[Effect, hazards and risks of the new vaccination against tick-borne encephalitis (TBE) as calculated by special formulas (author's transl)].

The effect and risks of the vaccination against TBE virus was calculated by means of formulas for Q and D. Q considers the relation between total risk of unvaccinated and vaccinated persons and D the yearly difference in risks between unvaccinated and vaccinated members of a community. In recommendable vaccinations Q should exceed 1,0 and D should be greater than 0. Vaccination against TBE was performed by 2 injections at an interval of 4 weeks followed by a 3rd injection after 9 months. No major side effects were observed in vaccinations of about 50,000 persons. After one injection only, the conversion rate was 76% and Q 4,17, after 2 injections the conversion rate was 96% and Q 25 and after the total course of 3 injections the conversion rate was 98% and Q was calculated to be 50. With respect to morbidity DM was 7,18 X 10(-5) and regarding mortality DL was 1,1 X 10(-6). That means that proper vaccination of persons at risk in Austria could prevent 500-600 cases of encephalitis and approximately 8 deaths due to TBE per year. It was concluded that the new vaccination is effective and recommendable. Revaccinations will be necessary probably at intervals of 2-3 years, the exact time period still being under study.