Why You Need a New Flu Vaccine Every Year

Annual flu shots can help protect you from becoming infected, but the flu virus changes, making new vaccines necessary.

It’s easy to think of influenza as a single type of respiratory viral infection. After all, symptoms are virtually the same, year to year, illness to illness. As many as 20% of Americans are affected by the flu each year, accounting for over 30 million patient visits to medical professionals.  

Yet, there are four types of influenza viruses, named A through D. The C type of virus produces only mild symptoms and isn’t known to occur on an epidemic scale, and D type usually affects only cattle and doesn’t make humans sick. Flu shots protect against various strains of A and B type flu viruses, the types that reach epidemic proportions annually.

The dangers of flu

For most healthy people, the flu, while unpleasant, isn’t a serious threat. Within a week or two, you’re feeling better again, although you may have missed school or work on the worst days. There are, though, segments of the population who are vulnerable to complications arising from the flu.

People over 65, particularly those in long-term care facilities, children under 2 years old, pregnant women, and people with compromised immune systems are among those for whom the flu could develop serious complications, including bronchitis, heart problems, or pneumonia. Though annual flu vaccines are never 100% effective, they can reduce the incidence of flu for those who are most vulnerable.

Flu mutations

Any vaccine works by exposing your body to an inactive form of a disease, so you can develop antibodies to fight off an attack by the active forms. For the flu, the most common type of vaccine protects against two versions of A type virus and one version of B type, though some years two versions of B type protection are offered.

The precise strains of flu viruses protected by a vaccine are constantly changing. As simple organisms, the viruses mutate quickly, so older versions of a vaccine are no longer effective at sensitizing your body against the newer, mutated version. All life works to perpetuate itself, so mutating is the way a flu virus stays alive. Only the healthiest mutations survive, and these are sufficiently different that previous vaccines are no longer effective.

Annual flu vaccines

Protecting against flu outbreaks takes a mix of research and statistical analysis to make educated guesses about which flu strains will be the most active in the coming flu season. The Centers for Disease Control and Prevention (CDC) works with institutions in other countries to test and predict influenza around the globe, and the Food and Drug Administration uses this information to decide on the vaccines available in the United States each year.

New strains of virus are assessed and compared to existing strains. Those strains that are predicted to spread fastest, and for which an effective vaccine exists, are chosen for vaccine prevention. The aim is to protect against viruses that have the potential for the most harm, since it’s not practical to immunize against all current and future strains.

An annual flu shot is important not only for you, but to reduce flu exposure to vulnerable people around you. In Cypress, Texas, Dr. Hammad Qureshi and the team at Creekside Family Practice can add a flu shot to your health care regimen. Call the office or request an appointment online to schedule your flu shot today.

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