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.

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.

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.

[A Case of Small Intestinal Metastasis with Intussusception Due to Barium]

A 48-year-old man noticed nausea and took health examination. After chest X-ray and gastrointestinal barium study was underwent, he was referred to our hospital because of abnormal shadow in the chest X-ray. CT scan revealed about 4 cm tumor in the hilum of left lung and target sign in the small intestine. He was diagnosed with intussusception and emergency operation was performed. During the laparotomy, we found 2 intussusceptions in the small intestine and we performed manual reduction using Hutchinson's maneuver. We confirmed the mass in oral side of the intussusception site but we did not confirmed any tumor in anal of the intussusception. This suggests the intussusception was caused by barium. Finally 3 small intestine tumor was observed and we resected and reconstructed each of the tumor. Histopathological examination showed small intestinal metastasis from pleomorphic carcinoma of the lung.

Assessing the risk of intussusception and rotavirus vaccine safety in Canada

BACKGROUND

Intussusception has been identified as a rare adverse event following rotavirus immunization. We sought to determine the incidence of intussusception among infants in Canada both before and after introduction of rotavirus immunization programs.

METHODS

We used Canadian Institute for Health Information (CIHI) Discharge Abstract Database (DAD) to identify infants under 1 y of age who were admitted to a Canadian hospital, which the exception of Quebec, which does not submit data to CIHI, with a diagnosis of intussusception (ICD-10 code K56.1, and ICD-9 code 560) between January 1st, 2003 and December 31, 2013. We compared rates of intussusception hospitalization before and after rotavirus vaccine program introduction. Rates were adjusted for calendar year, age (in months), sex and region using Poisson regression models. Denominator data for infants under 1 year, stratified by age in months, were obtained from Statistics Canada.

RESULTS

Annual intussusception hospitalization rates ranged from 20-30 per 100,000 infants over the study period, with no evidence of a trend over time. Intussusception hospitalization rates were highest in infants 4 to <8 months and lowest in those under 2 months or between 10 and <12 months. Males had higher rates than females both overall and within each age group. The rate of intussusception hospitalization after rotavirus vaccine program introduction was 22.4 (95% CI: 18.3, 27.4) compared to 23.4 (95% CI: 21.5, 25.4) per 100,000 before program introduction.

CONCLUSIONS

We have described baseline intussusception hospitalization rates for infants in Canada and have found no evidence of a change in rate after implementation of routine rotavirus immunization programs.

Risk of Intussusception with Rotavirus Vaccine

OBJECTIVE

To study the case series for intussusception associated with the vaccination of rotavirus vaccine in children.

METHODS

The study of spontaneous adverse event monitoring such as intussusception due to rotavirus vaccine was carried out from the year 2011 through 2015. The individual case safety reports (ICSRs) of this event were collated, assessed and recorded as per the requirement of Suspected Adverse Drug Reactions Reporting form of Pharmacovigilance Programme of India (PvPI).

RESULTS

In the present study, 10 ICSRs of intussussception due to rotavirus vaccine were reported to PvPI. Of which 3 ICSRs were found to be causal relationship with rotavirus vaccine, as evidenced by the adequate information provided in ICSRs.

CONCLUSIONS

Since intussusception, the emerging safety as one of the important safety concern, healthcare professionals are advised to monitor and report to the concerned authority for appropriate action.

Post-rotavirus vaccine intussusception in identical twins: A case report

The intussusception is one of the most frequent causes of occlusive syndrome in infants and in children. (1) The mesenteric lymphadenopathy, wich is very rare post rotavirus vaccination, can cause intussusception, (2-5) especially in genetically predisposed individuals. (6) There is an association between intussusception and some classes of genotype. (7-9) Two infants aged 3 months, vaccinated against rotavirus. After about a week, one of the 2 identical infants presented inconsolable crying, vomiting, loose stools mixed with blood, and was diagnosed with bowel obstruction with intussusception. He was operated in urgency. After a few hours, his brother presented vomiting, and was admitted to our Hospital for suspected intussusception. The controls carried out have confirmed the presence of intussusception that was treated early, before the onset of severe symptoms. The incidence of post rotavirus vaccine intussusception is very low. The determining factor hypothetically might be linked to the presence of a genotype that exposes infants to a greater risk of developing mesenteric lymphadenitis and intussusception. In our case, the diagnosis of intussusception occurred in a twin, which allowed us to recognize early symptoms which accused the brother and schedule the surgery with less urgency. Our experience may want to sensitize families and pediatricians to report cases of intussusception given a theoretical familiar association. The study of the genotype could be decisive for or not to exclude the presence of a risk of invagination, thus avoiding vaccination.

