Hepatitis A Exposure Response and Outbreak Prevention in a Large Urban Jail — Los Angeles County, California, May–July 2023

Discussion

Since 2016, person-to-person outbreaks of hepatitis A in the United States have been increasingly occurring among persons who use drugs, those who experience homelessness, and men who have sex with men (1). The risk for hepatitis A transmission is elevated in jails because they house a disproportionate number of persons in these populations, in addition to their crowded living conditions and transient population. Identification of an acute hepatitis A case in a jail, therefore, requires a prompt response and contact identification (2).

CHS was able to implement a timely infection control response by identifying all possible incarcerated contacts and initiating a mass vaccination response within 48 hours of notification of the index case (Figure 1). Mass vaccination campaigns for time-sensitive responses in jail settings can be challenging because they involve a large number of persons, as well as logistic issues, and obstacles to timely vaccine procurement. During 2007–2010, hepatitis vaccination campaigns were conducted at LACJ among men who have sex with men (3) and during 2017–2019 among the entire LACJ population (CHS, unpublished data, 2019) in response to the 2017 hepatitis A outbreak in San Diego (4).

An effort to improve compliance with the mandatory reporting to the California immunization registry led to steps being taken to improve the quality and completeness of hepatitis A and B vaccination records in the state immunization registry as well as hepatitis A and B vaccination and serology records in the electronic health record. These records helped focus vaccination efforts on persons who were not immune and offer postexposure prophylaxis to those identified as eligible for receipt within 2 weeks of identifying the index patient. The prompt vaccine rollout likely helped reduce transmission and prevent an outbreak among the LACJ population, and the enhanced surveillance, which included the monitoring of emergency hospital transfers made because of suspicion of acute hepatitis A, helped identify possible secondary cases or clusters needing further investigation. Because of the range of the hepatitis A incubation period (15–50 days) and the date of incarceration of the index patient, whether his infection was acquired before or during incarceration is uncertain. The index patient had reported risk factors at the time of intake (i.e., homelessness and injection drug use) for which hepatitis A vaccination is recommended (1,2). The correctional environment presents a unique opportunity to reduce hepatitis A transmission and disease through vaccination (5–7); accordingly, CHS might consider a more comprehensive routine vaccination strategy, including offering vaccination at intake.

Implications for Public Health Practice

The infection control response initially included a plan to offer hepatitis A vaccine and Ig to persons who were immunocompromised, aged >60 years, or both (8); however, Ig could not be obtained within the indicated time frame because of logistic issues. Future infection control planning at CHS involves maintaining a supply of hepatitis A Ig for emergency use in case of an exposure or outbreak. A major limitation of the CHS hepatitis A surveillance process was that reactive IgM anti-HAV laboratory results from LAGMC did not appear in CHS communicable disease laboratory reports because of the different electronic health record identifiers used by the two facilities. A modified communicable disease surveillance report that retrieves reactive IgM anti-HAV results from LAGMC conducted on CHS patients that contains CHS-specific identifiers was created after the response to help prevent delays in identifying cases and planning for exposure response and mitigation. This exposure response highlights the importance of initiating a rapid response to hepatitis A exposure in a jail setting to minimize risk for transmission and help prevent an outbreak. Having relevant laboratory results for reportable communicable diseases consistently and seamlessly communicated electronically across different health systems with mutual patients and using serology and vaccination records from electronic health records and state immunization registries can facilitate and optimize the response to a potential exposure by ensuring the timely administration of postexposure prophylaxis to those who are at greatest risk.