Safety, tolerability, and immunogenicity of a two-dose regimen of high-titer varicella vaccine in subjects ≥13 years of age

A new manufacturing process, known as process upgrade varicella vaccine (PUVV) was developed for a refrigerated formulation of varicella vaccine and for an investigational zoster vaccine. Safety and tolerability of a two-dose regimen of high-titered (∼50,000 PFU) PUVV were compared to a lower-titer formulation (∼5400 PFU) of VARIVAX™; in 1366 healthy subjects ≥13 years old. Only one vaccine-related clinical serious adverse experience (pruritus; no hospitalization) was reported, in the VARIVAX™ group. Injection-site adverse experiences following any dose were higher in the PUVV group, 70.0%, than in the VARIVAX™ group, 56.2%, but generally were mild. Immunogenicity were similar in both groups in seronegative subjects. PUVV was generally well tolerated, and elicited an immune response similar to that induced by the marketed formulation of VARIVAX™.