Serological testing before zoster vaccination is recommended for some people

It is not necessary to have serological evidence of immunity to varicella-zoster virus (VZV) or a history of previous varicella infection before routine administration of Shingrix or routine administration of Zostavax.

However, serological testing before zoster vaccination is recommended if the person receiving Zostavax:

• has HIV (see People with HIV in Contraindications and precautions)
• has an uncertain level of immunocompromise and there is potential risk for adverse events identified in pre-vaccination screening (see People with mild to moderate immunocompromising conditions)

People who are immunosuppressed and have negative VZV IgG should not receive Zostavax. See also Contraindications and precautions.  If a person who is immunocompromised does not have evidence of previous VZV natural infection and is seronegative, they may have very severe outcomes after receiving Zostavax.¹⁵ A cautious approach with detailed individual clinical assessment is required to determine whether it is safe to administer Zostavax.

Interpreting serology for varicella (chickenpox) is difficult, as there is no serological correlate of protection. A positive result indicates past exposure from either natural infection or vaccination. More than 97% of people in Australia are seropositive to VZV by 30 years of age,¹⁶ even if they cannot recall having varicella at a younger age. In some small studies, high-dose VZV-containing vaccine (comparable to Zostavax) was given to healthy VZV-seronegative adults and previously infected adults. The limited data suggest that Zostavax was well tolerated and immunogenic in seronegative people.^17,18