Fetal safety of macrolides

Macrolide antibiotics are largely used in pregnancy for different bacterial infections. Their fetal safety has been studied by several groups, yielding opposing results. In particular, there have been studies claiming an association between macrolides and cardiovascular malformations. Exposure in early infancy has been associated with pyloric stenosis and intussusception. This has led to an avoidance in prescribing macrolides to pregnant women in several Scandinavian countries. The Objectives of the present study was to investigate the fetal safety of this class of drug by linking a large administrative database of drug dispensing and pregnancy outcome in Southern Israel. A computerized database of medications dispensed from 1999 to 2009 to all women registered in the Clalit health maintenance organization in southern Israel was linked with two computerized databases containing maternal and infant hospitalization records. Also, medical pregnancy termination data were analyzed. The following confounders were controlled for: maternal age, ethnicity, maternal pregestational diabetes, parity, and the year the mother gave birth or went through medical pregnancy termination. First- and third-trimester exposures to macrolide antibiotics as a group and to individual drugs were analyzed. During the study period there were 105,492 pregnancies among Clalit women that met the inclusion criteria. Of these, 104,380 ended in live births or dead fetuses and 1,112 in abortion due to medical reasons. In the first trimester of pregnancy, 1,033 women were exposed to macrolides. There was no association between macrolides and either major malformations [odds ratio (OR), 1.08; 95% confidence interval (CI), 0.84 to 1.38)] or specific malformations, after accounting for maternal age, parity, ethnicity, prepregnancy diabetes, and year of exposure. During the third trimester of pregnancy, 959 women were exposed to macrolides. There was no association between such exposure and perinatal mortality, low birth weight, low Apgar score, or preterm delivery. Similarly, no associations were demonstrated with pyloric stenosis or intussusception. Use of macrolides in the first trimester of pregnancy is not associated with an increased risk of major malformations. Exposure in the third trimester is not likely to increase neonatal risks for pyloric stenosis or intussusception in a clinically meaningful manner.

Inflammation-induced intussusceptive angiogenesis in murine colitis

Intussusceptive angiogenesis is a morphogenetic process that forms new blood vessels by the division of a single blood vessel into two lumens. Here, we show that this process of intraluminal division participates in the inflammation-induced neovascularization associated with chemically induced murine colitis. In studies of both acute (4-7 days) and chronic (28-31 days) colitis, intravital microscopy of intravascular tracers demonstrated a twofold reduction in blood flow velocity. In the acute colitis model, the decreased velocity was associated with marked dilatation of the mucosal plexus. In contrast, chronic inflammation was associated with normal caliber vessels and duplication (and triplication) of the quasi-polygonal mucosal plexus. Scanning electron microscopy (SEM) of intravascular corrosion casts suggested that pillar formation and septation, previously linked to the morphogenetic process of intussusceptive angiogenesis, were present within days of the onset of inflammation. Four weeks after the onset of inflammation, SEM of vascular corrosion casts demonstrated replication of the mucosal plexus without significant evidence of sprouting angiogenesis. These data suggest that mucosal capillaries have comparable aggregate cross-sectional area in acute and chronic colitis; however, there is a significant increase in functional capillary density in chronic colitis. We conclude that intussusceptive angiogenesis is a fundamental mechanism of microvascular adaptation to prolonged inflammation.

Adult idiopathic intussusception: a case report and review of the literature

Adult intussusception is a rare condition. Most of the cases are due to an organic lesion and unlike the incidence in children idiopathic forms are really exceptional, occurring at a rate of 5% of all cases. Whereas in children a main cause is seldom found, adult intussusception is usually characterised by the presence of a leading intraluminal benign or malignant lesion. The authors report their experience with a clinical case of ileocolic intussusception occurring in an 28-year-old white male. In spite of the patient's age, the clinical presentation was very typical with the classic triad of abdominal pain, blood per rectum and a palpable mass. Diagnostic tools, namely US and TC scan, together with colonoscopy confirmed the physical examination, so that surgery was initiated with a definite diagnosis of intussusception. A large polyp or a lymphoma were considered the possible leading causes. After right hemicolectomy, pathology revealed that there was no organic lesion and the bulging mass was caused only by oedema and haemorrhagic infiltration of the invaginated loop. The patient had been on antipsychotic drugs for several months and the possible explanation of the pathology was linked to altered peristalsis induced by the pharmacological agents he was taking. The authors compare their experience with the data reported in the literature, evaluating in particular the incidence, pathology, clinical presentation, diagnosis and treatment of adult intussusception.

Rotavirus vaccines: an overview

Rotavirus infection is the most common cause of severe diarrhea disease in infants and young children worldwide and continues to have a major global impact on childhood morbidity and mortality. Vaccination is the only control measure likely to have a significant impact on the incidence of severe dehydrating rotavirus disease. In 1999, a highly efficacious rotavirus vaccine licensed in the United States, RotaShield, was withdrawn from the market after 14 months because of its association with intussusception. Two new live, oral, attenuated rotavirus vaccines were licensed in 2006: the pentavalent bovine-human reassortant vaccine (RotaTeq) and the monovalent human rotavirus vaccine (Rotarix). Both vaccines have demonstrated very good safety and efficacy profiles in large clinical trials in western industrialized countries and in Latin America. Careful surveillance has not revealed any increased risk of intussusception in the vaccinated groups with either vaccine. The new rotavirus vaccines are now introduced for routine use in a number of industrialized and developing countries. These new safe and effective rotavirus vaccines offer the best hope of reducing the toll of acute rotavirus gastroenteritis in both developed and developing countries.

Rotavirus vaccines--an update

Rotavirus infection is the most common cause of severe diarrhea disease in infants and young children worldwide and continues to have a major global impact on childhood morbidity and mortality. Vaccination is the only control measure likely to have a significant impact on the incidence of severe dehydrating rotavirus disease. Rotavirus disease prevention efforts suffered a severe setback in 1999 with the withdrawal of the RRV-TV vaccine less than a year after its introduction. Several new rotavirus vaccines have been developed and have proven to be safe and efficacious. These new safe and effective rotavirus vaccines offer the best hope of reducing the toll of acute rotavirus gastroenteritis in both developed and developing countries.

