Vaccines for grandparents question

Alyssa

So my mom and stepdad will be around baby alot when she's born for about the month or so. I have been telling them to get their tdap and flu shot for like the past 2 months, but they have completely put it off. Now im 4 weeks until my due date and my doctor even thinks baby may come a little early, and this concerns me because ive read everywhere that they need to get the shots at least 2 weeks before having contact with her. My question is, how important is this 2 week rule? Not looking for opinions, just maybe things your doctors may have told you? Im going to ask mine at my next appointment, but this is kind of stressing me out and my appointment isnt for another 6 days.