SALT LAKE CITY — As many as half of Utahns may now have immunity against COVID-19, a top doctor at the region’s largest health care system said Friday as state health officials reported 651 new cases of the virus and 17 additional deaths and a third vaccine is poised to receive federal approval.

The number of residents who have either been vaccinated against the virus or contracted it could hit 70% by June or July, Dr. Mark Briesacher, Intermountain Healthcare’s chief physician executive, told reporters during a virtual news conference.

Estimates have suggested it will take between 70% to 90% of a population acquiring the antibodies needed to fight off COVID-19 before herd immunity is reached. But the World Health Organization and other experts say the level varies by disease and has not been established for the virus,

“This is a bit of a complicated question, because it really is based on a combination of facts and assumptions. What are the facts? We know 180,000 Utahns have had COVID-19 over the past 90 days. We know that 750,000 have been vaccinated,” Briesacher said.

That adds up to about 30% of Utahns, “a great place to be in,” he said. But assuming that there are also residents who caught the virus but never showed symptoms so weren’t diagnosed, “we’re probably between 40% and 50% immune and I could see that growing to 50% to 60% by April-May, and to about 70% by June-July.”

Third vaccine could start arriving in Utah next week

A third vaccine, from Johnson & Johnson, is expected to be authorized for emergency use as soon as Saturday after getting the nod from a federal Food and Drug Administration advisory panel Friday. The two vaccines currently approved for use in the United States, Pfizer and Moderna, require a booster shot.

Gov. Spencer Cox welcomed the news.

“So many have suffered through this pandemic,” Cox said in a statement. “A third authorized vaccine tells me that even through some of our darkest times, miracles still happen. This is a testament to modern research, science, public health and medicine.”

The governor said “we are in a race to save as many lives as possible through vaccines. This vaccine will do that. Remember, all three vaccines are safe and effective. You can have confidence that any of them will protect you and those around you from COVID-19.”

Cox, who told reporters at his weekly briefing on the coronavirus Thursday the federal government has approved more than 20,000 doses of the Johnson & Johnson vaccine for the state, said Utahns shouldn’t hesitate to get the new vaccine even though its efficacy rates aren’t quite as high as for Pfizer and Moderna.

“We never branded vaccines before,” the governor said, adding that what’s important is preventing severe illnesses that requires hospitalization and deaths from COVID-19, something the Johnson & Johnson vaccine appears to be 100% effective in stopping.

The governor said Johnson & Johnson’s efficacy rate, around 66% when moderate cases are included compared to above 90% for the other vaccines, are still “incredibly good. These numbers are amazing and by the way, it was tested against other variants, which may have brought those numbers down a little bit.”

Briesacher also said Utahns shouldn’t worry about which shot they get.

“When eligible, go to a place that works best for you and get the vaccine. Don’t worry about which manufacturer it is because in the end, they’re all very effective” against severe cases of the virus, he said.

Herd immunity coming but for now, ‘let’s hang in there’

The doctor cautioned that getting to 70% immunity within the next few months would require that the vaccines remain effective — as well as the antibodies generated by having had COVID-19 — against new and more transmissible and possibly more lethal variants of the virus that continue to emerge.

“But overall, I think that’s why we and state leaders and many others in health care — certainly my peers in the other health systems — are optimistic about where we are today,” he said, adding that doesn’t mean it’s time to ease up on public health mandates that include wearing masks, social distancing and avoiding crowds.

“As our immunity grows, we will be getting to a point where we can and will relax those restrictions on public gatherings. And I think wearing a mask will become less important in the future. But I think the message today is, let’s hang in there.”

Briesacher’s comments echo a new statewide health order in effect through March 25 that would lift the mask mandate in counties designated as having low COVID-19 transmission rates once the state has gotten 1,633,000 first vaccine doses from the federal government, enough for about 70% of the state’s adults.

Utah governor eyeing threshold to end mask mandates across state

The governor said Thursday he now expects every Utah adult who wants to be vaccinated will be able to do so by the end of April, a month earlier than he has forecast. “There is an end in sight,” he said during his weekly COVID-19 update.

Thursday, Utahns 16 and older with specified medical conditions became eligible to get vaccination shots, a few days sooner than the March 1 date initially set. They join health care workers, first responders, long-term care facility residents and staffs, K-12 teachers and school staffs and Utahns 65 and older on the eligibility list.

Utah expanding list of who can now get their COVID-19 vaccines, governor announces

Information on making appointments for the vaccinations provided through Utah’s 13 local health departments, federally designed pharmacies and a state contractor is available at In Salt Lake County, the health department is phasing in those with comorbidities through Monday based on age.

Latest Utah COVID-19 statistics

The Utah Department of Health said Friday another 22,092 vaccine doses have been administered in Utah for a total of 682,536, a number that’s smaller than Briesacher’s estimate because there is a lag on reporting to the state.

Utah has had 370,084 positive cases including the 651 reported Friday. The rolling seven-day average for positive COVID-19 tests is 694 per day, and 5,498 Utahns have been tested and another 15,599 tests conducted since Thursday.

The state’s rolling seven-day average for percent positivity is 5.6% if all tests are counted, Utah’s new preferred method, and 12.3% if multiple tests by an individual over the past 90 days are excluded. Currently, 231 people are hospitalized with the virus in Utah.

Utah’s death toll is 1,907 with the 17 deaths reported Friday, which include eight that occurred before Feb. 5. The newly reported deaths are:

  • A Washington County man, between 65 and 84, long-term care facility resident
  • A Utah County man, older than 85, not hospitalized
  • A Salt Lake County man, between 45 and 64, long-term care facility resident
  • A Salt Lake County man, between 65 and 84, long-term care facility resident
  • A Salt Lake County man, older than 85, not hospitalized
  • An Iron County man, between 45 and 64, not hospitalized
  • A Salt Lake County man, older than 85, long-term care facility resident
  • A Weber County man, older than 85, not hospitalized 
  • A Salt Lake County man, between 45 and 64, hospitalized at time of death
  • A Tooele County man, between 45 and 64, not hospitalized
  • A Uintah County woman, older than 85, long-term care facility resident
  • A Salt Lake County woman, between 65 and 84, long-term care facility resident
  • A Salt Lake County woman, older than 85, long-term care facility resident
  • A Salt Lake County woman, older than 85, long-term care facility resident
  • A Salt Lake County woman, between 65 and 84, long-term care facility resident
  • A Weber County woman, older than 85, not hospitalized 
  • A Utah County woman, between 45 and 64, not hospitalized