If it seems like your child is always getting sick, you’re not alone. Children are highly susceptible to contagious diseases as a result of their developing immune systems and their close proximity to other children all day during school hours.

Many of these illnesses may be caused by viruses. So, what is a virus and how do they affect children?

What Is a Virus?

Viruses are a type of microorganism that can spread from person to person, causing illness. Some viruses can even spread to humans from mosquitoes. Unlike bacteria, parasites, and fungi, which can also cause infections,viruses are smaller and consist of only a core of genetic material, such as RNA, mRNA, or DNA, plus a protective protein coat.

A virus particle requires a host cell to survive and make copies of itself. After viruses attach to the healthy cells of a person, animal, or plant, they can use the host cells as factories for creating more viruses, leading to a viral infection. Viruses that infect plants are known as plant viruses, and an infected plant, like tobacco plants infected with the tobacco mosaic virus, can transfer the virus to insects.

While many people associate bacteria with common illnesses and infections, many of the most common illnesses in both adults and children are caused by different types of viruses.

Common viral infections may include:

• The common cold
• Influenza, or the flu
• Coronavirus or SARS-COV-2
• Chickenpox
• Bronchiolitis
• Tonsillitis
• Acute otitis media (ear infection)
• Hepatitis C or hepatitis B
• Herpes
• Yellow fever

Respiratory viruses like influenza primarily spread from person to person through the air. When an infected individual sneezes, coughs, or speaks, the virus is released into the air through tiny droplets of water vapor that can then be inhaled by a nearby individual.

Once the virus has entered the nose, mouth, or eyes, the warm temperatures in the body begin to break down the protective coating that surrounds the genetic material that makes up the virus. Then, the virus begins to replicate, causing an infection and a wide range of symptoms.

How Do Viruses Affect Children?

Viruses spread particularly easily among children for several reasons.

First, children gather together more closely than adults in various settings each day, such as school or daycare.

Second, children generally struggle with basic hygiene, such as washing their hands regularly, covering their mouth when they cough, or blowing their nose into a clean tissue.

As a result, it is common for children to come down with various viral illnesses throughout the year.

Common signs and symptoms of viral illnesses include:

• Nasal congestion or runny nose
• Sore throat
• Rashes that turn white when pressed
• Vomiting
• Diarrhea
• Loss of appetite
• Red, watery eyes
• Fever
• Coughing
• Sneezing
• Fatigue or feelings of extreme tiredness

What Are the Most Common Viruses In Children?

No matter how hard you try to prevent it, your child is likely to get sick a few times every year. Many of the most common illnesses in children are caused by viruses, and although children are most commonly affected, these illnesses can pass to other members of the household. These eight viral infections are the most common among children.

Common Cold

It is estimated that children under the age of six catch approximately six to eight colds per year, with colds more common among children who attend daycare. The number of colds experienced by children decreases with age, with teenagers experiencing about four colds per year.

The common cold can be caused by many different viruses, but the most common culprit is the rhinovirus family of viruses.

Symptoms of the common cold vary from person to person but often include:

• Tickle in the throat
• Runny or stuffy nose
• Cough
• Low-grade fever
• Loss of appetite
• Headache
• Tiredness
• Sore throat
• Cold sores

While most colds need three to five days to run their course, there are several steps you can take to make your child more comfortable while they are sick. Saline nasal sprays can be used to help reduce congestion and prevent the nasal passages from becoming dry and painful, and cool-mist humidifiers can also help reduce congestion.

Make sure your child gets plenty of rest while sick. The “common cold” is extremely common, and there is no vaccine available to prevent them.

Roseola

Roseola is a common disease that is most often caused by a virus known as human herpesvirus 6; however, other enteroviruses passed through saliva can also cause the condition.

Roseola is most commonly associated with a high fever that gives way to a rash. The virus often incubates for an extended period of anywhere from 5 to 15 days before symptoms appear.

Symptoms commonly associated with roseola include:

• Fever, often over 103 degrees Fahrenheit
• Rash
• Mild diarrhea
• Loss of appetite
• Irritability
• Swollen eyelids

Roseola is commonly associated with a high fever, which can be very dangerous in young children.

Extremely high fevers can cause seizures, which require immediate medical attention. Seek medical attention if your child’s fever exceeds 103 degrees Fahrenheit.

