The following is true about prevalence and incidence:
Incidence rate is defined as 'the number of NEW cases occurring in a defined population during a specific period of time.' Disease prevalence refers specifically to all current cases(old and new) existing at a given point in time or over a period of time in a given population. Although referred to as a rate, prevalence rate is really a ratio. Ref: 25th edition, Park's Textbook of Preventive and Social Medicine, Page no. 68, 69
Both are rates
Prevalence is a rate but incidence is not
Incidence is a rate but prevalence is not
Both are not rates
Epidemiology