Rotavirus vaccines: new drug. Rotavirus infection: one case of severe diarrhoea prevented per 100 vaccinated infants

(1) Each year in France, diarrhoea caused by rotavirus kills about 10 infants under three years of age and leads to about 210 hospitalisations per 100 000 children under 5 years of age. (2) Two new oral rotavirus vaccines designed for immunisation during infancy are marketed or shortly to be marketed in France for the first time; one is based on a human strain and the other on both bovine and human strains. (3) The vaccine based on a human strain has been tested in a double-blind placebo-controlled trial involving about 63 000 infants. It had no statistically significant impact on mortality but prevented about 10 cases of severe diarrhoea per 1000 vaccinated infants during the following year. Other, smaller trials provided similar results. (4) In two double-blind placebo-controlled trials involving a total of about 70 000 infants, the human-bovine vaccine prevented about 16 cases of severe diarrhoea per 1000 vaccinated infants during the year following vaccination. As with the human vaccine, there was no impact on mortality. (5) An analysis of data on 60 000 to 70 000 infants immunised with each vaccine showed no increase in the risk of acute intestinal intussusception, a severe adverse effect observed with another rotavirus vaccine that was marketed in the 1990s in the United States (but not in France). This product has since been withdrawn from the market. (6) The two new rotavirus vaccines do not appear to have more adverse effects than placebo. (7) Rotavirus vaccination does not seem to reduce the efficacy of other vaccines. (8) Vaccination is simpler with Rotarix than with Rotateq, requiring two oral doses instead of three. However, Rotarix is sold in kits containing a vial of powder, a prefilled solvent syringe, and a syringe-bottle adaptor, creating a risk that this vaccine might be accidentally injected instead of being given orally. (9) In practice, rotavirus vaccination during infancy is not a public health priority in western countries. Vaccination of individual infants may be useful, especially when access to healthcare may be difficult.

The epidemiology of paediatric intussusception in Singapore: 1997 to 2004

INTRODUCTION

The world's first rotavirus vaccine, Rotashield or RRV-TV, was registered in the US in 1998, but withdrawn within a year because of an observed association with intussusception (IS). Surveillance for IS has consequently become important in safety monitoring of new-generation rotavirus vaccines during development. Post-marketing surveillance is also important, and requires the availability of local baseline epidemiology data on IS.

MATERIALS AND METHODS

An eight-year study of IS in children under 2 years of age in Singapore was performed by retrospective review of admissions to KK Women's and Children's Hospital, the main paediatric hospital, from 1997 to 2001, followed by prospective surveillance of all hospitals from 2001 to 2004, using the case definition of the Brighton Collaboration Intussusception Working Group.

RESULTS

The average IS incidence was 60 per 100,000 in under-ones, and 32 per 100,000 in under-twos, with a downward trend between 1999 and 2004. Ninety-two per cent of subjects were aged below one year, with 51% aged 6 months to 11 months. The mean age at which IS occurred increased from 6.4 months to 12.5 months over the study period. The male-to-female ratio was 1.3:1. No trend in IS numbers was observed over different months of the year.

CONCLUSION

IS in Singapore shows no seasonality, but has demonstrated a trend of decreasing incidence in recent years. While highest in the first year of life, the risk of IS is increasing in the second year of life. Males have a slightly higher risk.

Rotavirus infection enhances lipopolysaccharide-induced intussusception in a mouse model

Unexpected reports of intussusception after vaccination with the live tetravalent rotavirus vaccine RotaShield resulted in voluntary withdrawal of the vaccine. Intussusception, a condition in which the intestine acutely invaginates upon itself, is the most common cause of intestinal obstruction in children. We report here the development of a mouse model to study rotavirus-induced intussusception. In this model, both homologous murine and heterologous simian rotavirus strains significantly enhanced the rate of lipopolysaccharide (LPS)-induced intussusception, and this enhancement was replication dependent, requiring rotavirus doses of greater than one 50% infectious dose. Rotavirus-induced intussusceptions did not have observable lymphoid lead points, despite the induction of intestinal lymphoid hyperplasia after rotavirus infection. Intussusceptions are also postulated to result from altered intestinal motility, but rotavirus infection had no effect on gastrointestinal transit. LPS-induced intussusception is associated with the induction of inflammatory mediators, and intussusception rates can be modified by inflammatory antagonists. We show that rotavirus infection significantly enhanced serum tumor necrosis factor alpha and gamma interferon cytokine levels after LPS treatment compared to uninfected mice. Together, these data suggest that rotavirus infection sensitized mice to the inflammatory effects of subsequent LPS treatment to enhance intussusception rates.

Intussusception of vermiform appendix with microscopic melanosis coli: a case report

Intussusception of the appendix is a rare occurrence. Due to the similarity of its symptoms with appendicitis, preoperative diagnosis of this condition is extremely difficult. In this report, we present appendiceal intussusception with histological melanosis coli that occurred in a patient on long-term anthranoid laxative use for chronic constipation. Melanosis coli in the appendiceal tissue, as an indicator of chronic laxative intake, may be a clue implying that the appendical exposure to hyperperistalsis for a long time in our case led to the intussusception. We conclude that colonoscopy may help in preoperative diagnosis of appendiceal intussusception in patients with suspicious appendicitis, particularly in those using laxative medication.

