The safest vaccines have many variables to determine how safe they are in comparison to other vaccines. If you have one key variable in mind that will allow you to measure it against other vaccines in history...
Regardless of the variable, there has never been a vaccine that has been safe for every single person that took a vaccine. It does take many years of a vaccine being used in the population to do a proper comparison to other vaccines in history.
Just as important, manufacturing / distribution of vaccines is one critical variable in the safety of vaccines. For example, I think the
Smallpox vaccine has been the most "tampered" vaccine in history due to actions by Pharmacists, Doctors, and anyone else that didn't like vaccination while having the trust of the people to vaccinate them in a safe manner.
Some of these idiots are caught...many are not.
Anyways, it takes many years after vaccination to determine how safe it is for a proper comparison with other vaccines regardless of the variables you're using to determine how safe the vaccine and how safe the vaccination has been.
Deaths, Hospitalizations, New Diseases (Adverse Events), Statistical abnormal increases in other Diseases (Adverse Events), Number of Recalls, Number of incidences in using expired vaccines, Number of lives saved, Number of unregulated vaccines on the black market, and many other variables.
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