https://www.ncbi.nlm.nih.gov/books/NBK216813/
There were 45 million people vaccinated for the swine flu....that never recurred. Guess by the time they got the vaccine, the virus had burned out or mutated. Hmm, go figure.
Ever heard of Guillain-Barre syndrome? Wicked reaction to a vaccine gone bad. But don't worry. It only happened to 1 out of every 100,000 vaccinated.