What Is Influenza (Flu)?

Influenza is a viral infection that attacks your respiratory system — your nose, throat and lungs. Influenza, commonly called the flu, is not the same as stomach “flu” viruses that cause diarrhea and vomiting.

 What Are the Symptoms?

Initially, the flu may seem like a common cold with a runny nose, sneezing and sore throat. But colds usually develop slowly, whereas the flu tends to come on suddenly and last longer. And although a cold can be a nuisance, you usually feel much worse with the flu.

The symptoms usually are the worst for the first 3 or 4 days, but it can take 1 to 2 weeks to get completely better.

Most people get better without problems, but sometimes the flu can lead to a bacterial infection, such as an ear infection, a sinus infection, or bronchitis. In rare cases, the flu may cause a more serious problem, such as pneumonia. It usually takes 1 to 4 days to get symptoms of the flu after you have been exposed to it.

What Causes the Flu?

Flu viruses travel through the air in the form of droplets when someone with the infection coughs, sneezes or talks. You can inhale the droplets directly, or you can pick up the germs from an object, such as a telephone, and then transfer them to your eyes, nose or mouth.

Common signs and symptoms of the flu include:

– Fever over 100 F (38 C)
– Aching muscles, especially in your back, arms and legs
– Headache
– Chills and sweats
–  Dry, persistent cough
–  Sore throat
–  Fatigue and weakness
–  Nasal congestion

 People with the virus are likely contagious from the day or so before symptoms first appear until about five days after symptoms begin, though sometimes people are contagious for as long as 10 days after symptoms appear.


How Is the Flu Diagnosed and Treated?

Initially, your doctor will ask you about your symptoms and examine you. In some cases, the doctor may do a blood test or take a sample of fluid from your nose or throat to find out what type of flu virus you have. Your doctor may be able to give you medicine that can make the symptoms milder.

The best treatment is the prevention of influenza by getting annual flu vaccinations.

Preventing the Flu

The best prevention is to get a flu vaccination every year. The best time to get the vaccine is in October or November, just before the start of flu season. You can get the vaccine as a shot or in a spray that you breathe in through your nose.

Almost anyone over 6 months old can have the flu vaccine. The vaccine is especially important for people who are at higher risk of problems from the flu, including children 6 months through 4 years of age, adults ages 50 and older, adults and children who have long-term health problems or an impaired immune system, and women who will be pregnant during the flu season.

The vaccine usually prevents most cases of the flu. But even if you do get the flu after you’ve had the vaccine, your symptoms will be milder and you’ll have less chance of problems from the flu. You cannot get the flu from the flu vaccine.