What to Know About Adenovirus Infections

Medically Reviewed By Lauren Castiello, MS, AGNP-C
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Adenoviruses cause illnesses that mostly affect your respiratory system. These can include the common cold, pneumonia, and acute bronchitis. Medical treatment is not usually necessary except for severe infections. Adenovirus spreads when a person who has the virus coughs or sneezes and you inhale the resulting droplets. You can also get it if you touch a contaminated surface, such as doorknobs or toys, and then touch your eyes, mouth, or nose.

Adenovirus infections typically go away without treatment. Symptoms can be more serious in children and people with weakened immune systems.

Read on to learn more about adenovirus and how you can limit its spread. This article will also explain how researchers use adenovirus for gene therapy and to make vaccines.

What is adenovirus?

Father sitting on floor blowing bubbles with young children reaching up
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Adenovirus is a common virus that causes colds and other respiratory infections. Adenovirus can also infect the bladder and central nervous system, but this is not common.

Adenoviruses can affect both adults and children, but those between the ages of 6 months to 2 years are often more likely than other age groups to get adenovirus. However, most adenovirus infections do not cause symptoms.

You can get this virus any time of the year, and in general, most children get at least one infection by the time they turn 10. 

Types

About half of the 100 known types of adenovirus can infect humans. However, the Centers for Disease Control and Prevention (CDC) lists the types that can lead to outbreaks:

  • Types 3, 4, and 7: These cause acute respiratory illnesses like colds. Types 4 and 7 can also cause viral conjunctivitis.
  • Type 14: It is responsible for causing outbreaks of acute respiratory illnesses in the United States, especially among people in the military.
  • Types 8, 19, 37, 53, and 54: These cause inflammation of the conjunctiva and cornea.
  • Types 40 and 41: These cause gastroenteritis in children. Learn more about viral gastroenteritis.

How does adenovirus affect people?

An adenovirus infection most commonly causes cold and flu-like symptoms, per the CDC

Adenovirus in adults

Adults may experience: 

Fever is possible with adenovirus infection but is not as common in adults as in infants and young children.

Adenovirus in infants

Adenoviruses in children can cause:

Infants and young children may:

  • experience more fussiness and irritability than usual 
  • not nurse or eat as much as usual
  • breathe noisily and more quickly
  • develop a fever
  • have swollen lymph nodes

Symptoms appear 2–14 days after a person contracts the virus. Intestinal tract infection symptoms may be noticeable 3–10 days after exposure.

Adenovirus symptoms and illnesses last 7–14 days. 

How contagious is adenovirus? 

Adenoviruses are highly contagious, mostly during the first few days of symptoms. They can spread through:

  • the air after someone coughs or sneezes
  • touch, such as touching an object with the virus on it
  • close physical contact
  • stool, such as when changing diapers
  • water, less commonly

The virus may remain longer in people with weakened immune systems.  

Adenovirus outbreaks are possible and more likely to occur when people live or work together in crowded or closed places.

How do you diagnose an adenovirus infection?

Doctors do not typically run tests to determine if adenovirus is the underlying cause of symptoms unless:

  • symptoms are severe or persist longer than anticipated for a cold or bronchitis, for example
  • another health concern is present, such as chronic illness
  • a doctor reports a cluster of infections to a local or public health department

Physicians do not have to test for or report adenovirus infections to the health department, explains the CDC. However, adenoviruses can cause infection clusters, or outbreaks. The CDC encourages doctors to report unusual clusters of infections that adenovirus may cause. These include respiratory infections and conjunctivitis.

Adenovirus hepatitis outbreak

In 2021, several children ages 1–6 years old had severe hepatitis and developed liver injury and liver failure. Most of them also tested positive for adenovirus.

The CDC recommends that doctors test children for adenovirus if they have hepatitis and test negative for hepatitis virus. The organization is investigating the relationship between the two illnesses. 

