The CDC has acknowledged it misreported Pennsylvania’s coronavirus vaccination rates by not using updated data from the Commonwealth, an error that this month caused it to wrongly rank the state as first in the nation for adults with at least one dose.

The agency is updating the vaccination data it uses for Pennsylvania, which will correct the vaccination rates it posts online, though the adjustment is not likely to occur before the end of the year.

The Pennsylvania state’s Department of Health announced last Wednesday that the CDC would rectify its data, 10 days after the The Inquirer reported that the agency was still using the state’s outdated numbers.

Though there may be multiple discrepancies between the state’s vaccination data and the CDC’s, the main issue stems from July, when a data cleanup by the Department of Health corrected an overcount of the number of first doses and a smaller undercount of the number of second doses. The CDC never picked up the new data, despite Pennsylvania health officials’ requests.

Data posted this month by the federal government’s top health agency erroneously suggested about 95% of Pennsylvania’s adults had gotten at least one dose of a COVID-19 vaccine. State health officials said the vaccination rate isn’t that high, although they could not say how inflated that number was.

The changes made so far by the CDC appeared to bring the percentage of all residents who are fully vaccinated more closely in line with the state’s own statistic, putting it at nearly 69%, though that may not be a final number.

» READ MORE: CDC says 95% of Pa. adults have gotten at least one COVID-19 vaccine dose. That’s wrong.

The CDC did not immediately respond to questions about the process. In September, a spokesperson told The Inquirer the agency was aware of the need for a fix yet had no timeline for doing so.

In response to questions earlier this month, a CDC spokesperson said: “It’s important to know that the vaccine administration process is complex and requires strong cooperation and partnership with all parties at the jurisdictional, local, and federal levels.”

The CDC pulls data from states, cities, federal vaccine providers, and other sources to keep the nation’s most comprehensive vaccination database, making the accuracy of its numbers of key importance for the public and policymakers. Vaccination statistics can drive policy and vaccine outreach decisions.

That means state and federal policymakers rely on the CDC to provide the most accurate picture for Pennsylvania: It combines vaccination numbers from Pennsylvania with the numbers from Philadelphia and some other sources.

In an interview early this month, Acting Health Secretary Alison Beam said the state “continue[d] to try and ask the CDC for the ability to refresh our data.” At the time, she recommended against using the CDC’s data until it had been fixed.

On Monday, the Department of Health confirmed that some corrections had already been made by the CDC with more still to come.

“The full update of all Pennsylvania DOH data with the CDC is not completed, but we anticipate that to occur by the end of the year,” said spokesperson Mark O’Neill.

The CDC also will do similar corrections for other states, according to the Department of Health.

» READ MORE: Some states know a lot about vaccinated people who have gotten COVID-19. Pennsylvania doesn’t.