Serious complications occur in about 1 of 10, 000 patients after their first (primary) vaccination and include Postvaccinial encephalitis Progressive vaccinia Eczema vaccinatum Generalized vaccinia Myocarditis and / or pericarditis Vaccinia virus keratitis Noninfectious rashes Postvaccinial encephalitis occurs in about 1 of 300, 000 recipients of primary vaccination, typically 8 to 15 days postvaccination.