Aviva It'll only be known if you go out of your way to look for them. Many side effects from drugs or vaccines aren't officially recognized and so doctors and the media will not report on it.
Take accutane, for example. Many people who take accutane develop horrific symptoms that doctors refuse to recognize, because the mechanism isn't understood. As someone who has a friend who took accutane, the symptoms were mind-blowing. He lost 4 inches in height, lost all of his muscles, lost his hair, developed osteoarthritis and osteoporosis, etc. None of these side effects were listed in the official side effect list.
I was his roommate when he took accutane for the first time, so I saw first-hand how the drug destroyed him, and it was through 1 dose. Look up post accutane syndrome. There's also post finasteride syndrome for people who take the hair loss drug finasteride.
We like to think we understand everything about the human body, but we really don't. Just because doctors and scientists don't understand how vaccines or drugs can cause horrific symptoms doesn't mean they don't cause them.