The change in data indicates that the US has counted too many shots as first doses when they are instead second doses or booster shots. Three states, Illinois, Pennsylvania and West Virginia, found enough over-counting of first shots to indicate millions of unvaccinated people had mistakenly been counted as having received a dose. An official from the Philadelphia Department of Public Health criticized the CDC saying "we don't have any faith in the numbers on the CDC website, and we never refer to them." Unvaccinated people have been blamed for causing the surge in the new "Omicron" variant, which is causing more division among Americans.

The U.S. government has overcounted the number of Americans who are at least partly vaccinated against the coronavirus, Bloomberg reports.

Why it matters: Millions more people than initially thought are unprotected as coronavirus infections, hospitalizations and deaths are rising across the country.