Long-term laboratory-based surveillance of TORCH seroprevalence: A nine-year analysis of 188,251 routine diagnostic tests.

BACKGROUND: Large-scale, long-term serological data are essential for accurately monitoring temporal changes in population immunity and exposure to TORCH pathogens. The aim of this study was to evaluate nine-year temporal trends in IgG and IgM seroprevalence of TORCH-related pathogens using a large, routine laboratory-based dataset, and to assess age- and sex-related differences in seropositivity.

METHODS: This retrospective study analyzed TORCH-related serological test requests performed at a tertiary-care hospital in southern Türkiye between 2015 and 2023. A total of 188,251 serological tests for Toxoplasma gondii, Rubella virus, Cytomegalovirus, and Herpes Simplex Virus (HSV)-1/2 IgG and IgM were reviewed. Chemiluminescent microparticle immunoassay was performed to detect Toxoplasma gondii, Rubella virus, and CMV IgG and IgM, while Triturus fully automated ELISA system was performed to detect HSV-1/2 IgM antibodies. Temporal trends, age- and sex-related differences, and independent predictors of seropositivity were assessed using descriptive statistics and multivariable logistic regression.

RESULTS: Marked pathogen-specific temporal changes were observed over the nine years. Toxoplasma gondii and rubella IgG seropositivity declined, whereas Cytomegalovirus IgG seropositivity increased steadily, while IgM seropositivity remained consistently low for all TORCH pathogens. Age and sex were significant, pathogen-dependent predictors of seropositivity. The large sample size and extended observation period allowed reliable assessment of year-to-year variations.

CONCLUSION: This study, based on one of the largest and longest uninterrupted laboratory-based TORCH datasets reported to date, demonstrates significant pathogen-specific shifts in seroprevalence over time. Routine laboratory data provide a valuable resource for monitoring population-level immunity and supporting public health planning and diagnostic practice.