A serological study of herpes simplex virus type 1 antibody over a 13-year period

HSV-1 serum antibody titers determined by 50% plaque reduction and confirmed by radioimmunoassay in 11 samples from an individual over a 13-year period indicated a significant increase between the first sample and a sample taken 9 years later. This increase did not seem to reflect loss of antibody in the low titered serum sample due to storage.