On the basis of the dynamic model combining a single vaccination with asymptomatic immunization, control problem consisting in seeking a vaccination regime providing a minimum negative effect at a given positive effect was formulated. The size of the negative effect consists of the cases of excessive and insufficient vaccination, and the size of the positive one the cases of normal vaccination. The opposite dependence of these effects on the time of vaccination beginning is considered, which leads to the optimization issue. An example showing the advantage of this approach compared to the practiced one is given.