Development of next generation medical countermeasures to nerve agent poisoning

Medical countermeasures provide a key role in the UK integrated approach to chemical defence and are aimed at preventing or mitigating the effects of exposure to nerve agents. It is UK policy that medical countermeasures will be licensed products. Demonstration of efficacy relies on extrapolation of animal-derived data to man which means that species selection is extremely important. For the foreseeable future it is likely that a combination of pretreatment and therapy will be required to provide protection against nerve agent poisoning. There is a longer-term aspiration to develop a post poisoning-therapy which would reduce the reliance on pretreatment, prevent or mitigate the effects of exposure to all nerve agents and decrease the requirement for three autoinjectors. Immediate therapy comprising physostigmine (0.2mg/kg), hyoscine hydrobromide (4mg/kg) and HI-6 (93.6mg/kg) protected all animals against the lethal effects of a supralethal dose of GD, when given 1min after nerve agent poisoning in the absence of any pretreatment. In contrast when hyoscine hydrobromide was replaced with hyoscine methyl nitrate most of the animals died within 24h, whereas when an equal mixture of hyoscine hydrobromide and hyoscine methyl nitrate was used all the animals survived. None of these animals had an intussusception. It would not be possible to deliver these doses of HI-6 to a human from a single autoinjector device. Recent studies have shown that a lower dose of HI-6 (7mg/kg) which can be delivered via an autoinjector, in combination with physostigmine and hyoscine hydrobromide provides good protection against the lethal effects of a supralethal dose of GD. A number of animals died between 6 and 24h and had an intussusception. The surviving animals did not begin to regain weight until 48h after poisoning. In contrast when a mixture of hyoscine hydrobromide and hyoscine methyl nitrate was used, one animal died within 15min, the other animals all survived, regained weight from 24h and did not have an intussusception. These studies will now be extended to include other agents and will be taken forward to studies in non-human primates where the incidence of intussusception will be closely monitored.

The Rotavirus Vaccine Saga

Rotavirus is the single most common cause of acute, dehydrating gastroenteritis worldwide. This is a highly contagious and highly democratic disease. The attack rate in infants and young children is similar regardless of sanitation, socioeconomics or geography. Rotavirus vaccine development began in the early 1980s using a "Jennerian" approach based on rotaviruses that normally infect animals. Although these vaccines were found to be generally safe, protection from disease was inconsistent. The second generation of vaccines was based on the same animal viruses configured to carry the relevant coat proteins of human rotaviruses. An attenuated human rotavirus vaccine has also been developed. After close to 20 years of laboratory and clinical studies, safe and effective rotavirus vaccines are approaching regulatory approval.

Physicians' knowledge and attitudes about rotavirus gastroenteritis and rotavirus vaccine

The morbidity and mortality associated with rotavirus gastroenteritis are significant. Despite the past safety concerns with RotaShield, many physicians believed the need for rotavirus vaccination remains. Although most physicians were not aware of specific rotavirus gastroenteritis disease burden statistics, they perceive rotavirus gastroenteritis to pose a serious risk for children for which a vaccine would be beneficial. Proof of safety and efficacy, an ACIP/AAP/AAFP recommendation, and private insurance coverage/reimbursement were critical features that would allow physicians to overcome barriers to the adoption of a new rotavirus vaccine.

Intussusception incidence relative to rotavirus vaccine use in Honolulu

Rotavirus vaccine was in use during the period August 1998 to October 1999. Epidemics of intussusception during this period were allegedly due to rotavirus vaccine, which prompted the vaccine to be withdrawn. Hawaii's geographic location between Asia and the mainland United States may subject it to infectious disease epidemic periods midway between occurrence in Asia and occurrence in the mainland United States. In contrast, immunization recommendations are temporally identical across all 50 states. The purpose of this study was to determine whether an epidemic of intussusception was experienced in Honolulu during the period of rotavirus vaccine use. This is a retrospective study of data obtained from inpatient and emergency department discharge diagnosis codes of intussusception for children up to 36 months of age. The incidence data were plotted by time periods to identify possible epidemic periods. The data are graphed. The arrows on the graphs indicate the period of time that rotavirus vaccine was in use. These graphs are most consistent with an increase in the cases of intussusception during the period July 2000 to December 2000, and a possible decline of intussusception during the rotavirus vaccine period. These incidence data are inconsistent with a temporal association between rotavirus vaccine and an epidemic of intussusception in Honolulu.

Intussusception in children with ALL receiving chemotherapy for acute lymphoblastic leukaemia

Acute abdominal complications of chemotherapy are common but the differential diagnosis wide. We describe two cases of intussuception of the bowel in children receiving chemotherapy for acute lymphoblastic leukaemia (ALL) and discuss how a high clinical suspicion is critical for the correct diagnosis to be made rapidly.

Active surveillance of vaccine safety: a system to detect early signs of adverse events

BACKGROUND

There currently are no population-based systems in the United States to rapidly detect adverse events after newly introduced vaccines. To evaluate the feasibility of developing such systems, we used 5 years of data from 4 health maintenance organizations within the Centers for Disease Control and Prevention (CDC) Vaccine Safety Datalink.

METHODS

Within every year, each week's vaccinated children were followed for 4 weeks, and rates of adverse events were compared with rates among children of similar ages before the introduction of the new vaccine. We assessed risks for intussusception after rotavirus vaccination and risks for fever, seizures, and other neurologic adverse events after the change from whole cell diphtheria-tetanus-pertussis (DTPw) to acellular DTP vaccine (DTPa). We used sequential probability ratio testing, adjusted for age, sex, calendar time, season, and HMO, and with a stopping value based on the probability of an adverse event under the null hypothesis and under a preset alternative hypothesis.

RESULTS

We detected an increase in intussusception after 2589 vaccine doses of rotavirus vaccine, about the same time initial reports of intussusception were made to the Vaccine Adverse Events Reporting System. Decreases in risk for fever, seizures, and other abnormal neurologic events became detectable within 12 weeks, 42 weeks, and 18 months, respectively, after the change from DTPw to DTPa.

