I had the jab last year at about 32 weeks, went full term and baby seems fine (so far!).
Google informed me that whooping cough can only be confirmed / verified if they do a test within a week-ish of contracting it while the bacteria which cause it are still detectable, so I suspect there may be a lot more of it around than has been 'confirmed'.
Anecdotal - My hubby got a really nasty cough when I was a few weeks pregnant, he gasped for breath at the start of each coughing fit?then I got the exact same cough 10 days later, which was strange as a smoker of um about 20 years normally I get phlegmy bronchial coughs but this was totally different (was trying to stop for pregnancy at the time)..I sent him to doctors after about 2 weeks and they said it was a virus so I didn't bother going?I sent him back a few weeks later they said it was a really nasty virus?then a few weeks later I sent him again, and they gave him tablets for acid reflux.
I went to doctors separately about my cough, pointed out hubby had it too, and was also independently given tablets for acid reflux - so two people in the same house who have never had digestive issues suddenly have a cough for many weeks and both have 'acid reflux'? In fairness, the tablets were awesome for heartburn later in pregnancy but still.
In Europe whooping cough is called the 100 day cough. We both shook our cough's about 4 months after first getting them. Oh and I think we gave it to a house guest too (as didn't know we were infectious). My guess is we had whooping cough, but remained un diagnosed, so be cautious at simply asking the docs for how many cases in an area.