Received 4th forward of a show, where host states vaccines that prevent disease are *medicine* not vaccines because they do not prevent infection. Let us get this straight, vaccines primarily prevent DISEASE. They stop you getting badly sick or sick when you encounter the bug.1/6

3 preventive outcomes to look for
1. Disease/illness, many but not all vaccines completely prevent illness when infected, but those that do not completely prevent will modify to make us less sick, converting life-threatening to manageable. 2/6

2. Infection, not the same as illness. You must be infected to be ill, but it is possible to be infected and not be sick. If vaccines prevent infection, that is a bonus. E.g. inactivated polio vaccines prevent polio but not infection with polioviruses. 3/6

3. Transmission, the ability to spread infection. Obviously vaccines that prevent infection prevent transmission as well, but vaccines that prevent disease MAY also decrease transmission if less viruses are shed by people who are not sick. 4/6

Vaccines are useful for individuals (preventing disease) and populations (preventing transmission). Important to remember that no vaccine and no drug is 100% effective, and that is mostly because of our individual variation in response. 5/6

Vaccines are intended to prevent disease and are given to healthy people for that purpose. If something/someone/TV host does not make sense, please dig deeper or ask credible people. 6/6