Herd immunity is also called herd effect, community immunity, population immunity, or social immunity. According to the Minnesota Department of Health, this is when most people in a population or group are immune to a disease. Being immune means they cannot get the disease because either they got a vaccine, or they already had the disease and cannot get it again, at least for a while.
When a lot of people cannot get the disease, it helps to protect other people in the population who are not immune and can get the disease. Having herd immunity can stop or slow the spread of disease.
We do not know enough about COVID-19 to be sure herd immunity is possible. This is a new disease, so there has not been enough time to fully study immunity yet.
We do not know how long a person cannot get sick again after they already were sick with COVID-19 (how long they are immune).
We do not know if being infected before will make the next infection better or worse.
We do not know if a person who was sick before, and then has contact with COVID-19 again, will be able to pass the virus to others again.
We cannot let herd immunity happen naturally, at the cost of thousands of Minnesotans getting very sick and possibly dying. Vaccination is a way to reach herd immunity without people getting sick and/or dying. Vaccination lets a person’s body develop protection against a disease without having to actually get sick.
This message brought to you by the Minnesota Department of Health.