turd immunity 

Often confused with "herd immunity" by people who don't want to get a vaccine even though they are able to get one. They believe that because most people around them get vaccines, they won't get it. Herd immunity works when the population that is able to receive vaccines gets them to protect people who are unable to get them(like infants), but it does not work if members of the population that is able to receive vaccines refuses them and tries to join the same class as babies and those with allergies.

Man 1: "Aren't you going to get the polio vaccine?"
Man 2: "Nah, I'll be protected by herd immunity"
-Later-
Man 2: *crippled by polio*
Man 1: Turd immunity doesn't protect against shit.

turd immunity by MissLadyGrim December 16, 2015

Turd Immunity 

(noun) the phenomena where one's mind accepts shitty and unsubstantiated theories, "fact", and/or views from a crazy uncle, solely because it somehow supports one's often privileged, sociopathic, or depraved viewpoints. Often one will use vocabulary that they do not understand. Also often occurs in fields where one is an expert because the read some "stuff" on the Internet.

Johnny said the COVID-19 shelter in place is stupid because Sweden has no restrictions and relies on herd immunity and this showing the rest of the world is stupid.

Johnny has turd immunity, because there is not reason to think the percentage of Swedish people that have COVID-19 antibodies is more than 10% and herd immunity usually requires 80-90% of people to have antibodies but believing this would allow Johnny to go outside and do what ever he wants w/o distancing and a mask (my body my choice) as tons of people are still getting sick and dying.

Turd Immunity by CaliWiseGuy April 20, 2020