Sep 26, 2025 · Seasonal flu vaccines in the United States are formulated to protect against three influenza viruses known to cause human epidemics, including: one influenza A (H1N1) virus, …

Dec 21, 2018 · Influenza — also known as the flu — is a contagious viral infection that attacks your respiratory system. Influenza viruses that infect humans can be classified into three main …

Oct 19, 2025 · Influenza A often causes fever, cough, and fatigue. This highly contagious virus primarily affects the respiratory system, including your nose, throat, and lungs.

Influenza A virus, or IAV is a pathogen with strains that cause seasonal flu in humans; it can also infect birds and some mammals. [1] .

Dec 19, 2025 · Flu, also called influenza, is an infection of the nose, throat and lungs, which are part of the respiratory system. The flu is caused by a virus. Influenza viruses are different from …

Nov 13, 2025 · Is the Flu a Virus or Bacteria? The flu is a contagious respiratory illness caused by influenza viruses that infect the nose, throat, and sometimes the lungs. 2 However, it is not the …

What is the flu (influenza)? The flu is an illness you get from the influenza virus. It causes symptoms like head and body aches, sore throat, fever and respiratory symptoms, which can …

Jan 23, 2025 · Both the flu and the common cold are caused by viruses and are contagious. However, the common cold can result from many viruses, including rhinoviruses and seasonal …

4 days ago · Influenza is an acute viral infection of the upper or lower respiratory tract, marked by fever, chills, and a generalized feeling of malaise. Seasonal influenza (the flu) is a major global …

Feb 28, 2025 · Seasonal influenza (the flu) is an acute respiratory infection caused by influenza viruses. It is common in all parts of the world. Most people recover without treatment. Influenza …