Aerosol‐phase activity of iodine captured from a triiodide resin filter on fine particles containing an infectious virus

AIMS: To avoid interference by water–iodine disinfection chemistry and measure directly the effect of iodine, captured from a triiodide complex bound to a filter medium, on viability of penetrating viral particles. METHODS AND RESULTS: Aerosols of MS2 coli phage were passed through control P100 or iodinated High‐Efficiency Particulate Air media, collected in plastic bags, incubated for 0–10 min, collected in an impinger containing thiosulphate to consume all unreacted iodine, plated and enumerated. Comparison of viable counts demonstrated antimicrobial activity with an apparent half‐life for devitalization in tens of seconds; rate of kill decreased at low humidity and free iodine was captured by the bags. CONCLUSIONS: The results support the mechanism of near‐contact capture earlier proposed; however, the disinfection chemistry in the aerosol phase is very slow on the time scale of inhalation. SIGNIFICANCE AND IMPACT OF THE STUDY: This study shows that disinfection by filter‐bound iodine in the aerosol phase is too slow to be clinically significant in individual respiratory protection, but that it might be of benefit to limit airborne transmission of infections in enclosed areas.