CONCLUSIONS

We conclude that it is feasible to develop systems for rapid and routine population-based assessments of new vaccine safety.

Antibiotic-induced mesenteric adenopathy in an intussusception mouse model: a randomized, controlled trial

BACKGROUND

Idiopathic intussusception is a leading cause of intestinal obstruction in young children. Although the etiology remains obscure, lymphoid hyperplasia is found in a majority of cases. Antibiotics, the most frequently prescribed medication class in the pediatric population, have been recently associated with intussusception. The authors sought to determine whether enteral antibiotic exposure influences the development of mesenteric adenopathy, bowel dilation or intussusception in an animal model.

MATERIALS AND METHODS

The authors conducted a randomized, controlled animal trial using a previously described intussusception model. Mice were gavaged with normal saline, amoxicillin-clavulanate or azithromycin twice daily for 5 days to assess the influence of enteral antibiotic exposure on intussusception, mesenteric adenopathy and bowel dilation. One pediatric surgeon performed all laparotomies and was blinded to group designation. Chi2 and Fisher exact tests were used to evaluate differences between antibiotic exposed and control groups.

RESULTS

Mesenteric adenopathy was identified in 4.1% of the normal saline controls compared with 54.1% (P < 0.01) and 38.9% (P < 0.01) of the amoxicillin-clavulanate and azithromycin exposed animals, respectively. A total of four intussusceptions were observed in the antibiotic-exposed groups combined whereas no intussusception cases were identified in the control group (P = 0.30).

CONCLUSIONS

This is the first study to describe a significant association between antibiotic use and mesenteric adenopathy in any animal species.

Rotavirus vaccines: an update

PURPOSE OF REVIEW

Rotavirus infection is the most common cause of severe diarrhea disease in infants and young children worldwide and has a major global impact on childhood morbidity and mortality. Vaccination is the only control measure likely to have a significant impact on the incidence of severe dehydrating rotavirus disease.

RECENT FINDINGS

Rotavirus disease prevention efforts suffered a great setback in 1999 with the withdrawal of the RRV-TV vaccine less than a year after its introduction. Several new rotavirus vaccine candidates have now been developed and are undergoing clinical trials.

SUMMARY

New safe and effective rotavirus vaccines offer the best hope of reducing the toll of acute rotavirus gastroenteritis in both developed and developing countries.

Rotavirus disease and its prevention

PURPOSE OF REVIEW

Rotavirus infection is the foremost cause of severe gastroenteritis of young children worldwide. Efforts to develop safe and effective vaccines resulted in licensure of the first live oral vaccine, tetravalent, rhesus-based rotavirus vaccine (RRV-TV), which was incorporated into the US immunization schedule in 1998. Less than 1 year later, however, the vaccine was withdrawn when reports of cases of intussusception were linked to recent vaccination. This setback created significant hurdles as well as new opportunities for the development of the next generation of rotavirus vaccines. This review focuses on new information related to the clinical presentation and pathogenesis of rotavirus infection, the associated global disease burden, and the ongoing efforts to develop and introduce the next generation of rotavirus vaccines for widespread use.

RECENT FINDINGS

Recent studies have confirmed that rotavirus infection is not confined only to the gut but can have extraintestinal manifestations, including viremia. Estimates of the global disease burden of rotavirus diarrhea have been refined and suggest that mortality has not declined, and that among hospitalized cases of diarrhea, the fraction associated with rotavirus has increased in many countries. In the United States, the estimated number of hospitalizations attributed to rotavirus has increased. Debate continues about the magnitude of the attributable risk of the association between RRV-TV and intussusception. Several new rotavirus vaccines are in late stages of development. One vaccine was licensed in Mexico in 2004 and a second has completed clinical trials in the United States and Europe and may be licensed within 2 to 3 years.

SUMMARY

The tremendous burden of rotavirus diarrhea among children all over the world continues to drive the remarkable pace of vaccine development and the variety of approaches to creating rotavirus vaccines.

Rotavirus vaccines and intussusception risk

PURPOSE OF REVIEW

Rotavirus infection is the leading cause of severe dehydrating gastroenteritis, responsible for an estimated 440,000 deaths per year in children less than 5 years of age worldwide. There was great optimism when the first rotavirus vaccine was licensed in the United States in July 1998 (rhesus rotavirus tetravalent, RRV-TV, Rotashield, Wyeth Laboratories, Marietta, PA). However, 9 months after the vaccine become available, the rotavirus immunization program was suspended due to reports of an association between the vaccine and intussusception. The estimation of risk of intussusception with Rotashield immunization has been the subject of debate and is discussed in this review.

RECENT FINDINGS

The risk of intussusception following Rotashield immunization is estimated to be between 1 in 10,000 to 1 in 32,000 vaccinees. The risk is highest during the 3 to 14 days following receipt of the first dose of vaccine. Infants older than 3 months at the time of the first dose of vaccine are at increased risk of intussusception.

SUMMARY

The association between Rotashield and the development of intussusception has presented a major challenge to the development of rotavirus vaccines. Intussusception risk is greatest in the first 3 to 14 days following the receipt of the first dose of Rotashield in infants older than 3 months of age. Although there continues to be debate surrounding the exact quantitation of risk of intussusception, it is accepted as a rare adverse event. The development of alternate rotavirus vaccines and emerging manufacturers in developing countries has renewed optimism for the reduction of the global burden of rotavirus disease.

Intussusception and oral poliovirus vaccination: is there an association?

