Adenovirus is a DNA virus that causes cold-like symptoms and spreads rapidly in crowded places, infecting the respiratory tract, eyes, and gastrointestinal system. Often confused with the common cold or flu, adenovirus can produce a wide range of symptoms that may last up to two weeks, though some symptoms like coughs can persist longer. With COVID-19 and flu now at baseline levels in the UK, adenovirus has emerged as a significant culprit behind the "mystery illness" currently circulating .

What Are the Symptoms of Adenovirus?

Adenovirus symptoms vary depending on which of the more than 100 subtypes you encounter, though only 49 subtypes infect humans. Most people experience mild symptoms, and some may not realize they're infected at all. However, the virus can cause severe illness in immunocompromised individuals .

The symptoms you might experience include:

• Respiratory Symptoms: Sore throat, runny nose, cough, and shortness of breath are common upper and lower respiratory tract infections caused by adenovirus.
• Fever and Body Symptoms: Fever and enlarged cervical lymph nodes in the neck are typical signs that your body is fighting the infection.
• Eye and Ear Issues: Conjunctivitis (pink eye) and ear pain can occur, making adenovirus easy to confuse with other viral infections.
• Gastrointestinal Symptoms: Diarrhea, vomiting, and stomach pain may develop, which is why some people mistake adenovirus for a stomach bug.
• Urinary Tract Symptoms: In some cases, urinary tract infections can occur as part of the broader infection.

According to Dr. Deborah Lee at Dr Fox Online Pharmacy, "Adenovirus is a DNA virus. Adenoviruses infect the upper and lower respiratory tract, but also the eye, the gastrointestinal tract, the kidney, and other organs (in those who are immunosuppressed)." She notes that symptoms "may last up to two weeks, although the cough may last longer" .

Dr. Deborah Lee

How Does Adenovirus Spread, and Who Is Most at Risk?

Adenovirus is highly contagious and spreads through multiple routes, making it a concern in crowded environments like offices and public transportation. Understanding transmission is key to protecting yourself and others .

"Adenovirus infection is highly contagious. It is spread from breathing in infected aerosol droplets, by inadvertently rubbing the virus directly into the eye, or via the faecal-oral route (not handwashing after using the toilet). It spreads rapidly in places where people are in close proximity," explained Dr. Deborah Lee.

Dr. Deborah Lee, Medical Professional at Dr Fox Online Pharmacy

Certain groups face higher risk from adenovirus infection. Babies and children under five, the elderly, pregnant women, and anyone who is immunocompromised are most vulnerable to severe illness. This is why awareness and prevention are especially important during adenovirus outbreaks .

How to Protect Yourself and Others From Adenovirus

• Hand Hygiene: Regularly wash your hands with soap and warm water and dry them thoroughly, especially after using the toilet or changing a nappy, since the virus spreads via the faecal-oral route.
• Face and Nose Protection: Avoid touching your face and nose, and blow your nose into a clean paper handkerchief before throwing it in the bin to prevent spreading infected droplets.
• Environmental Cleaning: Clean and disinfect worktops, changing areas, toilets, and bathrooms regularly. Use bleach solutions or hydrogen peroxide, as the virus is resistant to soap and many common cleaning products.
• Toy and Surface Sanitation: Wash children's toys regularly and avoid sharing cups, plates, food, or towels with others who may be infected.
• Ventilation and Masks: Keep windows open and maintain good ventilation in your rooms and workspaces. Consider wearing a mask if you must go out while symptomatic or around others who are ill.
• Social Distancing: Keep away from others showing symptoms to reduce your risk of catching the virus.

How Is Adenovirus Different From a Cold or Flu?

While adenovirus produces cold-like symptoms, it differs from seasonal flu in important ways. Flu typically occurs during winter months and has a relatively sudden onset with fever, chills, and aches and pains. Adenovirus, by contrast, can occur year-round and develops more gradually, with symptoms that resemble the common cold rather than the dramatic presentation of influenza .

Dr. Lee stated that "Flu tends to occur in the winter months, whereas adenovirus can occur all year round. Flu has a relatively sudden onset with fever, chills, and aches and pains, whereas adenovirus is not so dramatic. Instead, adenovirus usually causes typical symptoms of the common cold" .

Dr. Lee

What Should You Do If You Think You Have Adenovirus?

If you suspect you have adenovirus, testing is unlikely to be offered because it's simply another respiratory virus that typically resolves on its own. Instead, focus on managing your symptoms as you would with a common cold. Antibiotics are ineffective against viral infections, so treatment centers on symptom relief and rest .

Recommended approaches include taking anti-inflammatory medications such as ibuprofen or paracetamol for fever and discomfort, gargling with saltwater to soothe a sore throat, using Vicks inhalations to relieve a blocked nose, and drinking hot lemon and honey to soothe a cough. Getting adequate rest until you feel better is also essential. For those with severe infections or immunosuppression, medical professionals can provide specialized treatments .

As adenovirus continues to circulate across the UK, staying informed about symptoms, transmission routes, and prevention strategies can help you protect yourself and your community during this outbreak.