Question with scenario attached - Another team of investigators reviewed medical records to determine which military personnel among several basic

Question with scenario attached - Another team of investigators reviewed medical records to determine which military personnel among several basic training units had received a previous type of meningitis vaccine during training two decades ago. Two study groups were formed, those who had not received the vaccine and those who had. These were followed forward by record review throughout the duration of their active military service, and if they had a record of care through the VA system, these records were searched as well. The outcome of interest was the occurrence of any of a number of autoimmune diseases that were thought to have a possible association with the vaccine. In this study, of a vaccine group of 60, 4 individuals were found to have been diagnosed with lupus at some subsequent point in time. In the non-vaccine group of 90, only 2 individuals had that diagnosis. 

Would the dependent variable be an autoimmune disease or would it be the lupus in particular?

Also, when calculating the relative risk I came up with 3.0000 would that also mean that the group that received the vaccine has a 30% greater chance for developing autoimmune(lupus)? If not how would I calculate the % of greater chance? Thank you very much!