Inadvertent inoculation can be by autoinoculation or contact inoculation.
Inoculation Cases per 1,000,000 Primary Vaccinations(*)
|Totals >1 yr
||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 inadvertent inoculation.
||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.
As indicated from these data, inadvertent inoculation is one of the most common adverse events following
primary vaccination. It is far less common after revaccination but the threat of transfer to contacts remains.
Although no age group is spared, infants and children are most susceptible to more extensive inoculations
because of their tendency to scratch an itching vaccination site. Older individuals may be able to control such
scratching, despite the itching, but younger individuals most often cannot. Older individuals tend to have fewer
lesions but they are seen more frequently. Older individuals implant virus frequently on the face as a result of
inadvertent contamination of the hands or via fomites. Minute injuries, such as occur in shaving establish the potential
Individuals who are particularly susceptible to inadvertent inoculation,
either by autoinoculation or contact inoculation, include those
||Skin disorders with open lesions
||Inflammatory eye diseases
These individuals are also more susceptible to serious disease
as a consequence.