Hand-Foot-and-Mouth Disease

Hand-foot-and-mouth disease is a highly contagious disease that is often contracted during summer and fall, particularly in young children. Commonly caused by a virus called the coxsackievirus, hand-foot-and-mouth disease is usually associated with painful sores inside the mouth and a rash that may appear on the hands and feet.

Symptoms include:

• Mouth sores
• Sore throat
• Skin rash
• Fever
• Loss of appetite

Hand-foot-and-mouth disease usually presents in a mild form and is rarely fatal. However, your child may be very uncomfortable while sick. Make sure they stay hydrated and consider offering acetaminophen for pain and fever if appropriate.

Respiratory Syncytial Virus (RSV)

Respiratory syncytial virus, or RSV, is one of the most common childhood illnesses. The Center for Disease Control and Prevention (CDC) estimates that nearly every child will experience RSV at least once before the age of two, and the condition accounts for more than 2 million outpatient visits for children under the age of five in an average year.

RSV is the most common cause of pneumonia and bronchiolitis in infants and can be serious, causing nearly 60,000 hospitalizations in the United States each year.

RSV commonly affects the airways, causing symptoms that may include:

• Runny nose
• Coughing
• Sneezing
• Decrease in appetite
• Fever
• Wheezing

Most children outgrow the risk of a severe episode of RSV by the age of five. If your child comes down with RSV, keep them comfortable and hydrated, offering lots of clear fluids like water and electrolyte drinks made for kids.

Over-the-counter medications like acetaminophen can be used to reduce a fever and help with aches and pains associated with the illness.

Gastroenteritis

Many people are surprised to find that gastroenteritis, or inflammation of the stomach and intestines, is commonly caused by a virus, and may be contracted from contaminated food.

Often referred to as the stomach flu, gastroenteritis is responsible for approximately 1.5 million outpatient visits and 300,000 hospitalizations in children under the age of five in the United States each year, and it can be fatal.

The biggest concern with gastroenteritis is dehydration, as constant vomiting and diarrhea can make it difficult for children to retain fluids. Although the condition may also be caused by bacterial infection, certain medications, parasitic infections, or exposure to chemicals, the most common cause of gastroenteritis is a norovirus.

Symptoms include:

• Vomiting
• Diarrhea
• Fever
• Poor appetite
• Abdominal cramps

If your child develops the stomach flu, it’s critical that you help them stay hydrated in order to prevent dehydration. Encourage your child to take small sips of clear liquids frequently rather than attempting to drink large amounts at once, as the latter can contribute to vomiting.

If your child is unable to keep down fluids, seek medical attention from your pediatrician. When caused by a virus, gastroenteritis needs time to run its course and cannot be treated with antibiotics.

Fifth Disease

One of the less well-known diseases in children is fifth disease, sometimes referred to as erythema infectiosum. Commonly caused by a virus called parvovirus B19, fifth disease tends to incubate for a period of about 15 days before causing symptoms.

One of the earliest signs of fifth disease is a reddish appearance on the cheeks caused by a rash. After several days, an additional rash may start to appear on the extremities, back, or buttocks.

Symptoms associated with fifth disease include:

• Rash, which may be itchy or painful
• Fever
• Painful or swollen joints
• Runny nose
• Headache

Fifth disease typically starts to improve after a period of approximately one week. Acetaminophen and other over-the-counter medications can be helpful in reducing symptoms of pain and swelling in the joints.

Influenza (Flu)

Influenza, also known as the flu, commonly affects children and can be particularly dangerous in children under the age of two. This highly contagious disease is caused by the influenza virus, which varies in strain from year to year.

The flu is one of the most common causes of pneumonia in younger children and can also contribute to infections of the ears and sinuses.

Symptoms commonly associated with the flu include:

• Fever
• Body aches
• Cough
• Vomiting
• Headache
• Sore throat
• Runny or stuffy nose
• Diarrhea
• Fatigue

The best way to prevent your child from getting sick from the flu is to take children over six months of age for their annual flu vaccine.

Summary

Viruses are contagious diseases that can cause a wide range of uncomfortable symptoms in children, including fever, cough, runny nose, rash, sore throat, vomiting, and diarrhea.

Children are considered at increased risk of contracting viruses because they are both surrounded by other children in close quarters every single day, and may also struggle with basic hygiene, such as regular hand washing, covering their mouths when coughing, or blowing their nose into a tissue.

The most common viruses in children include the common cold, influenza, roseola, gastroenteritis, fifth disease, hand-foot-and-mouth disease, and RSV.