What is the flu?
The flu is a common infectious disease caused by influenza (flu) viruses. The flu usually affects a person’s breathing system. Seasonal flu generally occurs in the fall and winter and is caused by human influenza viruses.
How does the flu spread?
The flu spreads through tiny wet drops produced when a person coughs, sneezes, or talks. A person can get the flu by breathing in these wet drops, or by touching items and surfaces covered with these drops and then touching their mouth, nose, or eyes.
When can someone spread the flu to others?
People who have the flu may spread it to others about 1 day before getting sick to 5 -7 days after. Children and people with weak immune systems can spread the flu virus for a longer period of time. However, people are most contagious during the first three days of illness.
How can I protect myself from the flu?
Use healthy habits:
- Get vaccinated every Fall/Winter. Annual flu vaccination is the best way to prevent flu in our community.
- Clean hands often with soap and water or use alcohol-based hand rub
- Don’t share personal items like toothbrushes or drinks
- Cover your mouth and nose with a tissue (or shirt sleeve) when sneezing, coughing, or nose blowing
- Clean frequently touched items and surfaces with soap and water
Is there a vaccine?
Yes. It is important for everyone 6 months and older to get a flu shot this fall and winter. Contact your health care provider for updates on where you can get the vaccine. If you do not have a doctor, click here to find out where to go in San Francisco.
What are signs and symptoms of the flu?
The usual signs and symptoms of the flu are cough, sore throat, runny or stuffy nose, body aches, headache, chills, and feeling very tired. Most people also have a fever. Others may vomit and have diarrhea.
Is it a cold or the flu?
In general, the flu is worse than the common cold. Colds are usually milder than the flu.
| Symptom | Flu | Cold |
|---|---|---|
| Fever | Can go up to 104 degrees F and usually lasts 3 to 4 days. | Rare in adults and older children, but can be as high as 102 degrees F in infants and small children. |
| Headache | Sudden onset and can be severe | Rare |
| Muscle Aches | Usually, and often severe | None or mild |
| Tiredness/Weakness | Can last 2 or more weeks | Mild |
| Extreme Exhaustion | Sudden onset and can be severe | Never |
| Runny Nose | Sometimes | Often |
| Sneezing | Sometimes | Often |
| Sore Throat | Sometimes | Often |
| Cough | Usually, and can become severe | Mild to moderate |
How serious is the flu?
Occasionally flu can cause severe disease. Some people have had to go to the hospital and a small number of people have died. Historically, seasonal flu causes between 3,000 to 49,000 deaths in the United States each year.
Who is more likely to get very sick with the flu?
Below is a list of groups of people who may get very sick if they have the flu. It is important that they, and the people around them, get a flu shot.
- People with lung disease like asthma
- People of all ages with ongoing medical conditions like diabetes, heart disease, kidney or liver disease, blood cell disease including sickle cell, or neurological diseases that affect swallowing or breathing
- Pregnant women and women who have given birth within 2 weeks
- Children younger than 5 years, especially those younger than 2 years
- Adults age 50 years and over
- People with weak immune systems (due to disease or medicines)
- Household contacts and caregivers of children younger than 5 years and adults aged 50 years and older, with particular emphasis on vaccinating contacts of children aged younger than 6 months; and
- Household contacts and caregivers of people with medical conditions that put them at higher risk for severe complications from influenza.
What should I do if I am sick with a flu-like illness?
We recommend that you stay home and stay away from others until 24 hours after your fever is gone (without the use of fever-reducing medicine like acetaminophen (e.g., Tylenol) or ibuprofen (e.g., Motrin, Advil).