Development of varicella vaccine

Area of Science:

• Virology
• Immunology
• Vaccinology

Background:

• Varicella-zoster virus (VZV) causes chickenpox and shingles.
• Developing an effective VZV vaccine is crucial for public health.
• Previous VZV vaccine candidates faced challenges in replication and efficacy.

Purpose of the Study:

• To evaluate the safety and efficacy of a passaged Oka strain VZV as a vaccine.
• To assess the vaccine's impact on herpes zoster (HZ) incidence in vaccinated children.

Main Methods:

• The Oka strain of VZV was passaged in human embryonic lung fibroblasts and guinea pig embryo fibroblasts (GPEFs).
• The passaged virus exhibited temperature sensitivity and host dependency, replicating better in GPEFs.
• The passaged VZV was administered as a vaccine to healthy and immunocompromised children.

Main Results:

• The VZV vaccine proved safe and effective in both healthy and immunocompromised children.
• Vaccinated children with acute lymphocytic leukemia showed a significantly lower incidence of HZ.
• Children without a post-vaccination rash had a markedly reduced risk of developing HZ.

Conclusions:

• The passaged Oka strain VZV vaccine is a safe and effective prophylactic measure against VZV infection.
• Vaccination with this VZV strain is predicted to lower the incidence of VZV latency and subsequent HZ.
• The VZV vaccine offers a promising strategy for reducing the burden of chickenpox and shingles.