Systematic Review and Meta-Analysis of UV-C Viral Inactivation: Mechanistic, Environmental, and Terminological Insights

This systematic review and meta-analysis evaluated ultraviolet-C (UV-C, 100–280 nm) irradiation for viral inactivation in liquid media as an environmentally sustainable, non-chemical strategy for research and health infrastructure. Included studies reported viral strain identification, baseline titers (PFU or TCID₅₀), UV-C wavelength, dosage, and log reductions, excluding studies subjected to alternative treatments. We searched (PubMed, Ovid Medline, Scopus, Embase, Web of Science; April 10, 2024) identified 2,813 records, of which 33 met 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 = 3.382, 95% CI [2.946, 3.817], p < 0.001) with low heterogeneity (I² = 15.1%). Strain and wavelength-specific efficacy peaked at 267 nm (β = 6.418) and 275 nm (β = 3.776), 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.’ Findings support reproducible UV-C evaluation, regulatory alignment, and safe implementation in pathogen control, biosafety, and water treatment.