By Conor McCue

(CBS4) – The United States is seeing a growing problem with millions of people not getting their second dose of the Moderna or Pfizer COVID-19 vaccines. Experts at the Centers for Disease Control say around 5 million people across the country have skipped that second dose. If you have been putting it off, it might not be too late.

(credit: Craig F. Walker/The Boston Globe via Getty Images)

CBS4 Medical Editor Dr. Dave Hnida says there are a variety of factors leading people to skip that second dose. Some are worried about the side effects getting worse when they get the second shot. Others are inconvenienced and can’t make it back for their second appointment. Vaccine hesitancy about one option can affect people who need to get another one.

Hnida said it’s still unclear how much one dose on its own can protect you, and pointed out that variants of COVID-19 are still a threat.

“So, if you’re on the fence right now and you’re saying, ‘Well, do I really need this second vaccination?’ Please get your second dose,” Hnida said.

“And you do have a little bit more time than you probably thought,” Hnida added.

According to the Colorado Department of Public Health and Environment, 62,478 Coloradans are overdue for their second dose. That amounts to about 2.7 percent of people immunized with one dose, though it is possible that some of the individuals received their first or second dose out of state or through a federal entity that doesn’t report into the state system.

Around the state, the rate of people missing their second dose varies. According to data made public by the city of Denver, 8,635 residents are overdue for their second dose. In Jefferson County, 16,204 residents are eligible for a second dose and have not received it, but only 2,880 people are more than six weeks overdue.

In Weld County, about 10 percent of people do not show up for their second shot at clinics run by the health department, a spokesperson said, though the department has only been running second shot clinics for several weeks now. (An earlier version of this story contained incomplete information about the health department’s no-show rate. It has been updated.)

“Because the virus is changing, it’s even more important now that people get that second dose to get that full immunity,” said Dr. Andrew French, vice president of quality, safety, and clinical operations at Centura Health.

Centura Health is seeing a much smaller rate of no-shows. According to French, only about one percent of people who get their first shot at a clinic don’t show up for their second appointment. For patients who go to Centura’s mass vaccination sites, the no-show rate is slightly higher, he said.

“We know that as that scale broadens, as those numbers go up, the more likelihood you’ll have where things get in the way for people to get in and receive that second dose,” French said.

Initially experts were focused on getting people within a few days of either the three week or four week mark of the first shot, depending on the vaccine. But Dr. Hnida says you now have six weeks to get that second dose and get the full benefits.

Dr. French agreed, but said anyone who missed their appointment should look to reschedule as soon as possible.

On Thursday, Centura Health will make 2,500 doses of the Moderna vaccine available for people still needing their second dose.

The doses will be available on April 29 at the Dick’s Sporting Goods Park in Commerce City.

Centura Health offered these guidelines for interested patients:

  • Individuals who are interested in this event should have received their first dose of Moderna vaccine before April 2 to be eligible.
  • They may register at using the Commerce City Drive-Up Event link. Then follow the link and instructions to sign up for “2nd Dose Only.”
  • Patients should bring their vaccine card from their first dose vaccination with them to their appointment on Thursday.

Conor McCue