ACIP suggestions for smallpox preparation

With risk low,’ Joe Public is out for now

On June 20, 2001, the Centers for Disease Control and Prevention’s (CDC) Advisory Committee on Immunization Practices (ACIP) made recommendations for the use of smallpox vaccine to prepare for a possible bioterrorism attack. As Hospital Home Health goes to press, the following recommendations remained under review by the U.S. Department of Health and Human Services. Therefore, these key recommendations, summarized below, may be subject to change. For updated information, consult the web site: www.cdc.gov/nip/smallpox/default.htm.

Smallpox transmission and control

Smallpox is transmitted from an infected person once a rash appears. Transmission does not occur during the prodromal period that precedes the rash. Infection is transmitted by large droplet nuclei, and only rarely has airborne transmission been documented. Epidemiologic studies have shown that smallpox has a lower rate of transmission than diseases such as measles, pertussis, and influenza. The greatest risk of infection occurs among household members and close contacts of people with smallpox, especially those with prolonged face-to-face exposure. Vaccination and isolation of contacts of cases at greatest risk of infection has been shown to interrupt transmission of smallpox. However, poor infection control practices resulted in high rates of transmission in hospitals. The primary strategy to control an outbreak of smallpox and interrupt disease transmission is surveillance and containment, which includes ring vaccination and isolation of people at risk of contracting smallpox. This strategy involves identification of infected people through intensive surveillance, isolation of infected people, vaccination of household contacts and other close contacts of infected people (i.e., primary contacts), and vaccination of household contacts of the primary contacts (i.e. secondary contacts). This strategy was instrumental in the ultimate eradication of smallpox as a naturally occurring disease, even in areas that had low vaccination coverage.

General population

Under current circumstances, with no confirmed smallpox and the risk of an attack assessed as low, vaccination of the general population is not recommended, as the potential benefits of vaccination do not outweigh the risks of vaccine complications. Recommendations regarding pre-outbreak smallpox vaccination are being made on the basis of an assessment that considers the risks of disease and the benefits and risks of vaccination. The live vaccinia (cowpox) vaccine virus can be transmitted from person to person. In addition to sometimes causing adverse reactions in vaccinated people, the vaccine virus can cause adverse reactions in the contacts of vaccinated people.

Smallpox response teams

Smallpox vaccination is recommended for people pre-designated by the appropriate bioterrorism and public health authorities to conduct investigation and follow-up of initial smallpox cases that would necessitate direct patient contact. To enhance public health preparedness and response for smallpox control, specific teams at the federal, state, and local levels should be established to investigate and facilitate the diagnostic work-up of the initial suspect case(s) of smallpox and initiate control measures. These smallpox response teams might include people designated as: medical team leader, public health advisor, medical epidemiologists, disease investigators, diagnostic laboratory scientist, nurses, personnel who would administer smallpox vaccines, and security/law enforcement personnel. Such teams also may include medical personnel who would assist in the evaluation of suspected smallpox cases. ACIP recommends that each state and territory establish and maintain at least one smallpox response team. Considerations for additional teams should take into account population and geographic considerations and should be developed in accordance with federal, state, and local bioterrorism plans.

Health care workers at designated hospitals

Smallpox vaccination is recommended for selected personnel in facilities pre-designated to serve as referral centers to provide care for the initial cases of smallpox. These facilities would be pre-designated by the appropriate bioterrorism and public health authorities, and personnel within these facilities would be designated by the hospital. As outlined in the CDC Interim Smallpox Response Plan and Guidelines, state bioterrorism response plans should designate initial smallpox isolation and care facilities (e.g., type C facilities). In turn, these facilities should pre-designate individuals who would care for the initial smallpox cases. To staff augmented medical response capabilities, additional personnel should be identified and trained to care for smallpox patients.

Source: Centers for Disease Control and Prevention; Advisory Committee on Immunization Practices, Atlanta.