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Influenza in Healthcare Settings

Question & Answers 

Influenza and Influenza Vaccine Information for

Healthcare Personnel

November 16, 2005

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, body aches, headache, tiredness, cough, sore throat, and nasal

congestion.

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 and worsening of chronic medical conditions (e.g.,

asthma, congestive heart failure, or diabetes).

How is influenza spread?

Influenza is easily passed from person-to-person. The virus is spread primarily by the droplets that

are generated by coughing and sneezing of infected persons. Transmission may also occur by

touching a surface contaminated with flu virus and then touching the eyes, nose or mouth.

When can a person spread influenza?

People develop symptoms 1-4 days after they are infected. 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 and young children can shed

influenza virus for several days before their illness onset.

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

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) inactivated influenza vaccine (flu shot), and 2) live, attenuated influenza vaccine (LAIV)

(nasal spray). LAIV is an option for all healthy individuals 5-49 years of age. 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 bone marrow 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 the 7 days after

receiving the vaccine. Another important way to prevent the spread of influenza is to follow infection

control recommendations including hand hygiene and Standard and Droplet Precautions.

How well do the influenza shot and nasal spray vaccines work?
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Both vaccines are usually very effective (i.e., 70-90%) 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. Although the vaccines may be less effective during years when the vaccine

strains do not perfectly match the strains causing illness; however, the vaccines can still provide

substantial protective benefit and reduce the severity of illness.

Why should healthcare personnel get vaccinated to prevent flu?

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.

What are the side effects of the influenza 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-in-a-million persons who get flu vaccine develop GuillainBarré syndrome, a rare neurologic illness that can cause paralysis. The viruses in the influenza shot

are killed (inactivated) viruses; therefore, influenza illness it not a side effect of vaccination.

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

The viruses in the nasal spray vaccine are weakened and do not cause the severe symptoms that are

often associated with influenza illness. 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.

Who should get influenza vaccine?

In general, people who want to reduce their chances of getting influenza can get vaccinated.

However, certain people should get vaccinated each year.

CDC recommends the following target groups for vaccination.

persons at increased risk for complications from influenza (e.g., children 6-23 months old,

adults ≥65 years old, and persons with chronic medical conditions)

persons aged 50-64 years

persons who can transmit influenza to those at high risk

all healthcare personnel

Who should get the flu shot?

The Advisory Committed on Immunization Practices (ACIP) recommends the use of the inactivated

influenza vaccine (flu shot) for persons who are at increased risk for complications from influenza or

who can transmit influenza to those at risk for complications from influenza. Persons who should

only receive the influenza shot include

persons >50 years

residents of nursing homes and other chronic-care facilities that house persons of any age who

have chronic medical conditions

adults and children who have chronic disorders of the pulmonary or cardiovascular systems,

including asthma

adults and children who have required regular medical follow-up or hospitalization during the

preceding year because of chronic metabolic diseases (including diabetes mellitus), renal
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dysfunction, hemoglobinopathies, or immunosuppression (including immunosuppression

caused by medications or by human immunodeficiency virus [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

children and adolescents (6 months–18 years of age) who are receiving long-term aspirin

therapy and, therefore, might be at risk of developing Reye’s syndrome after influenza

infection

women who will be pregnant during the influenza season

children 6-23 months of age

Who can get vaccinated with LAIV?

The following populations can get either the LAIV (nasal spray) or influenza shot if they are

not on the list of persons who should get the flu shot or are on the list of persons who should

not get LAIV.

healthy person 5-49 years of age

household contacts and other caregivers of children 0-23 months of age

persons who have contact with the persons at high-risk of complications, including household

members

all healthcare personnel

Who should not be vaccinated with LAIV?

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

persons <5 years of age or those >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

persons with a history of hypersensitivity, including anaphylaxis, to any of the components of

LAIV or to eggs

healthcare personnel who care for patients with severely weakened immune systems (i.e.,

patients who have recently had a bone marrow transplant and require a protected environment)

can receive LAIV, but should refrain from contact with severely immunosuppressed patients

for 7 days after vaccine receipt

persons with a fever or significant nasal congestion that may interfere with delivery of the

LAIV should postpone vaccination; persons with mild respiratory illness can receive LAIV

Should pregnant women or women who are breast-feeding be given the influenza shot?

Yes, during influenza season, women in any trimester of pregnancy should be vaccinated with

influenza shot; however pregnant women should not receive LAIV. The influenza shot is safe for

mothers who are breast-feeding and will not harm their breastfeeding infants.

Who should talk with their physician before getting the influenza 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
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persons with a fever should wait until after the fever has resolved to get the influenza shot

(persons with mild respiratory illness, especially children, can get an influenza shot)

Can influenza vaccines cause influenza in someone who is vaccinated?

No, neither type of vaccine causes influenza. The influenza shot contains killed or inactivated

influenza viruses and LAIV contains influenza viruses that have been altered so they do not cause

disease.

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

www.cdc.gov/flu/professionals/labdiagnosis.htm.

What should I do if I suspect influenza in a patient?

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 can look for

additional cases of influenza in the facility. Patients who have flu-like illnesses should be evaluated

for influenza.

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 by limiting contact with patients, covering your mouth when coughing or sneezing, and

performing hand hygiene after contact with your respiratory secretions.

Is there a treatment for influenza?

Yes. The antiviral medications amantadine and rimantadine are effective against influenza type A and

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.

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

Yes. Amantadine and rimantadine may also be used to prevent influenza A and oseltamivir may be

used to prevent influenza A and B, and all three can help control outbreaks in healthcare institutions.

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: January 12, 2006

Content source: Division of Healthcare Quality Promotion (DHQP)