Report: 80% vaccination of Colorado adults would prevent hundreds of COVID-19 hospitalizations this fall

It’s a fact: Receiving the COVID-19 vaccine greatly reduces the chances that someone could fall ill or end up in the hospital with the respiratory disease caused by the coronavirus.

But infectious-disease experts at the Colorado School of Public Health wanted to figure out exactly how many hospitalizations could be avoided under various vaccination scenarios.

The researchers, part of the Colorado COVID-19 Modeling Group, first modeled future COVID-19 hospitalizations based on the following three scenarios:

• The state continues on the same vaccine trajectory seen in late July.
• Vaccine uptake among adults increases so that 80% of adults receive at least one shot by Labor Day, while uptake among 12- to 17-year-olds remains the same.
• Vaccine uptake among 12- to 17-year-olds increases so that 70% of 12-to-17 years olds receive at least one shot by Labor Day, while uptake among adults remains the same.

Their report, published Monday, found that increasing the adult vaccination rate would be the most effective at keeping people out of the hospital. If 80% of Colorado adults got at least one shot by Labor Day, approximately 839 people who would have otherwise been hospitalized with COVID-19 would not have to go to the hospital.

That’s assuming levels of “transmission control” — factors such as mask-wearing and physical distancing that help limit COVID-19 spread — stay the same while adult vaccination rates increase. If transmission control simultaneously decreased by 10%, increasing adult vaccination would have a much bigger impact in this scenario, keeping more than 2,100 people out of the hospital.

Vaccinating 70% of 12- to 17-year-olds by Labor Day without increasing adult vaccine uptake would prevent 165 hospitalizations, under current levels of transmission control — or 435 hospitalizations if transmission control decreased by 10% at the same time, the report found.

In a fourth scenario, the researchers modeled increasing vaccination among both adults (80% by Labor Day) and 12- to 17-year-olds (70% by Labor Day), and found this would keep 939 people out of the hospital under current transmission control levels. If people also decreased mask-wearing and distancing by 10%, the increase in vaccine uptake among adults and kids would keep more than 2,300 people out of the hospital with COVID-19.

“As more adults are vaccinated, there are less hospitalizations, and as kids prepare to go back to school this fall, there will be more risk,” Dr. Jon Samet, dean of the Colorado School of Public Health and leader of the COVID-19 Modeling Group, said in a statement. “If we can reach the threshold of 80% of adults and 70% of teens vaccinated with at least one shot by Labor Day, we will prevent many cases of severe COVID-19 this fall.”

The state has a lot of work ahead to achieve those vaccination levels.

As of Tuesday, 71% of Coloradans 12 and older had received at least one dose of a COVID-19 vaccine, according to state data that’s published online. Gov. Jared Polis gave a higher number of 72% at a briefing Monday, and a CDPHE spokesperson later clarified that the governor was referring to the vaccination rate for adults 18 and older.

In late July, the rate of vaccination for 12- to 17-year-olds was much lower than that of adults — only about 48%, according to the researchers’ report.

The report found that reaching 80% of Colorado adults with at least one shot would require administering 456,000 first doses in August. Reaching 70% of Colorado teens with at least one shot would mean administering 90,500 first doses this month.

State data show that around 51,500 shots entered arms between July 26 and Aug. 2, but it’s unclear how many of those were first doses, and how many were second doses of the Pfizer-BioNTech or Moderna vaccines. The vaccine developed by Janssen only requires one dose.

The full report from the COVID-19 Modeling Group is available online.

Editor’s note: This story was updated at 9:04 a.m. Aug. 5, 2021, to add information from a CDPHE spokesperson.