Smallpox immunization in the United States.

The current international campaign to eradicate smallpox proposes to eliminate the threat of this dread disease to the health of man. In this massive worldwide effort, undertaken with the professional and technical aid of the World Health Organization, primary emphasis is placed on the eradication of the disease from endemic foci. Until the time that smallpox is no longer a medical problem of significance, questions will naturally continue to be raised about the proper role to be taken by physicians in the United States, where there have been no cases of variola major since 1949. The freedom from variola major enjoyed by the United States is widely but erroneously believed to be evidence of a high level of immunity. Actually, the United States is no better protected than Sweden, Poland, Great Britain, or the rest of Western Europe, where in 1963 the importation of 4 cases resulted in 141 secondary