School Nurse Notes: Keeping Your Classroom Healthy

A biochemist explains how to stop the stomach flu from taking over your class

By Michele Faehnle, RN, BSN

No one likes the stomach flu, but I think teachers hate it the most. A student getting sick in the classroom is never a good experience. Stomach viruses can spread rampantly in classrooms, causing multiple children to be out of school and sometimes even causing schools to close for short periods during an outbreak.

As the school nurse, I have found several misconceptions about stomach viruses; these misconceptions can con­tribute to spreading illness that could be prevented in classrooms. Dr. Annie Pryor, PhD, a Catholic mom of three, teaches third-grade religion classes at her parish near Dayton, Ohio, and is the founder of Dr. Annie, who holds a PhD in biochemistry from The Ohio State University, offers advice to teachers and school administrators about how to keep their students healthy.


The name “stomach flu” is just a nickname. The stomach flu is technically called viral gastro­enteritis. Gastroenteritis is the inflammation of the stomach and intestines that causes vomiting and diarrhea. The stomach flu (viral gastroenteritis) is caused by an assortment of different viruses, including norovirus and rotavirus. It is not related to influenza, which is the real flu. The flu shot protects against certain strains of influenza, but it does NOT protect against any of the viruses that cause the stomach flu.

The primary symptoms of the stomach flu are vomiting and diarrhea. Some people don’t get the diarrhea. Some people only get the diarrhea. Some people suffer with both simultaneously. The stomach flu is also commonly called stomach bug, stomach virus, GI bug, and GI virus. The stomach flu is highly contagious. Influenza can also cause vomit­ing and diarrhea, but it is primar­ily a respiratory illness.


The viruses that cause the stom­ach flu are present in the feces, vomit, and possibly saliva and na­sal secretions of the sick person. The illness is spread when a few of these viruses get into someone else’s mouth. The virus attacks your intestines and turns your cells into copy machines that make millions more viruses. The vomit and diarrhea of the sick person contain millions of viruses. It only takes a few viruses to make someone else sick.

A person will still have viruses in their feces and possibly saliva for a few days after symptoms have stopped. Unless the person is very care­ful, he will spread the illness to others even when he thinks he is all better.

"School nurse notes: keeping your classroom healthy" by Michele Faehnle, RN, BSN (

Image credit: Shutterstock.


Norovirus, the most common cause of the stomach flu, has been called the “perfect pathogen.” It is extremely contagious because it has evolved to maximize its spread. Norovirus has evolved to make people so sick that vomit flies far and wide. The viruses can become temporarily airborne and float all around the room when someone is throwing up. Each microscopic speck of vomit and feces contains thousands of viruses, and it only takes a few viruses to make someone else sick.

The norovirus has evolved to withstand stomach acid. That is why it also withstands most com­mon cleaning products. It is such a sturdy virus that it can live for weeks on household surfaces, allowing more time for other people to catch the virus. It can withstand freezing, but not heating to 180 degrees F. Most people don’t develop long-term immunity to norovirus, so you can always catch it again. It is best to try to avoid it altogether.


Kids can throw up for many rea­sons, and not all of them mean the child is contagious. However, it is best to err on the side of caution and assume an illness is contagious unless you know the child has other problems that cause random vomiting. If a child throws up in class, all the other children should immediately leave the room, stay­ing as far from the vomit as possi­ble. They should be kind as they go, telling the sick child how sorry they are that he is sick. Then they should go to the bathrooms and thoroughly wash their hands.

The teacher should quickly put on disposable gloves that she should keep in her desk, grab a plastic bag or trash can, and walk the sick student down to the nurse’s office. It should not be the job of a student to walk a vomit­ing student to the nurse’s office. That would put the healthy child even more at risk and most likely upset the parents. The sick student should go home and NOT be sent back to class. The janitor should clean up the vomit using one of the few products that kills these viruses, such as a solution of 10% chlorine bleach in water. The tops of all the desks and tables should be dis­infected before the students return to class.


The best thing a teacher can do is have the students wash their hands right before lunch and snack. I’m shocked that the teachers rarely do this at my children’s school. If you don’t let the viruses get into your mouth, you won’t get sick. It has to be a good hand-washing, and if students have to open the bathroom door on the way out with their hands, their hands can be re-contaminated.

Another thing a teacher can do is encourage the parents to keep children with the stomach flu home an extra day. Most schools have policies that a child must not return to class until he has not vomited or had diarrhea for 24 hours. However, many people don’t even follow that rule. I have heard so many stories about a child who comes to class in the morning and throws up and then tells the teacher, “I threw up last night, too.” It would be great if parents would keep kids home longer than 24 hours.

With the stomach flu, a child can often vomit again after the 24-hour mark. Sometimes diarrhea doesn’t even start for 24 hours after the vomiting. I would have the teacher tell parents to please keep a child with a vomiting/diarrhea illness home for a minimum of 24 hours after the last bout of vomit­ing or diarrhea and that the child needs to be eating normally and have normal bowel movements before returning to class. Schools that have norovirus outbreaks ALWAYS have to institute a “stay home for 72 hours after symptoms have stopped” policy, because that is really what it takes to prevent the spread. Most schools are hesitant to institute a 72-hour policy until they have a full-blown outbreak on their hands.


One fun experiment that the class can do is to compare the amount of bacteria on their hands before and after using hand sanitizer. You can buy ready-made agar plates on Amazon. Give each child two agar plates. Have the child rub dirty hands all over one plate. Then use hand sanitizer and rub clean hands all around the other agar plate. Let the plates sit in a relatively warm area for about 48 hours, then look at them. The children should not be allowed to handle the plates once the bacteria have grown. They can just look at the plates. Then the teacher can dispose of the agar plates by putting on disposable gloves and pouring a little bleach or hydrogen peroxide on each plate, putting the plates in a sealed plastic bag, then putting them in the trash.

If the teacher doesn’t want to actually use bacteria, there are fun experiments that you can do with germ-simulating glowing liquid that you put on hands. Try this experiment from the Centers for Disease Control: CDChandwash

Learn more illness-prevention tips at

MICHELE FAEHNLE, RN, BSN is the school nurse at St. Andrew School, Columbus, Ohio, and co-author of Divine Mercy for Moms and The Friendship Project.