RALEIGH, N.C. (WBTW) — North Carolina ranks as the worst state in the nation for its rate of fully vaccinated residents who have also received a booster dose of a COVID-19 vaccine, according to data from the Centers for Disease Control and Prevention.

About 28.7% of North Carolina’s population that had already been vaccinated has received a third shot, according to the data. It is followed by Texas, Alabama, Oklahoma and Mississippi.

The North Carolina Department of Health and Human Services told News13 that the percentage of the state’s population that has received at least one booster dose is 60%. A spokesperson said the discrepancy in the data comes from the way the CDC links data from the state.

The state can determine if a person received a booster through a different program than the primary series, but said the CDC’s system doesn’t link the data, causing the CDC’s numbers to be lower than the state’s numbers.

“This dashboard metric comes from the NCDHHS COVID-19 Vaccine Management System’s (CVMS) ability to link data within and between the North Carolina Providers program and the Federal Pharmacy Programs,” the NCDHHS said in a statement. “Through this linkage, NCDHHS can identify which individuals received another dose following their primary series, even if those doses were administered through different programs. Those doses are added to the Additional/Booster Dose Administered count. Because the CDC’s system does not make this linkage, its total number of additional/booster doses for North Carolina is lower.”

The state said there aren’t many things that it could do on its end to resolve the discrepancy. The spokesperson said the state has been working with the CDC to send pre-linked data to be used as the source for the dashboard.

Vermont has the highest rate of vaccinated residents with a booster, at 63.2%, according to the CDC data. It is followed by Minnesota, Wisconsin, Maine and Hawaii.

When it comes to vaccine types, more than 360.9 million people nationwide have received a dose of the Pfizer vaccine, followed by Moderna, at 229.59 million doses. Both vaccines require two doses for a person to be considered fully vaccinated.

Children between the ages of 5 and 11 years old have the lowest rate of receiving a booster, at 4.3% nationwide. About 30.7% children in that age group are considered fully vaccinated.

Among those 12 and 17 years old, 17.3% have received a booster. About 27.5% of people between the ages of 18 and 49 have received a booster, 43.6% of those aged 50 to 64 have a booster and 65% of people over the age of 65 have one.