Zoster Vaccination for Individuals Without Prior Varicella Infection

Rationale for Vaccination Without Prior Varicella

The US CDC recommends zoster vaccination for adults aged 50 years and older who have no history of varicella or unclear history of varicella, with a preference for the recombinant zoster vaccine (RZV), as it has been shown to be safe and immunogenic in varicella zoster virus (VZV)-seronegative individuals 1, 2
The Canadian and German guidelines recommend against screening for varicella history or conducting laboratory testing for serologic evidence of prior varicella when vaccinating immunocompetent adults aged 50 years and older 1, 2
High seroprevalence studies show that the majority of adults have been exposed to VZV, even if they don't recall having chickenpox, supporting the recommendation for zoster vaccination without prior varicella screening 1
There are no known safety risks associated with administering zoster vaccines to individuals susceptible to VZV 1, 2

A small study of 21 healthy adults aged 30 years who were either seronegative for VZV or had low VZV antibody titers showed that ZVL was both immunogenic and well-tolerated 1
Another small study conducted in 23 VZV-seronegative transplant patients demonstrated that RZV was both safe and immunogenic 1

For persons who are known to be seronegative for VZV, immunization with 2 doses of varicella vaccine with an interval of 4 weeks is suggested, according to the Australian immunization guidelines 3, 4
The Australian immunization guidelines suggest that adults who are VZV-seronegative and have no history of age-appropriate varicella vaccination may receive either 2 doses of varicella vaccine (preferable) or 1 dose of ZVL (if aged 50 years or older) 3

For immunocompetent adults aged 50 years and older, no screening for varicella history is necessary, and either ZVL or RZV can be administered, with RZV being preferred due to higher efficacy 1, 2, 3, 4
For immunocompromised individuals, healthcare providers should consider factors such as age, documentation of prior varicella or vaccination, and serology testing results, and RZV is preferred as ZVL is contraindicated in immunocompromised patients 2, 5

Don't assume that absence of recalled chickenpox history means the person is VZV-seronegative, as most adults have been exposed to VZV even without clinical disease 1, 2
Don't unnecessarily delay zoster vaccination to conduct varicella serology testing in immunocompetent adults aged 50 years and older 1, 2
Don't administer ZVL (live vaccine) to immunocompromised patients, even if they are VZV-seronegative 5