Evaluation of anatomic changes in young children with natural rotavirus infection: is intussusception biologically plausible?

Ultra-high-frequency ultrasound (48-70 MHz) is a promising tool for improved gastrointestinal diagnostics in infants

AIM

To investigate the clinical feasibility of ultra-high-frequency abdominal ultrasound (UHFUS) scans of preterm and term infants.

METHODS

Prospectively, 19 healthy term newborn infants were examined with conventional ultrasound (CUS) (Toshiba, Aplio i700, linear probe 14L5) and UHFUS (Visualsonics VevoMD, linear probes UHF48 and UHF70) according to a standardised protocol. Measurements of wall thickness were performed for; stomach, small intestine, colon and peritoneum. Five preterm infants, with or without suspected necrotising enterocolitis (NEC), were also examined with UHF48. Of these, only one was later diagnosed with NEC.

RESULTS

Differences between CUS and UHFUS (UHF48) were found in measurements of thickness; for peritoneum 0.25 versus 0.13 mm (p < 0.001), small intestine 0.76 versus 0.64 mm (p = 0.039) and colon 0.7 versus 0.47 mm (p < 0.001) in healthy term infants. Gaining frequency from 46 to 71 MHz showed a mean reduction in measurements of peritoneum from 0.13 to 0.09 mm (p < 0.001). One preterm infant with NEC showed a fivefold and twofold increase in peritoneal and gastrointestinal wall thickness respectively, compared to healthy preterm infants.

CONCLUSION

UHFUS was a clinically feasible, promising method with potential to improve gastrointestinal diagnostics in infants. Lower peritoneum thickness and gastrointestinal wall thickness were demonstrated with UHFUS compared to CUS, suggesting an overestimation by CUS.

Characteristics of intestinal-related lymphoid hyperplasia in children and its correlation with intussusception of children

BACKGROUND

Primary intussusception in children is a common acute abdominal disease. The cause of this disease is still not fully understood. Many articles have reported that children with intussusception are often accompanied by hyperplasia of mesenteric lymph nodes and submucosal lymphoid tissue of the terminal ileum. Therefore, hyperplasia of intestinal-associated lymphoid tissue (mesenteric lymph nodes and submucosal lymphoid tissue of the intestinal tract) may be one of the main causes of intussusception. However, the characteristics and differences of intestinal-associated lymphoid tissues in healthy children and children with intussusception at different ages have not been reported. In addition, the relationship between mesenteric lymph nodes and intestinal submucosal lymphatic tissue also needs to be further understood.

METHODS

73 patients with intussusception during the recovery phase who were treated in our hospital from October 2019 to October 2021 were collected as the observation group, while 101 children with healthy physical examination or diseases unrelated to intestinal lymphoid hyperplasia were collected as the control group. They were divided into different age groups of 1-6 months, 7-12 months, 13-18 months, 19-24 months, 25-36 months, 3-4 years, 5-6 years, and 7-8 years old. Ultrasonography was used to explore and scan mesenteric lymph nodes in fixed areas of the right lower abdomen and around the umbilicus. The size (cm³) and number (n) of detectable lymph nodes in each region were recorded and calculated, and the total mesenteric lymph node volume (cm³) of the right lower abdomen (RLTMLNV) and periumbilical region (PTMLNV) was calculated, respectively. The total mesenteric lymph node volume of each region in different ages of the two groups was analyzed.

RESULTS

(1) There were significant differences between the control group and the observation group in the right lower abdominal total mesenteric lymph nodes volume (RLTMLNV) and the periumbilical total mesenteric lymph nodes volume (PTMLNV) (P = 0.001). The mesenteric lymph nodes in the observation group showed severe hyperplasia. (2) Children with intussusceptions are usually accompanied by severe mesenteric lymphoid hyperplasia. The mean volume value of RLTMLNV was greater than that of PTMLNV. Especially within 2 years of age, the mean value of RLTMLNV was significantly higher than that of PTMLNV with statistical significance (P < 0.05). (3) In normal children (control group), lymph nodes in the right lower abdomen and periumbilical area showed low hyperplasia, and there was a significant difference between age groups of < 2 years old and 2-8 years old (p = 0.001). In the children with intussusception (observation group), the hyperplasia of mesenteric lymph nodes in the right lower abdomen and around the umbilicus was severe. There was no significant difference in the proliferation of mesenteric lymphoid tissue among different age groups in the right lower abdomen (P = 0.834). There was also no significant difference in hyperplasia of periumbilical mesenteric lymphoid tissue among different age groups (P = 0.097).

