A novel approach using an attenuated recombinant vaccinia virus to test the antipoxviral effects of handsoaps.

Evidence indicates an increase in nosocomial and household infections due to viruses (Jeffries, D.J., 1995. Viral hazards to and from health care workers. J. Hosp. Infect. 30, 140-155). An antiviral assay was developed for evaluating efficiency of handsoaps at inactivating cell-free and cell-associated virus. A recombinant vaccinia virus, lacking a virulence factor (Isaacs, S.N., Kotwal, G.J., Moss, B., 1992. Vaccinia virus complement-control protein prevents antibody-dependent complement-enhanced neutralization of infectivity and contributes to virulence. Proc. Natl. Acad. Sci. USA 89, 628-632), whose construction was described earlier (Kotwal, G.J., Isaacs, S.N., McKenzie, R., Frank, M.M., Moss, B., 1990. Inhibition of the complement cascade by the major secretory protein of vaccinia virus. Science 250, 827-830), was used as the representative poxvirus. Two antibacterial handsoaps, one surgical handsoap, one moisturizing handsoap, and a sanitizing agent were tested. An aliquot of the virus was mixed and incubated with soap, then titrated onto BSC-1 cells for incubation at 37 degrees C for 48 h. The soaps' effect on cell-associated virus was tested similarly. The antibacterial soaps inactivated all cell-free virus in 1 min. The surgical soap was effective with a 5-min incubation. None of the soaps eliminated all of the cell-associated virus in 1 min. This safe and reproducible assay seems efficient to establish the comparative efficacy of household and surgical soaps.