coronavirus illinois

Zocdoc Glitches Plague Registration for United Center COVID Vaccine Appointments

"We apologize to anyone who was unable to secure an appointment at the United Center, and we will continue to add new appointments to our platform from Chicago vaccine providers as they become available," Zocdoc said in a statement

NBC Universal, Inc.

Glitches plagued medical appointment booking website Zocdoc on Sunday as registration for COVID-19 vaccine appointments at the United Center opened to more Chicago residents.

Registration, previously open just to Illinois residents over the age of 65, opened to all Chicago residents eligible under Phase 1B Plus at 4 p.m. on Sunday.

When it opened, the website showed appointments that were available but in some cases did not allow users to book those appointments. Some also reported that they were able to book appointments that were later canceled without explanation.

"On Sunday afternoon, some users experienced difficulty booking a vaccination at the United Center," a spokesman for the company said in a statement.

"Zocdoc identified and resolved the root issue in less than one hour, and Chicago residents were successfully able to book vaccinations, reaching peak booking rates of more than 750 bookings per minute," the statement continued. "Due to high demand, our current allotment of United Center vaccine availability was quickly fully booked."

"We apologize to anyone who was unable to secure an appointment at the United Center, and we will continue to add new appointments to our platform from Chicago vaccine providers as they become available. We look forward to helping more eligible individuals find and book a COVID-19 vaccination," Zocdoc said.

When asked about the users who received unsolicited cancellation emails after booking their appointments, Zocdoc said that issue was related to multiple people attempting to book the same slot.

"At peak booking times, many users were concurrently selecting the same appointment slots. If multiple users were attempting to book the same appointment slot at the same time, and that time slot ran out of availability, some users may have received a cancellation notification if their pending booking was unable to be confirmed," Zocdoc said. "This was an edge case which occurred for fewer than 100 users."

Adding to the confusion and frustration, eligibility for the new vaccination site at the United Center narrowed less than an hour before the registration opened further.

After an exclusive registration period for Illinois residents over the age of 65 that began on Thursday, appointments for the United Center were initially slated to expand at 4 p.m. Sunday to all Illinois residents qualified to get vaccinated under Phase 1B Plus.

But just after 3 p.m. Sunday, officials announced that eligibility would change to include only Chicago residents in Phase 1B Plus, which is anyone over 65, some frontline workers, school staff and more, or anyone 18 and up who has certain health conditions or comorbidities.

For a full look at who's eligible under the expanded Phase 1B Plus, click here.

The last-minute change sparked confusion and frustration for some who had been waiting to book appointments at the new site. Roughly 70,000 appointments were made available Sunday after more than 40,000 seniors booked appointments in their exclusive registration period. All 110,000 appointments have now been filled, officials say.

The change in eligibility was made based on additional Federal Emergency Management Agency guidance, Gov. J.B. Pritzker's office said in a statement, to "ensure equity in vaccine distribution and that the people and communities most impacted by the COVID-19 pandemic have access to the vaccine."

During the exclusive registration period for people ages 65 and up, officials said less than 40% of the more than 40,000 appointments booked at the United Center - all of which will be honored - were made by Chicago residents.

The United Center was selected for the new vaccination site, announced late last month through a partnership with state, city, county and federal officials under a nationwide pilot program, was selected based in part based on its central location and accessibility for a "significantly medically underserved and marginalized population" to bring vaccines to "particularly vulnerable communities."

"Based on the early registration data, it became apparent this was not occurring, leading FEMA to provide additional guidance related to the site to better target communities hit hardest by the virus, including ones surrounding the vaccination site on the city’s West Side," officials said in a statement Sunday.

Registration is now open only to Chicago residents eligible under Phase 1B Plus.

Here's how to register:

  • To register online, visit The web site is projected to handle much higher volume of appointment requests. Zocdoc will show real-time appointment availability and eligible residents will then be able to select a date/time and book an appointment online. Date of birth will be required when booking an appointment to confirm vaccine eligibility.
  • To register by phone, call (312) 746-4835. A multi-lingual call center will be available to help seniors make an appointment from 8 a.m. to 8 p.m. Monday through Saturday and 8 a.m. to 4 p.m. on Sunday. Given the anticipated high demand for appointments, residents who can use the website should book their appointments online, as those who need to use the call center will very likely experience lengthy wait times.

Appointments will be set aside for Chicago residents who live in high CCVI (COVID Community Vulnerability Index) ZIP codes as well as ZIP codes with low vaccination rates, allowing anyone from these ZIP codes to register, officials said, promising more information on that registration process later this week.

Officials also said appointment blocks will also be provided to community-based organizations for targeted outreach to special populations in Chicago, including people with disabilities. 

Residents of suburban Cook County have been allocated appointment slots at the United Center as well, officials said, but cannot yet register. Cook County will announce the process of scheduling those appointments through the county’s COVID vaccine website "in the coming days," they said Sunday. Individuals who can’t access the website can call 833-308-1988 Monday through Friday from 7 a.m. to 7 p.m.

Some of the remaining doses from the United Center mass vaccination site will be given to mobile vaccination teams that will be sent to communities hit hardest by COVID-19 outside of Cook County, officials said, again noting that more information on that effort would be shared in the coming weeks.

Opening Tuesday, the United Center site will operate seven days a week for eight weeks and will be able to administer 6,000 shots per day at full capacity, officials said, noting that vaccinations would be by appointment only and that demand was "anticipated to be high." Those doses will be provided directly from the federal government and not diverted from the supply sent to Chicago or Illinois.

Vaccinations will be offered at no cost and insurance is not required, nor will it be requested at the site.

Contact Us