CONCLUSIONS

Our research shows: (1) The occurrence of primary intussusception in children is related to the hyperplasia of intestinal-associated lymphoid tissue. (2) Children with intussusceptions were usually accompanied by severe mesenteric lymphoid hyperplasia. The mesenteric lymphoid hyperplasia was more evident in the right lower abdominal ileocecal area than in the periumbilical area before 2 years of age. RLTMLNV has better predictability of intussusception than PTMLNV. The occurrence of intussusceptions was more closely related to the hyperplasia of intestinal-associated lymphoid tissue in the right lower abdomen. (3) Normal children showed a low degree of mesenteric lymphoid hyperplasia before 2 years old, moderate hyperplasia after 2 years old, and mesenteric lymphoid hyperplasia in the right lower abdominal ileocecal area was basically the same as the periumbilical area. The lymphatic tissue of the right lower abdomen and periumbilical mesentery in children with intussusceptions showed severe hyperplasia, and there were no significant differences among different age groups.

[The Effect of COVID-19 on Pediatric Intussusception: A Retrospective Study of a Single Center in South Korea with 10-Year Experience]

Purpose

To evaluate the effect of the emergence of coronavirus disease-19 (COVID-19) on pediatric intussusception.

Materials and Methods

Patients (< 18 years) who were diagnosed with intussusception and received enema reduction from 2011 to 2020 were included. We reviewed the demographics, yearly/monthly/seasonal incidence of intussusception, method and failure rate of enema reduction, recurrence rate of intussusception, surgical record, and pathologic report. Subsequently, we investigated the differences in mean age, failure rate of enema reduction, and recurrence rate of intussusception between the cases in 2020 and those in the period from 2011 to 2019.

Results

A total of 859 enema reductions were performed during the past decade, more in males and in the age < 1 year (mean age, 22.2 months). The yearly incidence was highest in 2014 and lowest in 2020, and the monthly incidence was highest on December and September. The cases in 2020 (n = 27) had a lower mean age (18.1 months vs. 22.8 months), higher failure rate of enema reduction (7.4% vs. 2.4%), and higher recurrence rate of intussusception (14.8% vs 7.3%) compared with those that occurred between 2011 and 2019 (n = 832). However, these results did not show statistical significance (p = 0.07, p = 0.15, p = 0.14, respectively).

Conclusion

With the emergence of COVID-19, the number of enema reductions was remarkably decreased with a lower mean age, higher failure rate, and higher recurrence rate.

Impact of rotavirus vaccine in reducing hospitalization rates in pediatric patients: a single center experience in Italy

Rotavirus is a major cause of acute gastroenteritis in children under 5 years of age, with severe illness occurring in 30-40% of cases. In Italian region of Liguria, vaccination with a two-dose human attenuated vaccine was introduced in 2013. We conducted a retrospective study to assess the impact of rotavirus vaccine on hospitalizations for rotavirus-related gastroenteritis (RVGE) at the IRCCS Istituto Giannina Gaslini. Every hospitalization due to laboratory-confirmed RVGE and acute gastroenteritis of unknown origin (AGUO) in patients aged 0-14 years in the period 2008-2019 were anonymously extracted. Vaccine coverage were obtained from the regional vaccination registry. The results were divided in 2008-2012 (before RV vaccine) and 2013-2019 (after) periods. From 2008 to 2012, there was a continuous reduction of AGUO hospitalizations while RVGE increased. Since 2013, a reduction in hospitalization rate was observed for RVGE with a sharp decrease from 17.81 per 10.000 children in 2012 to 0.79 per 10,000 in 2019, parallel with the ascending values of RV vaccination coverage that increased from 36.3% in 2013 to 63.9% in 2019. A significant negative correlation was found between the proportions of vaccinated newborns and RVGE rates (p = .012). Intussusception-related hospitalization did not show substantial modifications. We confirm vaccination as a safe practice that has a significant impact in pediatric hospitalization rates.

Rotavirus-related systemic diseases: clinical manifestation, evidence and pathogenesis

Rotaviruses, double-stranded, non-enveloped RNA viruses, are a global health concern, associated with acute gastroenteritis and secretory-driven watery diarrhoea, especially in infants and young children. Conventionally, rotavirus is primarily viewed as a pathogen for intestinal enterocytes. This notion is challenged, however, by data from patients and animal models documenting extra-intestinal clinical manifestations and viral replication following rotavirus infection. In addition to acute gastroenteritis, rotavirus infection has been linked to various neurological disorders, hepatitis and cholestasis, type 1 diabetes, respiratory illness, myocarditis, renal failure and thrombocytopenia. Concomitantly, molecular studies have provided insight into potential mechanisms by which rotavirus can enter and replicate in non-enterocyte cell types and evade host immune responses. Nevertheless, it is fair to say that the extra-intestinal aspect of the rotavirus infectious process is largely being overlooked by biomedical professionals, and there are gaps in the understanding of mechanisms of pathogenesis. Thus with the aim of increasing public and professional awareness we here provide a description of our current understanding of rotavirus-related extra-intestinal clinical manifestations and associated molecular pathogenesis. Further understanding of the processes involved should prove exceedingly useful for future diagnosis, treatment and prevention of rotavirus-associated disease.

