Colorado doctors mostly support local efforts to give kids their flu shots and other vaccines at school - but they also have misgivings, a new study shows.

In particular, they threw more support to school flu shots, versus other vaccinations. They were also worried about how school vaccinations would affect their record-keeping and their bottom line.

The study, reported in the journal Pediatrics, looked at doctors' feelings on so-called school-located vaccination - one-day "clinics" where local health officials and school districts offer kids flu shots or other vaccinations.

The programs are seen as a potential way to bring more kids up-to-date with government-recommended vaccinations.

Since 2010, the U.S. has advised nearly all Americans age six months and up to get an annual flu shot.

Even though only a minority follow that advice - about 43 percent of Americans did during the 2010 flu season - that still translates to more than 100 million people clambering for the flu vaccine within the space of a few months.

"To get all of those people into the doctor's office is impossible," said Dr. Judith Shlay of the Denver Public Health Department, the senior researcher on the new study.

In Denver, a project funded by the Centers for Disease Control and Prevention has provided in-school flu shots, as well as vaccinations recommended for older kids and teenagers: the meningococcal meningitis vaccine, the human papilloma virus (HPV) vaccine and the "Tdap" vaccine against tetanus, diphtheria and pertussis (whooping cough).

For the current study, Shlay's team wanted to know how pediatricians and family doctors felt about school vaccinations.

Of the 584 doctors who responded to the survey, most supported in-school flu shots.

About two-thirds were in favor of their privately insured patients getting the shot at school, while around three-quarters liked the idea for their patients on Medicaid.

A financial consideration likely factors in there, since the federal government provides free vaccines for kids on Medicaid, but doctors may have a tough time being reimbursed for the administration costs. Shlay's team found less support for kids getting other vaccinations at school. Half of pediatricians and 59 percent of family doctors were for it when it came to patients with private insurance; 59 percent and 67 percent, respectively, supported it for Medicaid patients.

One concern was that if older kids get all their vaccinations at school, they won't come in for routine check-ups. Many doctors were also worried they'd have a hard time keeping their patients' records straight.

"If we give vaccinations in schools and the doctor doesn't know about it, then that's a concern," Shlay said.

There is a way to address that, though. Colorado, and all other U.S. states, have computerized immunization registries that offer a consolidated record of children's vaccination histories.

"That's a really important tool," Shlay said.

But of the doctors in this survey, about one-third were not participating in Colorado's immunization registry.

If more providers get involved in state registry systems, that could help ease worries over record-keeping, Shlay's team writes.

Many doctors were also concerned about their bottom line. Most were at least somewhat worried that if an unpredictable number of patients got their vaccinations at school, their offices would have a tough time estimating how many vaccine doses to have in stock.

Shlay said that's a legitimate concern, since the vaccines for older kids and teens are expensive. (The retail price of the HPV vaccine, for example, is about $130 per dose.)

"If (doctors) end up with unused, expired vaccines, that's a problem," Shlay said. The potential waste, she added, is a concern not only for doctors, but for everyone who needs the vaccines.

So that may mean doctors' offices will need to be more careful in terms of inventory, Shlay noted.

But even if your child gets vaccinated at school, that's not a replacement for check-ups with the doctor.

"There's more to health and healthcare than just vaccines," Shlay noted.

It's important, she said, for doctors, public health officials and schools to all work together to make school vaccination programs effective - and, in the bigger picture, get all kids their appropriate vaccinations.

A government study last year found that that goal is fairly far off: Only 49 percent of U.S. teens had received the first of three doses of the HPV vaccine, while 63 percent had gotten the meningitis vaccine and 69 percent the Tdap shot.

"School-located vaccine programs are an important approach to augment vaccine delivery," Shlay said.