DULUTH, MN (KDAL) - As the number of flu cases increases, the demand for the flu vaccine is also growing.  Essentia Health in Duluth is setting up a walk-in flu shot clinic on Friday and again next week in the lobby of their building at 420 East 1st Street.  No appointment is needed and the cost is covered by many private insurance companies and by Medicare Part B and Medicaid.   Flu shots will be available from 9 a-m to 5 p-m on Friday and again next Thursday and Friday (January 17th and 18th).  It's recommended that everyone six months and older get vaccinated against the flu.