Incidence of intussusception before and after the introduction of rotavirus vaccine in Korea

Background

Recent studies have reported that after the introduction of rotavirus vaccine the incidence of intussusception did not change among infants, or slightly increased at the age immediately after the first dose. The rotavirus vaccines were introduced in Korea for private market use in 2007–2008. We investigated the incidence of intussusception before (2002–2006) and after (2009–2015) the vaccine introduction in Korea.

Methods

We conducted an interrupted time series study that used data from the Korean National Health Insurance database to identify infants (<12 months of age) who were diagnosed with intussusception and underwent non-invasive or invasive reduction from 2002 to 2015. According to the recommended ages for immunization, the annual intussusception incidence and the incidence rate ratios were calculated among three age groups, 6–14, 15–24, and 25–34 weeks.

Results

The annual incidences in infants have decreased over time from 241.7 per 100,000 infants (pre-vaccine period) to 160.1–205.2 per 100,000 infants (post-vaccine period). The incidence rate ratio during the post-vaccine period ranged from 0.66 to 0.85. The incidences of intussusception in all three infant age groups have decreased in post-vaccine period compared to pre-vaccine period (incidence rate ratio range: 0.31–0.65, 0.47–0.75, and 0.68–0.94 in 6–14, 15–24, and 25–34 weeks, respectively).

Conclusions

The incidence of intussusception in infants did not increase after the rotavirus vaccine introduction in Korea, but rather decreased over the past decades. Since the incidence of intussusception varies according to country or region, continuous monitoring the incidence of intussusception in infants is necessary in each county or region.

Association between rotavirus gastroenteritis and intussusception: suggested evidence from a retrospective study in claims databases in the United States

The etiology of intussusception (IS), a serious gastrointestinal obstruction, remains unclear. Limited evidence suggests a role for viral infection. We investigated the risk of IS after rotavirus gastroenteritis (RV GE) in the first year of life. In this retrospective, self-controlled case series (SCCS), we assessed the risk of IS after RV GE using data from United States administrative claims databases. Incidence rate ratios (IRR) of IS were calculated for the 7- and 21-day risk periods after RV GE (main analysis) or after fracture (sensitivity analysis). A total of 290,912,068 subjects were screened; 42 presented claims for RV GE and IS, and 66 for fracture and IS. The IRRs of IS after RV GE were 79.6 (95% confidence interval, CI: 38.6-164.4) and 25.5 (95% CI: 13.2-49.2) in the 7- and 21-day risk periods. The sensitivity analysis showed an association between IS and fracture for both periods, suggesting potential confounding. Post-hoc analyses did not confirm the association between fracture and IS but suggested a potential association between RV GE and IS. A temporal association between RV GE and IS was detected using claims databases. Due to some limitations of the data sources, this association should be further investigated.

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.

Bowel ultrasound measurements in healthy children - systematic review and meta-analysis

BACKGROUND

Ultrasound (US) is a noninvasive method of assessing the bowel that can be used to screen for bowel pathology, such as Inflammatory Bowel Disease, in children. Knowledge about US findings of the bowel in healthy children is important for interpreting US results in cases where disease is suspected.

OBJECTIVE

To assess the bowel wall thickness in different bowel segments in healthy children and to assess differences in bowel wall thickness among pediatric age categories.

MATERIALS AND METHODS

We conducted a systematic search in the PubMed, Embase, Cochrane, and CINAHL databases for studies describing bowel wall thickness measured by transabdominal US in healthy children. We excluded studies using contrast agent. We calculated the pooled mean and standard deviation scores and assessed differences among age categories (0-4 years, 5-9 years, 10-14 years, 15-18 years), first with analysis of variance (ANOVA) and further with subsequent Student's t-tests for independent samples, corrected for multiple testing.

RESULTS

We identified 191 studies and included 7 of these studies in the systematic review. Reported bowel wall thickness values ranged from 0.8 mm to 1.9 mm in the small bowel and from 1.0 mm to 1.9 mm in the colon. The mean colonic bowel wall thickness is larger in children ages 15-19 years compared to 0-4 years (range in difference: 0.3-0.5 mm [corrected P<0.02]).

