What are the pros and cons of vaccinations?

Risk/benefit: The basic risk of immunization is negligible. Vaccine haters have come up with a new scare issue every decade or so only to be refuted by scientific data, most of which they never accept. The benefit is the avoidance of illness, injury or death.Ben franklin was once a vaccine hater, but in his later writings changed, sad over the preventable loss of a son to smallpox.