MY bitch didn't have the vaccine first time and missed, after 5 premates, possibly wrong timing. 2nd time, she had the vaccine (1st & 2nd) and had a litter of 6 (different dog). This time she didn't have the 1st vaccine as I didn't think she needed it, I then changed my mind and she had the 2nd vaccine 8 days before pups born as I thought even one vaccine would be good, she had 8 puppies.
On another note, I fell out with my Vets of 10 years over the vaccine as I was originally told that she could just have the 2nd vaccine. When I phoned to make the appointment I was then told that it was a complete waste of time and they refused to order it in for me

I told them that a lot of breeders I know were using it and after reading up (Kayc's written piece on here etc) that even would vaccine would be good. The reply was " so you're saying breeders know more than Vets"

On that sour note I said I would get the vaccine done at another practice, they said that would be OK. A few days later I got a letter saying they had closed my account and would not provide any emergency care for my due to whelp bitch