Harriet: Wash your hands often, and...
Narrator & Harriet: [in unison] Cover your mouth and nose when you cough and sneeze.
Many works and installments of works have some sort of moral. This is the trope for when the moral is about preventing disease (both lessons on preventing getting sick and preventing getting others sick qualify, and the two often overlap) and is very common in children's entertainment. Usually it's about diseases in general, but sometimes, they focus on one particular disease.
The lesson may teach about one, two, several, or all of these things: hand-washing (often with an instruction on singing Happy Birthday to You! twice (or singing the alphabet song) or washing for twenty seconds and instructions on when to wash hands, sometimes giving reasonable advice and sometimes giving advice that borders on Neat Freak tendencies), vaccinations, checkups (these two might have an added message of "Don't be Afraid of Needles or Afraid of Doctors"), covering one's mouth and/or nose while coughing and/or sneezing (which is less important if you're not sick, but often the viewers and characters are taught to do it anyway, because it's become an etiquette thing; they might also teach people to cough/sneeze specifically into their elbows), not eating off the ground, not sharing drinks, staying home when sick, and cleaning items that might have germs on. They might also give outdated advice like "Don't go outside in the cold/rain without proper clothes/with wet hair/at all". It might also talk about nutrition, bathing, keeping fit, dental hygiene, and/or getting enough sleep, but a message about any of these is not a Disease Prevention Aesop unless disease prevention is explicitly mentioned.
In a way, this could be an attempt to defy the Sick Episode trope, although these tropes can overlap: it might start with a sick character and another character will come and one (or occasionally a combination) of three things will generally happen:
1.) The arriving character will give the sick character Tough Love and say, "You could have avoided this." while explaining how.
2.) The arriving character will teach the sick character how to prevent their friends from getting sick.
3.) The arriving character will teach the character's healthy friends how to avoid getting sick.
Often, these messages tend to be rather blatant, with characters telling the audience what to do and/or very specific superheroes that seem to only exist to deliver these messages. It might also try and make these instructions seem cool, often by saying things like "even Superman washes his hands".
It may also have an explanation of what germs are, but the only real information these Aesops tend to give about germs is that they're too small to see, they can get inside us and make us sick, they are on dirty things and not on clean things, they are common, and occasionally that there are types called bacteria and viruses and that "some germs are good". It might portray germs as sentient, grotesque, and deliberately wanting to make humans ill, sometimes to Take Over the World or just because. The immune system might be explained, but generally not further than it needs to be kept strong, it gets rid of germs, and (if we're lucky) that it involves things called white blood cells. It may sometimes be depicted as soldiers.
This trope may overlap with Very Special Episode especially if the episode focuses on a particular, serious disease or the TV show/book series the installment belongs to does not normally teach Aesops. It can also overlap with Sneeze of Doom if the lesson (or one of the lessons) is covering the nose/mouth when sneezing: leaving a sneeze uncovered might cause highly unlikely and chaotic consequences as both a comedy device and a scare tactic.
- This is a persuasive ad about swine flu shots.
- Cells at Work!, despite being about anthropomorphic human cells, mainly averts this, but one chapter plays it straight, with an invading bacterium playing the villain taunts Neutrophil U-1146 on how to avoid heatstroke (not exactly a disease, but close enough) even though the host body already has heatstroke.
- In 2020, the official YouTube channel for Happy Heroes started to upload a series of shorts where the Supermen demonstrate what to do to keep healthy amid the COVID-19 Pandemic. The shorts with Chinese audio can be found here and the ones with English audio can be found here (don't worry, all the shorts have bilingual Chinese/English subtitles).
- The Killer That Stalked New York, a 1950 film Very Loosely Based on the 1947 New York City smallpox outbreak, lays out in no uncertain terms how terrible an out-of-control outbreak of smallpox in New York City would be and the importance of vaccinating the population in order to be able to contain it. In the film, Health Commissioner Ellis paints a dire picture of what an uncontained smallpox outbreak would be like:
"We're a threatened city. There's no limit to it, every case spreading out on its own until the very air is polluted and breath means death!"
- Felicity Floo Visits The Zoo has a message about blowing one's nose if they have a cold/the flu... and shows Felicity's illness spreading to zoo animals.
- In Germs, Germs, Germs, the germs are narrating and giving bad advice like "forget to wash your hands". Probably because the readers are expected not to obey germs.
- In the Little Princess book "I Don't Want to Wash My Hands", the Princess doesn't want to wash her hands, but changes her mind when she learns about "germs and nasties".
- Played with in Melanie's Marvelous Measles: It seems to have a rather questionable message of "catching measles is good and don't bother to get vaccinated" but also involves drinking melon juice to stay healthy.
- The book Sick Simon has a moral about staying home from school when ill.
- Sneezy Louise seems to have an Aesop about covering one's mouth while sneezing, because nearly every time Louise sneezes, people say, "Geeze, Louise! Cover your mouth, please!" Although the concern seems to be less about germs than the fact that Louise's uncovered sneezes cause funny accidents, like papers or peas flying everywhere.
- Blow Your Nose, Big Bad Wolf is a retelling of The Three Little Pigs in which the Big Bad Wolf has a cold. He keeps asking the pigs for a tissue, but they keep running away from him and he blows down the straw and stick houses with his sneezes. Finally, when they capture him in their cook-pot, he sneezes a big watery sneeze all over them. All three of them have a cold on the last page of the book and it's said that if only they had just given him a tissue, they wouldn't have caught it.
- Talk shows will sometimes have guests on who dispense health information for the host(s) and audience, especially if they have doctor friends. Then there are shows which are built around this, like The Doctor Oz Show and The Doctors.
