Influenza (flu) is a respiratory illness caused by influenza viruses. Influenza infections can cause mild to severe illness, and at times can lead to death. The virus is spread mainly by droplets when people cough, sneeze or talk. People might also get flu by touching an object or surface that has the virus on it and then touching their mouth, eyes or nose.
The best way to prevent the flu is by getting a flu vaccine each year. Everyone 6 months and older should get a flu vaccine each year. The annual flu vaccine is especially important for those people at high risk of having serious flu-related complications and those who live with or take care of those at high risk for developing complications. Good health habits can also help stop the spread of respiratory illnesses like the flu.
This season both trivalent and quadrivalent vaccines will be available. The trivalent vaccine will contain three influenza strains, like it has in previous seasons. The quadrivalent will contain four influenza strains. The technology and methods for making the new quadrivalent is the same as for the trivalent. The fourth strain that is included in the quadrivalent is another lineage of influenza B. Questions regarding the vaccine can be directed to your physician, pharmacist, or local health department.
Why do we need annual flu vaccines? Because influenza viruses go through antigenic drift.