CONCLUSION

The reported upper limit of bowel wall thickness in healthy children is 1.9 mm in the small bowel and the colon, and mean thickness increases slightly with age in jejunum and colon. These values can be used as guidance when screening for bowel-related pathology in children.

Intussusception in Children Presenting to the Emergency Department: An Asian Perspective

OBJECTIVE

This project examines the presenting complaints of children with intussusception in the emergency department in an Asian population, with a focus on older children, which has not been well described in previous studies.

METHODS

A retrospective study was conducted on children aged 6 months to 15 years, whose conditions were diagnosed with intussusception in KK Women's and Children's Hospital for a 5-year period (2009-2013), based on the case definition established by the Brighton Collaborate Intussusception Working Group.

RESULTS

Three hundred ninety-one cases were identified to fulfill the case definition as per the Brighton Collaborative Intussusception Working Group. The mean age of children diagnosed with intussusception is 2.59 years, predominantly in males (65.22%). A total of 3.33% were 10 years or older. Only 3.58% presented with the classical triad-intermittent abdominal pain, vomiting, and bloody stools. In contrast, 22.51% of our Asian patients presented with a triad of intermittent abdominal pain, indrawing of legs, and vomiting. A total of 76.73% of our subjects were treated by air enema only, whereas 22 required surgical treatment after unsuccessful attempts of air enema, and 63 resolved spontaneously, including 7 with ileoileal intussusception. No mortality was documented.

CONCLUSIONS

Intussusception is usually diagnosed in the younger population (age <1 year) and predominantly in males. Our study has established that older Asian children can also have intussusception. The classical triad is not a very sensitive diagnostic tool, but the combination of abdominal pain, indrawing of legs, and vomiting may be a more common presenting triad in Asian children.

Hospitalization rates for intussusception in children aged 0-59 months from 2009 to 2014 in Italy

The real cause of intussusception is not fully understood and a variety of conditions have been associated with it (Meckel diverticulum, polyps, duplication cysts, parasites, Henoch-Schönlein purpura, cystic fibrosis, hemolytic-uremic syndrome and infectious gastroenteritis). Furthermore few European countries, following WHO recommendation to monitor baseline incidence of intussusception before implementation of immunization program for rotavirus, used intussusception rate as a baseline value to compare the same figures in the period before and after introduction of vaccination. In this study, data of intussusception hospitalizations occurred among Italian children aged 0 through 59 months from 2009 to 2014 were analyzed. A total amount of 3,088 children were included, accounting for a hospitalization rate of 20.2 per 100,000. Overall, the hospitalization rate for intussusception had a slight increase in trend from 2009 to 2014 (18%). In particular children 0-11 months had a hospitalization rate higher than 12-59 months with an aggregate value of 36 Vs. 16 per 100,000 respectively. Among all children hospitalized for intussusception a total of 239 (7.7%) had also a previous or concomitant hospitalization for gastroenteritis. This study demonstrates that Italian hospitalizations for intussusception are increasing by time and the role played by different risk factors, including acute gastroenteritis, have to be investigated in the future. These data could be useful to monitor intussusception hospitalization in the perspective of anti-rotavirus vaccination introduction in Italy.

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.

Rotavirus vaccination: a risk factor for intussusception?

Recently published pharmacoepidemiological studies associate the currently authorized Rotavirus (RV) vaccines with intussusception (IS). We aimed at investigating whether, in Germany, there are excess IS cases in RV vaccinees compared with the background incidence before market authorization in 2006. Suspected cases of IS following receipt of RV vaccines reported to the Paul-Ehrlich-Institut (PEI) from 2006 to 2010 were reviewed and validated against the criteria of the Brighton Collaboration's definition for IS. An observed-versus-expected analysis was conducted using standardized morbidity ratio (SMR) methods based on age-specific incidence rates for IS ranging from 19.2 to 98.5 per 100,000 person-years. A total of 27 cases of suspected IS in RV vaccinees were reported to the PEI. No excess of IS cases could be detected 1-7 days after receipt of either RV vaccine after any dose in the first year of life; however, in infants aged 3-5 months, a significantly increased SMR for IS was found in a risk window of 1-7 days after the first dose of either RV vaccine [SMRs: Rotarix® 4.6 (95% CI 1.5-10.7); RotaTeq® 5.8 (95% CI 1.2-17.1)]. A significantly increased risk of IS in a risk window of 1-7 days after RV vaccination was not found when the first dose was administered earlier. Therefore, it is recommended to start the vaccination course at 6-12 weeks of age.

