6 Common Back-To-School Illnesses In Children
August 6, 2025
It’s almost that time of year again. Time to stock up on school supplies, pick out some new outfits and plan packed lunches. That’s right, the start of a new school year is upon us.
With the flurry of activity that surrounds a return to school, there’s also a rather unwelcome factor that can crop up: back-to-school illnesses. The crowded classroom environment is indeed an ideal place for germs to spread.
If you feel like your child gets sick almost immediately after going back to school, it’s not just you. Previous studies suggest that infection risk is higher in the weeks after school restarts.
How They Spread: The Basics
There are three general ways that common back-to-school illnesses can spread between people:
Respiratory droplets
Respiratory droplets are made when a sick person coughs or sneezes. These droplets can contain germs such as viruses or bacteria, that can be inhaled by another person, leading to spread of an illness.
Direct contact
Having direct contact with a person who’s sick, such as by shaking hands or kissing and then touching the mouth, nose or eyes afterward can also lead to the spread of illness.
Indirect contact
Sometimes germs can be found on items and surfaces like doorknobs, countertops and toys. Touching a contaminated item and then touching the mouth, nose or eyes can spread an illness.
The Likely Culprits
If your child does come down with a bug after school restarts, it’s likely due to one of the following six illnesses.
1. The Common Cold
If your child has been feeling under the weather, a cold may be the likely culprit. On average, children get six to eight colds each year. In the United States, cold season typically starts in September (right around when school starts) and continues into spring.
Colds can be caused by over 200 different viruses. When it comes down to numbers, rhinoviruses lead the way, causing more than half of all colds.
The common cold causes symptoms like:
● Runny or stuffy nose
● Sneezing
● Coughing
● Sore throat
● Headache
● Body aches and pains
● Low-grade fever
The common cold is spread via respiratory droplets, direct contact and indirect contact.
2. The Flu
The flu is also a common viral infection in children that have recently returned to school. It’s estimated that up to 10% of children in the United States aged 0-17 come down with the flu each year.
Potential flu symptoms in children include:
● Fever
● Cough
● Runny or stuffy nose
● Headache
● Sore throat
● Body aches and pains
● Vomiting or diarrhea
● Fatigue
The flu can be spread by respiratory droplets, direct contact and indirect contact.
The seasonal flu is caused by influenza A and influenza B viruses. Flu season encompasses the fall and winter, with the number of cases peaking between December and February.
Changes in temperature and humidity are one part of this equation. As fall kicks in and moves into winter, temperature and humidity start to drop. If you’ve ever noticed that your skin becomes dry and cracked in cold weather, you’ve felt the effects of this transition firsthand.
As I learned from my graduate mentor, who researched this very topic, cold and dry weather are ideal for the spread of flu viruses in temperate climates like the United States. That’s because flu viruses are quite stable in these conditions.
Further, more recent research has suggested that dry air may reduce our body’s natural defenses against the flu, increasing the risk of becoming sick. Couple these factors with more people moving indoors as the school year kicks in and the weather cools and you’ve got a recipe for flu season!
3. COVID-19
In 2025 we’re all probably rather familiar with COVID-19, the illness caused by the SARS-CoV-2 coronavirus.
Unlike the common cold and the flu, COVID-19 doesn’t follow as much of a seasonal pattern. While cases do increase in the winter, they can also spike at other times of the year, typically when a new variant emerges.
According to the CDC, the most common COVID-19 symptoms in kids are fever and cough. They also note that many children experience additional symptoms, such as:
● Sore throat
● Runny or stuffy nose
● Headache
● Fatigue
● Shortness of breath
● Digestive symptoms like nausea, vomiting or diarrhea
COVID-19 may be spread through respiratory droplets, direct contact and indirect contact. At-home COVID-19 tests can diagnose whether a person is positive or negative for COVID-19.
4. Strep Throat
Strep throat is a bacterial infection caused by Group A Streptococcus. While anyone can get strep throat, it’s most common in children between the ages of 5 to 15.
That means that strep throat is something you may encounter if you have a school-aged child. Researchers estimate that globally there are 288.6 million cases of strep throat in children aged 5 to 14 each year.
Symptoms of strep throat are:
● Sore throat
● Enlarged tonsils that may have white or yellow spots on them
● Red spots on the roof of the mouth
● Painful swallowing
● Fever
Strep throat can be spread by respiratory droplets, direct contact and indirect contact.
5. Stomach Bugs
We’ve all heard about “stomach bugs” or “the stomach flu”. The medical term for these illnesses is gastroenteritis. In the United States, researchers estimate that gastroenteritis in children accounts for 1.5 million visits to the pediatrician each year.
Most cases of gastroenteritis in children, a whopping 75 to 90%, are caused by viruses. Norovirus is the most common cause of viral gastroenteritis.
Norovirus is highly contagious, making it ideal for spreading in schools. In fact, some research has suggested that as little as 18 individual virus particles can cause an infection!
Symptoms of viral gastroenteritis in your child can include:
● Nausea
● Vomiting
● Diarrhea
● Abdominal cramping
● Fever
The viruses that cause gastroenteritis can be found in a person’s stool and vomit and can be spread by both direct and indirect contact, especially when proper hand washing or sanitation procedures aren’t followed.
6. Pink Eye
Pink eye, also called conjunctivitis, causes inflammation of the tissue that covers the eye. It’s most often caused by viruses. Bacteria and allergies can also cause pink eye.
According to the American Academy of Ophthalmology, children are most likely to develop pink eye due to viruses and bacteria since they have high contact with others in school and day care settings.
Pink eye can impact one or both eyes and lead to symptoms like:
● Red eyes
● Itchy, watery eyes
● Burning or painful eyes
● Eye discharge that may be clear, white or yellow
● A sensation that something is stuck in the eye
● Blurry vision
Viral and bacterial pink eye are most often spread through direct or indirect contact with fluid from the eyes of a person with pink eye.
Reducing the Risk
While it’s not possible to prevent every back-to-school illness, there are a handful of simple steps that you can take to reduce the risk of your child coming down with a bug. These include:
● Keeping children up-to-date on vaccines for things like the flu and COVID-19
● Teaching children how to properly wash their hands
● Encouraging children to wash their hands after using the bathroom, before eating, and after blowing their nose, coughing or sneezing
If your child does get sick with symptoms like fever, runny nose or vomiting, an at-home test for COVID-19 and the flu can help narrow down a potential cause.
However, don’t hesitate to reach out to a pediatrician as well. Your child’s pediatrician can give you guidance on how to manage your child’s symptoms, as well as prescribe medications to treat their illness if necessary.
Additional References
Neumann G, et al. (2022). Seasonality of influenza and other respiratory viruses.
