A cold and the flu are caused by viruses. Both are respiratory infections.
While flu symptoms may seem similar to those of the common cold, flu is a
more serious disease and its symptoms come on quickly. Use the symptom
checker as a guide to better understand some of the differences.
It takes about 2 weeks after vaccination for the body to develop antibodies that provide protection against flu viruses, so don't wait until peak flu season to get vaccinated.