Susan Nasif, an expert on viruses and an artist, helps educate kids about vaccines with comics. In this one, she tells a story about poliovirus, which paralyzed thousands of people before a vaccine was developed. Polio cases nearly disappeared until some people avoided the vaccine. (Illustration by Susan Nasif)

While the sting of a needle in the arm or leg is nobody’s favorite thing, the vaccines within those shots are some of the most important medical inventions in the history of science. But there can be a lot of misunderstanding about what vaccines are and how they work. So this month, we reached out to Susan Nasif, a virology expert and artist who specializes in creating comics that tackle difficult scientific subjects.

“When I was 8 years old, I remember watching a cartoon that explained the immune system to children,” writes Nasif in an email. “I loved it, and I decided then to draw and create my own comics.”

The immune system is the body’s natural defense against viruses, bacteria and other nasty stuff, Nasif says. But viruses are especially good at developing disguises that help them hide from the immune system. Which is why we need vaccines to help our bodies see through the act.

Most vaccines contain a weakened or dead version of the virus they are meant to protect against, though some vaccines carry only the proteins found on the virus’s surface. In either case, once these substances are injected into the body, your immune system grabs them up and learns how to identify them, kind of like a cheat sheet that helps you prepare for a big test.

Then, when the body comes into contact with the real thing — a healthy virus — it knows how to protect against it and can set to work gobbling up the viruses before they can do too much damage.

You may be wondering why you still have to get shots for something such as polio, even though no one you know has gotten it. This is where a term called “herd immunity” comes into the discussion.

“Vaccines act as a firewall that prevents the spread of diseases to others,” Nasif says.

When enough people develop resistances to a disease by getting a vaccine, the chance that a virus can infect someone and then keep spreading drops to near zero. This is how polio went from a disease that was infecting 350,000 people a year in 1988 to one that caused just 33 cases reported worldwide in 2018. Of course, the protection only continues if people continue to give their bodies a cheat code to beat polio — vaccines.

Many people are concerned that a new virus coming from the Wuhan region in China could become a big problem for people around the world. Nasif says that scientists are working hard to create a vaccine for this coronavirus, which causes a disease called covid-19, but that it takes time to produce a vaccine that will be safe to use in people.

For now, she says the best thing you can do to protect yourself against this or any other viruses, bacteria and other things that cause diseases, is to wash your hands frequently and avoid being close to people who are coughing or sneezing.

Nasif also suggests eating a healthy diet and getting plenty of sleep at night — two ways you can give your immune system a helping hand.