COVID-19 Current State Analysis and
Forecasting for the DFW Region
Department of Internal Medicine
Lyda Hill Department of Bioinformatics
Department of Emergency Medicine
UTSW Health System Information Resources
Updated July 6 with data as of July 4-5
About the Model
The following slides illustrate a model of how COVID-19 is spreading across
the DFW region based on real patient data. This provides a snapshot based on
data available as of July 4-5. Every time we receive new data, we re-run the
model and refine the graphs.
In the following slides we examine how well preventive measures including
vaccinations, masking, staying at home, physical distancing, hand hygiene and
others have limited the spread of COVID-19, and what might happen looking
forward.
Model-building is an iterative process with inherent uncertainty in its
predictions. It facilitates planning and should not be the sole basis for policies
or management decisions for any emerging infection.
We thank the Dallas and Tarrant County health departments, the hospitals,
and health systems that have contributed data to help us build this model.
2
Updated 7/6/22
Commentary
While the number of people hospitalized in the region remains relatively low, hospitalizations continue to grow at a quick pace and are
expected to continue to do so for the next several weeks. Notably, Dallas County Health and Human Services has just raised its county
COVID-19 risk level to yellow. The local Rt value, which represents how effectively the virus is spreading, is above 1 in the region. Test
positivity rates are high and increasing, indicating that many positive cases are being missed in official records, even as test volumes
are increasing. Based on these trends, our medium-term forecast predicts that hospitalizations should continue to rise over the near-
term but should remain at manageable levels over the next several weeks because of the low starting point. Hospitalizations could
return to elevated levels by mid-summer if trends persist. We are no longer receiving updated survey data on masking behaviors, so
those trends will no longer be included here.
Vaccination remains our most powerful tool for preventing severe COVID-19. Although breakthrough infections are more common with
Omicron than with previous variants, vaccinated individuals still have a significantly decreased chance of catching COVID-19
compared to unvaccinated individuals, and even more importantly, significantly decreased risk of hospitalization and death. All Texans
over the age of 6 months are now eligible for vaccination, and everyone over the age of 5 is encouraged to get a booster. As part of our
ongoing commitment to an equitable, effective, and efficient vaccination rollout, Texans aged 12 and older can schedule a vaccination
appointment using UT Southwestern’s online scheduling portal: utswmed.org/vaccines.
Both nationally and locally, Omicron is now by far the dominant variant of the virus, representing nearly 100% of positive tests
sequenced at UT Southwestern. The closely related BA.4/BA.5 Omicron sub-lineages are more transmissible and now represent over
50% of our samples, outcompeting the “original” BA.1 Omicron variant and subsequent BA.2 sub-lineage.
Based on the latest CDC “COVID-19 Community Levels” guidance, which considers hospital admissions and capacity, Tarrant and
Collin Counties are now medium risk, while Dallas and Denton are still low risk. Visit the CDC website for guidance on individual and
household-level prevention measures recommended during times of low or medium risk. The CDC “Community Transmission” levels for
the DFW region, which consider new cases and test positivity, are currently high. Use of high-quality masks when appropriate, physical
distancing, increased ventilation, staying home when feeling unwell, and other interventions recommended by health experts will help
continue to curb transmission and protect the health of all Texans, especially those who are currently unvaccinated, unable to be
vaccinated, or who may be immunocompromised. Anyone who is experiencing symptoms or exposed to someone with COVID-19 is
encouraged to get tested and quarantine to break the chain of transmission.
3
Updated 7/6/22 with
COVID-19 Hospitalizations in Dallas County: data from 7/4/22
Past, Present, and Future Forecasting
Hospitalized COVID-19+ Patients: Past and Predicted
COVID-19 hospitalizations (black
squares) are rising again.
The blue line shows the estimated
number of hospitalizations for the last
three weeks, as well as our 21-day
forecast starting from 7/5.
Dallas County total COVID-19
hospitalizations expected to exceed
400 within the next several weeks.
4 Source: NCTTRAC EMResource Master Data Set - County Level for data through 8/1/20-7/4/22
Shaded regions in the model’s forecast represent 90% credible interval.
Updated 7/6/22 with
data from 7/4/22
Dallas County’s Trajectory Is Increasing
Total hospitalizations due to COVID-19 are expected to increase over the next several weeks.
– Hospitalizations could return to elevated levels by mid-summer if trends persist.
Lines
– These trends are influenced by reduced immunity over time from past infections during Delta and Red Line is if all behavior
earlier waves, as well as the effect of more transmissible Omicron subvariants. returns to unmitigated, pre-
pandemic patterns with
Hospital admissions are primary driver of CDC recommendations for Dallas County but should Omicron-like severity
remain at manageable levels over the next several weeks because of the low starting point.
Blue Line is if we maintain
our current trajectory
Shading
High Risk: Recommend
indoor masking
Medium Risk: Recommend
indoor masking for high-risk
groups and their contacts
Low Risk: Indoor masking is
personal preference
5
Updated 7/6/22 with
COVID-19 Hospitalizations in Tarrant County: data from 7/4/22
Past, Present, and Future Forecasting
Hospitalized COVID-19+ Patients: Past and Predicted
COVID-19 hospitalizations (black
squares) are climbing again.
The blue line shows the estimated
number of hospitalizations for the last
three weeks, as well as our 21-day
forecast starting from 7/5.
