Influenza in Healthcare Settings

Question & Answers

Influenza and Influenza Vaccine Information for Healthcare Personnel

Revision: November 7, 2007

What is influenza (the flu)?

Influenza is a respiratory illness caused by the influenza virus. Symptoms of influenza infection may include sudden onset of fever, muscle aches, headache, extreme tiredness, cough, sore throat and runny or stuffy nose.

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How serious is influenza?

Influenza infects an average of 5-20% of the US population each year. On average, over 200,000 people are hospitalized and 36,000 people die of influenza or its complications each year. Complications of influenza include pneumonia, bronchitis, sinus and ear infections, and worsening of chronic medical conditions (e.g., asthma, congestive heart failure or diabetes).

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How is influenza spread?

Influenza is easily passed from person-to-person. The virus is spread primarily by droplets that are generated by coughing and sneezing of infected persons. Transmission may also occur by touching a surface contaminated with influenza virus and then touching the eyes, nose or mouth.

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When can a person spread influenza?

People develop symptoms 1-4 days after they are infected with an average of 2 days. Adults may be able to spread influenza to others from the day before developing symptoms to approximately 5 days after symptoms start. Children may be able to spread influenza to others for 10 or more days after their illness onset.

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What can I do to prevent myself and my patients from getting influenza?

Get vaccinated! Influenza vaccination is the best way to reduce your chances of getting ill from influenza and from giving influenza to your patients, your co-workers and your family. There are two types of influenza vaccine: 1) trivalent inactivated influenza vaccine (flu shot), and 2) live, attenuated influenza vaccine (LAIV) (nasal spray). The inactivated vaccine is approved for persons 6 months of age or older. LAIV is an approved for healthy children aged 2-4 years old who do not have recurrent wheezing and healthy persons 5-49 years of age who are not pregnant. For further information about influenza vaccine see http://www.cdc.gov/flu/. The inactivated influenza vaccine is preferred for healthcare personnel who work with patients with severely weakened immune systems (i.e., patients who have recently had a hematopoietic stem cell transplant and require a protected environment) because of a theoretical risk that LAIV could be transmitted to severely immunocompromised persons. Healthcare personnel who are vaccinated with LAIV (nasal spray) should not care for patients with severely weakened immune systems for 7 days after receiving the vaccine.

In addition, influenza antiviral medications oseltamiver and zanamivir can be used for the treatment and prevention of influenza. For more information about influenza antiviral medications see http://www.cdc.gov/flu/protect/antiviral/keyfacts.htm

Another important way to prevent the spread of influenza is to follow infection control recommendations including hand hygiene and Standard and Droplet Precautions.

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How well do the flu shot and nasal spray vaccines work?

Both vaccines are usually 70-90% effective in preventing influenza among healthy young adults. The ability of influenza vaccine to protect a person depends on the age and health status of the person getting the vaccine and the similarity or "match" between the virus strains in the vaccine and those causing disease. Testing has shown that both types of influenza vaccine are effective at preventing influenza. The vaccines may be less effective during years when the vaccine strains are not well matched to the strains causing illness; however, the vaccines can still provide substantial protective benefit and reduce the severity of illness.

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Why should healthcare personnel get vaccinated to prevent influenza?

All healthcare personnel should get vaccinated to protect themselves from getting influenza and to prevent transmission of influenza to their patients, coworkers, family members, and close contacts. Vaccination can also prevent persons at highest risk of complications from developing severe influenza-related illness and death.

Recent standards have been published requiring that healthcare organizations offer influenza vaccination to personnel including volunteers and licensed independent contractors with close patient contact. The level of vaccination among healthcare personnel is recommended as a measure of quality for quality improvement programs and implementation of policies is recommended to encourage healthcare personnel vaccination (e.g., obtaining signed statements from personnel who decline influenza vaccination). Some states have enacted laws requiring influenza vaccination of healthcare personnel.

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What are the side effects of the flu shot?

Mild arm soreness and redness or swelling at the injection site are the most common side effects and may last 1 to 2 days. Other potential side effects such as allergic reactions, fever, fatigue and body aches are uncommon. Approximately one out of 1 million persons who get influenza vaccine may develop Guillain-Barré syndrome, a rare neurologic illness that can cause paralysis. The viruses in the flu shot are killed (inactivated) viruses; therefore, influenza illness it not a side effect of vaccination.

