WALNUT CREEK (CBS SF/KPIX) — Hoping to reach their goal of distributing 1 million doses of COVID-19 vaccines by May 31, Contra Costa health officials became one of the first counties in California to lower eligibility to everyone 16 and older who lives or works in the county on Tuesday.

Contra Costa County Health Services opened the former Waterworld parking lot to help accommodate those now eligible for the vaccine. Getting an appointment here was the hard part as the online site crashed and people were told to try again Wednesday.

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“Kind of a little irritated. To have such a hard time getting a vaccine through them and even though I’m an essential worker, I couldn’t get a vaccine,” said Shirley, a resident.

As of Tuesday, county health officials said, they had distributed 630,428 doses of vaccine. Of that number, 234,102 local residents or 25.4 percent of the county’s population have received the required two doses of Pfizer or Moderna vaccines.

When it comes to residents 16-to-50, the county dashboard reveals that nearly 138,000 doses have already been distributed to the age group.

Demand is still high, though. The newly opened Waterworld vaccination site in Concord had a line snaked around the parking lot on Tuesday.

The county’s health director Anna Roth is pleading with residents to be patient. Roth says,

“We don’t actually give appointments at a first come first serve basis,” said Contra Costa County Health Director Anna Roth. “First, every day we go through the appointment requests and we deliver appointment invitations to those in the hardest hit communities using the healthy places index.”

Officials said lowering the age eligibility will allow another 375,000 county residents to be vaccinated.

“Since we gave the first dose in our county on Dec. 15, getting vaccine to everyone and anyone has been our top priority,” said Anna Roth, Contra Costa County Health Director. “Removing barriers of all kinds, including confusing eligibility criteria is an important step in furthering our equity goals. This is an important day.”

Contra Costa County Health Services noted that those appointments need to be made through their website rather than the state’s MyTurn portal.

The county will continue to prioritize giving appointments to those living in low-income areas hardest hit by COVID. Officials also were planning to begin accepting walk-ins at the Richmond Auditorium and Bay Point Health Center with additional locations coming online in the near future.

But as health officials expanded vaccine eligibility to everyone 16 and older, they also warned that the county’s infection and hospitalization rates went up last week.

“I also want to sound a note of caution. Our case numbers have actually leveled off and bumped back up a little bit, as well as our hospitalization numbers,” Deputy Health Officer Dr. Ori Tzvieli said at the county’s Board of Supervisors meeting.

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He said the county hit another grim milestone this past week.

“We received coroner data about a 15-year-old who passed away back in December from COVID-19,” he said. “This is the first pediatric death in our county, that we know of. While these events are incredibly rare, they’re also very tragic. It’s just one more reminder of how urgently we need to vaccinate our community.”

The health officials said the county could move from the red to the orange tier of the state’s reopening guidelines by next week, once total state vaccinations hit 4 million in underserved communities. Then restrictions loosen.

“Even when we do get to the orange tier, it’s really important we continue to mask, to socially distance out in public,” Tzviell said.

“If you’re 16 and over and you live or work in Contra Costa County, it’s your turn,” Roth said at the board meeting. “We still have appointments available,” Roth said. “We already are getting people — we just updated it and we’re getting one request per second.”

On Wednesday, a new drive-through COVID-19 vaccination site will be unveiled at the former Waterworld site in Concord. Health officials said they were targeting the new site to provide 15,000 vaccines weekly when fully operational.

People age 16-64 who live and work in the county are advised to register online at cchealth.org/coronavirus or by calling 1-833-VAX-COCO (1-833-829-2626).

State health officials have announced they will expand vaccination eligibility to residents 16 and older on April 15.

“Governor Gavin Newsom announced last week that his goal was to move the state quickly through the eligibility tiers,” said Roth. “We agree and applaud this goal. We have appointments to fill. By expanding eligibility now, we can ensure that no appointments go unused.”

Contra Costa County has administered more than 630,000 doses of vaccine, covering more than 45 percent of its population. Roth said 97 percent of county residents 75 and over have received at least one dose; 85 percent of 65 to 74-year-olds, and 45 percent of those 50 to 64.

Roth said the county will see a bigger influx of vaccine in coming weeks, thanks to ramped-up federal efforts. Aside from tiers based on age and serious health issues, vaccine allocation is distributed based on community need, with those hit hardest by the virus getting priority.

“Last week we delivered almost 100,000 vaccines in one week,” Roth said. “Even with that, we still have thousands of appointments now available because of this increased supply of vaccine. We really want to see them; we want to get them their first dose. We’ve made a lot of progress, but our work’s not done.”

Andrea Nakano contributed to this report

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