The federal vaccination clinic at the Pennsylvania Convention Center is contending with a flood of illegitimate vaccination appointments even before its official opening on Wednesday.

A private online link solely for some essential workers who met eligibility requirements was spread to an untold number of other people who had no trouble using it to sign up for vaccination at the clinic, which is being run in cooperation with the Federal Emergency Management Agency.

The restricted link was supposed to be the gateway to ensure only certain people got appointments on Monday or Tuesday. Once anyone had it, though, there was no immediate vetting mechanism to screen for people who are eligible for vaccination — mainly Philadelphia health-care workers, certain essential workers, people over 75, and those with specific underlying conditions that could make a COVID-19 infection deadly. There was also nothing in the link indicating it was intended for a select group of people, or that filling it out would automatically get a person an appointment.

“I filled it out honestly,” said Ben Parker, 29, of the registration form he received Friday from a friend. “I’m 29 years old. I’m healthy. I’m not overweight. I don’t smoke. I work remotely. I answered it all truthfully and I would have thought, I’m the last person to be getting this.”

Yet as soon as he hit the button on his application, the Philadelphia resident received an appointment to be vaccinated Monday. The two-day soft opening Monday and Tuesday was supposed to be only for essential workers, SEPTA employees, and some federal employees who work with the public.

“Anyone who has received a private appointment link should consider what their sharing of that link could do,” said Matthew Rankin, a spokesperson for the Philadelphia Department of Health, “and make sure they are OK with taking vaccine away from those who could die as a result of their action.”

There is software that can limit access to a link only to an addressed recipient, and would not allow anyone else to use it. The city is working with the registration software, PrepMod, to find ways to make the process more secure, but acknowledged that for now they were essentially relying on an honor system.

“The majority of people are following the rules and not forwarding an invite that they are specifically told is not supposed to be forwarded,” Rankin said.

New technology could be debuted on the system this week, he said.

PrepMod also is used by Pennsylvania for vaccine registration, and has been criticized by county officials for being unable to create private registration links, overbooking, scheduling errors, and allowing ineligible people to make appointments.

As of Monday morning, city officials had to purge hundreds of appointments like Parker’s from its system, many made by people living outside the city. Officials expected more would need to be voided. The city is reviewing the names of people with appointments against a list of workers legitimately eligible for vaccination who were emailed the registration link. Anyone who wasn’t a direct recipient of that link will have their appointment canceled.

It is unlikely the city will be able to identify the person or people who improperly shared the registration link, Rankin said.

After the FEMA site’s full opening Wednesday more people who are eligible through the city’s requirements can get appointments. The city is culling from those appointments people who either had not entered their information in the city’s vaccine interest database or have addresses outside the city. People legitimately eligible for vaccination at the site Wednesday and after will receive a different link than the one circulated last week.

“Our vaccination department has been flooded with appointment request from people who were inappropriately sent a private link,” Rankin said. “The headache and strain this has caused not only is frustrating but as stated could deny lifesaving vaccine to someone who fits all eligibility criteria.”

The glut of improper appointments hasn’t stopped the people who should be getting vaccinated Monday and Tuesday from getting shots, though, he said.

Willie Brown, president of one of the unions representing SEPTA’s city workers, said he has not heard of any eligible workers having trouble getting appointments.

» READ MORE: Mass clinic will open in Philly and vaccinate 6,000 people a day, White House says

The FEMA site at the Convention Center is the first federally operated mass clinic in the city. On Wednesday, vaccinations will be available, by appointment made online or through calling 311, to people eligible for vaccination in the city’s 1A and 1B categories, though the 1B people being prioritized are those 75 and older and adults with high risk conditions. The site expects to vaccinate 6,000 Philadelphians a day, seven days a week, from 8 a.m. to 8 p.m., over the next six weeks, a major boost in a city struggling to get vaccine administered.

The clinic is intended to benefit people in communities with a high risk of exposure or infection; Philadelphia’s Black and brown residents have borne an outsized share of COVID-19 hospitalizations and deaths.

This isn’t the first instance of people sharing private vaccination links contributing to unfair vaccine distribution. Seniors and other groups with limited internet access have struggled to find appointments to get vaccine they are eligible to receive. Yet others, many of them young and without health issues, have wrangled appointments through networks that are sharing restricted links. Links designed to help eligible Philadelphians get vaccinated at Rite Aids were shared widely among ineligible people in January, city officials said. Chester County canceled all appointments made through a link for 1A-eligible people in mid-February after a technical error allowed dissemination of an email containing a personalized registration link and password.

Cleaning up the rolls of registered people, Rankin said, creates a huge burden on the agencies responsible for vaccination.

“We are having to dedicate staff who could be out at [vaccination] sites helping in any capacity to this,” he said.

» READ MORE: All of the Black Doctors COVID-19 Consortium’s vaccine clinics will now be walk-up

Parker received the link to the clinic from a friend who got it from a sibling who got it from a college network, he said. He was suspicious right away.

“Deep down I kind of assumed this had to be some sort of error,” he said.

He didn’t realize simply filling out the form would get him an appointment, he said, and once it did he faced a conundrum.

“Morally I know I shouldn’t be getting it, but at the same time isn’t it just going to be taken up by some other healthy person?” he said. “I think I likely would have canceled just because of the guilt and all of that associated with it but I’m not 100% sure.”

He didn’t have to make a decision. The city canceled his appointment Sunday.

“I feel better,” Parker said, “knowing that it got canceled.”