Differentiation between wild-type and vaccines strains of varicella zoster virus (VZV) based on four single nucleotide polymorphisms.

Varicella-zoster virus (VZV) infection (chickenpox) results in latency and subsequent reactivation manifests as shingles. Effective attenuated vaccines (vOka) are available for prevention of both illnesses. In this study, an amplicon-based sequencing method capable of differentiating between VZV wild-type (wt) strains and vOka vaccine is described. A total of 44 vesicular fluid specimens collected from 43 patients (16 from China and 27 from the UK) with either chickenpox or shingles were investigated, of which 10 had received previous vaccination. Four sets of polymerase chain reactions were set up simultaneously with primers amplifying regions encompassing four single nucleotide polymorphisms (SNPs), '69349-106262-107252-108111'. Nucleotide sequences were generated by Sanger sequencing. All samples except one had a wt SNP profile of 'A-T-T-T'. The sample collected from a patient who received vaccine 7-10 days ago, along with VZV vaccine preparations, Zostavax and Baike-varicella gave a SNP profile 'G-C-C-C'. The results show that this method can distinguish vaccine-derived virus from wt viruses from main four clades, (clades 1-4) and should be of utility worldwide.