In column C ..... I would like to ask the question....if A2=1 and B2 which
is formatted as "general" has a year date in its string which is 2003 the
answer = "vaccine given" but if the year date is <2003 then the answer
="vaccine due". Also I should add if A2 is 0 then the answer =na.

I'm not sure how to proceed and any help would be appreciated.

A B C
1 HIST-Pnuemo-10/01/2007 vaccine given
0 HIST-Pnuemo-07/24/2009 na
1 HIST-Pnuemo-01/01/2003 vaccine due