Adenovirus vs. coronavirus

Both adenoviruses and coronaviruses cause respiratory tract infections and spread through direct contact or respiratory droplets. 

However, adenovirus is not known to cause loss of sense of smell, which links with SARS-CoV-2, the coronavirus that causes COVID-19.

The only way to know for sure if symptoms are due to adenovirus versus coronavirus is through testing. Many health clinics test for SARS-CoV-2.

Learn about COVID-19 tests.

How do you treat adenovirus infections?

The CDC explains there are no antiviral medications specific for adenovirus. You may opt for home remedies or take over-the-counter (OTC) medications to relieve symptoms. 

Home care

Most adenovirus symptoms go away on their own without treatment. However, these tips can help aid recovery in both adults and children:

  • resting
  • staying hydrated
  • using sterile saltwater (saline) nasal spray to relieve congestion
  • applying cool compresses for conjunctivitis

Medications

Your doctor may recommend these OTC medications to relieve symptoms:

Prescription medications may include corticosteroids and bronchodilators to help with breathing.  

Hospital care may be necessary for a severe adenovirus infection.

Antibiotics are not helpful for adenovirus infections. Antibiotics work on bacteria, not viruses. If your clinician thinks there could be a bacterial infection, they may run tests and prescribe antibiotics.

What complications are possible?

Adenovirus infections can be severe sometimes. This is more likely in people with weakened immune systems. People with a greater likelihood of an adenovirus complication include those who:

Worldwide, some documented complications include:

How can you prevent adenovirus infections? 

Some home care tips may help limit its spread:

  • Avoid close physical contact with people who do not feel well.
  • Cough and sneeze in a tissue and throw it away.
  • Clean your hands with soap and water for 20 seconds.
  • Refrain from touching your mouth, eyes, and nose with unwashed hands.
  • Use your own cups and eating utensils.

Adenovirus vaccine

An adenovirus vaccine is available for individuals who work in the military in the United States. It provides protection against illnesses that adenovirus types 4 and 7 can cause. The adenovirus vaccine can help prevent outbreaks.

Adenovirus vaccine vectors and gene therapy explained

Scientists have studied adenovirus for a long time. Over the years, they have discovered that they can use it to prevent and treat other diseases.

Adenovirus as a vector vaccine

Experts use adenovirus to make vaccines for other infectious diseases, including COVID-19. 

The Johnson and Johnson and Astra-Zeneca COVID-19 vaccines use the DNA present in adenovirus, explains the Infectious Disease Society of America. Researchers remove some of the genetic material from a virus and replace it with a gene that makes part of SARS-CoV-2. 

The modified adenovirus shell, known as a “vector,” can get inside human cells, but it can’t replicate or cause infection. Still, the cells make the SARS-CoV-2 protein and the immune system creates antibodies against it.

Adenovirus gene therapy

Gene therapy is a technique in which experts combine a gene with adenovirus to treat, prevent, or cure an illness. The vector carries a healthy human gene to replace a missing or damaged one. This technique has had some success with disease treatment. Gene therapy may work for cancer, too. 

Summary

Adenovirus infections are common in adults and children. They usually affect the upper respiratory system or cause conjunctivitis. These viruses tend to cause more serious illnesses in those with weakened immune systems.

There is no specific adenovirus treatment but various OTC medications can help relieve symptoms.

You can get adenovirus any time of the year. You can limit the spread of adenovirus by practicing good handwashing techniques and avoiding close physical contact with people if you or they are feeling unwell. 

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Medical Reviewer: Lauren Castiello, MS, AGNP-C
Last Review Date: 2022 Oct 27
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THIS TOOL DOES NOT PROVIDE MEDICAL ADVICE. It is intended for informational purposes only. It is not a substitute for professional medical advice, diagnosis or treatment. Never ignore professional medical advice in seeking treatment because of something you have read on the site. If you think you may have a medical emergency, immediately call your doctor or dial 911.
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