Centers for Disease Control and Prevention guidelines from 2008 states: “In the health care setting, ‘alcohol’ refers to two water-soluble chemical compounds — ethyl and isopropyl alcohol — that have generally underrated germicidal (killing) characteristics. FDA has not cleared any liquid chemical sterilant on high-level disinfectant with alcohol as the main active ingredient. These alcohols are rapidly bacteriocidal (bacteria killing) rather than bacteriostatic (stunting their growth) ... they are also tuberculocidal, fungicidal, virucidal, but do not destroy bacterial spores.”
Both alcohols, ethyl and isopropyl, can kill several bacteria in 10 seconds or fewer in the lab, including Staph aureus, Strep pyogenes, E. coli, Salmonella typhosa, and Pseudomonas species, some of the bad actors in infections. For M. tuberculosis, it may take as long as five minutes of contact. Many, but not all, viruses are goners, too, like HIV, hepatitis B, herpes, influenza, etc. Even some systemic bad fungal infections are susceptible, but again not all.
Alcohol rub sanitizers kill most bacteria, and fungi, and stop some viruses. Alcohol rub sanitizers containing at least 70% alcohol (mainly ethyl alcohol) kill 99.9% of the bacteria on hands 30 seconds after application and 99.99% to 99.999%[note 1] in one minute.