No Intussusception
Rise Seen With Vaccine Reintroduction
Nancy A. Melville
January 6, 2012 — The reintroduction of rotavirus
vaccination in the United States has not resulted in an increase in
hospitalization for intussusception among infants, according to a study published online January 2, 2012, in the Archives of
Pediatric Adolescent Medicine.
A live, attenuated tetravalent rotavirus vaccine (RotaShield,
Wyeth) that was introduced in 1998 was withdrawn a year later amid concerns of
an increased risk for the severe bowel obstruction among infants within several
weeks of their being vaccinated.
Two updated versions of the vaccine were introduced several
years later: a pentavalent rotavirus vaccine in 2006 (RotaTeq, Merck),
and a monovalent rotavirus vaccine in 2008 (Rotarix, GlaxoSmithKline).
Although surveillance studies in the United States showed no
increased risk for intussusception among rotavirus vaccine recipients after the
reintroduction, studies from Mexico, Brazil, and Australia showed small, but
clinically significant, increases and raised concerns about the new vaccines.
To take a closer look at intussusception rates among infants
in the United States since the reintroduction of the vaccines, Joseph S.
Zickafoose, MD, from the Child Health Evaluation and Research Unit, Division of
General Pediatrics, University of Michigan, Ann Arbor, and colleagues evaluated
data from the Healthcare Cost and Utilization Project's Kids' Inpatient
Database. The database covers 80% of pediatric hospital discharges and
therefore has the power to uncover rare adverse events.
The investigators found no change in the number of children
younger than 1 year with a discharge diagnosis of intussusception in the United
States during the 4 years before the vaccine reintroduction (1997, 2000, 2003,
and 2006), and 1 year after (2009). After population adjustments, there was a
small decrease in the rate of intussusception discharges between 1997 and 2006,
from 41.6 discharges (95% confidence interval [CI], 36.7 - 46.5 discharges) to
36.5 discharges (95% CI, 31.7 - 41.2 discharges) per 100,000 infants. In 2009,
after the reintroduction of vaccine, the rate was 33.3 (95% CI, 29.0 - 37.6)
per 100,000 infants
"Our findings are consistent with prior studies showing
intussusception rates in the range of 20 to 50 per 100 000 infants, depending
on population and data source," the authors write.
"Our results are also consistent with the gradual
decrease in intussusception cases in the United States over time found in these
studies, suggesting that this downward trend has continued after the widespread
implementation of rotavirus vaccine."
Limitations of the study include the fact that only 1 year
of data were available for the period after the vaccine was reintroduced
(2009).
Although the proportion of intussusception-related
hospitalizations treated with radiologic reduction has increased since 1997,
the proportion of cases requiring surgical reduction has remained constant — a
trend supported in the current study's findings.
"At a minimum, these findings provide evidence that
there has not been an increase in the severe forms of intussusception that
require surgical intervention and may lead to additional morbidity and
mortality," the authors write.
Rotavirus, once the leading cause of gastrointestinal
illness among children in the United States, is associated with vomiting,
abdominal pain, and severe diarrhea. The illness commonly requires hospitalization
for young infants and children.
Since the vaccines' reintroduction, more than 70% of infants
in the United States have been vaccinated against rotavirus, and the number of
diarrhea-related outpatient visits, emergency department visits, and hospitalizations
among children has declined.
"We always need to carefully weigh the risks and
benefits of childhood vaccines. Fortunately, our results suggest that rotavirus
vaccines have not increased the rate of intussusception in the US," said
Dr. Zickafoose in a press statement.
The study is believed to be the first of its kind to examine
nationally representative hospitalization rates for intussusception among
infants after the reintroduction of rotavirus vaccine in the United States.
The authors have disclosed no relevant financial
relationships.
Arch Pediatr Adolesc Med.
Published online January 2, 2012.
Hospitalizations for
Intussusception Before and After the Reintroduction of Rotavirus Vaccine in the
United States
Joseph S. Zickafoose,
MD, MS; Brian D. Benneyworth, MD, MS; Meredith P. Riebschleger, MD; Claudia M.
Espinosa, MD; Matthew M. Davis, MD, MAPP
Arch Pediatr Adolesc Med. 2012;166(4):350-355. doi:10.1001/archpediatrics.2011.1501
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.
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