Formula for calculating vaccine profitability.

A mathematical formula is developed for calculating the profitability of real or stimulated vaccination campaigns, in relation to the years elapsed since the vaccination date and within the period of immunity given by the vaccine. According to the formula, profitability depends on the annual attack rates and corresponding costs, vaccine price and efficacy, and number of postvaccination years considered. The factors that do not affect profitability are values of local currency, annual discount rates and the absolute number of vaccines, provided the relative proportion of subjects vaccinated is maintained constant among the distinct risk groups, when comparing different policies. Examples of vaccinations against hepatitis B and measles are presented.