Patients do not need to schedule an appointment for the first-come, first-served events, which are being provided by the Centers for Disease Control.

Officials with Denver Health advise checking the hospital's flu line at 303-436-6100, or visit denverhealth.org to confirm the clinic is still on as scheduled and that vaccines are still available.

Health officials recommend high risk groups receive the vaccine. Those groups include: Children 6 months to 18 years old, people 19 through 24 years old, pregnant women, health care personnel, people 25 to 64 with underlying medical conditions such as asthma or diabetes, and caregivers for children under 6 months old.

Denver Health will hold free H1N1 vaccination clinics:

Tuesday, Nov. 3:

7 - 10 a.m., and 4 - 7 p.m., Rita Bass Trauma & EMS Institute, 190 W. 6th Ave., Denver

Wednesday, Nov. 4:

7 - 10 a.m., and 4 - 7 p.m., Rita Bass Trauma & EMS Institute, 190 W. 6th Ave., Denver

Saturday, Nov. 7:

8 a.m. - Noon, and 1 - 5 p.m., at Eastside Family Health Center, 501 28th St., and at Westside Family Health Center, 1100 Federal Blvd., Denver

Sunday, Nov. 8:

8 a.m. - Noon, and 1 - 5 p.m., at Eastside Family Health Center, 501 28th St., and at Westside Family Health Center, 1100 Federal Blvd., Denver

Wednesday, Nov. 11:

7 - 10 a.m., and 4 - 7 p.m., Rita Bass Trauma & EMS Institute, 190 W. 6th Ave., Denver

Tuesday, Nov. 17:

7 - 10 a.m., and 4 - 7 p.m., Rita Bass Trauma & EMS Institute, 190 W. 6th Ave., Denver

Wednesday, Nov. 18:

7 - 10 a.m., Rita Bass Trauma & EMS Institute, 190 W. 6th Ave., Denver

Saturday, Nov. 21:

8 a.m. - Noon, and 1 - 5 p.m. at Eastside Family Health Center, 501 28th St., and at Westside Family Health Center, 1100 Federal Blvd., Denver

Sunday, Nov. 22:

8 a.m. - Noon, and 1 - 5 p.m. at Eastside Family Health Center, 501 28th St., and at Westside Family Health Center, 1100 Federal Blvd., Denver

Tuesday, Nov. 24:

7 - 10 a.m., and 4 - 7 p.m., at the Rita Bass Trauma & EMS Institute, 190 W. 6th Ave., Denver