I know the recommendation is to have the whooping cough vaccine before 38 weeks but I assume that if you are breastfeeding the baby will still get antibodies in your breast milk?
By the way any first time mums that are thinking about breastfeeding, please don't watch that Cherry Healy 'documentary'. It's incredibly biased against breastfeeding and it will put you right off. I breastfed my first two and it's almost putting me off. According to Cherry, breastfeeding is painful, tedious, you'll get infections, cracked and bleeding nipples. Oh and expressing is almost impossible. It's just complete bollocks. Apparently breasts are purely decorative sex objects and not designed to feed your baby at all. They try to pare down the argument to the whole 'breast is best' thing and completely gloss over the fact that breastfeeding can be a lovely, relaxing bonding experience with your baby. I can't wait to feel that again, the feedback that goes through your body and makes you feel utterly in harmony with your baby. Or taking baby into bed with you and snoozing away with them while they feed until they pop off your boob with a sigh of utter contentment.
I know some ladies on here have already decided to formula feed and I think that's fine and a decision that is up to each mummy. I just want to emphasise to those mummies that are still undecided/are going to give it a go/plan to breastfeed, please don't be put off by these stupid things you hear about pain, cracked nipples, etc. It won't necessarily happen to you and if you do have problems then there are usually ways to resolve them and get back to the natural, pleasant experience it is supposed to be.