Adenovirus

What are adenoviruses?

Adenovirus is a common virus that can cause a range of cold- or flu-like infections. Researchers have identified about 50 types of adenoviruses that can infect humans. Adenovirus infections occur throughout the year, but they tend to peak in the winter and early spring. Infections range from mild to severe, but serious illness doesn’t happen often.

Who do adenoviruses affect?

Adenoviruses can affect people of all ages. But they’re most common in children younger than 5 years old. The spread of adenoviruses in babies and young children occurs often in daycares. Babies and children in this setting come into close contact with one another. They’re also more likely to put objects in their mouths and less likely to wash their hands frequently.

The spread of adenoviruses in adults can occur in crowded environments. If you spend time in a dormitory or military quarters, you may be at a higher risk of contracting the virus. The virus also commonly spreads in hospitals and nursing homes.

If you have a weakened immune system, you’re more likely to get seriously ill from an adenovirus infection. This includes people who’ve had stem cell transplants or organ transplants. It also includes people who have cancer or HIV/AIDS. If you have cardiac or respiratory disease, your chances of severe infection increase as well.

What are the symptoms of an adenovirus infection?

The symptoms of adenovirus infections you experience depend on which part of your body the virus infects. The virus most commonly infects your respiratory system. An adenovirus infection in your respiratory tract can cause symptoms similar to the common cold or flu. Symptoms or conditions you may experience include:

• Cough.
• Fever.
• Runny nose.
• Sore throat (pharyngitis).
• Pink eye (conjunctivitis).
• Ear infection (otitis media).
• Swollen lymph nodes.
• Chest cold (bronchitis).
• Pneumonia.

Adenoviruses can also affect your gastrointestinal tract. An infection in your gastrointestinal tract may cause diarrhea. You may also experience gastroenteritis. Gastroenteritis is inflammation of your stomach or intestines. It can cause stomach pain, diarrhea, nausea and vomiting.

More rarely, adenoviruses can affect your bladder or nervous system. Viruses in your bladder can cause urinary tract infections. Viruses in your nervous system can cause conditions that can affect your brain. These conditions include encephalitis and meningitis.

How long can adenovirus symptoms last?

Most adenovirus symptoms last from a few days to up to two weeks. Severe infections may last longer. You may have symptoms that continue to linger for a while, such as a cough.

What causes adenovirus infections?

There are approximately 50 types of adenoviruses that cause infections in humans. The different types infect different parts of your body. The virus can spread easily. Young children and people with compromised immune systems are especially vulnerable to infection.

Are adenoviruses contagious?

Adenoviruses are very contagious. They can easily spread through:

• Close contact: The virus can spread from person to person through shaking hands, kissing or hugging.
• The air: The virus can spread through sneezing and coughing. Respiratory droplets released in sneezes and coughs can transfer to other people through the air.
• Surfaces and objects: After touching a contaminated surface, you can get the virus by touching your eyes, nose or mouth before washing your hands.
• Poop (stool): The virus can spread through the stool of an infected person. For example, you can be infected while changing your baby’s diaper.
• Water: The virus can spread through unchlorinated water. For instance, if a person infected with an adenovirus swims in a swimming pool without adequate chlorine, they can spread the virus. This type of spread isn’t common though.

Adenoviruses are resistant to many common disinfectants. Therefore, they can remain infectious on surfaces for a long time.

In addition, these types of viruses can release from your body (shed) for days or even weeks after you’ve recovered from an infection. So the virus can continue to spread even if you no longer have symptoms.

How is adenovirus diagnosed?

If you have a mild infection, you probably don’t need to go to your healthcare provider. If you have severe symptoms, see your healthcare provider. They may order laboratory tests to confirm an adenovirus diagnosis. They may swab your nose or throat to collect a sample of your mucus. If your community is experiencing an outbreak, they may order lab tests as well. But lab tests for adenoviruses aren’t routine.

How are adenoviruses treated?

There aren’t any specific treatments for adenovirus infections. Most infections are mild and require only symptom relief. You can relieve most symptoms with over-the-counter fever reducers and pain relievers. In addition, make sure to drink plenty of water and get plenty of rest.

Antiviral medications aren’t useful for treatment in people with healthy immune systems. Antibiotics won’t work on an adenovirus.

