COLUMBUS, Ohio (WCMH) — As more businesses, schools, and cities begin to require the COVID-19 vaccine, reports are surfacing of fraudsters making, selling, and using fake vaccination cards.

This spring, the FBI warned about false vaccination cards for sale that were circulating online. In July, the Department of Justice announced the arrest of a naturopathic doctor in Northern California. The agency said the doctor gave patients false vaccine cards and homeopathic remedies claiming they would help the body fight off COVID-19.

The DOJ said that misrepresenting the official seal of a U.S. agency, like the CDC logo on vaccine cards, could be a violation of federal law. Violators could face up to five years in prison or a $5,000 fine.

Local health officials are encouraging people to take care of their paper vaccine cards, which is currently the best proof of vaccination against the virus.

In a statement, a spokesperson from Ohio Department of Health said:

“It is important to keep updated medical and vaccination records, whether that is for someone’s latest tetanus shot, the shingles vaccine, or their COVID-19 vaccination records. All Ohioans are encouraged to keep track of their COVID-19 vaccination card just like they would any other important medical record. To be clear, the COVID-19 Vaccination Card is currently the standard way to show proof of vaccination if requested by a medical provider or other entity requiring proof of vaccination.”

Ohio Department of Health

With more than 600 colleges and universities now requiring proof of COVID-19 inoculations, an online industry has sprung up offering fake vaccine cards. The easy access to fake documents has set off alarms at some schools where officials worry that unvaccinated students with forged credentials might cause an outbreak.

Dozens of students interviewed by The Associated Press said they were aware of fake COVID-19 vaccination cards, though none admitted to actually using one. On the dark web, sellers on websites such as Counterfeit Center, Jimmy Black Market, and Buy Express Documents list COVID-19 vaccine cards, certificates and passports for sale, some costing €400 Euros or about $473 in U.S. dollars.

Meanwhile, some states, businesses, and schools are creating their own verification services, like apps, digital passports, or certificates, according to the Federal Trade Commission.