Adenovirus

*Adenovirus facts written by Melissa Conrad Stöppler, MD

• Adenoviruses are very common viruses that infect humans.
• There are many types of adenoviruses.
• Adenovirus infections occur throughout the year.
• In most cases, adenoviruses do not cause any symptoms or signs, but in some people, they cause a range of illnesses including respiratory infections like the common cold, pinkeye, pneumonia, diarrhea, and inflammation of the bladder, intestines, or nervous system.
• Adenovirus is contagious and spreads by contact with infected people, breathing air that contains droplets produced by coughing or sneezing by an infected person, or touching a surface contaminated with the virus.
• There is no vaccine available for the general public, although a vaccine against two types of adenovirus is available for U.S. military personnel.
• Outbreaks of adenovirus infection can occur in anyone at any time of year.

Adenoviruses usually cause respiratory illnesses or conjunctivitis, and outbreaks can occur throughout the year. There is no specific time of year when adenovirus infections and outbreaks are more common.

Adenoviruses is not a nationally notifiable disease in the United States, meaning clinicians are not required to test for or report cases to health departments or CDC. Therefore, many outbreaks of adenovirus likely go either undetected or unreported.

Reported sporadic cases and outbreaks of adenovirus have included:

• Adenovirus types 3, 4 and 7, which are most commonly associated with acute respiratory disease.
  • Adenovirus type 7 has been associated with more severe outcomes than other adenovirus types, particularly in people with weakened immune systems. In the last 10 years, instances of severe illness and death from adenovirus type 7 infection have been reported in the United States.
• Adenovirus type 14, which since 2007 has been associated with outbreaks of acute respiratory illness among U.S. military recruits and the general public.
• Adenovirus types 8, 19, 37, 53, and 54, which can cause epidemic keratoconjunctivitis
• Enteric adenovirus types 40 and 41, which cause gastroenteritis, usually in children
• Some adenoviruses (e.g., 4 and 7) that spread in bodies of water such as small lakes or swimming pools without adequate chlorine and can cause outbreaks of febrile disease with conjunctivitis

Adenoviruses can cause a wide range of illnesses such as

• common cold or flu-like symptoms
• fever
• sore throat
• acute bronchitis (inflammation of the airways of the lungs, sometimes called a "chest cold")
• pneumonia (infection of the lungs)
• pink eye (conjunctivitis)
• acute gastroenteritis (inflammation of the stomach or intestines causing diarrhea, vomiting, nausea and stomach pain)

Less common symptoms of adenovirus infection include

• bladder inflammation or infection
• neurologic disease (conditions that affect the brain and spinal cord)

Adenoviruses can cause mild to severe illness, though serious illness is less common. People with weakened immune systems, or existing respiratory or cardiac disease, are at higher risk of developing severe illness from an adenovirus infection.

Adenoviruses are usually spread from an infected person to others through

• close personal contact, such as touching or shaking hands
• the air by coughing and sneezing
• touching an object or surface with adenoviruses on it, then touching your mouth, nose, or eyes before washing your hands

Some adenoviruses can spread through an infected person's stool, for example, during diaper changing. Adenovirus can also spread through the water, such as swimming pools, but this is less common.

Sometimes the virus can be shed (released from the body) for a long time after a person recovers from an adenovirus infection, especially among people who have weakened immune systems. This "virus shedding" usually occurs without any symptoms, even though the person can still spread adenovirus to other people.

There is no specific treatment for people with adenovirus infection. Most adenovirus infections are mild and may require only care to help relieve symptoms, such as over-the-counter pain medicines or fever reducers. Always read the label and use medications as directed. There are no approved antiviral medicines for adenovirus infections.

Adenovirus vaccine is for U.S. military only

There is a vaccine for adenovirus types 4 and 7 that is used in military personnel who may be at higher risk for infection from these two adenovirus types. This vaccine contains live virus that can be shed in stool and potentially cause disease in other people if transmitted. The safety and effectiveness of this vaccine has not been studied in the general population or in people with weakened immune systems, and it is not approved for use outside of the military. There is currently no adenovirus vaccine available to the general public.

Follow simple steps to protect yourself and others

You can protect yourself and others from adenoviruses and other respiratory illnesses by following a few simple steps:

• Wash your hands often with soap and water.
• Avoid touching your eyes, nose, or mouth with unwashed hands.
• Avoid close contact with people who are sick.

If you're sick you can help protect others:

• Stay home when you are sick.
• Cough and sneeze into a tissue or your upper shirt sleeve, not your hands.
• Avoid sharing cups and eating utensils with others.
• Refrain from kissing others.
• Wash your hands often with soap and water for at least 20 seconds, especially after using the bathroom.

Frequent handwashing is especially important in childcare settings and healthcare facilities.

Maintain proper chlorine levels to prevent outbreaks

It is important to keep adequate levels of chlorine in swimming pools to prevent outbreaks of conjunctivitis caused by adenoviruses.