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Generalized Vaccinia: Frequency & Susceptible Populations

History unknown, extensive generalized vaccinia lesions

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Generalized Vaccinia (GV) Cases per 1,000,000 Primary Vaccinations(*)

Age (yrs)	1968 National Survey(†)	1968 10-State Survey(§¶)
1-4	17.6	258.7
5-19	11.7	157.2
>20	45.1	242.4
Totals >1 yr	17.5	222.8

The 1968 Ten State Survey rates may be over estimates as generalized vaccinia was often confused with other, non-specific immune mediated rashes, such as erythema multiforme, that can occur following vaccination.

* Numbers rounded to the nearest tenth, total number of vaccinations estimated in both studies. Observations missing age were distributed according to the existing age distribution for GV.

† Case sources include: American Red Cross Vaccinia Immune Globulin (VIG) distribution system, Red Cross VIG consultants, State and Territorial Epidemiologists, Burroughs-Wellcome Thiosemicarbazone distribution list, smallpox vaccine manufacturers complication reporting files, state reports to the Encephalitis Surveillance Unit of the National Communicable Disease Center (NCDC), and specimen submissions for vaccinia testing to the Viral Exanthems Unit of NCDC.

§ Case sources include: Physician reporting via survey in 10 states with active case information follow-up and chart review for post-vaccinial encephalitis and vaccinia necrosum reports.

¶ Rates may be overestimates as generalized vaccinia was often confused with other, non-specific immune-mediated rashes, such as erythema multiforme, that can occur following vaccination.

Susceptible Populations

Since most of these individuals are children, and most were seen and studied at a time when immunologic knowledge was less complete than at present, characteristics that enhance susceptibility are not known for certain. It is likely that many of these children had subtle and minor immunologic abnormalities that permitted some extension of virus spread, but not morbid or lethal disease.