The One Sign Your Flu Is Actually Adenovirus — And Why You Need To Know The Difference

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There is no doubt the flu season this year is one of the worst in recent history, as predicted by doctors, but experts are also warning another virus could be causing flu-like symptoms. Adenoviruses are a group of viruses that are known to cause respiratory and intestinal illnesses. It may look a lot like the flu, but there is one major difference: Dr. William Schaffner, an infectious disease at Vanderbilt University, told CNN, "Most of the time, adenoviruses produce influenza-like illness with cough and runny nose and feeling crummy, but you get better. [In some cases,] they can also cause conjunctivitis and, particularly in children, diarrhea."

Unfortunately, according the CDC, there is currently no adenovirus vaccine available to the general public in the United States — a vaccine is only available for military use. Like the flu, the illness is spread through bodily fluids, but it can also be contracted through touching infected surfaces or coming into contact with infected fecal matter (which happens often through diaper changing). The best way to avoid adenoviruses is by frequently washing your hands, cleaning surfaces in your house, avoiding contact with sick people or public places, and not touching your face.

Though most adenovirus infections are typically mild, with symptoms lasting a week at most for healthy adults, groups like children, older folks, and those with chronic illnesses are more susceptible to severe symptoms. Moreover, there are over 50 kinds of adenovirus that can infect humans, and the symptoms you experience with each one can differ. If you unsure if if you have an adenovirus or the flu, here are seven symptoms to look out for.

Conjunctivitis (aka, Pink Eye)

Adenoviral Conjunctivitis, or Pink Eye, is commonly caused by some strains of adenoviruses. The symptoms of Pink Eye include redness around the eyes, flakiness or crustiness on the eyelashes, watery eyes, and swollen eyelids. Some people use topical solutions to relieve irritation caused conjunctivitis and help prevent it spreading to others, but symptoms of Pink Eye pass with the virus.

Intestinal Infections

Certain strains of adenovirus can cause gastroenteritis, which is inflammation and an infection in your gut. When you have gastroenteritis, you can expect to experience diarrhea, and possibly vomiting.


According to the CDC, acute bronchitis is an infection that "occurs when the airways of the lungs swell" and it causes intense coughing due to mucus production. Viruses, such as the flu and adenovirus, are estimated to cause 85 to 95 percent of bronchitis cases in otherwise health adults. So, while the flu could definitely be behind a severe cough, it could also be a symptom of the adenovirus. Antibiotics are not typically prescribed for bronchitis since they aren't super effective against viruses, but doctors may give you medicine to relieve the symptoms.

UTIs and other bladder infections

The majority of urinary tract infections (UTIs) are caused by bacteria, but adenoviruses can also cause them. This leads to viral cystitis, which can cause symptoms such as painful urination, blood while urinating, discomfort or pressure in your lower stomach, and frequently peeing. Again, this symptom is more common in children and people with compromised immune health, but it's good to be aware you could experience bladder issues if you have the adenovirus.

Common cold and pneumonia

One of the main reasons adenovirus is often mistaken for the flu is because it also causes a range of respiratory illnesses — including the common cold with an accompanying sore throat, and in more severe cases, pneumonia. The best way to tell the difference is by being aware of additional symptoms that are unique to adenoviruses, like vomiting and bladder infections.


Another shared symptom of both the adenovirus and the flu is having a fever. Since spiking a fever is your body's way of defending itself against illnesses, almost any and every kind of infection or disease can lead to this rise in body temperature. Whether caused by the flu or adenovirus, the Mayo Clinic suggest that adults should call their doctor once their fever reach 103 degrees Fahrenheit.

Neurological issues

Neurological issues and brain infections caused by the adenovirus are extremely rare. However, the CDC does note serious neurological disorders of the brain and spinal cord, such as encephalitis and meningitis, can be caused by adenoviruses, can occur in populations more vulnerable to severe illness.

For most people who contract the adenovirus, the illness will be NBD, and symptoms will pass within a week. However, it's important to be aware of the symptoms you are experiencing, so if the virus worsens, you can seek the proper medical treatment — without wasting your time misdiagnosing the adenovirus as the flu.