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What are the side effects of the nasal spray vaccine (LAIV)?

The viruses in the nasal spray vaccine are weakened and do not cause influenza. In children, side effects from LAIV can include runny nose, headache, vomiting, muscle aches and fever. In adults, side effects from LAIV can include runny nose, headache, sore throat and cough. Fever is not a common side effect in adults receiving the nasal spray influenza vaccine.

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Who should get influenza vaccine?

In general, people who want to reduce their chances of getting influenza can get vaccinated. However, certain people should definitely get vaccinated each year. CDC recommends that the following groups receive annual influenza vaccination:

People at high risk for complications from the flu, including:

  • Children aged 6 months until their 5th birthday,
  • Pregnant women,
  • People 50 years of age and older,
  • People of any age with certain chronic medical conditions;
  • People who live in nursing homes and other long term care facilities.

People who live with or care for those at high risk for complications from influenza, including:

  • Household contacts of persons at high risk for complications from influenza (see above)
  • Household contacts and out of home caregivers of children less than 6 months of age (these children are too young to be vaccinated)
  • Healthcare personnel.

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Who should get influenza vaccine (flu shot) rather than LAIV?

The Advisory Committed on Immunization Practices (ACIP) recommends influenza vaccination (flu shot) for persons who are at increased risk for complications from influenza and their contacts. Persons at increase risk who should be vaccinated (flu shot) include:

  • All children aged 6-59 months;
  • All persons aged =50 years;
  • Children and adolescents (aged 6 months-18 years) who are receiving long-term aspirin therapy and who therefore might be at risk for experiencing Reye syndrome after influenza virus infection;
  • Women who will be pregnant during the influenza season;
  • Adults and children who have chronic pulmonary (including asthma), cardiovascular (except hypertension), renal, hepatic or renal dysfunction, hematological or metabolic disorders (including diabetes mellitus);
  • Adults and children who have immunosuppression (including immunosuppression caused by medications or by HIV);
  • Adults and children who have any condition (e.g., cognitive dysfunction, spinal cord injuries, seizure disorders, or other neuromuscular disorders) that can compromise respiratory function or the handling of respiratory secretions or that can increase the risk for aspiration;
  • Residents of nursing homes and other chronic-care facilities.

In addition, to prevent transmission to persons identified above, persons who live with or care for persons at high risk for influenza-related complications and children <6 months of age should also be vaccinated including:

  • Healthcare personnel;
  • Household contacts (including children) and caregivers of children aged <59 months (i.e., aged <5 years) and adults aged >50 years; and
  • Healthy household contacts (including children) and caregivers of persons with medical conditions that put them at higher risk for severe complications from influenza.

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Who should not get the flu shot?

  • Persons known to have anaphylactic hypersensitivity to eggs or to other components of the influenza vaccine without first consulting a physician.
  • Persons with moderate-to-severe acute febrile illness usually should not be vaccinated until their symptoms have abated. However, minor illnesses with or without fever do not contraindicate use of influenza vaccine, particularly among children with mild upper-respiratory tract infection or allergic rhinitis.
  • Persons who are not at high risk for severe influenza complications and who are known to have experienced Guillian Barré Syndrome within 6 weeks after a previous influenza vaccination should not be vaccinated. (Benefit may outweigh risk in persons at high risk of severe influenza complications.)

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Who can get vaccinated with LAIV (nasal spray) rather that the flu shot?

The following populations can get either the LAIV (nasal spray) or the flu shot:

  • Healthy person 5-49 years of age who are not pregnant, including persons who have contact with the persons at high-risk of complications, including household members.
  • Healthy children ages 2-4 years old (24-59 months old) without a history of recurrent wheezing
  • Healthcare personnel who do not care for severely immunocompromised patients in protected environments.

 

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Who should not be vaccinated with LAIV (nasal spray)?

