The effect of blood on the antiviral activity of sodium hypochlorite, a phenolic, and a quaternary ammonium compound

OBJECTIVE: To assess the virucidal activity of three disinfectants (sodium hypochlorite, a phenolic, and a quaternary ammonium compound) in the presen ce and absence of blood. METHODS: Disinfectants at varying concentrations (hypochlorite: 5,000, 500, or 50 ppm; phenolic: 1:10 or 1:128 dilution; quaternary ammonium compound: 1:10 or 1:128 dilution) were added to either saline or whole blood (final concentration, 80% or 20% blood) and mixed. Test organisms included an atte nuated vaccine strain of poliovirus type 1 (prototype for relatively resist ant hydrophilic viruses) and herpes simplex virus (HSV) type 1 (prototype f or relatively susceptible lipophilic viruses). Virus was added to create a viral-blood suspension. Viral survival was tested at room temperature at th e following times: 0, 15 seconds, 30 seconds, 1 minute, 2 minutes, 5 minute s, and 10 minutes. A neutralizer stopped the reaction, and virus was assaye d using a plaque technique. RESULTS: In the absence of blood, complete inactivation of HSV was achieved within 30 seconds with 5,000 (1:10 dilution of bleach) and 500 (1:100 dilu tion of bleach) ppm chlorine, 1:10 and 1:128 diluted phenolic (use dilution ), and 1:10 and 1:128 diluted quaternary ammonium compound (use dilution). In the presence of 80% blood, only 5,000 ppm hypochlorite, 1:10 phenolic, a nd 1:10 or 1:128 quaternary ammonium compound were effective. In the absenc e of blood, complete inactivation of polio was achieved within 30 seconds b y 5,000 and 500 ppm chlorine and 1:10 quaternary ammonium compound. In the presence of 80% blood, no solution tested was capable of completely inactiv ating poliovirus within 10 minutes. CONCLUSIONS: Our data suggest that, in the absence of visible blood, enviro nmental surfaces may be disinfected with a diluted hypochlorite solution (1 :10 or 1:100), a phenolic, or a quaternary ammonium compound. Based on our studies using HSV, which has similar susceptibilities to disinfectants as h uman immunodeficiency virus (HIV), phenolics at their use dilution and 1:10 0 diluted hypochlorite are unlikely to inactivate HIV or hepatitis B virus reliably in the presence of blood. Hypochlorite at a final concentration of 5,000 ppm (1:10 dilution) should be used to decontaminate blood spills, bu t, even after decontamination, care should be used to avoid sharps injuries (Infect Control Hosp Epidemiol 1999;20:821-827).