Final answer:
Alcohol-based hand rubs are a valid alternative to handwashing when soap and water are not available. They effectively kill a broad range of microbes but are not sporicidal and must be used on clean hands to be effective.
Step-by-step explanation:
True. Alcohol-based hand rubs are considered reasonable alternatives when soap and water are not available for hand hygiene. These hand sanitizers contain isopropanol or ethanol as active ingredients, making them effective at killing a broad range of vegetative microbes, including bacteria, fungi, and some viruses, particularly enveloped ones.
Hand sanitizers typically have an alcohol concentration between 60% to 80%, which ensures the maximum germicidal effect. The presence of water enhances their effectiveness, as proteins in microbial cells are more readily denatured in the presence of water, allowing the alcohol to penetrate more effectively.
However, when using hand sanitizers, it's important to note that they are not effective in the presence of visible dirt, they do not kill bacterial spores, and they may cause skin irritation due to their dehydrating effect. As alcohols have a high volatility, their disinfectant action is limited to the period immediately after their application. Always use hand sanitizers in a well-ventilated area to prevent inhalation hazards.