A critical time for rotavirus vaccines: a review

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

Incidence of intussusception in Singaporean children aged less than 2 years: a hospital-based prospective study

Background

Continuous surveillance for intussusception (IS) is important for monitoring the safety of second-generation rotavirus vaccines. The present study aimed to assess the incidence of IS in Singaporean children aged < 2 years.

Methods

This was a prospective, hospital-based, multi-center surveillance conducted in seven hospitals - two public hospitals and five private medical centers between May 2002 and June 2010 in Singapore. Diagnosis of IS (definite, probable, possible, suspected) was based on the case definition developed by the Brighton Collaboration. Children < 2 years of age who were diagnosed with IS were enrolled in this study. Incidence of IS was calculated per 100,000 child-year with its 95% confidence interval.

Results

Of the 178 children enrolled, 167 children with definite IS cases were considered for final analyses; 11 were excluded (six diagnosed as probable IS and four diagnosed as suspected IS; one child’s parents withdrew consent). Mean age of children with definite IS was 11.6 ± 6 months; 67.7% were males. The overall incidence of IS was 28.9 (95% CI: 23.0–34.8) and 26.1 (95% CI: 22.2–30.0) per 100,000 child-year in children < 1 year and < 2 years of age, respectively. The majority of IS cases (20 [12.0%]) were reported in children aged 6 months. Most children (98.2% [164/167]) recovered, two (1.2%) children recovered with sequelae and one (0.6%) child died of septic shock.

Conclusions

The incidence of IS remained low and stable in Singaporean children aged < 2 years during the study period (May 2002 to June 2010).

Trial registration

NCT01177839

Towards a human rotavirus disease model

While the clinical importance of human rotavirus (RV) disease is well recognized and potent vaccines have been developed, our understanding of how human RV causes diarrhoea, vomiting and death remains unresolved. The fact that oral rehydration corrects electrolyte and water loss, indicates that enterocytes in the small intestine have a functional sodium-glucose co-transporter. Moreover, RV infection delays gastric emptying and loperamide appears to attenuate RV diarrhoea, thereby suggesting activation of the enteric nervous system. Serotonin (5-HT) receptor antagonists attenuate vomiting in young children with gastroenteritis while zinc and enkephalinase inhibitors attenuate RV-induced diarrhoea. In this review we discuss clinical symptoms, pathology, histology and treatment practices for human RV infections and compile the data into a simplified disease model.

Hospitalizations for intussusception before and after the reintroduction of rotavirus vaccine in the United States

OBJECTIVE

To determine whether hospital discharges for intussusception in children younger than 1 year have changed since the reintroduction of rotavirus vaccine in the United States.

DESIGN

Serial cross-sectional analysis.

SETTING

US hospitals.

PARTICIPANTS

Children younger than 1 year with a discharge diagnosis of intussusception identified in the Kids' Inpatient Database, a series of nationally representative data sets of pediatric hospital discharges in the United States with 4 available years prior to vaccine reintroduction (1997, 2000, 2003, and 2006) and 1 year after (2009).

MAIN EXPOSURES

Hospital discharge before vs after rotavirus vaccine reintroduction.

OUTCOME MEASURES

Total number and rate of hospital discharges for infants younger than 1 year with a diagnosis of intussusception (International Classification of Diseases, Ninth Revision, Clinical Modification code 560.0).

RESULTS

From 1997 to 2006, there was no change in the total number of hospital discharges for intussusception, with a small decrease in the rate of intussusception discharges (41.6 [95% CI, 36.7-46.5] to 36.5 [95% CI, 31.7-41.2] per 100,000 infants). Based on the trend, the predicted rate of discharges for intussusception in 2009 was 36.0 (95% CI, 30.2-41.8) per 100,000 infants. The measured rate of hospital discharges for intussusception in 2009 was 33.3 (95% CI, 29.0-37.6) per 100,000 infants.

CONCLUSION

The reintroduction of rotavirus vaccine since 2006 has not resulted in a detectable increase in the number of hospital discharges for intussusception among US infants.

Rotavirus infection and intussusception in Tunisian children: implications for use of attenuated rotavirus vaccines

BACKGROUND

A licensed rotavirus vaccine was withdrawn from use because of an increased risk of intussusception. The association of rotavirus vaccination with intussusception raised concerns about a potential link between natural rotavirus disease and intussusception. The objectives of the present study were to determine whether an epidemiological association with natural rotavirus infection existed.

