Influenza, commonly known as the flu, is a viral infection that targets the respiratory system, which is made up of your nose, throat and lungs.
Symptoms can include cough, congestion, muscle aches, fever and chills. Most people who get the flu will feel sick for a few days and then recover with no complications. However, in some people if the flu is left untreated, it can lead to long-term hospitalization and even death. Certain groups, such as children, seniors and people with a compromised immune system, are more vulnerable to getting infected and having complications than others.
The Centers for Disease Control and Prevention (CDC) recommends everyone 6 months and older with rare exceptions get an annual flu shot.
For optimal protection, individuals should get vaccinated in September or October, before peak flu season starts in December and February. Like the virus itself, the flu vaccine is constantly changing. Researchers create formulas based on the previous year's strains and the strains currently circulating in other areas of the world to combat the latest variants.
The flu shot uses a small amount of inactivated virus to trigger the body’s natural defenses. This exposure helps the immune system better identify and combat incoming pathogens in the future. It takes about two weeks for the body to create antibodies after the flu shot. Since the flu shot is an inactivated form of the flu virus, it cannot spread the infection.
In some instances, people experience side effects like low-grade fever, headache or muscle aches after taking the shot. Others may develop redness, soreness or swelling at the site of injection. These issues are usually resolved in one or two days.
For the 2024-2025 season, all flu vaccines will be trivalent, meaning they protect against three viral strains. Standard versions are grown and synthesized from chicken eggs. The CDC now recommends the same vaccine for people with egg allergies, but everyone should get the vaccine in a safe environment where immediate medical care is available.
Generally, flu vaccines can be administered to individuals six months and older.
Although the success rate varies from year to year, the flu vaccine has been shown to reduce the chance of infection by 40% to 60%. For vaccinated people who get the virus, they experience much milder symptoms and have fewer influenza-related complications.
Public health officials recommend getting both the flu and COVID-19 vaccines, and it’s safe to get them together.
Looking for more flu-prevention info? Read these posts:
- The Difference Between COVID-19 and the Flu
- To Help Fight Coronavirus, Get a Flu Shot
- 6 Things Everyone Should Know About the Flu Shot
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