 I want to cover a couple of terms that are very important with epidemiology, the study of disease. And that is incidence versus prevalence. So incidence is the number of people who actually develop a disease during a particular time period. So I like to say that incidence is how many people get a disease during a given time period. Prevalence is the number of people that actually have it, right? So it's the people that already had it prior to this time period and still have it, and the people that acquire it at that time period. So the way I look at it is real simply, incidence, how many people got a disease during whatever time period we're talking about. So you could be talking about cancer in 2019, you could be talking about the flu in January of 2014, it doesn't matter. So whatever the time period is, the incidence is how many people got the disease, the prevalence is how many people have it. So think about like HIV for example, usually you see numbers right in the ballpark of 40,000 Americans, it's slightly less than that, but 40,000 Americans get HIV every year. So that means the incidence of HIV infection in 2019 will be somewhere in the ballpark of 40,000. But think about the prevalence, how many people have HIV in the United States in the year 2019. That's everyone that's got the disease in 2018, 2017, 2016 and back. So think about like, I believe it was 1996 when Magic Johnson was infected and he's still alive. So the prevalence is the new cases plus the old cases. So the prevalence will always be a larger number. All right, so that is incidence versus prevalence. How many people get a disease versus how many people have it? Hope this helps. Have a wonderful day. Be blessed.