What to Know About Adenovirus

May 30, 2025

University Hospitals Rainbow Babies & Children'sExperts in Children's Health

There are many different viruses that can cause respiratory infections. The most well-known include influenza, RSV, COVID and the common cold. Another lesser known but still very common virus is adenovirus.

Symptoms of adenovirus are generally mild and are very similar to other respiratory viruses, but there are a few key differences, explains University Hospitals pediatric infectious disease specialist Amy Edwards, MD.

What Is Adenovirus?

Adenoviruses are a group of viruses that can cause mild to severe infection throughout your body. Unlike the flu, adenovirus is not considered seasonal and is typically seen year-round in both adults and children. It most commonly affects the upper respiratory system, causing cold-like symptoms such as runny nose, sore throat, cough, body aches and fever. Additionally, adenovirus can cause gastrointestinal issues such as vomiting, nausea and diarrhea.

Another common symptom of adenovirus is conjunctivitis, or pink eye. Adenovirus is the most common cause of pink eye, which causes the eye to become red, irritated and crusty, with watery or thick discharge.

“Most people think they need antibiotic drops when they have pink eye. But since it’s often caused by adenovirus, an antibiotic will be ineffective at treating it,” says Dr. Edwards.

Like most respiratory viruses, adenovirus is very contagious. It spreads through droplets from an infected person’s cough or sneeze. You can catch it through droplets in the air, direct contact with an infected person or contact with contaminated surfaces.

How Is Adenovirus Different From Other Viruses?

Adenovirus usually can’t be distinguished from other common respiratory viruses because symptoms are often the same and it is not routinely tested for. However, there are some features of adenovirus that set it slightly apart.

Pink eye is one of the more identifiable features of adenovirus, along with very high fevers – which are generally associated with bacterial infections more than viral. If you have typical respiratory symptoms along with red, watery or crusty eyes and a high fever, there’s a good chance that you have adenovirus, says Dr. Edwards.

Adenovirus can also last longer than a typical cold. The average length of an adenovirus infection is about seven days, but some people can be symptomatic for two to three weeks. As long as you’re symptomatic, you’re contagious, so it’s important to maintain good hygiene to avoid spreading adenovirus to others.

Risks for Severe Infection and Complications

Adenovirus is generally mild in otherwise healthy people. However, certain groups of people may be more at risk for severe disease or complications from adenovirus. This includes the immune-suppressed (such as transplant recipients), very young children and the elderly, people with asthma and people with heart and lung disease.

A severe adenovirus infection can lead to hospitalization and complications such as pneumonia, myocarditis (inflammation of the heart muscle) and encephalitis (inflammation of the brain).

Treatment Focused on Rest and Self-Care

Because it is caused by a virus and not bacteria, adenovirus can’t be treated with antibiotics. Therefore, treatment usually focuses on managing symptoms and letting the virus run its course, says Dr. Edwards. This includes getting plenty of rest, staying hydrated and using over-the-counter pain relievers as needed. The best way to treat pink eye due to adenovirus is to gently clean the eye twice a day using a washcloth and room temperature water.

“Adenovirus is an inflammatory virus. It can cause a lot of body aches and can be a pretty miserable illness,” says Dr. Edwards. “The best way to treat it is to allow yourself the time you need to rest and recover.”