For some suppliers, it’s supply and demand at work. For consumers, it’s gouging. The head of Missouri’s immunization program, Sue Denney, says some companies with supplies of flu vaccine have jacked up the price more than 500 percent as supplies have gotten shorter. The Health Department says it’s price gouging. A spokesman for a company charging $215 for a vial that once cost $40 has told the St. Louis Post-Dispatch her company is performing a public service. She says it has located some supplies, and people seem to be willing to pay the going price.