What is an Adenovirus, and how can they be harmful? Infectious disease experts weigh in

• Adenoviruses are a family of viruses that cause cold and flu symptoms.
• Although typically mild, Adenoviruses can be serious for immunocompromised folks.

Along with influenza, RSV, and COVID-19, another virus is making headlines. The University of Michigan recently announced a campus outbreak of adenovirus, a family of more than 100 viruses that typically cause upper respiratory symptoms.

In otherwise healthy individuals, "it could be as mild as the common cold or as severe as influenza," says Dr. Richard Martinello, infectious diseases doctor and professor of medicine at Yale School of Medicine.

But for immunocompromised individuals, Martinello says adenovirus could be more severe or spread to other parts of the body, causing pneumonia or infections in other organs.

Below, infectious disease experts explain how you're most likely to get adenovirus, how to tell it's not some other infection, and the necessary steps to take to treat it.

What is an adenovirus?

Adenoviruses are a family of viruses that most typically cause upper respiratory symptoms like sore throat, runny nose, and fever, says Dr. Laraine Washer, a hospital epidemiologist at University of Michigan Health.

However, it can also infect other parts of the body without triggering any respiratory symptoms. For example, if an adenovirus infects your eye that's a common cause of conjunctivitis, aka pink eye, says Dr. Gregory DeMuri, a pediatric infectious disease physician with UWHealth.

Adenoviruses can also infect the digestive tract, resulting in vomiting and diarrhea, or other parts of the body, such as the lungs, kidneys, liver, and pancreas.

How is adenovirus transmitted?

Adenoviruses are more common in children, but DeMuri says anyone can be infected. Like many other viruses, adenoviruses spread through respiratory droplets and physical contact.

So, you can get sick when an infected person sneezes or coughs near you, DeMuri says, or by touching a surface with droplets on it then touching your nose, mouth, or eyes before washing your hands.

Symptoms of an adenovirus infection

Most of the time, symptoms of an adenovirus infection are mild. DeMuri says adenoviruses account for about 5% of common cold cases, but infections can range in severity.

Typically, symptoms last a week or two, DeMuri says. But in vulnerable populations — like people who have undergone organ transplants or have heart or lung disease — adenovirus infections can last longer, with more severe symptoms.

According to the Centers for Disease Control and Prevention, adenoviruses commonly cause cold- or flu-like illness. But ultimately, the symptoms they trigger depend on what part of the body is infected.

The most common symptoms for an adenovirus infection include:

• Runny nose
• Congestion
• Sore throat, similar to strep
• Dry cough
• Fever up to 103 °F
• Nausea, diarrhea, vomiting
• Red, burning eyes with pus-like discharge

How to treat an Adenovirus

According to Martinello, there's no FDA-approved treatment for adenovirus because it's a viral infection. Antibiotics, for example, treat bacterial infections, so they won't help with adenovirus symptoms.

Medical providers may give antiviral medications through an IV to hospitalized people who are at risk of developing complications from adenovirus infections.

However, "for those with normal immune systems, adenovirus infections can be irritating, but they get better on their own," says Martinello.

Home treatment can help you feel better until the infection goes away. Martinello recommends the following:

• Drinking plenty of water to stay hydrated
• Taking over-the-counter pain relievers, such as ibuprofen (Motrin) and acetaminophen (Tylenol) for fever or sore throat
• Taking nasal decongestants or cough suppressants

But if you're having trouble breathing or catching your breath, or you have any fever that doesn't resolve after three days, DeMuri suggests seeing your medical provider.

If you're sick, frequent hand-washing, wearing a mask, and physical distancing can prevent spreading your infection to others.

"We recommend keeping to yourself until you're fever-free for at least 24 hours and your other symptoms have been improving for at least a day's time," Martinello says.

Insider's takeaway

Adenoviruses are a common cause of cold- and flu-like symptoms, but they can also cause pink eye and gastrointestinal infections.

While immunocompromised individuals might have longer-lasting, severe illness, "most people with adenovirus infection have mild symptoms that can be managed with supportive care at home," says Washer.