METHODS

From 1984 to 2003, all children younger than 5 years with intussusception were retrospectively identified by medical charts, and from 1995 to 2003, a prospective surveillance study of rotavirus infection in children younger than 5 years was independently conducted. Epidemiological characteristics of intussusception and rotavirus infection were then compared.

RESULTS

A total of 533 cases of intussusception and 146 cases of rotavirus infection were identified. The incidence of intussusception for infants younger than 1 year was 62/100,000 child-years. The age distributions of intussusception and rotavirus gastroenteritis overlapped, and a masculine predominance was noted in both cases. No significant association was observed between the monthly distribution of intussusception and rotavirus infection.

CONCLUSION

The present study has not convincingly shown that rotavirus diarrhea plays a major role in intussusception. However, data about age and sex distributions supported the biologic plausibility of such an association.

An Update of Paediatric Intussusception Incidence in Singapore: 1997-2007, 11 Years of Intussusception Surveillance

Introduction: Understanding baseline epidemiology of intussusception (IS) in different geographical settings is important for the safety assessment of rotavirus vaccines. This paper presents IS surveillance data from Singapore between 1997 and 2007, including the period between November 2005 and December 2007 when rotavirus vaccines (primarily Rotarix™) were available to newborns in Singapore. Materials and Methods: Case ascertainment, collection, analyses and presentation of IS data was done as per recommendations of the Brighton Collaboration Working Group. For estimating the IS incidence rate in infants, live births for the years of the study were used as denominators, while for incidence in children age <2 years, the expected numbers of infant deaths occurring between 1 and 2 years of age was deducted from the combined live births for the 2 years, to obtain the denominator. Results: The incidence of IS among children aged <1 year throughout this 10-year period was higher than the incidence of IS in children between 1 and 2 years of age. In 2005, 2006 and 2007, the incidence of IS per 100,000 was 39.9, 26.4 and 35.6 in children aged <1 year and 26.2, 23.8 and 28.7 in children <2 years. Conclusion: This IS surveillance study provides reassuring preliminary evidence that there is no increase in the incidence of IS in Singapore after the introduction of rotavirus vaccines (including Rotarix™) in Singapore. Key words: Epidemiology, Incidence, Rotarix, Rotavirus

Abnormal computed tomography findings among children with viral gastroenteritis and symptoms mimicking acute appendicitis

OBJECTIVE

To evaluate computed tomography (CT) findings in pediatric patients with viral gastroenteritis who presented with clinical features of acute abdomen.

PATIENTS AND METHODS

During 2 seasons of viral gastroenteritis from 2005 to 2007, 302 children with acute gastrointestinal symptoms were admitted to our center for treatment of dehydration and associated complications. Stool specimens obtained from 130 of the 302 were tested for norovirus with the reverse transcriptase-polymerase chain reaction method.

RESULTS

Among the 130 patients, 44 tested positive for norovirus, 34 for rotavirus, and 1 for adenovirus. In the remaining 51, except one with Campylobacter jejuni, no viral or bacterial pathogen was detectable. An abdominal CT scan was performed in 4 patients with norovirus and in 1 with rotavirus for suspected acute abdomen including acute appendicitis. Computed tomography (CT) findings were similar among the 5 patients, including thickening of the bowel wall and fluid-filled bowel loops in the small intestine with no pathological findings in the stomach, appendix, or colon.

CONCLUSIONS

Anatomical changes in the small intestine were shown by CT in 5 children with viral gastroenteritis who presented with acute abdomen. These imaging features of viral gastroenteritis may be useful in differential diagnosis of acute abdomen to avoid unnecessary surgery.

Rotavirus fecal antigen retrieval in infantile intussusception

This study was designed to assess the plausibility of an association between natural rotavirus infection and intussusception. It was conducted on 21 infants suffering from acute gastroenteritis (GE) complicated by intussusception who were compared to another 40 age- and sex-matched infants suffering from acute GE characterized by watery nonmucoid diarrhea without surgical complications. All enrolled patients were subjected to detailed history documentation, thorough clinical examination and laboratory investigations, complete stool analysis, and detection of rotavirus antigen in stools using the ELISA technique. Plain abdominal X-ray and ultrasound were also performed. The results of this study revealed 24 positive cases for rotavirus antigen in the stools of the acute uncomplicated GE patients (60.0%), while there were only ten positive cases in the intussusception group (47.6%). No significant difference in severity was detected between the two groups studied, especially in terms of signs of dehydration and need for IV fluids (p > 0.05). Most of the rotavirus positive cases among the intussusception group presented either in February or December (p < 0.05) with no significant seasonal pattern among the acute GE group (p > 0.05). In conclusion, rotavirus antigen retrieval from stools of GE patients complicated with intussusception was not statistically different from those detected among acute uncomplicated GE. Additionally, there was no association between seasonality or severity of rotavirus positive cases in acute GE patients and those with intussusception. It is thus prudent to say that wild rotavirus infection in GE patients does not carry an extra risk for the occurrence of intussusception.

