The Justice Department on Tuesday charged a Chicago pharmacist with selling vaccine cards online — something that law enforcement and health authorities worry will become more widespread as more institutions demand proof of vaccination.

Tangtang Zhao, 34, was charged with stealing authentic cards and listing them on eBay for around $10 a card. He had 11 different buyers, the Justice Department alleged, and sold a total of 125 cards. Most of the buyers purchased between eight and 10 cards each, spending nearly $100 or more.

Anyone living in the United States can get vaccinated — and thus receive protection from the coronavirus and a card to prove it — free. Health and law enforcement authorities have worried the sale of cards to those who do not get vaccinated could undermine efforts to protect the population from the coronavirus.

“We take seriously, and will vigorously investigate, any criminal offense that contributes to the distrust around vaccines and vaccination status,” Assistant Attorney General Kenneth A. Polite Jr. said in a statement announcing Zhao’s case. “The Department of Justice and its law enforcement partners are committed to protecting the American people from these offenses during this national emergency.”

Though it did not name him at the time, The Washington Post reported on some of Zhao’s listings — under the account “asianjackson” — in an April story about scams involving coronavirus vaccination cards and the potential threat they posed to public safety.

In an interview with The Post in April, Zhao confirmed that he was the owner of the eBay account, “asianjackson,” and had made other sales linked to the account. But Zhao said he had no knowledge of the dozens of vaccination cards sold by “asianjackson” through the auction website, claiming that he had been repeatedly unable to access his account.

“I’ve been having issues with my eBay account for the past two weeks,” Zhao said. “I mean, they keep asking me [about] changing the password.”

Zhao, who confirmed that he worked at a Chicago-area pharmacy, also said he was surprised that anyone would buy a vaccination card, having witnessed the cards being handed out to people receiving a shot of the coronavirus vaccine.

“I’m in the health-care field, and I mean, people just get those cards for free,” Zhao said.

After The Post brought the listings to eBay’s attention, the company removed them.

The criminal case is the second the Justice Department has brought involving vaccine cards. Last month, the department arrested a California-licensed naturopathic doctor who prosecutors alleged was selling both fake “immunization pellets” and vaccination cards.

Online records show that Zhao worked at Walgreens.

Gal Pissetzky, Zhao’s attorney, said in a brief phone call that though his client had been criminally charged, “At this point, it is the government’s burden to prove him guilty.”

“He is presumed innocent at this point,” Pissetzky said. He declined to comment further, but said Zhao no longer worked at Walgreens.

A Walgreens spokesperson in April said that all pharmacies administering coronavirus vaccines had designated a staffer to oversee the inventory of related supplies, including the vaccination cards. “Our pharmacies receive a limited number of CDC dose cards as part of the CDC immunization supply kits shipped to the stores that are receiving and administering COVID-19 vaccines,” said spokesperson Erin Loverher.