Live varicella immunization in healthy non-immune nurses

Area of Science:

• Immunology
• Vaccinology
• Public Health

Background:

• Varicella-zoster virus (VZV) infection poses risks, particularly in healthcare settings.
• Assessing vaccine efficacy and duration of immunity in adults is crucial for public health strategies.

Purpose of the Study:

• To evaluate the safety, immunogenicity, and protective efficacy of the live varicella vaccine (Varilrix) in VZV-seronegative adult nurses.
• To determine the persistence of immune response and identify potential factors influencing long-term immunity.

Main Methods:

• Thirty-four VZV-seronegative nurses received the Varilrix vaccine.
• Participants were monitored for vaccine reactions, seroconversion, antibody levels, and lymphocyte transformation responses for up to 36 months.
• Clinical outcomes, including VZV reinfection and chickenpox development, were recorded.

Main Results:

• No major adverse reactions to the Varilrix vaccine were observed.
• High seroconversion rates (94%) were achieved at 5 and 12 months post-vaccination.
• Antibody levels declined by 3 years, with only 64% retaining activity, though cell-mediated immunity persisted in some.
• Vaccinated individuals who did not seroconvert were susceptible to chickenpox, while vaccinated and seroconverted individuals showed protection against symptomatic reinfection.

Conclusions:

• The Varilrix vaccine is safe, immunogenic, and protective in adults, warranting consideration for susceptible healthcare workers.
• Long-term immunity assessment requires both antibody and cell-mediated immune response evaluations.
• Further studies are needed to ascertain the duration of vaccine-induced immunity and the need for booster doses.