Wavelength-Specific UV-C Inactivation of Viruses in Liquids: Dose–Response, Mechanistic Insights, and Structural Integrity—A Systematic Review and Meta-Analysis

This study evaluates fragmented data on ultraviolet-C (UV-C, 100–280 nm) irradiation for viral inactivation in liquid media, supporting advances such as whole-pathogen vaccine development and downstream research. Included studies reported viral strain identification, baseline titers (PFU or TCID50), UV-C wavelength, dosage, and log reductions, excluding studies employing alternative treatments. We searched (PubMed, Ovid Medline, Scopus, Embase, Web of Science; 10 April 2024) and identified 2813 records, of which 33 met the inclusion criteria. Risk of bias was assessed using ROBINS-I V2 to evaluate methodological rigor and inform improved reporting. Narrative synthesis summarized findings across viruses, while meta-analysis focused on 16 SARS-CoV-2 studies with standardized reporting. Meta-regression revealed a strong dose–response relationship (log_dose β = 3.38, 95% CI [2.95, 3.82], p < 0.001) with low heterogeneity (I2 = 15.1%). Strain and wavelength-specific efficacy peaked at 267 nm (β = 6.42) and 275 nm (β = 3.78), while 253.7 nm offered structural preservation for downstream applications. Limitations included inconsistent dose reporting, matrix effects, and assay sensitivity. We propose a refined reporting framework and standard definitions for ‘inactivation’, ‘‘disinfection,’ and ‘complete inactivation.’ Our findings support reproducible UV-C evaluation, regulatory alignment, and safe implementation in pathogen control, biosafety, and clinical applications.