Pox in the docks: varicella outbreak in an Australian prison system

1. Describe an outbreak of varicella in a prison system. 2. Highlight the risks of disease transmission within the prison environment. 3. Promote infection control guidelines for high-risk sub-groups within the prison system, including the application of quarantine.

Four prisons, one prison hospital, the prison transport system, one courthouse.

Number of cases of varicella infection; reported varicella immunity status of cases and contacts; immunity status of known HIV antibody positive inmates.

Five cases of chickenpox were identified. There were 23 contacts of the Index Case occurring during transport between prison and court and whilst being held in the court holding cells. Two of these contacts developed chickenpox despite having given a prior history of infection. There were over 300 inmates exposed to varicella zoster virus (VZV) during the outbreak, including one HIV antibody positive inmate who had serologically confirmed immunity. This inmate developed shingles following exposure to VZV from one of the cases.

There is an elevated risk of respiratory transmission of infections such as chickenpox in prisons. Clear guidelines should be in place to protect HIV antibody positive people, pregnant women, and others who are at increased risk of complications from such infections. In the case of varicella, all inmates and staff without documented immunity should be screened to determine immunity, and if non-immune, should be offered VZV vaccination. Every effort should be made to prevent HIV antibody positive inmates being exposed to varicella, regardless of their varicella immunity status. If an HIV antibody positive inmate, who is known to be non-immune is exposed to varicella, Varicella Zoster immunoglobulin should be given within 96 h.