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MIT Flu Central:


Updated September 15, 2014

What is the incubation period for the influenza virus?
"Incubation period" refers to the period between the time an individual becomes infected with an illness and the time they begin showing symptoms. For flu, the Centers for Disease Control and Prevention (CDC) estimates that this period is between one and four days. According to the CDC, people infected with influenza are probably infectious—able to transmit the infection to other people—one day before they begin showing symptoms.

How can I keep from getting sick?
Viruses are spread mainly through uncovered coughs and sneezes, which can end up contaminating doorknobs, keyboards, and other surfaces. You may become sick after touching a contaminated surface, and then touching your eyes, mouth, or nose. Follow these guidelines to protect yourself and others:

  • Wash your hands frequently and thoroughly with soap and warm water, or use an alcohol-based hand sanitizer
  • Cover coughs and sneezes
  • Avoid touching your eyes, nose, and mouth
  • Stay home if you are feeling sick

How should we clean work spaces if someone in our area becomes sick with flu-like symptoms?
To prevent the spread of illness, disinfect commonly touched hard surfaces in the workplace by wiping them down with a household disinfectant according to directions on the product label. This includes counter tops, door knobs, telephones, copy machines, work stations, and bathroom surfaces. Studies have shown that flu viruses do not remain infectious on environmental surfaces for more than eight hours. Frequent hand washing is the best way to avoid infection from contaminated surfaces.

What are the symptoms of influenza, and how serious is it?
Symptoms of influenza include fever, cough, sore throat, body aches, headache, chills, and fatigue. Some people also report diarrhea, nausea, and vomiting.

What should I do if I have flu symptoms?
If you have flu-like symptoms, stay home and rest. If you are an MIT student, call MIT Medical to notify them of your illness and to get advice on treatment. If you do become ill, you should avoid contact with other people except to get medical care. Stay home until your temperature has remained normal for 24 hours without the use of fever-reducing drugs such as acetaminophen and ibuprofen.

Most patients do not get seriously ill with flu and recover completely without medical intervention. Antiviral drugs including Tamiflu and Relenza should be used only in severe cases or in patients with medical conditions that put them at risk for serious complications from the flu (see "Who is at higher risk for developing serious complications from influenza?").

To avoid spreading the illness to others, the Massachusetts Department of Public Health recommends that individuals who become sick with the flu should avoid close contact with other people until 24 hours after a fever has resolved and body temperature has remained normal without the use of fever-reducing drugs such as acetaminophen and ibuprofen. Human Resources at MIT has additional information on leave and payment policies for employees, and policies that would go into effect in the case of more widespread illness or another emergency.

When should I see a medical provider?
You probably don't need to be seen for flu-like symptoms unless you are pregnant or have an underlying medical condition that puts you at higher risk for developing serious complications from the flu (see "Who is at higher risk for developing serious complications from influenza?", or unless your symptoms are serious.

Serious symptoms in adults include:

  • difficulty breathing or shortness of breath
  • pain or pressure in the chest or abdomen
  • sudden dizziness, confusion
  • severe or persistent vomiting
  • flu-like symptoms that improve but then return with fever and worse cough

In children, serious symptoms include:

  • fast breathing or trouble breathing
  • bluish skin color
  • not drinking enough fluids
  • not waking up or not interacting
  • not urinating, or no tears when crying
  • severe and persistent vomiting
  • flu-like symptoms that improve but then return with fever and worse cough

Who is at higher risk for developing serious complications from flu?
People who are at higher risk of serious complications from influenza include:

  • pregnant women
  • people older than 65 or younger than 2
  • people with chronic medical conditions such as asthma, diabetes, or heart disease
  • people whose immune systems are suppressed due to medications or medical conditions

If a member of my family is sick with the flu, do I need to stay home from work?
No. You should stay home only if you get sick with flu-like symptoms (see "What should I do if I have flu symptoms?"). Human Resources at MIT can provide additional information on the Institute's policies regarding time off to care for a sick family member.

How many flu vaccinations will I need for the 2014–15 flu season?
Adults will need just one vaccination. Children between 6 months and 9 years old will need two doses, spaced at least a month apart, if this is the first time they're receiving a flu vaccination.

How do I get vaccinated against flu?
See our vaccination page to learn how to get a flu vaccination.

Is the flu vaccine safe?
Every year, the seasonal flu vaccine produces mild side effects in approximately 5 to 10 percent of people (most commonly, soreness at the site of the vaccination). An extremely small number of people experience a more serious allergic reaction. In general, however, most experts believe that the risk from flu itself is greater than any potential risks from a vaccine, particularly for the most vulnerable groups. The CDC estimates that during a 30-year span (the period from the 1976–1977 flu season to the 2006–2007 season), the number of flu-associated deaths in the U.S. ranged from about 3,000 to 49,000 people per season.

However, some people should not get a flu vaccine without first consulting a physician. These include:

  • People who have a severe allergy to chicken eggs
  • People who have had a severe reaction to an influenza vaccination
  • People who developed Guillain-Barré syndrome (GBS) within six weeks of getting a previous influenza vaccine
  • Children less than six months old
  • People who have a moderate to severe illness with a fever (they should wait until they recover to get vaccinated)

Can people with egg allergy receive flu vaccine?
Yes! There is one brand of flu vaccine that is produced without chicken eggs - FluBlok. FluBlok is not available at MIT Medical but is available at retail pharmacies.

Should persons over age 65 get the Fluzone High-Dose vaccine?
Fluzone High-Dose is approved for persons aged 65 and older. However, since it has not yet been proven to reduce the risk of pneumonia or death compared to regular flu vaccine, the American College of Immunization Practices has not recommended that persons over age 65 should receive Fluzone High-Dose rather than the regular flu vaccine. Fluzone High-Dose is not available at MIT Medical but is available at retail pharmacies.

Who should get the FluMist nasal spray vaccine?
The American College of Immunization Practices recommends that healthy children aged 2 years through 8 years who have no conditions that would make receiving FluMist inadvisable should receive the FluMist, which is a live attenuated influenza vaccine. They should receive the regular injectable vaccine if FluMist is not available. FluMist should not be given to children who have asthma. FluMist is not be available at MIT Medical but is available at retail pharmacies.

Should I get the pneumonia vaccination?
One of the most severe complications of influenza is the increased risk of developing bacterial pneumonia—especially with the pneumococcus bacteria. For this reason, pneumococcal vaccine (Pneumovax) is recommended for some people, including:

  • Adults aged 65 or older
  • Smokers
  • People with underlying medical problems such as asthma, diabetes, heart disease, lung disease, and several other conditions.

In addition, the American College of Immunization Practices recently voted to recommended that adults aged 65 or older should also receive a second type of pneumonia vaccine, Prevnar-13, in addition to the Pneumovax. Ask your primary care provider if this is right for you. For more information, see this Pfizer page.

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