Most Utahns shouldn’t need another COVID-19 booster shot any time soon, an Intermountain Healthcare infectious diseases physician said, despite a new multistate study he helped author that found the effectiveness of a third dose of vaccine sharply declines after about four months.

“Here in Utah, I think we’re in a position where we should wait on a fourth dose,” Dr. Eddie Stenehjem told the Deseret News on Tuesday. He called the 78% protection against hospitalization provided by booster shots after four months cited in the study published by the Centers for Disease Control and Prevention “still quite, quite good.”

Also, the doctor said, COVID-19 transmission is going down in Utah, as measured by case counts and other factors, such as the presence of the virus in wastewater, as well as in hospitalizations and emergency room visits for the virus. While COVID-19 deaths in the state remain high, Stenehjem said they’re expected to start dropping, too.

Combined with the largely milder disease caused by the omicron variant of the virus that continues to be dominant in Utah and the rest of the United States, he said that means the decrease in the effectiveness of booster shots in preventing hospitalizations from 91% at two months isn’t enough to warrant an additional dose now.

A recommendation could come later this year, perhaps in the fall when annual flu shots are given, Stenehjem suggested, although he said the CDC could act sooner if another variant, such as the so-called “stealth” omicron that is already prevalent in other countries, starts driving cases back up in the United States.

President Joe Biden’s chief medical adviser, Dr. Anthony Fauci, cited the study involving health care systems in 10 states including Intermountain Healthcare in Utah during a White House COVID-19 briefing Wednesday about “the sharp downward direction” of the current outbreak.

Fauci described the 78% effectiveness of booster shots after four months as “still a good protective area” for Americans.

“Vaccination and boosting will be critical in maintaining that downward trajectory,” he said, noting “the potential future requirement” for an additional booster shot “is being very carefully monitored in real time and recommendations, if needed, will be updated according to the data as it evolves.”

Time for another COVID-19 booster shot? Not in the U.S. — yet

But some Utahns already qualify for a fourth dose of COVID-19 vaccine under CDC guidelines because they are moderately or severely immunocompromised, due to chemotherapy treatments for cancer, an organ transplant or other conditions that limit antibody production.

Dr. Hannah Imlay, a University of Utah Health associate professor of infectious diseases who treats the immunocompromised, acknowledged the confusion surrounding the additional dose, even though the CDC first backed a fourth shot for that group last October.

“There’s a lot of information — and misinformation and confused information out there — about who is due for what when,” Imlay said during a virtual news conference Wednesday. She said some pharmacies may not yet be offering a fourth shot to the immunocompromised.

Imlay said the fourth shot amounts to a first booster shot of vaccine for the immunocompromised because they already need an extra dose to be considered fully vaccinated. For the general population, that takes two doses of Pfizer or Moderna or a single dose of Johnson & Johnson.

The timing of booster doses for the immunocompromised is different, too, now just three months after the initial COVID-19 shots are completed. For everyone else 12 and older, booster shots — which can be mixed or matched — come five months after two doses of Pfizer or Moderna or two months after one dose of Johnson & Johnson.

The guidelines for the immunocompromised could eventually include a fifth or even sixth shot, Imlay said.

Like Stenehjem, she said additional booster shots for everyone else hinges on what happens next with COVID-19.

“I don’t know that answer yet. So it will really depend on how much spread we continue to have and what we next see in terms of variants,” Imlay said, particularly if resistance develops to current vaccines. Both Pfizer and Moderna are currently experimenting with omicron-specific vaccines.

Hardest hit ‘long’ COVID-19 patients may be those who least expect it

The study published last Friday is the first in the United States to estimate the waning effectiveness of vaccines and booster shots against the omicron variant, Stenehjem said. Besides Utah, data was contributed by health care systems in California, Colorado, Indiana, Minnesota, New York, Oregon, Texas, Washington and Wisconsin.

Their findings are similar to those from the United Kingdom, where experts advised the government against offering additional booster shots last month, even though other countries, including Israel, Denmark and South Korea, are offering them to at least some at-risk populations such as the elderly.

Stenehjem said the priority should be increasing the number of Utahns who get the booster shot already available. Less than 61% of all Utahns are fully vaccinated, and just 26.2% have gotten a booster shot despite the significant impact the extra dose has against omicron, according to a previous study by the same health care systems.

“We have a long ways to go on getting people boosted in general,” he said.

Utahns can protect themselves from COVID-19 in other ways, both Stenehjem and Imlay said, including by wearing well-fitting, high-filtration masks indoors. Imlay said everyone should be taking precautions to protect not just themselves, but those in the community who are immunocompromised.

“These patients are working jobs just like everybody, they’re going to school just like everybody. It’s really a population that needs to be protected,” Imlay said. Besides masking, she urged Utahns to get vaccinated and boosted, and to avoid large gatherings, to keep from catching and spreading the virus.

The Utah Department of Health is sticking to the CDC guidelines on booster shots for the virus despite the new findings, spokesman Tom Hudachko said.

“We are continuously learning more and new things about COVID-19 and our efforts have always been informed by data and research. This research will help add to that body of knowledge,” he said. “However, we continue to follow the existing recommendations from CDC on the timing and frequency of COVID-19 booster doses.”