Discontinuance of Routine Smallpox Vaccination

To the Editor.—  The immunity status of the US population by age and geographic area is well known from previous immunization surveys. However, a study of European importations and control efforts in west Africa have shown that population immunity is not the single most important factor in determining whether an importation spreads widely. Instead, the important factors appear to be the specific population immunity in the hospital admitting the patient, the speed with which smallpox is recognized, and appropriate control procedures. The administration of attenuated smallpox vaccine or killed vaccine prior to smallpox vaccination cannot be recommended at this time. While it is known that attenuated vaccines can reduce fever and local reactions at the time of vaccination, information is not available regarding life-threatening complication rates with attenuated vaccine. Also, there is no information concerning the protective effect of attenuated vaccine alone or followed by calf lymph vaccine against smallpox