Time trends in herpesvirus seroepidemiology among Swedish adults

Human herpesviruses are widespread among the human population. The infections often occur unnoticed, but severe disease as well as long-term sequelae are part of the symptom spectrum. The prevalence varies among subpopulations and with time. The aim of this study was to describe the seroprevalence of Immunoglobulin G against Herpes simplex 1, Herpes simplex 2, Epstein-Barr virus and Cytomegalovirus in the adult Swedish population over a time period of several decades. Serum samples (n = 892) from biobanks, originating from 30-year-old women, 50-year-old men and 50-year-old women sampled between 1975 and 2018, were analyzed for presence of anti-herpesvirus antibodies. Linear regression analysis was used to test for a correlation between birth year and seroprevalence. Multiple linear regression analysis was used to differentiate between other factors such as age and gender. Birth year correlated negatively with the prevalence of immunoglobulin G against Herpes simplex 1 and Epstein-Barr virus (p = 0.004 and 0.033), and positively with Immunoglobulin G against Cytomegalovirus (p = 0.039). When participant categories were analyzed separately, birth year correlated negatively with the prevalence of Immunoglobulin G against Herpes simplex 1 and Herpes simplex 2 (p = 0.032 and 0.028) in 30-year-old women, and with the prevalence of Immunoglobulin G against Cytomegalovirus in 50-year-old men (p = 0.011). The prevalence of Immunoglobulin G against Herpes simplex 1, Herpes simplex 2 and Epstein-Barr virus decreases in later birth cohorts. This indicates a trend of declining risk of getting infected with these viruses as a child and adolescent.