Here is my incidence and prevalence problem please work it out so I can understand it. I turned it in already but this problem will show up again.

Community X=pop 20,000. In 2012 2.2% pop. had HIV, How many people had HIV? Over next 12 mos. 50 more cases from 2012-2013. Population stayed at 20,000.

1. How many people had HIV in 2012?
2. Calculate the incidence rate, no HIV deaths

Does the epidemiologist need to be concerned about the new 50 cases. Assuming incident rate of 0.5/1,000

Rapid testing has a 99.1% sensitivity and a 90% specificity. Based on pop prevalence of 2.2 in 2012 show me how a 2x2 table showing true/false positives true/false negatives