Studies on air-borne virus infections: II. the killing of virus aerosols by ultra-violet radiation

The experiments show that rapid and effective sterilization of atmospheres containing atomized particles of influenza and vaccinia viruses, and probably also of herpes simplex virus, can be obtained by ultra-violet radiation of wave-length 2537 A. At least 99 % and probably more of an aerosol of influenza virus was killed by exposure for 6 sec. at. a distance of 2 cm. from either a Hanovia lamp or a G.E.C. ‘Sterilamp’. These findings confirm the work of Wells and his associates who first demonstrated the susceptibility of this virus to ultra-violet radiation (Wells & Brown, 1936; Wells & Henle, 1941). At the same distance the ‘Sterilamp’ produced more than a 99 % kill of vaccinia virus with an exposure of 1 sec. and about a 90 % kill in 0·5 sec. The experiments with herpes were less satisfactory but suggested a similar sensitivity. These results support the view that ‘germicidal’ lamps are likely to be useful in reducing the infectivity of air contaminated with particles from persons suffering from virus infections of the respiratory tract.We wish to acknowledge our indebtedness to the late Sir Patrick Laidlaw who, although his name does not appear as author, largely inspired the investigation and took an active part in it until his death.