AUSTIN (KXAN) — Hundreds of thousands of Texans have either missed or chosen not to receive the second dose of the coronavirus vaccine, according to state records.

As of this week, Texas Department of State Health Services data revealed more than 11 million people have been vaccinated in total. Of those, 763,703 people were overdue for their second shot — that’s 6.67% of the total.

“To not get the second is kind of like having surgery, and then not going back for a follow-up to get the stitches taken out,” said Dr. Nicholas Steinour, Emergency Department Medical Director at US Acute Care Solutions in Austin. “You’ve made the big leap. This is just a necessary step to complete the process.”

The Centers for Disease Control and Prevention reports a recommended interval of 21 days between doses for the two-shot Pfizer-BioNTech vaccine. They recommend 28 days between Moderna shots. However, it’s “permissible” to wait up to 42 days between doses when a delay is unavoidable.

Steinour acknowledged there were technical issues with some providers, as well as supply chain issues, early on in the distribution process. Delays after February’s winter storm also prevented people from getting their second vaccine on time, but he noted “that is no longer the case.”

With adequate supply and expanded eligibility, he told KXAN he and other medical professionals were hearing about more and more patients opting out of the second shot.

“That’s really something I don’t think any of us really predicted — especially in the numbers we are seeing,” Steinour said.

Number of patients overdue for second COVID-19 shot is growing

Data requested by KXAN investigators just last week revealed the number of overdue patients is growing. As of Sunday, May 2, only 5.7% of the total were overdue for their second shot, meaning more than 100,000 people fell behind in a week’s time.

Steinour said patients tell him the primary reasons for the delay are fears about increased side effects on the second round and misinformation about the vaccine’s efficacy.

A CDC study of vaccinated healthcare workers revealed Pfizer and Moderna offered partial protection after one dose, appearing to be 80% effective. The second dose, however, appeared to be closer to 90% effective — with the 95% and 94% efficacy that Pfizer and Moderna vaccines showed, respectively, in the clinical trials.

According to the state data, another 5.56% of people are due for their second shot this week.

“Do it as soon as you can. Stick to the recommended plan,” Steinour said.

It’s not just about your personal health, he noted. Public health officials allocate certain amounts of vaccine to certain providers in order to ensure patients can return to the same place they received their first shot after the three-week waiting period.

“In order to not have a mismatch of supply and demand at these sites, we are banking on people coming on those days.”