If you have severe symptoms and/or a weakened immune system, make sure to see your healthcare provider. You may need treatment in the hospital to help you recover from a serious infection. In rare cases, you may need treatment with an antiviral medication such as cidofovir or ribavirin.

How can I reduce my risk of catching an adenovirus?

You can reduce your risk of getting sick with an adenovirus infection by protecting yourself and your family. Ways to prevent infections include:

• Wash your hands with soap and water often. Wash for at least 20 seconds.
• Avoid touching your mouth, nose or eyes if you haven’t washed your hands.
• Try to stay away from people who are sick.
• Clean and disinfect your child’s toys often.
• Clean counters, sinks and other hard surfaces with a bleach and water mixture.

If you’re already sick with adenovirus infection, take steps to prevent the spread. You can protect others by:

• Staying home if you’re sick.
• Sneezing and coughing into your elbow or a tissue. Don’t cough or sneeze into your hand.
• Not sharing utensils, cups, towels and pillows with others.
• Keeping your distance from other people. Avoid hugging and kissing.
• Washing your hands frequently.

Is there an adenovirus vaccine?

No adenovirus vaccine is currently available to the general public. The military uses a vaccine for certain types of the virus. Only military personnel who are at a higher risk of infection receive the vaccine. The FDA hasn’t approved the vaccine for use outside the military.

The adenovirus vaccine contains a live virus that can be shed in stool. That means it can be released from your body. If transmitted, the virus can cause illness in other people. Researchers haven't studied the safety and effectiveness of the vaccine in the general population yet. They also haven't tested it on people with weakened immune systems.

What is the outlook (prognosis) of an adenovirus infection?

If you’re otherwise healthy, an adenovirus infection has a good prognosis. With rest and other supportive measures, the virus will pass and you’ll be on your way back to good health.

But in people who are immunocompromised, mortality rates can be as high as 70%. Therefore, see your healthcare provider as soon as you develop symptoms.

When should I call my healthcare provider?

Most adenovirus infections will pass quickly on their own. But if you or your child develop any of the following symptoms, it’s important to call your healthcare provider:

• Fever higher than 104°F (40°C) or a fever lasting longer than five days.
• Difficulty breathing.
• Dehydration.
• Decreased alertness or activity.
• Fussiness or poor sleep.

What’s the difference between adenovirus and a coronavirus?

Adenoviruses and coronaviruses cause infections that share many common symptoms, so it can be hard to tell the two apart. Both can be transmitted through respiratory droplets or direct contact. Both can cause severe respiratory tract infections. But adenoviruses can linger longer than coronaviruses because they’re more resistant to disinfectants.

Coronaviruses have an extra layer (envelope) that covers their protein shell (capsid). The envelope is a membrane made up of lipids and proteins that protect the virus when it’s outside of its host cell. The images you’ve seen of the coronavirus have spike proteins coming out of their envelopes.

Adenoviruses don’t have an extra envelope covering their capsid. The absence of an envelope actually makes them more resistant to disinfectants.

You’d think having an extra layer would help protect a virus. But it’s a little more complicated than that. Coronaviruses (and other enveloped viruses) have proteins that bind to their envelopes. When the envelopes break down, they lose the proteins that made them infectious. This makes them less resistant to disinfectants. Adenoviruses (and other non-enveloped viruses) bind their proteins directly to their capsids. The capsids stay intact and are more resistant to disinfectants.

What are adenovirus vectors?

Researchers use adenoviruses as viral vectors. That means they take an altered, harmless version of adenovirus and use it to make a vaccine. The altered version is called a vector. It delivers information to your cells to help protect you.

Viral vector vaccines don’t give you any viruses, and they don’t affect your DNA. These types of vaccines have been thoroughly tested for safety and effectiveness.

A note from Cleveland Clinic

If you have a cough, sniffles or a sore throat, there’s a chance you picked up an infection from an adenovirus. Adenoviruses are usually mild and go away on their own without medical treatment. But you should call your healthcare provider if you have a compromised immune system. You should definitely call if your symptoms are severe or last longer than two weeks. If you’re otherwise healthy, drink plenty of water and take a rest. You’ll be back on your feet in no time.