A high level of disinfection is achieved when instruments are boiled for 20 minutes. This is the simplest and most reliable method of inactivating most pathogenic microbes, including HIV, when sterilization equipment is not available. Boiling should be used only when sterilization by steam of dry heat is not available. Hepatitis B virus is inactivated by boiling for several minutes; HIV, which is very sensitive to heat, is also inactivated by boiling for several minutes. However, in order to be sure, boiling should be continued for 20 minutes.
Chemical disinfection is used for heat-sensitive equipment that may be damaged by high temperatures. Most disinfectants are effective against a limited range of microorganisms only and vary in the rate at which they destroy microorganisms. Items must be dismantled and fully immersed in the disinfectant. Care must be taken to rinse disinfected items with clean water so that they do not become recontaminated. Chemical disinfectants are unstable and chemical breakdown can occur. They may also be corrosive and irritating to skin. Protective clothing may be required. Chemical disinfection is not as reliable as boiling or sterilization. The agents include:
• chlorine-based agents, e.g., bleach
• aqueous solution of 2% glutaraldehyde
• 70% ethyl or isopropyl alcohol.
(Source: WHO - GPA/TCO/HSC/95/16 p.16 and WHO AIDS Series 2, 2nd edition, p.3, 1989.)