Oral rotavirus vaccine was voluntarily withdrawn from the market after studies observed an increased risk of intussusception within 2 weeks after immunization. Concern has been raised that other orally administered vaccines, such as oral poliovirus vaccine (OPV), may also be associated with intussusception. In this 1990-1998 case-control study, the authors examined the association between OPV and intussusception in the Washington State Medicaid population, evaluating receipt of OPV during the month prior to intussusception among 119 cases and 589 controls matched by date of birth. Analysis was conducted via matched conditional logistic regression, controlling for sex. Between 1990 and 1998, 119 children younger than age 2 years had a therapeutic enema, surgical reduction, or hospitalization for intussusception and had been enrolled in Medicaid for at least 1 month prior to their intussusception date. There was no significantly elevated risk of intussusception associated with receipt of OPV; 9.2% (11/119) of cases and 8.5% (50/589) of controls were given OPV 0-28 days prior to the case's intussusception date (odds ratio=1.1, 95% confidence interval: 0.5, 2.2). However, to address the hypothesis that risk of intussusception is related to receipt of a particular dose of OPV, a larger study would be required.

Recombinant human erythropoietin induces intussusceptive microvascular growth in vivo

The role of erythropoietin (Epo) in angiogenesis has not been completely clarified. Epo induces endothelial cell proliferation and migration and stimulates angiogenesis on rat aortic rings in vitro and in vivo in the chick embryo chorioallantoic membrane (CAM) assay. The aim of the present study was to evaluate the ultrastructural aspects of angiogenesis in the CAM vasculature after recombinant human Epo (rHuEpo) exposure. The results demonstrated that after rHuEpo stimulation, the generation of new blood vessels occurred more frequently following an intussusceptive microvascular growth (IMG) mechanism. We have performed our experiments between days 8 and 12 of incubation, that is, when in the normal condition the capillary network expands mainly by IMG, and because it is generally accepted that implants made from days 8 to 10 are strongly angiogenic. This response is peculiar of rHuEpo, because it is abolished when an Epo-blocking antibody was coadministered with Epo.

Association between antibiotic use and primary idiopathic intussusception

BACKGROUND

Intussusception is the leading cause of intestinal obstruction in young children. Antibiotics are the most frequently prescribed medication in the pediatric population and have common adverse effects on the gastrointestinal tract.

OBJECTIVE

To determine whether a relationship exists between primary idiopathic intussusception and antibiotic drug use.

DESIGN

Case-control study.

PARTICIPANTS

Ninety-three case patients with intussusception and 353 injury controls younger than 4 years who were seen at the emergency department of the Children's Hospital of Alabama between January 1, 1996, and April 30, 2001, were included. Controls were matched to cases by quarter and year of time of diagnosis, age, and sex.

MAIN OUTCOME MEASURES

Odds ratios and 2-sided 95% confidence intervals were estimated using conditional logistic regression. Prevalence of antibiotic use in an age-standardized, representative sample of US children from NHANES III (Third National Health and Nutrition Examination Survey) was used for external comparisons.

RESULTS

Antibiotic use within 48 hours of diagnosis was found in 23 cases (25%) and 33 controls (9%) (odds ratio, 4.15; 95% confidence interval, 2.17-7.92; attributable risk, 18.7%). Antibiotic use among US children according to NHANES III was 10.7%. In cases, the beta-lactam class accounted for 78% of all medications used. Cephalosporin use was associated with more than a 20-fold increased risk of intussusception.

CONCLUSION

An association between antibiotic drug use and intussusception was identified.

Lack of association between intussusception and oral polio vaccine in Cuban children

Two exploratory investigations found an increased risk of intussusception after oral polio vaccine (OPV). A large, national, population-based study was undertaken in Cuba to investigate a possible association. Three hundred and thirty-five cases of intussusception in children under 2 years of age occurring in 1995-2000 were identified and their OPV records retrieved. The relative incidence (RI) of intussusception in defined periods up to 42 days after OPV in children under 1 year was estimated using the self-controlled case series method, controlling for age and season. The RI was not significantly raised in any of the time intervals examined within the 0-42 day period after OPV. For the period 0-42 days as a whole the RI was 1.11, 95% CI 0.74-1.67. This study does not support the hypothesis that OPV causes intussusception.

Does oral polio vaccine cause intussusception in infants? Evidence from a sequence of three self-controlled cases series studies in the United Kingdom

BACKGROUND

The use of live oral poliomyelitis vaccine (OPV) has led to the elimination of poliomyelitis disease in many countries since licensure in 1960. The discovery of an increased risk of an intestinal obstruction known as intussusception following live rotavirus vaccination raised questions about the possibility of a link between live OPV and intussusception.

METHODS

Three self-controlled case-series studies were carried out. The first was exploratory and included 218 intussusception episodes from hospital admissions data linked to vaccination records in the Thames region. The two subsequent studies, which used further hospital admissions data and the General Practice Research Database (GPRD) included 107 and 198 episodes respectively and were used to test hypotheses generated in the first study.

RESULTS

In the exploratory study risk periods of up to 6 weeks after each dose were examined. The only period with some evidence of an increased risk was the 14-27-day period after the third dose (relative incidence (RI) = 1.97, p = 0.011). The second hospital admissions study and the GPRD study showed no evidence of an increased relative incidence in any putative risk period and did not confirm the increased risk in the 14-27-day period after dose 3 with a combined RI of 1.03.

CONCLUSIONS

The sequence of studies does not support the hypothesis that OPV causes intussusception. The increased RI in the first study may be explained as a chance finding due to the number of risk periods examined and highlights the need for caution when looking at many risk periods without an a priori hypothesis.

