Medical questions & health advice by board certified doctors

"What's the difference between the flu and mono?"

ZocdocAnswersWhat's the difference between the flu and mono?


I've had flu like symptoms for weeks after I thought I was over being sick. Like I'm still tired and achy. Is this just a bad case of the flu or mono? How do you know if you have mono?


The flu (known as an influenza virus infection) and mono (known as mononucleosis syndrome) are two different types of infections that can have similar symptoms. Most cases of the flu are fairly short, between 1 and 2 weeks at the most. The symptoms include fatigue, feeling achy, fever, cough, and nausea. If you have had your symptoms for weeks (more than 2 weeks), it is less likely to be the flu. Plus, this is not flu season. If your symptoms occurred in November, it would be more likely to be the flu. Mononucleosis causes similar symptoms that can last longer. Other symptoms which are common include a sore throat that can be red and swollen, enlarged lymph nodes in the neck, and sleepiness. I suggest that you schedule an appointment with your primary care physician. He or she can take a more detailed history of these symptoms and perform a thorough physical exam. In most cases, your doctor will be able to tell what type of infection you have just by the interview. If not, there are blood tests that can look for an active mono infection. If you have mono, then there are certain types of activities your doctor may want you to abstain from.

Zocdoc Answers is for general informational purposes only and is not a substitute for professional medical advice. If you think you may have a medical emergency, call your doctor (in the United States) 911 immediately. Always seek the advice of your doctor before starting or changing treatment. Medical professionals who provide responses to health-related questions are intended third party beneficiaries with certain rights under Zocdoc’s Terms of Service.