Here's a look at various flu clinics and what they are asking people to bring with them:

Larimer County

It hosted its first public vaccine clinic Wednesday.

They have pre-registered 2,400 patients, and already know these people fit into one of these high risk categories:

pregnant woman
parents/caretakers of children under 6 months
children 6 months old to 4 years old
children 5 to 18 with underlying medical conditions

They are asking people to bring a driver's license or utility bill. Something that proves they are a resident of Larimer County.

Jefferson County

Jefferson County has already administered 25,000 doses through health care and daycare clinics.

They plan their first public clinics on Nov. 21 at five schools and are asking people to understand the importance of honoring the system that's been set up to vaccinate those in high risk categories first.

"We will not hold up the line to show proof of everything," said Nancy Braden of the Jefferson County Health Department.

They define high risk as:

pregnant women
children 6 months to 24 years
people 25 – 64 with underlying medical conditions
parents/caretakers of children under 6 months
health care and emergency workers

Denver Health

It says, "We won't hold up the line, but if you obviously don’t fit one of the high risk categories we may pull you out."

They won’t ask for proof of residency but they will ask health care workers to bring their health care ID.

Denver provides vaccine for health care workers at the eight major hospitals in Denver. Jefferson County, for comparison, only has one major hospital.

Tri-County Health

Tri-County health officials will host their first public clinics, Thursday, at Byers School district, Bennett Middle School and Thornton Middle School.

Dr. Richard Vogt, executive director of Tri-County Health Department, said they won't ask for a note from a doctor to prove that you're in a high risk group, but they will ask for a driver's license or some other proof that you are a resident of Adams, Arapahoe, Douglas, Elbert or Broomfield counties.

Elbert and Broomfield are not part of Tri-County Health Department but have made special arrangements to have vaccine provided.