Nonsteroidal anti-inflammatory drug-induced colonic stricture: case report

Nonsteroidal anti-inflammatory drug-induced colonic strictures are uncommon and usually occur in the proximal ascending colon. We describe the progressive findings of nonsteroidal anti-inflammatory drug-induced strictures in the ascending colon and at the ileocecal valve with subsequent bowel obstruction secondary to intussusception.

[Rotaviral vaccines]

Rotaviral infections are frequent cause of the severe diarrhea in children. The only way to eliminate rotaviral infections is safe and effective vaccine. Among various rotaviral vaccines elaborated in many countries, the human-rhesus reassortant vaccine (RRV-TV) was chosen for routine immunization of infants. However, post-licensure surveillance of a rotavirus vaccine showed an increased risk of a serious adverse event following vaccination--intussusception. That forced the Centers for Disease Control and Prevention to withdraw the license of RRV-TV. In spite of this defeat, works for receiving safe and effective rotaviral vaccine still last.

Rotavirus vaccine and the news media, 1987-2001

CONTEXT

In August 1998, the US Food and Drug Administration licensed the first vaccine against rotavirus, the most important cause of severe childhood diarrhea. Fourteen months later, amid intense media activity, the vaccine was withdrawn after an association was found with intussusception.

OBJECTIVES

To examine the character of news media stories about rotavirus vaccine before and after intussusception became an issue, to evaluate what prompted the stories, and to assess the extent to which they evoked public reaction.

DESIGN AND SETTING

We searched Lexis-Nexis and Video Monitoring Services of America databases for rotavirus vaccine stories from the first US clinical trials (January 1, 1987) until 17 months after withdrawal (March 31, 2001) and examined calls to the National Immunization Hotline during the period in which rotavirus vaccine information was captured (July 1-December 31, 1999).

MAIN OUTCOME MEASURES

Mention of vaccine benefits and adverse events, classification of stories as positive, negative, or neutral toward the vaccine, story stimuli, and public response.

RESULTS

We included 280 newspaper (primary subject of analysis), 49 wire service, and 257 television stories. Prior to identification of the intussusception association (January 1, 1987-July 14, 1999), 21% of 188 newspaper stories mentioned vaccine adverse events and only 2 stories were negative toward the vaccine. Ninety-nine percent of stories mentioned vaccine benefits. During the period surrounding withdrawal (July 15-December 31, 1999), 93% of 90 stories mentioned adverse events and 77% were negative toward the vaccine. Eighty-four percent mentioned vaccine benefits. The rate of stories per month was 14-fold greater than the preceding period (P<.001); temporal and geographic patterns of media and hotline activity were similar. Thereafter (January 1, 2000-March 31, 2001), only 2 stories focused on rotavirus vaccine. Scientific research or public health actions prompted 80% of stories. Wire service and television stories showed similar patterns. The increase in rotavirus stories in July 1999 was followed by an increase in calls to the National Immunization Hotline regarding rotavirus but not other topics. The number of rotavirus calls that month was 57% higher than for any other childhood vaccine for any month since the hotline began in 1997. Rotavirus calls ceased almost completely after withdrawal of the vaccine in October 1999.

CONCLUSIONS

In response to reports about an adverse event, news media stories about vaccines can change abruptly from positivity to negativity. Since most vaccine stories may be stimulated by research and public health actions, opportunities exist to provide the media with accurate information necessary to avoid the "early idealization-sudden condemnation" pattern seen with rotavirus vaccine.

Live attenuated polio vaccine and the risk of intussusception

AIMS

Since suspicion has been raised that administration of an oral live attenuated rotavirus vaccine may increase the risk of intussusception in young children, there has been concern about the possible effects of oral polio vaccine. The aim of the study was to evaluate the relationship between oral attenuated polio vaccine and intussusception in children below the age of 1 year.

METHODS

We conducted a nested case-control analysis based on data from the General Practice Research Database which encompassed 133 children who developed documented intussusception during the first year of life and 515 controls.

RESULTS

The time from oral polio vaccine to the index date was similar in cases and controls. Relative risk estimates for intussusception ranged from 0.7 (95% CI 0.2, 2.1) for babies whose last oral polio vaccine was given 29-35 days before their index date to 1.0 (95% CI 0.4, 2.3) for those whose last oral polio vaccine was given 15-21 days before their index date (compared with babies vaccinated more than 43 days before their index date).

CONCLUSIONS

There is no suggestion that oral polio vaccine increases the risk for intussusception.

Intussusception, infection, and immunization: summary of a workshop on rotavirus

This article summarizes the proceedings of a workshop sponsored by the National Institutes of Health and the National Vaccine Program Office, and held in Bethesda, Maryland, on January 21, 2000. The objective of the meeting was to focus research toward an understanding of the basis for the possible association between intussusception and the reassortant rhesus-human rotavirus vaccine tetravalent (RRV-TV). After numerous reports of intussusception after administration of RRV-TV, the manufacturers of this vaccine voluntarily withdrew it from the United States market. The American Academy of Pediatrics, the Advisory Committee on Immunization Practices, and the American Academy of Family Physicians also withdrew their original recommendations for administration of RRV-TV to children at 2, 4, and 6 months of age. These actions will have global implications for the prevention of morbidity and mortality attributable to rotavirus infection. Benefit-cost ratios for the use of RRV-TV will be substantially different in developing countries compared with developed countries. Therefore, extensive research is needed in both of these settings, to further our understanding of the epidemiology, pathogenesis, and pathology of both rotavirus disease and intussusception to enable optimal prevention. The workshop reviewed the current understanding of the possible association between RRV-TV and intussusception, as well as the possible association between a variety of viral infections and intussusception. The workshop also identified critical areas of research regarding this possible association. This research will be essential not only for the development of safe and effective rotavirus vaccines, but for the development of other oral vaccines as well.

