Illnesses caused by lifestyle factors were prevented by the government passing a law to make sure ro reduce air and water pollution and improving food safety to reduce outbreaks of salmonella and E Coli poisoning.
Illnesses caused by genetic factors were prevented if docters knew the exact gene for the medical condition so they can test or screen patients as part of prevention medicine.
Infectious diseases were prevented by vaccines. Meningitus can be prevented by cervical smears.
