Does the Vaccine Work?

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The Washington Post,03 Oct 2006

How effective is flu vaccine in preventing the flu? Not perfect, but pretty good. Flu vaccine works by stimulating your immune system to recognize and attack specific strains of flu viruses. Because these viruses change fast, a yearly vaccination is required. The current vaccine is based on these changes.

Each year the Centers for Disease Control and Prevention tracks flu virus strains worldwide in an attempt to predict which new strains will be circulating during the coming flu season. Based on this information, the agency recommends the makeup of that year’s flu vaccine. When virus strains in the vaccine are wellmatched to actual virus strains circulating about, the flu vaccine appears to be 70 to 90 percent effective in preventing the flu among healthy adults younger than 65.

Researchers are busy sequencing the genes in the human influenza virus. This information will enable scientists to quickly zero in on currently circulating virus strains and their variants, which should lead to more-effective vaccines.

Researchers are busy sequencing the genes in the human influenza virus. This information will enable scientists to quickly zero in on currently circulating virus strains and their variants, which should lead to more-effective vaccines.

Oral antiviral drugs play second fiddle to the flu vaccination, but are valuable in helping to prevent or treat the flu in certain situations.

These antiviral drugs include the older agents amantadine (Symmetrel) and rimantadine (Flumadine) and the newer agents Tamiflu and Relenza. They prevent flu viruses from replicating once they get inside the body.

This season, however, the CDC recommends that the older agents not be used. Testing in the United States and Canada indicates that flu virus strains have become too resistant to them.

The good news is that Tamiflu and Relenza still appear to work and can be given if needed.

— Richard Harkness