Two rotavirus outbreaks caused by genotype G2P[4] at large retirement communities: cohort studies.

BACKGROUND: Outbreaks of rotavirus gastroenteritis in elderly adults are reported infrequently but are often caused by G2P[4] strains. In 2011, outbreaks were reported in 2 Illinois retirement facilities. OBJECTIVE: To implement control measures, determine the extent and severity of illness, and assess risk factors for disease among residents and employees. DESIGN: Cohort studies using surveys and medical chart abstraction. SETTING: Two large retirement facilities in Cook County, Illinois. PATIENTS: Residents and employees at both facilities and community residents with rotavirus disease. MEASUREMENTS: Attack rates, hospitalization rates, and rotavirus genotype. RESULTS: At facility A, 84 of 324 residents (26%) were identified with clinical or laboratory-confirmed rotavirus gastroenteritis (median age, 84 years) and 11 (13%) were hospitalized. The outbreak lasted 7 weeks. At facility B, 90 case patients among 855 residents (11%) were identified (median age, 88 years) and 19 (21%) were hospitalized. The facility B outbreak lasted 9.3 weeks. Ill employees were identified at both locations. In each facility, attack rates seemed to differ by residential setting, with the lowest rates among those in more separated settings or with high baseline level of infection control measures. The causative genotype for both outbreaks was G2P[4]. Some individuals shed virus detected by enzyme immunoassay or genotyping reverse transcription polymerase chain reaction for at least 35 days. G2P[4] was also identified in 17 of 19 (89%) samples from the older adult community but only 15 of 40 (38%) pediatric samples. LIMITATION: Medical or cognitive impairment among residents limited the success of some interviews. CONCLUSION: Rotavirus outbreaks can occur among elderly adults in residential facilities and can result in considerable morbidity. Among older adults, G2P[4] may be of unique importance. Health professionals should consider rotavirus as a cause of acute gastroenteritis in adults. PRIMARY FUNDING SOURCE: None.