infection control & hospital epidemiology july 2018, vol. 39, no. 7 research briefs


Outbreak of Hepatitis A Virus Infection Among Adult Patients of a Mental Hospital—LosAngeles County, 2017


In July 2017, 2 persons with immunoglobulinM(IgM) antibodies to hepatitis A virus (HAV) were reported to the Los Angeles County (LAC)Department of PublicHealth (DPH). The 2 adults (patient A and patient B) were residents of a multiunit mental hospital in LAC, which raised concern about possible transmission within the hospital. This hospital houses both long-term conservatorship patients as well short-term patients receiving acute-care psychiatric treatment. The LAC DPH conducted a site investigation to confirmthe suspected cases, to assess risk forHAV transmission to hospitalized patients, to assess environmental conditions, to conduct active case surveillance, and to discuss enhanced infection control practices with infection control staff. Both reported patients (patient A and patient B) were housed in the same 45-patient locked hospital unit, but resided in separate patient rooms. Several environmental cleaning issues were iden- tified and addressed with the hospital staff during the site visit, including substandard cleaning practices, cleaning solutions improperly diluted, and poorly maintained patient restrooms. The LAC DPH consulted with infection control staff at the


hospital and recommended administering HAV vaccine to all patients and staff on the affected unit who did not have a record of previous HAV immunity. Because the incubation period for HAV ranges from 15 to 50 days, the surveillance period was maintained for 50 days after the onset of symptoms of the last case, during which time the unit was closed to any new admissions or discharges. Hepatitis A virus causes an acute liver infection in humans,


reported in the United States each year since 2010.4 In the United States, vaccination is recommended for children at age 1 year, adults at risk for acquisition of infection (eg, travelers, men who have sex with men, immunocompromised persons, injection drug users) and close contacts of patients with acute HAV infection.1,3 Outbreaks of HAV infection in congregate living situations in the post-vaccine era are uncommon but have been reported.5,6 Among 45 patients in the outbreak unit of this hospital,


2 patients (4.4%) were initially identified as acute HAV cases (patients A and patient B); 11 patients (24.4%) had documented HAV immunity; and 32 patients (71.1%) were presumed to be susceptible. Of the presumed susceptible patients, 30 (93.8%) received a single dose of hepatitis A vaccine, and 2 patients (6.2%) refused vaccination. Of 61 staff in the outbreak unit, 27 (44.3%) also received vaccination. Two additional acuteHAV cases (patient C and patient D) were identified during the surveillance period, including 1 patientwho received vaccine and 1 patientwho had refused vaccination, for a total of 4 acuteHAV cases. Patients A through Dhad symptomonset within 1month and had clinical signs and symptoms and laboratory results consistent with acute HAV infection (Table 1). The ribonucleic acid (RNA) genotype for patients A through D was 1B, which was indistinguishable from the dominate strain circulating in the concurrent San Diego County hepatitis A outbreak.8 Patient A (index) became ill 3 weeks after arriving at this


transmissible from person to person via the fecal–oral route.1–3 Approximately 1,500 cases of HAV infection have been


LAC mental hospital and was transferred from a San Diego hospital where his HAV exposure likely occurred. In addition, 3 secondary cases (patients B, C, andD) occurred in personswho had close contact with patient A (n=1), shared living quarters with patient A (n=1), and shared a hospital unit restroomwith patient A (n=1). Patients in this hospital were often poor historians, and some had limited verbal abilities; these commu- nication difficulties led to delays in confirming illness, assessing possible exposures, and identifying contacts. Patients also had limited ability tomaintain adequate hygiene, which affected


table 1. Demographics, Signs and Symptoms, Laboratory Results, and Hospitalization Days for Hepatitis A Outbreak Cases, Los Angeles County, California, 2018


Demographics Signs and Symptoms Case Age Range, y Sex Onset Day Signs and Symptoms


A25–29 M Day 1 Jaundice, yellow sclera, dark urine B40–44 F Day 16 Vomiting, lethargic, decreased appetite Cb


Laboratory Results


AST (U/L)a ALT (U/L)a Bilirubin (mg/dL) Hospital Days 1,239


65–69 M Day 26 Vomiting, lethargic, abdominal pain, jaundice 1,176 D40–44 M Day 27 Vomiting, abdominal pain


945 129


2,618 714


2,419 547


NOTE. AST, aspartate aminotransferase; ALT, alanine aminotransferase; M, male; F, female. aHighest measure within 1 week of illness. AST reference range: 5–46 U/L. ALT reference range: 13–69 U/L. bHepatitis C virus coinfection.


*Article type has been corrected since original publication. An erratum notice detailing this change was also published (DOI 10.1017/ice.2018.157).


6.6 1.5


10.1 1.8


1 1 2 0


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