You have to use Bayes' Theorem:

pr(D)= the probability that the person has the disease = 0.012

pr(H)= the probability that the person does not have the disease = 0.988

pr(+|D)= the probability that the person will test positive for the disease given that they have it(sensitivity) = 0.86

pr(+|H)= the probability that the test will return positive given that the person does not have the disease (1-specificity)=0.12

Using Bayes' Theorem: