Rotavirus Vaccine Impact Within an Integrated Healthcare Delivery System in the United States.

We assessed rotavirus vaccine impact using data on acute gastroenteritis (AGE) encounters within an integrated healthcare delivery system during 2000-2018. Following rotavirus vaccine introduction, all-cause AGE rates among children <5 years declined by 36% (95% confidence interval [CI]: 32%-40%) for outpatient and 54% (95% CI: 46%-60%) for inpatient encounters.

Norovirus and Other Viral Causes of Medically Attended Acute Gastroenteritis Across the Age Spectrum: Results from the Medically Attended Acute Gastroenteritis Study in the United States.

BACKGROUND: Acute gastroenteritis (AGE) causes a substantial burden in the United States, but its etiology frequently remains undetermined. Active surveillance within an integrated healthcare delivery system was used to estimate the prevalence and incidence of medically attended norovirus, rotavirus, sapovirus, and astrovirus. METHODS: Active surveillance was conducted among all enrolled members of Kaiser Permanente Northwest during July 2014-June 2016. An age-stratified, representative sample of AGE-associated medical encounters were recruited to provide a stool specimen to be tested for norovirus, rotavirus, sapovirus, and astrovirus. Medically attended AGE (MAAGE) encounters for a patient occurring within 30 days were grouped into 1 episode, and all-cause MAAGE incidence was calculated. Pathogen- and healthcare setting-specific incidence estimates were calculated using age-stratified bootstrapping. RESULTS: The overall incidence of MAAGE was 40.6 episodes per 1000 person-years (PY), with most episodes requiring no more than outpatient care. Norovirus was the most frequently detected pathogen, with an incidence of 5.5 medically attended episodes per 1000 PY. Incidence of norovirus MAAGE was highest among children aged < 5 years (20.4 episodes per 1000 PY), followed by adults aged ≥ 65 years (4.5 episodes per 1000 PY). Other study pathogens showed similar patterns by age, but lower overall incidence (sapovirus: 2.4 per 1000 PY; astrovirus: 1.3 per 1000 PY; rotavirus: 0.5 per 1000 PY). CONCLUSIONS: Viral enteropathogens, particularly norovirus, are important contributors to MAAGE, especially among children < 5 years of age. The present findings underline the importance of judicious antibiotics use for pediatric AGE and suggest that an effective norovirus vaccine could substantially reduce MAAGE.

A model for rapid, active surveillance for medically-attended acute gastroenteritis within an integrated health care delivery system.

BACKGROUND: This study presents a novel methodology for estimating all-age, population-based incidence rates of norovirus and other pathogens that contribute to acute gastroenteritis in the United States using an integrated healthcare delivery system as a surveillance platform. METHODS: All cases of medically attended acute gastroenteritis within the delivery system were identified from April 1, 2014 through September 30, 2016. A sample of these eligible patients were selected to participate in two phone-based surveys and to self-collect a stool sample for laboratory testing. To ascertain household transmission patterns, information on household members with acute gastroenteritis was gathered from participants, and symptomatic household members were contacted to participate in a survey and provide stool sample as well. RESULTS: 54% of individuals who met enrollment criteria agreed to participate, and 76% of those individuals returned a stool sample. Among household members, 85% of eligible individuals agreed to participate, and 68% of those returned a stool sample. Participant demographics were similar to those of the eligible population, although minority racial/ethnic groups were somewhat underrepresented in the final sample. CONCLUSIONS: This study demonstrates the feasibility of conducting acute infectious disease research within an integrated health care delivery system. The surveillance, sampling, recruitment, and data collection methods described here are broadly applicable to conduct baseline and epidemiological assessments, as well as for other research requiring representative samples of stool specimens.