Changes in seroprevalence to four herpesviruses over 30 years in Swedish children aged 9–12 years

BackgroundChanging social conditions and life-styles in Sweden may have affected the spread of varicella-zoster virus (VZV), herpes simplex virus (HSV), cytomegalovirus (CMV), and Epstein-Barr virus (EBV).ObjectivesTo study possible changes over 30 years in prevalence of antibodies against VZV, HSV, CMV, and EBV in Swedish children, using modern serological methods.Study designSerum samples from 819 Swedish children who were 9–12 years old in 1967–1968, in 1977–1978 (two cohorts), and in 1997, respectively, were examined. IgG antibodies against VZV, HSV, and CMV were measured by well validated enzyme-linked immunosorbent assays and against EBV by indirect immunoflourescense.ResultsThe seropositivity for VZV for 9–12 years old children was 50% in 1967–1968, 74–82% in 1977–1978, and 98% in 1997. The corresponding figures were 31%, 53%, 50%, and 58% for CMV, 35%, 35%, 32%, and 38% for HSV, and 64% in 1967–1968 and in 1977–1978 (both cohorts), and 62% in 1997 for EBV.ConclusionsThe seroprevalence for VZV increased significantly from 1967–1968 to 1997, and there was also a significant but smaller increase in the CMV seroprevalence, while seroprevalence to HSV and EBV remained relatively stable.