Detection of varicella-zoster virus DNA in nasopharyngeal secretions of immune household contacts of varicella.

Persons immune to varicella-zoster virus (VZV) are not at risk for developing clinical infection after exposure to varicella. However, the extent to which they might serve as vectors for the transmission of VZV to others is not known. Information in this regard would be important in establishing hospital infection control policies, especially in relation to the care of immunocompromised hosts. A polymerase chain reaction-based detection system was used to detect the presence of VZV DNA in the nasopharyngeal secretions of household contacts of children with varicella. VZV DNA was identified in 4 of 5 immune adults and 1 susceptible sibling when sampled within 3 days of recognition of a household case of varicella. Further investigations are needed to determine whether this represents a limited window of VZV replication in the nasopharynx of immune persons during which they may serve as vectors of VZV.