Rescue of Severely Immunocompromised HIV‐Positive Persons. Part 7
In this outbreak, it is likely that a single unrecognized herpes zoster case resulted in 3 generations of disease transmission in the facility and community. Herpes zoster typically occurs in older populations, although zoster can occur in younger persons with an estimated annual rate of 1–2/1000 persons for 20–40‐year‐olds. To prevent VZV transmission from herpes zoster cases, contact precautions should be followed. In this outbreak, proper infection control measures were not implemented because the herpes zoster case was retrospectively identified after the rash had resolved. It is important for staff in residential facilities to consider herpes zoster as a diagnosis for unilateral rashes and implement control measures as appropriate to prevent VZV transmission from these cases. This recommendation is also important for school settings and other residential facilities, such as long‐term care facilities, prisons, hospitals, army barracks, and shelters, in which there is a higher risk of exposure if VZV is introduced in this type of setting due to the constant close contact of students or residents.
Healthcare providers in residential facilities should be screened for immunity to varicella and other vaccine‐preventable diseases prior to employment. Birth before 1980 should not be considered evidence of immunity to varicella for US‐born healthcare staff, since it is important that they have confirmed immunity to varicella. For healthcare staff who are not born in the United States, it is also important that they are screened for immunity to varicella regardless of when they were born because the epidemiology of varicella may differ in other countries. Ensuring immunity among healthcare providers ensures protection for both them and the residents they care for, who may not have immunity to these diseases. For other staff in residential facilities, a requirement for evidence of immunity to varicella and other vaccine‐preventable diseases can be considered depending on their level of contact with residents and the prevalence of contraindications preventing vaccination of susceptible residents.
Laboratory testing of clinical and environmental samples are important tools for investigation and control of outbreaks. Varicella and herpes zoster can easily be mistaken for other rash illnesses. Pain, a characteristic commonly associated with herpes zoster, may be less prevalent in younger adults or difficult to ascertain in persons who are nonverbal. PCR of skin lesion specimens is the preferred method for laboratory confirmation of varicella cases while skin lesions are still present. Serology testing requires invasive blood collection procedures and is less sensitive for establishing a diagnosis. Laboratory testing also plays a critical role in identifying vaccine‐associated adverse events. Through genotyping, we were able to identify a resident with a vaccine‐associated rash during this outbreak.