Her van is stocked with all the vaccinations necessary for Oklahoma school enrollment, such as tetanus, measles and polio. But despite efforts to increase immunization rates by providing free and more accessible vaccinations, experts say Oklahoma’s overall child vaccination rates are down amid skepticism about the efficacy of vaccines. Image © iStock - designer491Tulsa County health officials said they have seen a decrease in overall vaccination rates for children. On a recent summer morning Caring Van staff were giving out free vaccinations at the Latino Community Development Agency. The program seeks to raise vaccination rates in Oklahoma by removing access barriers, said program coordinator Liz Davidson.