Worked for an international company had to take vaccines for travel all the time to Africa and the dungeons of South America, Asia, etc. The last VAX I took was the one for yellow fever. It is given to you 3 weeks prior to travel, one of the most painful injections I've ever taken. I was sick for three weeks before the travel, hence why they say to take it three weeks prior. I thought my left arm was going to fall off. It swelled, was red and painful to touch. Thankfully, I left the company before the other VAXs were due for renewal. Never took any flu vax. And when Covid vax came out, I knew it was a scam. I would cry with my young nieces and nephews during their childhood vaxes. Never knew why they needed so many shots.