The occurrence of encephalitis after smallpox vaccination has attracted the anxious interest of physicians and public health authorities. Since Lucksch1 in 1924 reported three cases of postvaccinial encephalitis there has been a growing literature on this subject, especially from England, Holland and Germany. The condition is characterized clinically by a definite incubation period of from ten to twelve days, hyperacute onset, headache, vomiting, fever, paralysis, and death in from 35 to 50 per cent of the cases. Anatomically there is a diffuse encephalomyelitis. When recovery occurs it is usually complete, though there have been reports of mental deterioration and residual paralysis. There is, of course, no established relationship of any kind between this condition and various types of epidemic encephalitis.
Infection of the nervous system after vaccination is no new fact. It has occurred in times past but has been overlooked (as many cases of so-called tetanus) or its
THE NATURE OF POSTVACCINIAL ENCEPHALITIS. JAMA. 1933;101(19):1485–1486. doi:10.1001/jama.1933.02740440045016