Issues of riskWhat is the government's plan to address an outbreak?The CDC Also known as the Centers for Disease Control and Prevention - A United States government agency that seeks to promote health and quality of life by preventing and controlling disease, injury, and disability. is planning to use the ring vaccination concept, if there is a smallpox outbreak. Smallpox was eliminated globally using a ring vaccination strategy. As an outbreak of smallpox was detected, public health representatives vaccinated the surrounding population. However, studies indicate a ring vaccination strategy may not effectively contain a smallpox outbreak from a bioterrorist attack.
The ring concept involves vaccinating and monitoring a “ring” of people around each case of smallpox and their contacts to help protect those at the greatest risk for contracting the disease as well as forming a buffer of immune individuals to prevent the spread of disease outside the ring. Ring vaccination includes quarantining A restraint on the activities of persons or the transport of goods that is designed to prevent the spread of disease. all confirmed and suspected smallpox cases and the tracing, vaccination, and close surveillance of contacts to these cases as well as vaccination of the household contacts of the contacts. Depending upon: 1. The option for outbreak control that is selected, 2. The size of the outbreak, 3. Personnel resources, 4. Effectiveness of other outbreak control measures, and 5. Vaccine availability, the size of the vaccinated “ring” of individuals surrounding a case or contact may be modified (expanded or contracted).
A terrorist attack with a biological weapon, such as smallpox, would most likely include the release of the biological agent in a large public area (e.g. office building, movie theater, sporting facility). Smallpox has a long incubation period The period of time between the infection of an individual by a disease-causing agent and the manifestation of the disease it causes. of 10 to 17 days from the time of infection. People with smallpox can spread the disease to others after they have developed a rash and fever. The long incubation period makes it very likely that some of the infected people will travel and infect others with smallpox before the disease is recognized and quarantine can be implemented. The result will be an "initial" outbreak of smallpox that includes both primary and secondary infections and affects many more people than were infected in the terrorist attack.
It has been reported that, even with a sufficient supply of smallpox vaccine, a quarantine enforced by police would probably not be effective in controlling an outbreak of smallpox. These studies doubt the speed at which an outbreak could be accurately identified, and note that the increase in worldwide travel would carry the disease too quickly for containment by ring vaccination. Should an outbreak of smallpox occur, however, we would know with certainty that it did not occur naturally. Therefore, there is little reason to believe that the outbreak will act in a familiar manner. A bioterrorist attack using smallpox might be staggered across time and locations. Any attempt to control an outbreak using ring vaccination could be quickly subverted by a strategic release of additional smallpox virus.
In the case of a terrorist attack, which may involve a large multi-site outbreak, a mass vaccination plan may be implemented as opposed to ring vaccinations. Learn More |