We were told that 6 months after the second dose you get the booster. I had mine in March, so Nov. was good for me. I think the booster was helpful as it basically knocked me out for a few hours, suggesting my immune system reacted to it. I'm glad I got that over with. I still have a bunch of other shots, mostly boosters, that I need, so I guess I get to look forward to getting poked regularly for the next month or so.