These Are the Most Common Germs Found in Classrooms

Don't touch that keyboard!

There is perhaps no place teeming with more germs than a school. The hallways are filled with children sneezing and then giving each other a hug or handshake—and if even just one student is sick, bacteria can easily bounce around from one kid to the next. Even worse, with contaminated chairs, desks, doorknobs, and more, kids are practically sitting in germ-filled bubbles and don't even realize it. But what in particular should you be on the lookout for when sending your kids off to school this year? From Staphylococcus to influenza, these are the most common classroom germs causing kids to miss school.

Staphylococcus aureus

pink eye with kid rubbing eyes, classroom germs

Conjunctivitis—better known as pinkeye—is one of the most common school-borne illnesses. It's often caused by Staphylococcus aureus, bacteria present on 12.5 percent of classroom floors and 8 percent of classroom desks, according to a 2018 study published in the journal PLOS One.

Most kids usually go through at least one bout of pinkeye in their early development years—and when they do have the inflammatory illness, they are extremely contagious. "Your child is contagious with bacterial or viral conjunctivitis until the redness and discharge are gone," writes Hannah Chow-Johnson, a pediatrician with Loyola University Health System. "Don't send your child to school until the redness is gone."


hand foot mouth disease, classroom germs

Hand, foot, and mouth disease—mostly often caused by a coxsackievirus—is commonly seen in younger children, and that's why it's often spread in school hallways.

And while some strands of the sickness are easy enough to overcome, Summit Medical Group's David Abrutyn warns about the other types of coxsackievirus that are harder to fight off. "There are some other types of the virus that, in very rare cases, can harm the central nervous system," he writes. So, if you think that your child might be sick with hand, foot, and mouth disease, keep them at home until you're 100 percent certain they aren't contagious; any contact with infected saliva, nasal mucus, blister fluid, or feces can put other children in harm's way.

Streptococcus pneumoniae

kid with meningitis, classroom germs

A 2010 study from the University of Arizona tested six elementary school classrooms for germs, and found that some of the most prevalent bacteria on desk surfaces, computer keyboards, and computer mouses was Streptococcus pneumoniae. And, according to the Centers for Disease Control and Prevention (CDC), Streptococcus pneumoniae is known to lead to meningitis, which is most commonly seen in "in the very young and the very old." There are about 17 cases per 100,000 children under five years old every year.

Both viral and bacterial meningitis are easily spread through close contact—and while vaccinations have significantly lowered the rate of meningitis cases in the United States since the late '90s, it's still something to be very wary of. The CDC reports that 10 to 15 people out of every 100 infected with meningitis will die, while 1 in 5 survivors will face long-term disabilities.

Streptococcus pyogenes

child with strep throat, classroom germs

Like other bacteria, Streptococcus pyogenes—which causes strep throat—runs rampant in schools because of how easily it passes from one person to the next. It's so common, in fact, that the CDC notes that there are several million cases of non-invasive strep throat each year in the United States alone, and up to 13,000 invasive cases. Even worse, one 2012 Nepalese study tested 468 school-aged children and found that 10.9 percent were carriers of S. pyogenes, despite the fact that they were asymptomatic.

Staphylococcus epidermidis

Little White Boy at the Nurse's Office Classroom Germs

Staphylococcus epidermidis is a bacterium that, though typically found on healthy skin, can cause serious infections and even staph infections in people with compromised immune systems or cuts. So what does this have to do with classrooms? One 2014 study published in the journal Microbiome tested samples from classroom chairs and found strains of this bacterium present. Yikes!

Rubeola virus

kid with measles, classroom germs

Measles is a childhood infection that, unfortunately for schools, is highly contagious. The CDC reports that the virus that causes it, rubeola virus, can live for up to two hours in the air when an infected person has coughed or sneezed—and once one child has it, up to 90 percent of people close to that infected child will also come down with it.

Even worse, a 2016 study published in the journal Proceedings of the National Academy of Sciences estimated the rate at which rubeola virus might spread in a current-day school setting. The researchers determined that even just one child getting rubeola virus could cause a school-wide outbreak.


kid with stomach pain, classroom germs

According to certified indoor environmentalist Tony Abate, one of the worst classroom germs is norovirus, which causes the stomach flu. In fact, the aforementioned University of Arizona study found that of all the surfaces they tested, up to 22 percent were contaminated with norovirus.

Abate also notes that air quality plays a factor in the spread of this virus. "Many school buildings and classrooms can suffer from poor indoor air quality due to a lack of proper ventilation, air cleaning, and space sanitization," he says. "This can allow for concentrations of bacteria, virus, germs, and molds in spaces where kids reside, which can spread illness and make kids sick."

Influenza A virus

child getting sick with the flu, classroom germs

The same University of Arizona study found that up to 50 percent of school surfaces they tested contained influenza A virus, so the likelihood of your child getting this illness at school is high. As you know, influenza can be transmitted simply via the cough or sneeze of an infected host and it can keep kids out of school for days or weeks at a time. In fact, a 2016 Marshfield Clinic study found that during the 2012-2013 and 2014-2015 influenza seasons, the flu accounted for 47 percent of school days missed for acute respiratory illness.

And while the flu may be common, it's certainly nothing to dismiss. During the 2017-2018 influenza season, the CDC reported that 186 children died from the flu. To put that in perspective, the only season that produced more deaths in the last 20 years was the 2009 swine flu epidemic.

Epstein-Barr virus

A Group of College Students Ways College is Different

Mononucleosis, better known as mono, is caused by Epstein-Barr virus. And given that mono is often referred to as "the kissing disease," it's no surprise that Epstein-Barr is one of the most common college classroom germs. One pivotal 1972 study published in the American Journal of Epidemiology analyzed the rates of mononucleosis in college students and found that the rate of infection was three times higher in this age group compared to the general population. And if you want to stay healthy this school year, here are 30 Smart Ways to Avoid Getting Sick When You Travel.

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