How are Vivian and Jason alike in the play Wit?

To add to the excellent answer given above, both
characters are involved in what are typically viewed as compassionate, people-oriented
professions.  Jason is a doctor, but his primary interest is not the patient but the
field of research itself.  He has his "own ideas" as to how to solve the cancer puzzle,
a puzzle that intrigues him so much that he is insensitive to the emotional state of his
patient Vivian.  Vivian, as a professor of the poetry of John Donne, is very similar to
Jason in this regard.  As Susie comments, poetry is seemingly emotional and intuitive,
but not the way Vivian Bearing taught it.  Like Jason, her heart was in the research
aspect of Donne's poetry, in solving the puzzle of the speaker's relationship with God,
rather than in her students or even the emotional aspects of the poems she studied.  She
was a hard nosed professor who refused to have compassion for her students as
individuals.  And in her analysis of Donne's work, it seems that she might have missed
the emotional impact that his eloquent words convey.

Both
Vivian Bearing and Jason Posner are gifted, talented, and highly intelligent
individuals, very capable in their chosen endeavors.   At the play's end, we come to
admire Vivian's toughness and strength. She never indulges in self pity and prides
herself on learning the cancer vocabulary.  She realizes the choices she has made in her
career, and accepts the consequences. We are not as certain of Jason.  He made a huge
mistake in not recognizing the fact that Vivian was No Code and in trying to revive her
"for research."  We don't know how he will fare in the future, and we do not have the
same admiration for him at the play's end.