The Vaccine Safety Datalink project

The Vaccine Safety Datalink (VSD) is a collaborative project between the National Immunization Program of the Centers for Disease Control and Prevention (CDC) and several large health maintenance organizations (HMOs) in the United States. The project began in 1990 with the primary purpose of rigorously evaluating concerns about the safety of vaccines. Computerized data on vaccination, medical outcome (e.g. hospital discharge, outpatient visits, emergency room visits, and deaths), and covariate data (e.g. birth certificates and census) are prospectively collected at multiple HMOs (initially four) and linked under joint protocol for analyses. Approximately 6 million people (2% of the US population) are members of HMOs participating in the VSD. The VSD has proven to be a valuable resource that has provided important information on a number of vaccine safety issues. The databases and infrastructure created for the VSD have also provided opportunities to address other immunization questions including vaccination coverage and cost-effectiveness. In a recent investigation of intussusception following rotavirus vaccination, the VSD methodology was expanded to include 10 managed care organizations. A cohort study was conducted that allowed estimation of incidence rates of intussusception and attributable risks associated with rotavirus vaccine.

Rotavirus vaccine AVANT/GlaxoSmithKline

AVANT Immunotherapeutics (formerly Virus Research Institute) and GlaxoSmithKline are developing a live oral rotavirus vaccine with potential to elicit a broadly-protective immune response against the most prevalent strains of rotavirus. Following successful completion of a phase II clinical efficacy trial in June 1999, SmithKline Beecham (now GlaxoSmithKline) assumed responsibility for all subsequent clinical and other development activities [328635], [333677]. Following a licensing agreement, the vaccine was refined and renamed RIX-4414 [371713]. In May 2000, AVANT reported the results of a second-year surveillance extension of the phase II study. The results suggested that AVANT's two-dose oral rotavirus vaccine should be helpful in preventing rotavirus gastroenteritis (RGE) disease in young children for at least two years following administration [365202]. In March 2000, SmithKline Beecham reported that it had initiated phase I/II bridging studies in Europe and the company planned to start phase III safety and efficacy studies in 2001 after review with the health authorities [358963]. In October 2000, Dain Rauscher Wessels stated that an estimated market penetration of 30 to 40% suggested potential sales in excess of US $500 million pa. As a result, the analysts also estimated that incremental revenues to AVANT could be over US $50 million pa [411122].

Intussusception among recipients of rotavirus vaccine: reports to the vaccine adverse event reporting system

BACKGROUND

Rotavirus vaccine was licensed on August 31, 1998, and subsequently recommended for routine use among infants. To assess rare adverse events, postlicensure surveillance was conducted.

OBJECTIVE

To describe the cases of intussusception among rotavirus vaccine recipients reported to the Vaccine Adverse Event Reporting System from October 1998 through December 1999.

SETTING AND PARTICIPANTS

Infants vaccinated with rotavirus vaccine in the United States.

OUTCOME MEASURES

Intussusception confirmed by radiology, surgery, or autopsy report with medical record documentation or confirmed by a primary health care provider.

RESULTS

There were 98 confirmed cases of intussusception after vaccination with rotavirus vaccine reported to the Vaccine Adverse Event Reporting System; 60 of these developed intussusception within 1 week after vaccination. Based on calculations using vaccine distribution data and intussusception incidence rates from 2 separate databases, an estimated 7 to 16 cases would have been expected to occur in the week after vaccination by chance alone.

CONCLUSION

Using a passive surveillance system for vaccine adverse events, we observed at least a fourfold increase over the expected number of intussusception cases occurring within 1 week of receipt of rotavirus vaccine. Other studies were initiated to further define the relationship between rotavirus vaccine and intussusception. In light of these and other data, the rotavirus vaccine manufacturer voluntarily removed its product from the market, and the recommendation for routine use of rotavirus vaccine among US infants has been withdrawn.

Endogenous heme oxygenase/carbon monoxide system mediates lipopolysaccharide-induced intussusception in rats

OBJECTIVES

To investigate the role of endogenous heme oxygenase (HO)/carbon monoxide (CO) system in regulating the process of intussusception (IN) induced by administration of lipopolysaccharide (LPS) in rats.

METHODS

IN model of rats were induced by lipopolysaccharide. HO activity was determined by the amount of bilirubin formation which was measured with a double-beam spectrophotometer, and HbCO formation was measured by CO-oximeter.

RESULTS

The results showed that LPS (10 mg/kg) caused IN in up to 40% of the rats at 6 h after each treatment of LPS. The incidence of IN were significantly increased by 50% (P < 0.05) and by 83.2% (P < 0.01) in HO substrate (heme-L-lysinate)-treated rats and in exogenous CO-treated rats, respectively; but it was sigificantly decreased by 41.8% (P < 0.05) after administration of ZnDPBG, an inhibitor of heme oxygense (HO) activity. Furthermore, LPS increased HO activity, HbCO formation cGMP content within colic smooth muscle and the plasma level of cGMP, and these parameters were significantly elevated by 62.6% (P < 0.01), 40.0% (P < 0.01), 49.3% (P < 0.05) and 38.9% (P<0.05), respectively, compared with LPS-non-IN rats.

CONCLUSION

It is suggested that endogenous HO/CO system plays an important role in the process of IN induced by LPS, and inhibition of HO activity may decrease the formation of IN.