well it comes to managing risk again, not all human's have strong immune systems.
many of us have weak immune systems, and if a vaccine can stop the weak people from spreading disease to other weak people it is a God send.
not all people have access to iodine or even the knowledge of what it can do, or other immune strengthening supplements, but until then the vaccines are the cheap fix.
vaccines aren't perfect, especially when they are made for profits rather than helping others through public funding, but it is the lesser evil until more states legalize Medical marijuana.