Researchers from the University of Colorado in Denver have conducted a study examining adult vaccination, revealing a public health concern over the “stubbornly low” vaccination rates in adults. They note that 30,000 people in the US die of vaccine-preventable diseases each year, the majority of whom are adults.

Published in the journal Annals of Internal Medicine, the study was led by Dr. Laura Hurley, assistant professor of medicine at the University of Colorado (CU) School of Medicine.

“Our study suggests that missed opportunities for adult vaccination are common,” she says, “because vaccination status is not being assessed at every (physician’s) visit, which is admittedly an ambitious goal.”

Dr. Hurley adds that “most physicians are not stocking all recommended vaccines.”

She and her team, in collaboration with the Centers for Disease Control and Prevention (CDC), created a national survey of primary care physicians for 2012 to look at how they determined vaccination status and stocked the 11 recommended adult vaccines.

The researchers note that only 65% of adults over the age of 65 received an influenza vaccine and only 62% received a pneumococcal vaccine.

Additionally, only 20% of high-risk adults between 19 and 64 years of age received a pneumococcal vaccine and only 16% over 60 years old got their shingles (herpes zoster) vaccination.

The study points to several reasons why adults are not getting the recommended vaccines, but the most prominent reason is financial barriers.

“Physicians in smaller, private practice often assume more risks from stocking expensive vaccine inventories and may be particularly affected by these financial barriers,” the authors write.

Many physicians also cited difficulty in getting reimbursed by insurance companies for vaccines, which may be a contributing factor.

Using the herpes zoster vaccine as an example, the researchers note that it has been recommended since 2008. However, many physicians do not stock the vaccine – which is covered by Medicare Part D – because of reimbursement issues.

Since the vaccine can cost patients significant amounts of money, many patients opt out of getting the vaccine altogether.

The researchers say that because of these difficulties, many doctors are sending patients to pharmacies or public health organizations to receive vaccinations.

In order to reduce the 30,000 preventable deaths a year, the researchers recommend using a confidential database called Immunization Information Systems (IIS) to record vaccines administered by providers in a certain area.

They say this system could alert doctors to the vaccination status of each patient.

Additionally, the investigators say the Affordable Care Act requires private insurers to cover the recommended vaccines without co-payments when administered by in-network providers, which should help to address any financial hurdles that privately insured individuals encounter.

However, Dr. Hurley warns that changes need to be made:

“I feel we need to take a more systematic approach to this issue. As the population ages this could easily grow into a more serious public health issue.”

The authors conclude their study by writing:

Improving adult vaccination delivery will require increased use of evidence-based methods for vaccination delivery and concerted efforts to resolve financial barriers, especially for smaller practices and for general internists who see more patients with Medicare Part D.”

The CDC recently updated their 2014 recommended adult immunization schedule. Key changes to the schedule included revised notes on administering vaccines for flu, tetanus, diptheria, human papillomavirus (HPV), zoster virus, pneumococcal disease and meningococcal disease.