Utah data helps confirm: COVID vaccine booster is crucial to avoiding hospitalization with omicron

“A two-dose series just isn’t enough,” according to new data from Intermountain Healthcare and other hospitals.

(Francisco Kjolseth | The Salt Lake Tribune) Asher Williams, 12, gets his second COVID-19 shot from Lee Moss, a member of the medical reserve core as Salt Lake City’s westside residents get the opportunity to get vaccinated while also picking up a new winter coat and shoes for their children thanks to a partnership between Salt Lake City, Salt Lake Education Foundation, Salt Lake City School District, Salt Lake County Health, Operation Warm and Intermountain Healthcare at Rose Park Elementary on Wednesday, Sept. 22, 2021.

New research shows vaccine boosters for COVID-19 nearly double a person’s protection against hospitalization with the omicron variant — and Utah patients helped supply the proof.

Data collected from Utah and nine other states show the vaccine booster is 90% effective in preventing hospitalization for the omicron variant of the virus, said Dr. Eddie Stenehjem, an infectious diseases physician for Intermountain Healthcare, which contributed to a large study released Friday by the U.S. Centers for Disease Control and Prevention.

That level of protection is a significant improvement over an unboosted, two-dose course of the Pfizer or Moderna vaccine. Researchers found that after six months, the initial vaccine course by itself produced just a 50% reduction in hospitalizations from the omicron variant, Stenehjem said.

The booster also led to about an 80% reduction in visits to emergency departments and urgent care clinics for omicron infections, Stenehjem said — slightly less than the 94% protection against urgent care visits the booster provided in infections with the delta variant, which dominated Utah in the fall. But that still far exceeds the protection provided by an unboosted vaccine course.

“Omicron is a different virus,” Stenehjem said in a news conference Friday. “The protection we have from a two-dose series just isn’t enough to protect against hospitalization and [emergency department] visits. A two-dose vaccine series, especially when that series was given six months prior, is not nearly as effective as someone who has had a boosted vaccine series.”

The study is one of three released Friday that demonstrate the vaccines’ effectiveness against the omicron variant — the first large U.S. studies to examine that question.

The papers echo previous research — including studies in Germany, South Africa and the U.K. — indicating available vaccines are less effective against omicron than earlier versions of the coronavirus, but also that boosters significantly improve protection.

Another study, also published Friday by the CDC, focused on COVID-19 case and death rates in 25 states from the beginning of April through Christmas. People who were boosted had the highest protection against coronavirus infection, both during the time delta was dominant and also when omicron was taking over.

The Journal of the American Medical Association published the third study, also led by CDC researchers. It looked at people who tested positive for COVID-19 from Dec. 10 to Jan. 1 at more than 4,600 testing sites across the U.S.

Three shots of the Pfizer and Moderna vaccines were about 67% effective against omicron-related symptomatic disease compared with unvaccinated people. Two doses, however, offered no significant protection against omicron, the researchers found. “It really shows the importance of getting a booster dose,” said the CDC’s Emma Accorsi, one of the study’s authors.

– The Associated Press contributed to this report.