Some parents are unable to vaccinate their children because the shots are too expensive and too complicated, experts say.The federal government each year buys enough vaccine to inoculate more than 10 million children and subsidizes vaccination through state Medicaid programs.But the government's cost to buy all vaccines for a child up to age 12 -- $155 in 1995 -- had grown by 2007 to $927 for a boy, and $1,214 for a girl (including the new vaccine against cervical cancer)."The increasing cost of vaccines has raised concerns that some children are being denied access to immunization and that overall immunity in society will also suffer,'' said Dr. Jerome Klein, a professor of pediatrics at Boston University, who's studied vaccine financing.Vaccine cost is a particular concern for families whose insurance either does not cover preventive care or who have high deductibles. A 2003 Institute of Medicine report noted that 16 percent of children covered by private health insurance are in plans that don't cover vaccines. And a 2007 study by researchers at Harvard Medical School found substantial vaccine coverage gaps for underinsured children, particularly for more expensive new shots protecting against meningitis and pneumococcal infections.Dr. Grace Lee and colleagues estimated that as many as 2.3 million to 1.2 million underinsured children were not getting help in up to 30 states, even if they were referred to public health clinics. The situation is compounded because many families lacking insurance don't have regular doctors, and even if they do, many doctors don't keep enough vaccines on hand to meet demand. In some states, Medicaid pays doctors as little as $2 to administer a vaccine -- barely enough to cover the cost of syringe and needle."So right now, we can't jump on the bandwagon to get everybody vaccinated because we can't afford to,'' said Dr. Stan Block, a pediatrician in Bardstown, Ky. "I mean we're talking about our practice going maybe $50,000 to $100,000 in the hole if we actually did what we're supposed to be doing,'' Block told a forum on vaccine expenses held by the American Academy of Pediatrics in Atlanta in the fall of 2006. "Physicians have a laundry list of complaints about the cost of buying and administering vaccines, everything from having a freezer where they can store serum to having to wait weeks to months to find out if insurance will even cover immunization,'' Klein said."It's hard to imagine parents skipping vaccines for their children because they -- or even their doctor -- can't afford to pay for them, but it certainly is part of the problem we're facing in getting full immunization coverage,'' Klein said.(Lee Bowman is health and science correspondent at Scripps Howard News Service. E-mail him at bowmanl(at)shns.com)(Distributed by Scripps Howard News Service, http://www.scrippsnews.com)