 877 (1.8%). AEs were reported in 91 patients (107 events), including liver dysfunction (n = 40), gastrointestinal symptoms (n = 21), headache (n = 13), and PAH (n = 11). No dose-effect relationship between IN and AEs was identified. Liver dysfunction tended to be mild and reversible. Ten cases of intussusception were reported, with 40% of these patients requiring surgical resection. IN-induced PAH was recovered in patients who discontinued to use IN. No IN-associated deaths were reported. CONCLUSIONS: IN-associated AEs were identified among patients with UC, with liver dysfunction often being reversible, while surgical resection was required in a high proportion of patients who developed intussusception. Both healthcare workers and patients should adequately recognize the potential for AEs with the use of IN.

A case-control study of risk factors for intussusception among infants in eastern France after the introduction of the rotavirus vaccine.

OBJECTIVE: The objective of the present study was to investigate the risk factors for intussusception (IS) among infants, including vaccination against rotavirus. METHODS: Case-control study with systematic inclusion of all infants aged <1 year with suspected IS admitted to emergency departments in the eastern region of France between 1 April 2008 and 31 March 2012. All cases classed level 1 according to the Brighton classification were matched to 4 hospital controls. Two exposure windows were examined; exposure to the first dose of rotavirus vaccine in the 7 and in the 14 days prior to the occurrence of IS. RESULTS: A total of 115 cases were matched with 457 controls. The average vaccination coverage rate over the 4 years of study was 8.6%. Rotavirus vaccine was not found to be significantly associated with the occurrence of IS in the 7 days (odds ratio (OR) not calculated; p = 0.99) and in the 14 days after administration of one dose vaccine (OR 1.33, 95% confidence interval (CI) 0.14-12.82). Infant formula alone or combined with breastfeeding was associated with an excess risk of IS (OR 2.74, 95% CI 1.10-6.79). A history of gastroenteritis within 2 weeks prior to hospitalisation was also associated with an increased risk (OR 2.24, 95% CI 1.07-4.67). CONCLUSION: Our study indicates that infant formula alone or combined with breastfeeding is a risk factor for IS. A small, non-significant increase in the risk of IS was observed after rotavirus vaccination, although the low vaccine coverage rate likely precluded detection of a significant increase in risk.