1.   Aware of the toll that mass vaccination would bring, the CDC has focused on coping with an outbreak through ring vaccination.

2.   Critics, though, say that public panic over an outbreak of smallpox would make ring vaccination implausible.

3.   If an outbreak occurs, the CDC says it will respond with the technique known as ring vaccination, which was used to eradicate the disease.

4.   Or save the vaccine for an attack and use ring vaccination and assume it would contain the epidemic.

5.   This tactic, ring vaccination, was used by the CDC and the World Health Organization to eradicate the disease.