HealthDay News — Norovirus far exceeds rotavirus as the leading cause of medically attended acute gastroenteritis in young children after the successful reintroduction of rotavirus vaccine, a CDC study shows.
Surveillance data from three U.S. counties indicates norovirus was responsible for acute gastroenteritis in 21% of young children brought for medical attention in 2009 and 2010 compared with 12% of children whose illness was assocated with rotavirus infection.
The norovirus percentages translate into an estimated 14,000 hospitalizations, 281,000 emergency department visits and 627,000 outpatient visits, for a combined $273 million in annual treatment costs, Daniel Payne, PhD, MSPH, of the CDC’s National Center for Immunization and Respiratory Diseases in Atlanta, and colleagues reported in New England Journal of Medicine.
“Given the substantial decline in pediatric rotavirus-associated acute gastroenteritis in the U.S. since the introduction of rotavirus vaccines, and given recent advances in the development of candidate norovirus vaccines, there is a need to directly measure the pediatric healthcare burden of norovirus-associated acute gastroenteritis,” the researchers wrote.
They conducted active surveillance for laboratory-confirmed cases of norovirus using the New Vaccine Surveillance Network. This included 1,295 children aged younger than 5 years who were diagnosed with acute gastroenteritis in hospitals, emergency departments, and outpatient clinical settings at three medical centers — the University of Rochester Medical Center in Monroe County, N.Y., Vanderbilt University Medical Center in Davidson County, Tenn., and Cincinnati Children’s Hospital Medical Center in Hamilton County, Ohio — and 493 healthy controls who underwent testing for the virus.
Overall, in 2009 and 2010 norovirus was detected in 21% of young children (n=278) seeking medical attention for acute gastroenteritis — 22% in 2009 and 20% in 2010. Average patient age among those who tested positive was 17 months. Among healthy controls, norovirus was identified in 4%, indicating a low rate of asymptomatic infection, according to the researchers.
During the same time period, a much lower proportion of children with acute gastroenteritis tested positive for rotavirus (12%), with the rate dropping substantially from 19% in 2009 to 2% in 2010. Only one healthy control tested positive for the virus.
As healthcare visits associated with rotavirus gastroenteritis have steadily declined, hospitalizations, emergency department visits, and outpatient visits for norovirus-associated acute gastroenteritis remained relatively steady from 2009 to 2010.
Norovirus accounted for approximately 8.6 hospitalizations per 10,000 children in 2010 vs. 5.8 in 2009; 146.7 ED visits per 10,000 in 2010 vs. 134.3 in 2009; and 367.7 outpatient visits per 10,000 children vs. 260.1, the researcherchers estimated.
“Since the introduction of rotavirus vaccines, norovirus has become the leading cause of medically attended acute gastroenteritis in U.S. children and is associated with nearly one million health care visits annually,” the researchers wrote.
They acknowledged the study results may not be nationally representative of a larger U.S. population younger than 5 years and may not accurately portray year-to-year variation in disease burden.