[After vaccination for tick-borne encephalitis must onset of neurologic disorders be expected?]

In Austria at present more than 5 million people are vaccinated against tick-borne encephalitis (TBE), some of whom have received up to 8 vaccinations. Since introduction of the mass vaccination programme an estimated 18 million TBE vaccinations have been given in this country. Hence, the change coincidental occurrence of various illnesses which might be interpreted as possible vaccination complications is inevitable. However, the appearance of true vaccination complications in addition to chance concurrent disease cannot be ruled out a priori. In any given case it is very difficult, indeed virtually impossible, to differentiate between these two possibilities since there is no available test for confirmation or exclusion of vaccine complications. Mainly disturbances of the nervous system have been ascribed to preceding TBE vaccination. From the incidence of such diseases we calculated how often their occurrence should inevitably be expected during a two-month observation period after vaccination; only significantly higher figures can be accepted as representing vaccination complications. Very large controlled field studies would be required to provide unequivocal results. This enormous expense is barely justifiable and the required money could be better spent on other projects in the public health system. All studies to date and theoretical considerations show that the potential risk of TBE vaccination is extremely low. Experts of the Paul Ehrlich Institute (Germany) came to the conclusion that one certain case of neuritis arises after 1 million TBE vaccinations. Virological investigations show that virologically unclarified (and, hence, vaccine-induced) neurological disturbances do not occur more frequently in TBE vaccines than in unvaccinated persons.(ABSTRACT TRUNCATED AT 250 WORDS)