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Flu prevention and flu vaccine

The flu can affect anyone at any age. Learn how to avoid contracting the virus and get facts about the vaccine.

Flu prevention

A new influenza, or flu, vaccine is introduced each September. It is usually recommended for specific groups of people (see below), as well as for persons who want to avoid having the flu. In addition, antiviral medications are approved for use in preventing the flu. All of these medications are available by prescription, and a physician should be consulted before any medication is used for preventing the flu.

Following these precautions may also be helpful:

  • When possible, avoid or limit contact with infected persons.
  • Frequent handwashing may reduce, but not eliminate, the risk of infection.
  • A person who is coughing or sneezing should cover her nose and mouth with a handkerchief to limit spread of the virus.

FluMist nasal spray flu vaccine

A nasal spray flu vaccine, called FluMist, is currently approved to prevent flu due to influenza A and B viruses in healthy children and adolescents, ages two to 17, and healthy adults, ages 18 to 49. As with other live virus vaccines, FluMist should not be given for any reason to pregnant women and people with immune suppression, including those with immune deficiency diseases, such as AIDS or cancer, and people who are being treated with medications that cause immunosuppression. FluMist also should not be given to the following groups of people:

  • Children less than two years of age
  • Any person with asthma
  • Children less than five years of age with recurrent wheezing

Flu vaccine effectiveness

Vaccine effectiveness varies from year to year, depending upon the degree of similarity between the influenza virus strains included in the vaccine and the strain or strains that circulate during the influenza season. Vaccine strains must be chosen nine to 10 months before the influenza season. Sometimes mutations occur in the circulating strains of viruses between the time vaccine strains are chosen and the next influenza season. These mutations sometimes reduce the ability of the vaccine-induced antibody to inhibit the newly mutated virus, thereby reducing vaccine effectiveness.

Vaccine effectiveness also varies from one person to another, depending on factors such as age and overall health.

Flu vaccine side effects

The most serious side effect that can occur after an influenza vaccination is an allergic reaction in people who have a severe allergy to eggs. For this reason, people who have an allergy to eggs should not receive the influenza vaccine.

The National Center for Infectious Diseases, a division of the Centers for Disease Control and Prevention, says that the influenza vaccine causes no side effects in most people who are not allergic to eggs. Less than one-third of people who receive the vaccine experience some soreness at the vaccination site, and about five to 10 percent experience mild side effects, such as headache or low-grade fever for about a day after receiving the vaccination.

Because these mild side effects mimic some influenza symptoms, some people believe the influenza vaccine causes them to get influenza. However, according to the CDC, "influenza vaccine produced in the United States has never been capable of causing influenza because the only type of influenza vaccine that has been licensed in the United States to the present time is made from killed influenza viruses, which cannot cause infection."

Who should immunize against the flu?

The flu causes complications that may develop into a more serious disease or become dangerous to some groups, such as elderly people and those with chronic medical conditions. For these reasons, the CDC recommends that the following groups immunize themselves each year. Always consult your physician for more information regarding who should receive the flu vaccine:

  • Persons 50 years old or older - vaccine effectiveness may be lower for elderly persons, but it can significantly reduce their chances of serious illness or death from influenza.
  • Children and adolescents six months to 19 years of age
  • Residents of nursing homes and any 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 children with asthma
  • Adults and children who have the following medical conditions:
    • Chronic metabolic diseases, i.e. diabetes
    • Renal dysfunction
    • Immunosuppression
    • Hemoglobinopathies
  • Children and teenagers - aged six months to 19 years- receiving long-term aspirin therapy
  • Women who will be pregnant during flu season

In addition, the following groups should be vaccinated:

  • Health care providers
  • Employees of nursing homes and chronic care facilities who have contact with patients or residents
  • Providers of home care to persons at high risk
  • Household members, including children, of persons in high-risk groups
  • Persons of any age who wish to decrease their chances of influenza infection, excluding persons who are allergic to eggs

When to get the flu shot

The Centers for Disease Control and Prevention recommends getting the flu shot every year, between September and mid-November, before the flu season hits, usually December to April. The flu shot takes one to two weeks to become effective.

Although there are many new medications designed to treat flu symptoms and even shorten the duration of the illness, the flu vaccine still offers the best protection against the flu.

If I get the flu shot, can I still get the flu?

Every year, the flu shot "cocktail" changes to combat the current strains of influenza affecting the population. The World Health Organization monitors flu outbreaks worldwide and recommends appropriate vaccine compositions to be used for the next year. However, sometimes, a strain may appear that was not included in the flu vaccine. People who have had the flu shot tend to have milder symptoms if they contract the flu.

Traveling & the flu

Because the flu is a highly contagious infection usually spread by droplets produced by an infected person who is coughing or sneezing, travelers are very susceptible to contracting the flu.

The CDC recommends that travelers have the flu vaccine at least two weeks in advance of planned travel to allow time to develop protective immunity. There are other anti-viral drugs available to help prevent viral infections and complications. Consult your physician for more information.

First Call for Children

When your doctor's office is closed, our Nurse Advice Line can answer your questions.

(303) 563-3300 Denver Metro Area/(877) 647-7440 Toll-free (outside of Denver)

Open Mon-Fri 5:00 p.m. - 8:00 a.m. 24 hours, weekends and holidays

For medical emergencies ALWAYS call 9-1-1

When your doctor's office is closed, our Nurse Advice Line can answer your questions.

(303) 563-3300 Denver Metro Area/(877) 647-7440 Toll-free (outside of Denver)

Open Mon-Fri 5:00 p.m. - 8:00 a.m. 24 hours, weekends and holidays

For medical emergencies ALWAYS call 9-1-1