Basic training in 1987? Why, you're just a young little whippersnapper, Peter!
Back in the 70s when I started my military career, the military were used as "guinea pigs" for flu shots....we didn't have a choice; it was directed that you report for your flu shot. They used a live vaccine in those days, which CAN give you the flu (killed vaccines that they use nowadays cannot give you the flu). We were vaccinated quite early, in about August if I remember right. A certain percentage of troops got vaccinated for one strain, a certain percentage for another strain, etc. Then any side effects were reported before the civilian populace was offered a flu shot. My flu shot in 1976, I remember it well....within 30 minutes of injection, I started shaking and felt faint and burst into tears....my boss rushed me to the hospital. I spent 12 hours in the hospital being monitored for heart palpitations, high fever, vomiting, and severe tremors. After 12 hours, it suddenly stopped and I was fine. Guess which flu shot was not marketed that year? I was able to dodge my flu shot for the next several years because of that reaction, until they started using killed vaccine. To this day, I hate taking a flu shot.