BACKGROUND: Varicella-zoster-virus (VZV) is a highly contagious virus with secondary attack rates of 65%-90%. Susceptible individuals in congregate settings, including prisons, are at increased risk of VZV infection due to close contact. We describe the epidemiology, control measures, and challenges of a varicella outbreak in a contract prison in Georgia.
METHODS: In January, 2016, the Georgia Department of Public Health (DPH) conducted a varicella outbreak investigation in a contract (privately-run federal) prison with a population of 2,600 primarily foreign- born inmates (Prison A). A varicella case was defined as a generalized, maculopapular rash that developed in an inmate or staff member between December 20, 2015 and February 28, 2016. DPH collected information regarding clinical characteristics and demographics of case-patients, and immunity of exposed persons. Laboratory testing to confirm varicella infection, isolation of cases, and vaccination of exposed, susceptible inmates was recommended. Active surveillance for secondary cases was conducted through two incubation periods (42 days) after onset of the last case-patient.
RESULTS: Eleven foreign-born case-patients (median age: 33 years) were identified in Prison A. All case-patients had unknown varicella vaccination status, and 9 (82%) had fewer than 50 lesions. Of 93 inmates exposed, nine of the 10 determined to be non-immune developed varicella. DPH offered varicella vaccine to the exposed, susceptible individuals for post-exposure prophylaxis (PEP). However, Prison A did not have a freezer appropriate for storage. Alternatively, DPH recommended obtaining local vaccine and following the Centers for Disease Control’s (CDC) guidance on vaccine storage, handling, and transport. Prison A declined, and instead continued to isolate new cases and sequester exposed inmates until 21 days after their last exposure (totaling over three incubation periods). No cases were laboratory-confirmed. DPH discussed the management of varicella outbreaks in contract prisons with the Federal Bureau of Prisons (BOP), who noted that due to contract prison limitations, PEP is not typically incorporated into varicella response efforts, and such outbreaks, which are common, often persist through multiple incubation cycles and involve extended isolation of inmates.
CONCLUSIONS: Identifying and controlling varicella outbreaks in contract prisons present unique challenges. These challenges often result in sub-optimal implementation of published CDC and BOP varicella outbreak guidelines, which include using PEP to prevent transmission. This outbreak highlights the need for collaboration between contract prisons, BOP, and state public health personnel to develop a more effective varicella outbreak protocol for these facilities.