At four UK hospitals, patients with severe asthma were screenedfor fungal sensitization by skin prick testing. those 3,610 whowere positive by skin prick were randomized to one of two treatmentregimens: 1,805 were assigned to take an antifungal agent in tabletform while 1,805 were assigned to take a similar looking placebotablet. The primary end point was the development of a particulartype of lung infection by 32 weeks. By the end of the study, 1,492of those who had taken the antifungal agent had not developed thelung infection, whereas 1,064 of those who had taken the placebohad not developed the lung infection. There was no loss tofollow-up and no censoring except for administrative censoring.
a) What is the study design?
b) Generate a contingency table:
| Lung Infection (+) | Lung Infection (-) | Total |
| Antifungal group | 313 | | |
| Placebo group | 741 | | |
| Total | 1054 | | |
c) Calculate the 32-week cumulative incidence for thoseexposed and unexposed to the antifungal agent, respectively. (CI=#new cases of disease during a given time period/total populationat risk)
d) Calculate and interpret the risk ratio betweenexposed group and unexposed group. (RR= CI exposed/ CIunexposed)
