About Influenza

About Influenza

Influenza (also known as the flu) is a contagious respiratory illness caused by flu viruses. Symptoms can range from mild to severe illness.

How is it transmitted?

Influenza can spread when sick individuals cough or sneeze. People may also contract influenza by touching their mouth or nose after touching something contaminated with the virus (e.g. doorknobs, tables, cups, an infected person's hand, etc.).

You may be able to spread the virus to someone else before you know you are sick. Most infected individuals shed influenza virus the day before symptoms develop and up to 5 to 7 days after becoming sick. Symptoms start 1 to 4 days after the virus enters the body. Some people can be infected with influenza but have no symptoms.

Signs and Symptoms

Influenza is different from a cold. The virus usually comes on suddenly and symptoms may include fever/chills, cough, sore throat, runny or stuffy nose, muscle or body aches, headaches, and/or fatigue.


Most cases of influenza get better with self-care and without medical treatment. If you suspect you have influenza, stay at home and away from others until you have been fever-free for 24 hours (i.e. self-isolate). This is an important prevention strategy to avoid the spread of influenza.

Self-care options include:

  • Manage your fever and pain with acetaminophen (325mg "non-aspirin," regular strength, 2-3 tabs) every 4-6 hours (not to exceed 3000mg in 24/hours) OR ibuprofen (200 mg, 2-3 tabs) ever 6-8 hours with food. You may alternate acetaminophen and ibuprofen every 3 hours
  • Prevent dehydration by drinking plenty of clear liquids (water, ginger ale, sport drinks, etc.)
  • Get plenty of rest

If you have trouble breathing, chest pain, suffer a relapse (begin to feel much worse after having felt better), severe headache and/or neck pain/stiffness, confusion, lethargy, severe or persistent vomiting please call Student Health at 215-746-3535 and press option 1 to speak with a nurse


Annual vaccination is the most effective way to protect oneself against influenza. Influenza vaccines are suggested for all Penn students and may be required for certain programs.  The easiest thing for students to do is to get the influenza vaccine at our annual Flu Clinics.

Practice good hand hygiene:

  • Wash your hands with soap and warm water or an alcohol-based hand sanitizer that contains at least 60% alcohol
  • Cover your mouth and nose with a tissue when you cough or sneeze. If you don't have a tissue, cough or sneeze into your sleeve or elbow
  • Self-isolate if you suspect you have influenza



Back to Disease Updates

(updated 7/14/2015)