Influenza, commonly known as the flu, is a respiratory illness that can infect the nose, throat, and lungs. The flu virus is contagious and spreads through the tiny droplets infected people expel when they cough, sneeze, or talk. You can also get infected if you touch a surface with the flu virus on it and then touch your mouth, nose, or eyes before washing your hands.
Symptoms of the flu can be mild to severe and often come on suddenly. Symptoms usually begin 1-4 days after initial exposure to the flu and can include any of the following:
- Fever and/or chills
- Sore throat
- Runny nose or congestion
- Muscle aches or body aches
- Feeling tired
- Vomiting and diarrhea (more common in children)
The flu can spread before you know you are sick, and while you are sick with symptoms. You are the most contagious 3-4 days after your illness begins, but you can start spreading the virus 1 day before your symptoms begin and up to 5-7 days after you become sick. Children and people with weakened immune systems may be contagious for longer.
Diagnosis and Treatment
Symptoms of the flu can mimic other viral illnesses such as COVID-19 so it is best to see your healthcare provider if you think you have the flu. Your healthcare provider may test you for the flu or make a diagnosis based on their clinical judgment. You may also be tested for COVID-19 to rule out other causes of your symptoms.
Most people who get the flu have mild illnesses and do not need medical care or antiviral drugs. If you get sick with flu symptoms, you should stay home and avoid contact with other people except to get medical care. Your healthcare provider will discuss treatment options such as antivirals or fever-reducing medications.
If you are considered at high-risk for contracting the flu, consult with your healthcare provider.
Seasonal flu causes large numbers of hospitalizations every year. Being sick with the flu makes some health conditions (like lung disease) worse, and can lead to other complications that require hospitalization.
Flu vaccination is the first and best way to prevent the flu and serious complications. Everyone 6 months and older should get vaccinated against the flu every year, especially people who are at increased risk for serious complications. These people include young children, adults 65 years and older, and people with certain chronic medical conditions. All flu vaccines this season will help protect against the four flu viruses that researchers predict will be the most common flu strains circulating this season.
Taking preventative measures every day helps lessen the spread of the flu. To do your part:
- Cover your coughs and sneezes.
- Cover your nose and mouth with a tissue when you cough or sneeze.
- Wash your hands often with soap and water for at least 20 seconds at a time. If soap and water are not available, use an alcohol-based hand sanitizer.
- Avoid touching your eyes, nose, and mouth.
- Clean and disinfect surfaces and objects that may be contaminated with flu viruses.
- Avoid close contact with sick people.
- If you are sick, limit contact with others as much as possible to keep from infecting them.
Treatment and Care
If you think you have the flu, it is important you see your healthcare provider as soon as possible, especially if you are in a high-risk group or are at high risk of developing complications. Your healthcare provider may prescribe antiviral drugs, but antiviral drugs work best when they are started one to two days after your symptoms begin, so don’t hesitate to get an appointment. Antiviral drugs can help decrease the severity of flu symptoms, shorten the time you are sick by one to two days, and may prevent more serious complications. Your healthcare provider may also recommend other preventive measures such as:
- Staying hydrated. Drink plenty of liquids to prevent dehydration.
- Getting rest. Get enough sleep to help your body’s immune system fight off infection.
- Taking over-the-counter medication for symptom relief. Over-the-counter medications such as acetaminophen and ibuprofen can help with symptoms of body aches and fever. Avoid using aspirin for children as it can increase the risk of Reye’s syndrome, a rare but potentially fatal condition in children.
It is always best to check with your healthcare provider or pharmacist before taking any medications. If you are sick, the CDC recommends avoiding others and staying home until you are free of fever without the use of fever-reducing medications for at least 24 hours.