Background: Two VZV glycoprotein E (gE D150N) mutant strains were collected in North America in 1995 and in 1999. We now report a novel VZV gE mutant virus discovered in Europe in two VZV strains collected in Stockholm, Sweden, in 1990 and 1999.
Objectives: To characterize the two isolates identified among a total of 634 VZV isolates collected over a 15-year period at the Karolinska University Hospital.
Study design: VZV genes were amplified by polymerase chain reaction and their sequences were compared to the genomic sequence of VZV-Dumas prototype strain.
Results: A mutation within the gE gene in an epitope recognized by the 3B3 monoclonal antibody was identified in both isolates. A different residue was changed (R152S) compared to the North American strains (D150N).
Conclusions: The occurrence of a VZV gE mutant virus is unusual, but probably a recurring event in Europe and North America. It is unknown whether widespread varicella vaccination programs will alter the rate at which these mutant viruses are isolated.