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. Key words: Adverse effects, Rotavirus vaccines

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 among young children in Europe

Intussusception, a potentially lethal condition with poorly understood etiology, is the most common cause of acute intestinal obstruction in children younger than 5 years old. In some cases, the condition has been associated with administration of the first licensed rotavirus vaccine, the reassortant rhesus-human tetravalent rotavirus vaccine (RRV-TV; RotaShield). No such association has to date been reported from large phase III safety trials with new rotavirus vaccines. As 2 new, live-attenuated oral rotavirus vaccines are currently under review for approval by the European Union regulatory authorities, a review of the clinical, etiologic and epidemiologic aspects of intussusception in Europe is urgently needed. We conducted a review of Medline literature, published from 1995 onwards on intussusception in the World Health Organization's European Region. The results are compared with data from previous reviews and other regions. The classic triad of intussusception symptoms (abdominal pain, abdominal mass, bloody stools) was present in 29-33% of patients according to the medical literature reviewed. Conservative treatment (barium, air or saline enema) was the rule (81% of cases), and few complications were observed during treatment. Treatment outcome was generally favorable, with recurrence occurring in approximately 1 in 10 patients, and only 1 death reported. Structural lead points were seen in 3% of patients; no other reliable data on the etiology of intussusception were found. The incidence of acute intussusception in young children in Europe, according to 6 heterogeneous hospital-based studies, ranged from 0.66 to 2.24 per 1000 children in inpatient departments and from 0.75 to 1.00 per 1000 children in emergency departments. Peak incidences were found in children 3-9 months of age. There are still gaps in our knowledge of intussusception with respect to its etiology and especially by which mechanisms RRV-TV might have caused it to occur. Data from regions outside Europe showed that rotavirus infection and disease are not associated with intussusception. As new rotavirus vaccines become available for use in Europe, postlicensure surveillance for intussusception is indicated and may be instrumental in further understanding the epidemiology of this condition and in further assessing the safety of future vaccines.

More on RotaShield and intussusception: the role of age at the time of vaccination

BACKGROUND

RotaShield, a vaccine intended to prevent severe rotavirus diarrhea, was withdrawn in July 1999, 9 months after it became available in the United States, because of a temporal association with intussusception events that occurred in vaccinated infants. We explore here the effect of age on the risk of intussusception.

METHODS

We reanalyzed a case-control database of the Centers for Disease Control and Prevention by use of a 21-day window, to define vaccine-associated events. We obtained data on vaccine use from the National Immunization Survey and estimated the age-stratified background incidence of intussusception by use of Healthcare Cost and Utilization Project data. We combined these data to estimate how absolute risk varies with age and to model the projected population-attributable risk associated with 3 different vaccination schedules.

RESULTS

We found that the incidence of intussusception associated with the first dose of vaccine increased with age. Infants > or = 90 days old accounted for 80% of cases of intussusception associated with a first dose but had received only 38% of first doses. Modeling of the recommended schedule of vaccination at ages 2, 4, and 6 months projected 1 intussusception event/11,000-16,000 vaccine recipients; modeling of a 2-dose schedule beginning in the neonatal period projected 1 intussusception event/38,000-59,000 vaccine recipients.

CONCLUSIONS

The practice of initiating immunization after age 90 days, which we call "catch-up" vaccination, contributed disproportionately to the occurrence of intussusception associated with the use of RotaShield. A fully implemented 2-dose vaccination schedule begun during the neonatal period would lead to, at most, a 7% increase in the incidence of intussusception above the annual background incidence.

Intussusception and rotavirus associated hospitalisation in New Zealand

AIMS

To describe the epidemiology of intussusception and its relation to rotavirus associated hospitalisation in New Zealand.

METHODS

National hospital discharge data between January 1998 and June 2003 for all children younger than 3 years of age with intussusception were reviewed. Independently, children from the same age group, admitted to eight paediatric units with rotavirus gastroenteritis between May 1998 and May 2000, were identified prospectively. Epidemiological characteristics of cases with intussusception were compared with those of hospitalised rotavirus disease.

