CDC will again recommend tiered influenza vaccine delivery

September 2002

ATLANTA — Individuals at high risk for complications from influenza should be vaccinated starting in October, and other people wishing to gain protection against influenza should wait until November or later, according to this year’s influenza vaccine recommendations.

For the first time, influenza vaccine will also be recommended for infants age 6 to 23 months. The decision to include an indication for infants was made earlier this year by the Advisory Committee on Immunization Practices (ACIP) because young children are at increased risk for morbidity and mortality.

The ACIP also voted to include the influenza vaccine in the Vaccine for Children program, which pays for vaccines for uninsured children.

According to the ACIP, vaccine providers should give priority to all high-risk individuals in October, including people 65 and older, residents of nursing homes or long-term care facilities, children or adults with chronic illnesses, children 6 months to 18 years on long-term aspirin therapy and pregnant women who will be in their second or third trimester during influenza season.

Health care workers who care for high-risk individuals and household contacts should also be vaccinated in October. Children younger than 9 years receiving the vaccine for the first time require a priming dose in October and a booster dose in November.

Individuals younger than 65, especially individuals aged 50-64, and anyone else who wants protection against influenza should be vaccinated in November or later. Although the influenza season can begin as early as December, influenza activity typically peaks between January and March.

The trivalent inactivated influenza vaccine is considered extremely safe and effective, conferring immunity in more than 90% of recipients. The vaccine is only contraindicated in individuals with anaphylaxis to chicken eggs and individuals with a previous vaccine-associated allergic reaction and individuals who develop Guillain-Barré syndrome in temporal relationship with receipt of vaccine.

Unlike previous years, there should be an adequate supply of influenza vaccine, about 88-93 million doses by the end of December.

A misunderstood vaccine

Many people avoid getting the influenza vaccine because they think influenza is a relatively harmless illness or that the vaccine could cause the disease. This is simply not true, according to Gregory Poland, MD, director of vaccine research at the Mayo Clinic, Rochester, Minn.

According to the CDC, about 20,000 people die each year from influenza, and influenza is responsible for about 114,000 hospitalizations. About 10% to 20% of the population becomes infected with influenza during a typical influenza season.

“People die because they don’t realize we have a safe and effective vaccine against influenza,” he said.

Another commonly held belief, that the vaccine can cause influenza, is also incorrect. The influenza strains in the vaccine are inactivated, meaning they are essentially dead and cannot cause illness.

According to the CDC, typical influenza includes a sudden onset of high fever, severe fatigue, severe muscle and joint aches and cough that could be complicated by pneumonia.

The influenza vaccine was designed to protect against the complications of influenza, especially morbidity and mortality, and not the symptoms of influenza. Most often breakthrough illness is probably infection with a non-influenza virus but mistakenly diagnosed as influenza, according to Poland.

While there are countless influenza strains circulating during a given winter, the vaccine only confers protection against three types. This year’s vaccine includes A/New Caledonia/20/99-like (H1N1), A/Moscow/10/99-like (H3N2) and B/Hong Kong/330/01-like viruses. The strains were chosen based on which strains are expected to circulate in the United States this winter based on analysis of influenza samples from around the world. Aside from 1997, when A/Sydney-like virus started circulating after the vaccine decision was made, the vaccine has been generally effective against circulating strains of influenza.

“It’s an educated guess, but it’s amazing how often we’ve been right,” Poland said.

For more information:

• Flu activity and additional information on influenza can be found at http://www.cdc.gov/ncidod/diseases/flu/fluvirus.htm.

• Dr. Poland has no direct financial interest in the products mentioned in this article, nor is he a paid consultant for any companies mentioned.