Flu Vaccine Protects Against Contagious Virus

Is Everyone Who Gets Flu Vaccine Equally Protected?

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What Is the Flu?

The flu (influenza) is a contagious respiratory illness caused by influenza viruses (illustration). Mild to severe symptoms can develop and in some cases the flu can be fatal. Flu vaccines are available each fall to help prevent the spread of flu. The optimal period for getting a flu vaccine is October - November.

Flu vaccines given in December or even later can still offer protection. Flu season can range from October through May.

Flu Statistics

According to the Centers of Disease Control and Prevention (CDC), statistics indicate that every year in the United States 5-20% of the population get the flu. More than 200,000 people are hospitalized with complications from the flu, and about 36,000 people succumb to the flu.

Who Should Get a Flu Vaccine?

According to the Centers of Disease Control and Prevention (CDC), flu vaccines are recommended for:

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

  • people 65 years and older
  • people who reside in nursing homes or other long-term care facilities
  • adults and children 6 months and older with chronic heart or lung conditions, including asthma
  • adults and children 6 months and older who required regular medical care or were in a hospital during the previous year because of a metabolic disease, chronic kidney disease, or weakened immune system, including immune system problems caused by medications or infection with human immunodeficiency virus (HIV/AIDS)
  • children 6 months to 18 years of age who are on long-term aspirin therapy because children given aspirin while infected with influenza are at risk of developing Reyes syndrome
  • women who will be pregnant during the influenza season
  • all children 6 to 23 months of age
  • people with any condition that can compromise respiratory function or the handling of respiratory secretions such as difficulty breathing or swallowing

#2 - People 50 to 64 years of age

#3 - People who can transmit flu to others at high risk from being in close contact (for example, health-care workers and caregivers).

The flu is spread by respiratory droplets, most commonly coughing or sneezing.

Healthy adults can possibly infect others beginning a day before symptoms appear for up to 5 days after becoming sick.

Who Should Not Get a Flu Vaccine?

A flu vaccine may be contraindicated in some people, including:

  • people who are severely allergic to chicken eggs
  • people who have had a severe reaction to a prior influenza vaccine
  • people who developed Guillain-Barre syndrome within 6 weeks of getting a previous flu vaccine
  • children under 6 months of age
  • people who have a moderate or severe illness with a fever should wait to get a flu vaccine

The Nasal-Spray Flu Vaccine

The nasal-spray flu vaccine which is made with live, weakened flu viruses that do not cause the flu (referred to as LAIV for Live Attenuated Influenza Vaccine). LAIV is approved for use in healthy people 5 years to 49 years of age who are not pregnant. It is not recommended for people with chronic conditions. People with chronic conditions should get the flu vaccine shot rather than the nasal spray.

Does the Flu Vaccine Protect Everyone Equally?

According to a report in the Cochrane Collaboration, a review of 71 studies revealed that flu vaccines prevented 45 percent of flu and complications of the flu among older adults residing in nursing homes and long-term care facilities. The rate of prevention dropped to 25 percent among older adults living in the community. The report also questioned the effectiveness of vaccinating health care workers.

A report which appears in the September 2006 issue of Rheumatology News concludes that the flu vaccine is less effective in patients with systemic lupus erythematosus. The small study of 56 lupus patients with low disease activity suggested that though the flu vaccine is safe, it is less effective than was evident in controls. The flu vaccine was even less effective in patients treated with azathioprine (Imuran) compared to other immunosuppressive medications.

"Less effective" does not mean "not effective" it must be noted. If you have any doubt about getting a flu vaccine, consult your doctor.

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Article Sources

  • Flu Vaccine Found Less Effective in SLE Patients, Rheumatology News. Vol 5, Issue 9, Page 19, Sept 2006.
  • Influenza vaccination for healthcare workers who work with the elderly, Cochrane Collaboration
  • Key Facts about Influenza and the Influenza Vaccine, CDC.
  • Vaccines for preventing influenza in the elderly, Cochrane Collaboration