Public Health

Public health is what society does to keep people healthy, prevent or reduce the effects of illness or injury, and prolong life. This includes policies, programs, and services.


In most cases, when an individual is susceptible they are more likely to get a disease because of lack of protection or poor resistance to it, or because of other health determinants.


The number of new cases of a disease, injury or other health issue, in a specific population over a given period of time.


Zoonoses (plural) are infectious diseases that have jumped from animals to humans. Rabies is an example of a zoonosis (singular form).


Vaccination is the act of introducing a vaccine into the body either by injection, orally (in the mouth) or sprayed into the nose. The vaccine uses your body’s natural defenses to produce protection against a specific disease. In most cases, vaccination, inoculation (link), and immunization are the same thing.

Social justice

Social justice addresses issues related to fairness in public health: a better distribution of opportunities and resources (such as money) among groups that have historically been at a disadvantage.


Prevalence generally refers to the proportion of a population affected by a disease at a given time, usually expressed as a rate or percentage. Compare with incidence.


A pandemic is when an epidemic spreads across borders, even the entire world. Compare with “epidemic”.


An outbreak is when the number of cases within an area and in a certain time period is higher than what we would normally expect. Compare with “epidemic”.