RESUMEN
A controlled experiment was carried out to study the epidemiological effectiveness of live mumps vaccine from the L-3 strain, the importance of urgent prophylaxis by vaccination in mumps foci and to evaluate the economic effectiveness of mass prophylaxis of mumps by vaccination. The observations involved 113,967 children of 1 to 12 years. Vaccinations were given to 51,701 subjects and 62,256 subjects were the control group. The groups were formed by random selection. One vaccination dose contained 10(4)HAdU50 of mumps virus. The results attest to high epidemilogical effectiveness of the mumps vaccine. The incidence of mumps among the vaccinees was 29.7-fold lower than among unvaccinated, and the coefficient of protection was 96.6%. The urgent vaccination vaccination prophylaxis carried out in children's institutions during the period of introduction of mumps arrested the outbreak within one month, nad the duration of quarantine was reduced 2-3-fold. As a result of the vaccination the economic effect of 290,000 roubles was achieved.