UDOH changes COVID-19 transmission index measurements

Feb 12, 2021, 12:24 PM | Updated: 5:44 pm
UDOH changes transmission index...
Photo: Utah Department of Health

SALT LAKE CITY — The Utah Department of Health (UDOH) announced changes to the COVID-19 transmission index in the state.  At first glance, it may look like the positivity rate has taken a huge drop, but state health workers say you need to take a closer look at the data.  



Beginning Thursday, Feb. 18, UDOH will transition to the “test over test” method to track positivity rates.

When it comes to measuring the number of positive cases, there are three different ways to look at the numbers.  Until now, UDOH has been using something called the “people over people” method.  That means they take the number of people who test positive and divide that by the total number of people who get tested.  That method has one drawback… duplicates.  Executive Director Rich Saunders says they’ve been weeding out the results from people who have come in for multiple tests in a short period of time.

However, the “test over test” model would change that.

“It’s just allowing us to capture all of the tests that are being done instead of having to sort out or de-duplicate people,” he says.

‘People over people’ v. ‘Test over test’: What’s the difference?

The “test over test” model looks at the total number of positive results and divides that by the total number of tests performed.  Saunders says this method is being used by the CDC, and switching to it will help health officials better align Utah with national figures.

Saunders says, “It also helps us to better compare to other states because most states are using this method of ‘test over test’ instead of ‘people over people.’”

They anticipate the transmission index will skew lower when the switch is made.  For instance, the rolling seven-day average positivity rate is 14.7% percent under the POP method, but it’s only 6.6% if you use TOT.  Is one number more accurate than the other?  Not necessarily.

Saunders says, “When we did the layover of the two methods, the trends were precisely the same.”

Which method’s will be posted to the state’s COVID-19 website?  Both.  If someone wants to compare Utah’s rate to what it used to be, the POP numbers would be best to measure that.  If they want to compare Utah to other states, TOT is the number to look for.

Changes to the state’s official transmission risk tables

However, since the numbers will skew lower, UDOH has made some adjustments to their transmission risk tables.  A 7-day average percent positivity of greater than 10% will belong to the “high” transmission category; a percent positivity between 5.1%-9.9% will belong to the “moderate” transmission category; and a percent positivity of 5% or less will belong to the “low” transmission category,” according to UDOH. 

A transmission level (high, moderate, low) is determined if a county has two of the three metrics in the designated level of transmission.  The other two are case rate per 100 thousand people, and hospital bed utilization.

Additionally, public gathering requirements in areas of “moderate” transmission will be changed.  The department added actions and precautions for businesses and individuals to take in areas of “low” to “moderate” transmission. 

In these areas, public gatherings may occur with side-by-side seating as long as the event host completes the event template and all patrons are wearing masks, are assigned seating and attest to not having any COVID-19 symptoms or exposures in the past 14 days.

UDOH said, “concessions stands must be closed in “moderate” due to increased risk that occurs with more people in attendance and when masks are removed to eat or drink.

Physical distancing between household groups is still strongly recommended at these venues as a precaution. 

In areas of “low” transmission, masks will be required, but no other restrictions are placed on these events.

Even though the positivity rates have been dropping, Saunders says none of Utah’s 29 counties, none of them would be dropped to a lower transmission risk level when this change takes place.

“It doesn’t look like it would be any time soon,” Saunders says.

As of today, the report stated 489,716 total vaccines have been administered, which is 26,996 more than Thursday.

How To Prevent the Spread of COVID-19 Coronavirus

COVID-19 coronavirus spreads person to person, similar to the common cold and the flu. So, to prevent it from spreading:

  • Wash hands frequently and thoroughly, with soap and water, for at least 20 seconds.
  • Don’t touch your face.
  • Wear a mask to protect yourself and others per CDC recommendations.
  • Keep children and those with compromised immune systems away from someone who is coughing or sneezing (in this instance, at least six feet).
  • If there is an outbreak near you, practice social distancing (stay at home, instead of going to the movies, sports events, or other activities).
  • Obtain a flu shot.

Local resources

KSL Coronavirus Q&A 

Utah’s Coronavirus Information 

Utah State Board of Education

Utah Hospital Association

The Church of Jesus Christ of Latter-day Saints

Utah Coronavirus Information Line – 1-800-456-7707

National Resources

Centers for Disease Control and Prevention

Commonly asked questions, World Health Organization

Cases in the United States

Today’s Top Stories


Utah Republicans are looking to ban transgender surgeries and other hormone-based care....
Mark Jones

Utah to receive additional $4.9 million from FEMA in response to COVID-19

FEMA has announced Utah will receive an additional $4.9 million to help with the housing costs during the COVID-19 pandemic.
1 day ago
Curt Gresseth

Former U.S. Attorney for Utah talks about what FBI can take off your cellphone

A legal expert joined Dave and Dujanovic to discuss how the FBI can obtain evidence of a crime from a cellphone.
1 day ago
mini-bottles Utah liquor store...
Elizabeth Weiler

“Mini-bottles” could return to Utah state liquor stores

Mini-bottles haven't been on Utah state liquor store shelves for more than two decades. A public hearing will be held on the proposal.
1 day ago
The Biden administration is preparing for the possibility of Texas Gov. Greg Abbott, left, and Flor...
MJ Lee, CNN White House correspondent

Biden administration prepares for Abbott and DeSantis to send more migrants to Democratic cities

The Biden administration is readying for more migrants to be sent to Democratic cities.
1 day ago
Gov. Cox mental health...
Mark Jones

Utah National Guard to host 67th annual Governor’s Day

The 67th annual Governor's Day will be held Saturday by the Utah National Guard at Camp Williams.
2 days ago
Samantha Herrera

Semifinalists for the new Utah flag design unveiled

The finalists for the new Utah state flag are on display at the Utah State Capitol, as well as in Logan and Cedar City through Oct. 5.
2 days ago

Sponsored Articles

a worker with a drill in an orange helmet installs a door in the house...
Price's Guaranteed Doors

Home improvement tip: Increase the value of your home by weatherproofing doors

Make sure your home is comfortable before the winter! Seasonal maintenance keeps your home up to date. Read our tips on weatherproofing doors.
Curb Appeal...
Price's Guaranteed Doors

How to have the best of both worlds for your house | Home security and curb appeal

Protect your home and improve its curb appeal with the latest security solutions like beautiful garage doors and increased security systems.
A paper reading IRS, internal revenue service is pictured...
Jordan Wilcox

The best strategies for dealing with IRS tax harassment | You have options!

Learn how to deal with IRS tax harassment. This guide will teach you how to stop IRS phone calls and letters, and how to handle an IRS audit.
spend a day at Bear Lake...
Bear Lake Convention and Visitors Bureau

You’ll love spending the day at Bear Lake | How to spend a day at Bear Lake

Bear Lake is a place that needs to be experienced. Spend a day at Bear Lake.
Prescription opioids can be disposed of during National Prescription Take Back Day...
Know Your Script

Prescription opioid misuse | How to protect your family from the opioid epidemic

Studies have shown that prescription opioid misuse has increased since COVID-19. So what do you need to know about these opioids?
national heart month...
Intermountain Healthcare

National Heart Month: 5 Lifestyle Changes to Make Today to Keep You Heart Healthy

Heart disease is the leading cause of death for both men and women. One person dies every 36 seconds in the United States from cardiovascular disease
UDOH changes COVID-19 transmission index measurements