- Barney & Friends has a song "Keep Your Sneeze to Yourself" about covering your mouth when you sneeze. There was also a song about washing your hands in a few episodes.
- Get Well Soon is all about medical stuff. While a lot of episodes talk about getting rid of diseases, a few talk about preventing getting/spreading them (such as wearing a sock so as not to spread warts and washing your hands after using the bathroom).
- The Go Show:
- One "George" segment is about hand-washing.
- One skit with the preschoolers Fizz, Jay, and Billie has Fizz drink from Jay's bottle and his friends explain that sharing bottles can spread germs.
- The first episode of Hip Hop Harry sees the titular bear and his friends have a little chat about germs, then launch into a song about hand-washing. In the future, the child cast is reminded to wash their hands before handling food,
- Sesame Street:
- This video is about preventing flu, as is this one.
- This skit is about sneezing into your elbow.
- One animated skit is called "Don't Be a Snerd When You Sneeze" and is about covering the mouth and nose when sneezing and coughing.
- While originally intended to supplement Bangladeshi, Indian, and Nigerian co-productions of the show, PSA segments featuring a muppet named Raya encourage habits like hand-washing and have since been featured more widely on Sesame Street social media.
- https://youtu.be/Edh7MYgOx4k instructs viewers to wear clothing that covers up their entire bodies when playing outside in order to avoid being bitten by mosquitoes, and presumably, risking becoming infected with the Zika Virus. There are other videos like it, too.
- The Wiggles: In one episode, Dorothy is taught to cover her mouth when she sneezes.
- Yo Gabba Gabba! has an episode where Muno has a cold and high-fives Toodie, so an anthropomorphic bar of soap named Super Soapy Pal teaches them both to wash their hands. In another episode, Brobee tries to eat bread off the ground but is taught not to because it has "tiny, ugly germs" on it.
- The Scrubs episode "My Cabbage" is a rare adult version, with the moral being that hospitals have hygiene rules for a reason, and if you don't follow them, people die.
- "Achoo, I've Got a Cold" is an outdated example: it teaches people to avoid catching colds by not going outside in the evening with wet hair and to put jackets on and not go out in rain without an umbrella.
- "Cover Your Mouth and Turn Your Head" is a children's song that teaches kids to obey the title when coughing and sneezing.
- "Germ Attack" is a song which partly parodies the Batman theme and is about coughing and sneezing into one's elbow.
- "Germ Smart" is a song about washing hands.
- "Here Comes a Sneeze" is about "catching" coughs and sneezes in tissues or one's elbow.
- Seans Music Factory has a song called "Sick Song". While mostly about how to have fun despite being sick, the final verse is about washing your hands every single time so that "no germs [will] go to the next [person]."
- In Yokoka's Quest, after Yokoka comes down with a fever, Yfa suggests that she should have dried herself off better after jumping into a river.
- Henry the Hand is a website that talks about hand-washing and the "don't touch your face" rule.
- Sneeze Safe is an Australasian site about preventing the spread of illnesses that spread through sneezing.
- NSF International's Scrub Club is a website that features seven "soaperhero" children who all represent steps of the handwashing process and join forces to fight germs in order to teach kids to wash their hands and stop the spread of illnesses.
- An entire episode of Arthur is about dealing with and preventing head lice. Of course, Muffy and her mother take a need to clean Muffy's room as an excuse to redecorate...
- Berenstain Bears: "Go to the Doctor" taught the importance of checkups to stay healthy, although Papa got sick by random bad luck and his family claimed that he could have avoided it by having checkups.
- Crawford's Corner:
- In "Crawford is a Sneezer Pleaser", Crawford gets a cold and he and his friend Harriet give advice on how not to spread colds.
- In "Crawford Washes His Hands", Crawford talks about how you should wash your hands after digging in the garden.
- How to Catch a Cold was a Disney video about how to avoid catching/spreading colds. It had to be redone, though, as the original version included misinformation.
- In the Lou and Lou: Safety Patrol special short "Don't Get the Flu," Lou and Louise teach their older sister Lulu to use a tissue when sneezing. Then they all wash their hands together.
- Ozzy & Drix: Nearly every episode has advice on staying healthy, as the series follows a white blood cell and some medicine fighting illnesses for an adolescent boy named Hector.
- Play Kids has a song about covering the mouth when sneezing and coughing.
- Robot Chicken has an early-season sketch where Optimus Prime gets prostate cancer; the sketch ends with him suggesting that the viewer can also develop it, and Jazz flat-out tells the viewer to get checked out. Later on, a quick gag has Torch telling his doctor about a symptom, prompting Optimus to barge in and state "What did I just tell you?''"
- Sid the Science Kid: In "Getting a Shot, You Can Do It", the kids learn the importance of vaccines and washing hands.
- Il était une fois... la Vie (Once Upon a Time... Life), being entirely about the working of the human body, frequently provides such lessons, for example about the importance of physical exercise or vaccination. Meanwhile, the Cast of Personifications fight those diseases inside the body.
- In the wake of the coronavirus pandemic, a Llama Llama clip was produced with Jennifer Garner as the voice of Mama Llama telling little llamas to not touch their faces and to remember to wash their hands. It comes complete with a modified snippet of the show's theme tune with lyrics encouraging handwashing.
- The Teen Titans Go! episode "Hand Zombie" has the other Titans teach Robin the importance of washing his hands when he refuses to do so.
- Many school systems have web pages and handbook sections titled "When to Keep Your Children Home" or something of the sort, and the list of guidelines usually includes making sure they don't have a fever or diarrhea for at least 24 hours before bringing them (back) to school.