There is some statistical data to suggest it's about 75% uptake or was when I last saw itIt's wholly unscientific and anecdotal, but I was amazed how many of my wife's team refuse to have the vaccine because they don't believe in it. I wouldn't suggest that alone accounts for the entirety of those who don't have it, but given the profession they're in, it is perhaps a lot more than the general public might think.