Prevalence refers to the total number of cases of a disease or condition in a population at a given time. It includes both new and pre-existing cases. Prevalence is often expressed as a proportion or percentage. There are two main types of prevalence:
Point Prevalence: This is the proportion of a population that has the condition at a specific point in time. It is calculated as:
Point Prevalence = (Number of existing cases at a specific point in time) / (Total population at the same point in time)
Period Prevalence: This is the proportion of a population that has the condition at any time during a specified period. It is calculated as:
Period Prevalence = (Number of existing cases during a time period) / (Total population during the same time period)
