The smallpox virus is fragile. In laboratory experiments, 90% of aerosolized (vaccinia virus [a model for smallpox virus]) dies within 24 hours; in the presence of ultraviolet (UV) light, this percentage would be even greater. If an aerosol release of smallpox occurs, 90% of virus matter will be inactivated or dissipated in about 24 hours.
Standard hospital-grade disinfectants such as quaternary-ammonia compounds are effective in killing the virus. They should be used on surfaces to disinfect hospitalized patients rooms or other contaminated surfaces. Although less desirable because it can damage equipment and furniture, hypochlorite (bleach) is an acceptable alternative. In the hospital setting, patients linens should be autoclaved or washed in hot water with bleach added. Infectious waste should be placed in biohazard bags and autoclaved before incineration.
The most important steps to stop a smallpox epidemic are isolation of smallpox cases, tracing of the contacts of these cases, and vaccination.
Patients showing signs of smallpox infection are capable of spreading the virus. Patients should be placed in medical isolation, so that they will not continue to spread the virus. In addition, people who have come into close contact with smallpox patients should be vaccinated immediately and closely watched for symptoms of smallpox. Vaccination and isolation are the key strategies for stopping a smallpox outbreak from spreading.