The following populations should not be vaccinated with LAIV (nasal spray):

  • Persons with a history of hypersensitivity, including anaphylaxis, to any of the components of LAIV or to eggs.
  • Persons 2-4 years old who have recurrent wheezing
  • Persons = 50 years of age;
  • Persons with asthma, reactive airways disease, or other chronic disorders of the pulmonary or cardiovascular systems;
  • Persons with other underlying medical conditions, including such metabolic diseases as diabetes, renal dysfunction, and hemoglobinopathies; or persons with known or suspected immunodeficiency diseases or who are receiving immunosuppressive therapies.
  • Children or adolescents receiving aspirin or other salicylates (because of the association of Reye's syndrome with wild-type influenza infection).
  • Persons with a history of Guillain-Barré syndrome.
  • Pregnant women.
  • Healthcare personnel who care for patients with severely weakened immune systems (e.g., patients who have recently had a Hematopoietic stem cell transplant and require a protective environment) can receive LAIV, but should refrain from contact with severely immunosuppressed patients for 7 days after vaccine receipt but should not be restricted from caring for less severely immunocompromised patients.

Administration of LAIV should be postponed for persons with a fever or significant nasal congestion that may interfere with delivery of the LAIV but persons with mild respiratory illness can receive LAIV.

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Should pregnant women or women who are breastfeeding be given the flu shot?

Yes, women who will be pregnant during the influenza season should be vaccinated with the flu shot; however, pregnant women should not receive live attenuated influenza vaccine (nasal spray). The flu shot or nasal spray are safe for mothers who are breastfeeding and will not harm their breast-feeding infants.

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Who should talk with their physician before getting the flu shot or delay getting the shot?

  • Persons with allergies to eggs or thimerosal or a prior allergic reaction to the flu vaccination.
  • Persons with a history of Guillain-Barré syndrome.
  • Persons with a fever should wait until after the fever has resolved to get the flu shot (persons with mild respiratory illness, especially children, can get an flu shot).

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Can influenza vaccines cause influenza in someone who is vaccinated?

No, neither type of vaccine causes influenza. The flu shot contains killed or inactivated influenza viruses and LAIV contains influenza viruses that have been altered so they do not cause disease; however, minor symptoms can occur with either vaccine.

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How can I tell if I or one of my patients has influenza?

Because the symptoms of influenza are similar to those caused by other respiratory viruses, laboratory testing is needed to confirm the diagnosis of influenza. Check with your hospital's laboratory or infection control personnel to find out what tests are available at your facility. Information about laboratory testing can be found at http://www.cdc.gov/flu/professionals/labdiagnosis.htm.

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What should I do if I suspect influenza in a patient seen in my facility?

First, notify the patient's physician and your facility's infection control personnel. Infection control personnel can recommend steps including Respiratory Hygiene/Cough Etiquette and Standard and Droplet Precautions to limit the spread of influenza to other patients and staff, and they can look for and isolate additional cases of influenza in the facility. All patients who have influenza-like illnesses (http://www.cdc.gov/flu/keyfacts.htm) during influenza season should be evaluated for influenza. Patients in long-term care facilities should be tested for influenza (http://www.cdc.gov/flu/professionals/infectioncontrol/longtermcare.htm).

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What should I do if I develop influenza symptoms?

Seek medical attention and report your illness to your supervisor and to the occupational health clinic or infection control department/personnel at your facility. You can avoid spreading influenza to others staying at home when you are ill and can spread influenza, covering your mouth with a tissue when coughing or sneezing, and performing hand hygiene after contact with your respiratory secretions.

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Is there a treatment for influenza?

Yes. The influenza antiviral medications zanamivir and oseltamivir are effective against influenza types A and B. To reduce the number of days of influenza illness, these medications must be started within the first 2 days after symptoms begin. They can also be used to prevent influenza. Amantadine and rimantadine are not recommended for use in the U.S. because of high levels of resistance among circulating influenza A viruses.

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Is there any medication to prevent disease if I am exposed to influenza?

Yes. Either oseltamivir or zanamivir can be used to prevent influenza A and B. However, zanamivir is not recommended for treatment for patients with underlying airway disease.

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For more information about influenza or influenza vaccine,
call 1-800-232-2522
or visit the CDC Web site at: www.cdc.gov/flu

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Date last modified: March 18, 2008
Content source: 
Division of Healthcare Quality Promotion (DHQP)
National Center for Preparedness, Detection, and Control of Infectious Diseases