ARE NEUROLOGICAL DISTURBANCES TO BE EXPECTED AFTER VACCINATION AGAINST TICK-BORNE ENCEPHALITIS

In Austria at present more than 5 million people are vaccinated against tick-borne encephalitis (TEE), some of whom have received up to 8 vaccinations. Since introduction of the mass vaccination programme an estimated 18 million TEE vaccinations have been given in this country. Hence, the chance 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 TEE 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 TEE 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 TEE vaccinations. Virological investigations show that virologically unclarified (and, hence, vaccine-induced) neurological disturbances do not occur more frequently in TEE vaccines than in unvaccinated persons. A part from its established high effectivity TEE vaccine also displays excellent tolerance.