Tarrant County total COVID-19
hospitalizations could exceed 250
over the next three weeks.
6 Source: NCTTRAC EMResource Master Data Set - County Level for data through 8/1/20-7/4/22
Shaded regions in the model’s forecast represent 90% credible interval.
More About the Measures We Follow to Build the Model
Mobility proxy measures indicate the degree to which residents are compliant with physical
distancing, determined using data from cell phones and surveys.
Visits to the doctor for COVID-like symptoms are a leading indicator that will likely rise
ahead of hospitalizations.
Test percent (%) positivity is a useful number to follow to make sure that enough tests are
being done and to follow over time. If it goes up, then cases and hospitalizations follow. %
positivity varies by the population tested. For example, the % positivity of samples from the
emergency department would be different than that of a group of asymptomatic individuals.
Hospitalizations trail new infections by 1-2 weeks but are not influenced by testing
capacity or test reporting delays, thus giving us a clear picture of severe cases in the
community.
Vaccinations indicate the level of protection that is present in the community against
severe disease.
Based on testing and hospitalization data, we calculate infection rates, which indicate how
prevalent COVID-19 is within an age group or community, and Rt, which represents how
many people 1 individual is likely to infect under current conditions.
7
Updated 7/6/22 with
data available 7/5/22
How Mobile Are North Texans?
The graphs above show mobility trends through July 1 based on cell phone data. Time
spent at home continues to decrease. Visits to other sites outside the home have
increased as well.
8 Source: Google COVID-19 Community Mobility Reports accessed 7/5/22, data through 7/1/22
Updated 7/6/22 with
data from 7/4/22
Cases of COVID-19 That Require Hospitalization Are Low, but Growing;
Test Positivity Rates Are Elevated and Increasing in North Texas
40% 4,500
35% 4,000
30% 3,500
3,000
25%
2,500
20%
2,000
15%
1,500
10%
1,000
5%
500
0%
-
Approximately 28% of COVID-19 tests are Hospital volumes for COVID-19 have increased 15%
positive in the state of Texas. compared to one week ago and increase 105%
compared to one month ago.
Source (left): TX DSHS data through 7/4/22, Accessed 7/5/22
9 Source (right): TX DSHS Combined Hospital Data by TSA Region data through 7/4/2022
“North Texas” is defined as Trauma Service Area E, % increases compare trailing 7-day averages
Updated 7/6/22 with
data from 7/4/22
COVID-19 Hospital Admissions Are at Low Levels, but Rising
Hospital admissions for
COVID-19 across all age
groups and counties in the
DFW area are at low levels, but
are climbing quickly
Please note the differing scales
for each county when reading
the graphs at left. Data show
location of hospital, not
necessarily patients’ resident
county.
Source: Admissions - NCTTRAC EMResource Master Data Set - County Level for data through 8/1/20-7/4/22
10 Undisclosed ages imputed using average regional age mix on the reported date
Includes both lab-confirmed and suspected COVID-19 admissions
Updated 7/6/22 with
data from 7/5/22
Dallas County Infection Rates Are Rising Across Across All Age Groups
Dallas County Weekly Case Rate per 100K
By Age Bucket
The redder the rectangle, the more
cases per 100,000 people.
Infection rates are low across all age
groups but are rising quickly
Please note that the upper bound
of the color scale is now 400 cases
per 100,000 people, as compared
to the recent upper bound of 1,000.
Source: Dallas County HHS, Accessed 7/5/22, data for positive tests with a specimen collection date of
11
6/25/22 or earlier
Updated 7/6/22 with
data from 7/5/22
Infection Rates in All Dallas County Cities Are Rising
Dallas County Weekly Case Rate per 100K
By City
The redder the rectangle, the more
cases per 100,000 people.
Infection rates are low but rising
quickly across Dallas County.
Please note that the upper bound
of the color scale is now 400 cases
per 100,000 people, as compared
to the recent upper bound of 1,000.
Source: Dallas County HHS, Accessed 7/5/22, data for positive tests with a specimen collection date of
12
6/25/22 or earlier
Rt Represents Contagiousness
Rt helps us measure how effective social
distancing measures are after they are
put into place.
If social distancing and measures like
masking are effective, then the number of
secondary infections is dramatically
reduced.
In this scenario where social distancing
measures were 50% effective, then only
five people end up infected, rather than
the original 31.
Updated 7/6/22 with
data from 7/5/22
How Contagious Was COVID-19 in Dallas Two Weeks Ago?
Dallas County
A. Winter Storm
B. Beginning of Delta Wave
C. Colleges/schools reopen
D. Halloween
E. Beginning of Omicron Wave
Rt
Epidemic grows/ persists
above this line
Epidemic declines
below this line
This graph shows the Rt value in Dallas County as of one-to-two weeks ago,
calculated using the date positive tests were collected. The Rt value has been
above 1 in Dallas County since May.
Source: Dallas County HHS, Accessed July 5; up to specimen collection date of June 29. Tarrant County data are no longer made available, so the Tarrant County graph has been
discontinued.
14 1) Cori, A. et al. A new framework and software to estimate time-varying reproduction numbers during epidemics (AJE 2013).
2) Assumes serial interval follows gamma distribution as calculated in Nishiura, et al . "Serial interval of novel coronavirus (COVID-19) infections." Int J Infect Dis. 2020 Mar 4;93:284-
286. doi: 10.1016/j.ijid.2020.02.060
