Letters Section Editor: Robert M. Golub,
MD, Senior Editor.
To the Editor: The last case of smallpox occurred
in 1977, and the world was declared free of the disease in 1980.1 In
the United States, recommendations for smallpox vaccination were withdrawn
in 1971 for the general public, 1976 for health care workers, 1982 for international
travelers, and 1990 for military personnel.2 Due
to an increased threat of biowarfare and bioterrorism, immunization against
smallpox has now resumed for certain health care workers and military personnel.
First-time vaccinees are considered protected after a “major reaction”
(papule, pustule, scab, scar) at the immunization site.2 In
a nonimmune person who is not immunosuppressed, the expected response to primary
vaccination is the development of a papule at the site of vaccination 2 to
5 days after percutaneous administration of vaccinia vaccine. The papule becomes
vesicular, then pustular, and reaches its maximum size in 8 to 10 days. The
pustule dries and forms a scab, which separates within 14 to 21 days after
vaccination, leaving a scar.2 Fewer than 5%
of primary vaccinees fail to develop such reactions.3,4 In
a recent report on the US military experience, among 623 244 primary
inoculations, minimal reactions were seen in approximately 4%.5 Revaccinees
often have less pronounced responses.
Kelso JM, Kuhn KM, Newman FK, Kennedy JS, Frey SE. Immune Status in a Primary Smallpox Vaccinee Who Failed to Develop an Immunization Site Reaction. JAMA. 2005;293(6):673-678. doi:10.1001/jama.293.6.677