Predictors of 5-Year Persistence of Antibody Responses to Zoster Vaccines.

BACKGROUND: Protection against herpes zoster is primarily conferred by cell-mediated immunity. However, anti-varicella-zoster virus (VZV) glycoprotein (anti-gp) antibody responses to zoster vaccine live (ZVL) are correlated with protection, suggesting a potential protective role for antibody. Detailed studies of antibody responses to the recombinant zoster vaccine (RZV) are provided. METHODS: We compared enzyme-linked immunosorbent assay-measured anti-VZV glycoproteins (anti-gp) and glycoprotein E (anti-gE) antibody levels and avidity in 159 participants randomized to RZV (n = 80) or ZVL (n = 79) recipients over 5 years after vaccination and identified predictors of antibody persistence. RESULTS: The comparison between vaccine groups showed higher anti-gE and anti-gp antibody levels after RZV than after ZVL over the 5-year study duration. RZV recipients also had higher anti-gE avidity for 5 years and higher anti-gp avidity in the first year after vaccination. Compared with prevaccination levels, RZV recipients maintained higher levels of anti-gE antibodies and avidity for 5 years, whereas ZVL recipients only maintained higher anti-gE avidity. Anti-gp antibody levels and avidity decreased to prevaccination levels or below beyond 1 year after vaccination in both groups. Independent predictors of persistence of antibody levels and avidity included vaccine type, prevaccination and peak antibody levels and avidity, prevaccination and peak cell-mediated immunity, and age. Sex or prior ZVL administration did not affect persistence. CONCLUSIONS: Antibody responses and avidity were higher and more persistent in RZV than in ZVL recipients. The effect of age on antibody persistence in RZV recipients is novel.

Revisiting the genotyping scheme for varicella-zoster viruses based on whole-genome comparisons.

We report whole-genome sequences (WGSs) for four varicella-zoster virus (VZV) samples from a shingles study conducted by Kaiser Permanente of Southern California. Comparative genomics and phylogenetic analysis of all published VZV WGSs revealed that strain KY037798 is in clade IX, which shall henceforth be designated clade 9. Previously published single nucleotide polymorphisms (SNP)-based genotyping schemes fail to discriminate between clades 6 and VIII and employ positions that are not clade-specific. We provide an updated list of clade-specific positions that supersedes the list determined at the 2008 VZV nomenclature meeting. Finally, we propose a new targeted genotyping scheme that will discriminate the circulating VZV clades with at least a twofold redundancy. Genotyping strategies using a limited set of targeted SNPs will continue to provide an efficient 'first pass' method for VZV strain surveillance as vaccination programmes for varicella and zoster influence the dynamics of VZV transmission.

Arm Paralysis After Routine Childhood Vaccinations: Application of Advanced Molecular Methods to the Causality Assessment of an Adverse Event After Immunization.

Post-licensure surveillance for adverse events following immunizations (AEFI) can identify rare complications of vaccinations and rigorous vaccine adverse event causality assessments can help to identify possible causal relationships. We report the development of arm paralysis after varicella vaccination in a 1-year-old child. Paralysis was initially presumed to be due to vOka because of the temporal relationship between vaccination and onset of arm weakness; however, molecular studies identified wild-type varicella zoster virus VZV (WT-VZV) in the CSF, leading the authors to conclude that WT-VZV was the probable cause. This case illustrates the complexity of assessing AEFI causality, and the importance of careful and complete evaluations when determining the most likely cause of an AEFI.