In this Dec. 23, 2021, file photo, a man is swabbed for COVID-19 at a walk-up testing site at Farragut Square just blocks from the White House in Washington. Credit: Jacquelyn Martin / AP

In just over one month after the omicron variant reached U.S. shores, the number of American adults who said they had been diagnosed with COVID-19 climbed by more than a quarter, according to Census data.

Self-reports of COVID rose to 57 million in the period of Dec. 29-Jan. 10 from 45 million from Dec. 1 to Dec. 13, according to the Census Bureau’s Household Pulse Survey. An additional 2.7 million said in the most recent survey that they weren’t sure if they had been infected, possibly because they suffered symptoms but weren’t tested.

Omicron has spread rapidly across the U.S. since it was first confirmed in a U.S. patient on Dec. 1. The highly transmissible variant may have been spreading in the U.S. days to weeks earlier, according to a genetic analysis of sewage released Thursday by the U.S. Centers for Disease Control and Prevention.

Many Americans responded by getting boosters, according to the survey. In early December, about one-third of adults reported that they had received three or more doses, but by early January this jumped to 43 percent.

Still, U.S. booster rates are lagging those in the U.K. and Germany, where about 49 percen and 55 percent, respectively, of the population have received third doses. In the U.S. just 24 percent of the total population has received a booster shot, and 17 million adults told the Census say they “will definitely not” get a COVID vaccine, down 2 million from early December.

The jump in cases has prompted a return to remote learning and work, million of sick calls and thousands of flight cancellations as pilots and other staff fell ill or were forced to quarantine. Millions of parents reported that their children were unable to attend day care in the past four weeks because of COVID safety concerns.

Some 13.7 million people who reported suffering from COVID-19 said they experienced loss of employment income in the four weeks leading up to the most recent survey. That was an increase of 4.4 million from the early December count.

More than 3 million people said in the most recent survey they had either lost a job or were unable to look for work over the past month. Among the infected, 54 percent were women.

Alex Tanzi, Bloomberg News