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About Influenza

What is influenza?   
Influenza (often called “flu”) is a contagious illness caused by the influenza virus.  Symptoms include fever, cough, muscle aches, headache, runny nose, sore throat and general weakness.  The onset of these symptoms may be sudden.  These symptoms can range from mild to severe.
How is flu spread?
The viruses that cause flu live in the nose and throat and are sprayed into the air when an infected person sneezes, coughs or talks.  People nearby can then breathe in the virus.  Flu symptoms usually start 1 to 4 days after a person breathes in the virus, but it can take longer.  Most people can spread the flu virus 1 day before their symptoms begin until about a week afterward.​
How serious is the flu?
Influenza is unpredictable and can be severe. Between 1976 and 2006, CDC estimates from 3,000 to 49,000 people died each year from influenza. In 2012-2013, 149 children in the US died from influenza.
How can I prevent the flu?
There are many ways you can help prevent the spread of germs.

  • Getting vaccinated is the best protection against influenza. To find a local vaccination site, contact your primary care provider or click here​.
  • 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 upper sleeve.
  • Wash your hands often with soap and water or use an alcohol-based hand gel.
  •  Keep your hands away from your eyes, nose, and mouth.
  • Clean surfaces in your home regularly with a household cleaner.
  • Avoid close contact with people who are sick when possible.
  • If you become sick, stay home. A person with the flu should stay home for 24 hours after their fever has gone away without the use of fever reducing medicine. For most people, this will be a minimum of 4 days.

How long does the flu season last?
Most influenza activity in Boston usually occurs from October through March each year.
Who should get a flu vaccine?
Everyone 6 months and older should be vaccinated against influenza. This is the best way to protect yourself and those around you. Certain people are at greater risk for serious illness if they get influenza including the elderly, young children, pregnant women and people with certain health conditions (such as asthma, diabetes, heart disease or other conditions). Some individuals may not be at risk for severe illness themselves, but can transmit the infection to their families, friends and patients.
Click here​ for the influenza fact sheet.
Information for Special Groups
During influenza season, businesses and other employers play a key role in protecting employees' health and safety as well as limiting the negative impact to the economy and society. Planning for and taking steps to limit the spread of influenza as below will help keep your employees and the community healthy.
Develop a Business Continuity Plan
Identify your office’s essential functions and the individuals who perform them. Make sure you have trained enough people to properly perform these essential functions and allow for potential absenteeism.
Review and Update Sick Leave Policies

  • Employees with the flu should stay home until they have been fever free without fever reducing medicines for 24 hours.  For most this will be at least 4 days.
  • Employees with sick minors should stay home with them if necessary.

Reduce the Spread of Infection

Encourage good infection control practices in the workplace by displaying posters that address and remind workers about proper hand washing, respiratory hygiene, and cough etiquette.  Everyone should cover their nose and mouth with a tissue when they cough or sneeze. Throw the tissue in the trash after using it.

  • Provide sufficient facilities for hand washing and put alcohol-based (at least 60%) hand sanitizers in common workplace areas such as lobbies, corridors, and restrooms. Encourage frequent hand washing.
  • Provide tissues, disinfectants, and disposable towels for employees to clean their work surfaces, as well as appropriate disposal receptacles for use by employees.
  • Allow sick employees to stay home so they don’t spread infection to others.
  • Encourage annual vaccination against influenza. To keep employees and reduce absenteeism, consider holding an influenza vaccination clinic at the worksite.


Boston Public Health Commission
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