RESULTS

During the 5.5 year study period, there were 277 cases of intussusception and no deaths. Most (72%) occurred in the first year of life (age adjusted incident rate 65 per 100,000 child-years, 95% CI 56 to 74). Risk of intussusception was less in females (risk ratio 0.58; 95% CI 0.43 to 0.78) and for Maori (risk ratio 0.52; 95% CI 0.35 to 0.77) when compared with European infants. In contrast to hospitalised rotavirus cases, intussusception peaked at a younger age and lacked seasonality.

CONCLUSIONS

This study provides national baseline data on intussusception for future rotavirus vaccine programmes in New Zealand. Wild-type rotaviruses do not appear to have a major role in triggering intussusception. Prospective surveillance systems, using standardised case definitions and nested case-control methodology, are needed to further our understanding of the aetiology and epidemiology of intussusception.

A Hexavalent Human Rotavirus–Bovine Rotavirus (UK) Reassortant Vaccine Designed for Use in Developing Countries and Delivered in a Schedule with the Potential to Eliminate the Risk of Intussusception

There is an urgent need for a rotavirus vaccine, because up to 592,000 infants and young children <5 years old die each year from rotavirus diarrhea, predominantly in the developing countries. We have developed a tetravalent human-bovine rotavirus (UK) reassortant vaccine with VP7 (G) specificity for serotypes 1, 2, 3, and 4, which has been shown to be safe, immunogenic, and effective in preventing severe rotavirus diarrhea. However, because of the emergence of VP7 (G) serotype 9 as an epidemiologically important serotype and the importance of VP7 (G) serotype 8 in focal areas, we are planning to add human-bovine (UK) reassortants with G8 and G9 specificity to the tetravalent vaccine, thereby formulating a "designed" hexavalent vaccine for universal use. In addition, we propose that the vaccine be administered orally in a 2-dose schedule, with the first dose given at 0-4 weeks of age and the second dose given at 4-8 weeks of age, when infants are relatively refractory to developing intussusception, thereby avoiding the age period when naturally occurring intussusception is most prevalent (i.e., ages 3-4 months through age 9 months). In this way, there may be the potential to eliminate or at least significantly decrease the risk of intussusception associated with rotavirus vaccination.

Intussusception and rotavirus vaccines

The association between the first oral rotavirus vaccine to be licensed in the U.S. (Rotashield) and intussusception has presented a major challenge to the effort to reduce the global burden related to rotavirus infection. Although the risk of developing intussusception following immunization with Rotashield is low, debate continues about the estimation of intussusception risk and the events surrounding the withdrawal of the vaccine. The experience with Rotashield has highlighted the wisdom of parallel clinical trials in developing and developed countries and the value of post-licensure surveillance for the detection of uncommon adverse events. This review retraces the steps leading up to the withdrawal of the Rotashield vaccine and reflects on how this experience has influenced the development of other rotavirus vaccines.

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.

Natural rotavirus infection is not associated to intussusception in Mexican children

AIMS

To determine whether natural rotavirus infection or infection by another enteropathogen is associated to intussusception (IS); and to describe the seasonality of IS compared with severe diarrhea (SD) and rotavirus SD in Mexican children.

METHODS

A prospective, observational, multicenter and case-control study was conducted in Mexico City from December 1999 to February 2001. Cases were children younger than 1 year old hospitalized for IS; diagnosis was made by clinical features, radiologic and/or surgery findings. Controls were children younger than 1 year old hospitalized for another disease than a gastrointestinal illness (NGI). Cases and controls were paired by age and date of admission (+/-3 months; for both), in a 1:2 ratio. A surveillance of IS cases, SD and rotavirus SD episodes was conducted during the study period. Stool samples collected soon after IS resolution or at admission were tested for rotavirus, adenovirus, astrovirus, bacteria and parasites.

RESULTS

Thirty cases of IS and 60 controls with NGI were studied. Rotavirus was not detected in any case of IS. Adenovirus (17%) was the only enteropathogen detected in IS. Rotavirus (8%), adenovirus (2%), astrovirus (2%) and bacteria (2%) were detected in NGI. Rotavirus infection was not associated with IS (odds ratio, 0; 95% confidence interval, 0-2.9), whereas adenovirus infection was strongly associated as risk factor for IS (odds ratio undefined; P = 0.003), compared with NGI. Seasonal variation in admissions for IS was small, whereas admissions for SD and rotavirus SD showed a marked seasonal increase during fall-winter.

CONCLUSIONS

In Mexican children, rotavirus infection was not associated to IS; whereas a significant association was observed between adenovirus and IS. Also there was no increase in IS cases during the sharply defined fall-winter rotavirus outbreak. Observations from this controlled study suggest that natural rotavirus infection is not a risk factor for IS. This information may have implications for development of a safer and effective rotavirus vaccine.