Flus are airborne diseases that cause respiratory illness. They are particularly dangerous as they can spread quickly, especially among children and other people with weak immune systems. The most common symptoms of the flu include fever, chills, body aches, and fatigue. The Centers for Disease Control and Prevention (CDC) recommend that people get a yearly flu shot to help protect against the most prevalent types of flu. Flus have been a major concern for centuries, but vaccinations have dramatically reduced the number of flu infections in recent decades. The flu shot contains a killed form of the virus that is injected into the body, which stimulates the immune system to make antibodies that can fight off an infection if it is exposed. While it is not 100% effective, the flu shot can significantly reduce the risk of infection. It is important to stay up to date with recommended flu vaccinations not just to protect yourself, but also to help protect those around you. People who are immunocompromised, such as the elderly and young children, are especially vulnerable to the flu, and can become much sicker than those with stronger immune systems. By getting your flu shot, you can help to prevent the spread of the disease and protect vulnerable populations.