Metrics for Success

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Overview

Current Level: Level 1: Stay Home

COVID-Meter-SEVERE-01


For schools and businesses to safely reopen, a coordinated effort across local government, public health experts, and business and community leaders will be paramount. A commitment to making decisions based on a common set of measurements will reduce the likelihood of see-sawing between opening and closing, which harms our economy and exhausts our community.

We are committed to safely moving forward together, but that commitment must coexist with awareness that reopening too quickly may pose health risks and economic setbacks.

The Centers for Disease Control and Prevention (CDC) recommends that reopening be dependent on a downward trajectory of hospitalizations and infections over a 14-day period. Additionally, we are tracking our ability to treat the sickest patients and our ability to test, track, and contain spread in the community. The County will use key health indicators in four categories to assess the threat level of COVID-19 and our ability to respond to it:

  • Hospital System
  • Cases
  • Testing
  • Contact Tracing

If any one of these indicators are not at a satisfactory level, it is a sign that our ability to manage the virus’s impact on our community is diminished. If cases and contact tracing indicators are at manageable levels, but our hospital population is high, we must continue to maintain preventative measures to ensure that we have the ability to treat the sickest patients. If our hospital population is low, but cases are increasing, we must continue preventative measures to control the spread. To move down the ladder of the threat level system, all of the thresholds for the below indicators must be met:

Hospital System Cases Testing Contact Tracing Capacity

14-day flat or decreasing trend in daily COVID-19 hospital population in Harris County.

14-day flat or decreasing trend in daily COVID-19 ICU population in Harris County.

14-day average of the general population and ICU beds in use by COVID-19 patients in Harris County:

  • Greater than 15% = red
  • Greater than 10% = orange
  • Greater than 5% = yellow

14-day flat or decreasing trend in new COVID-19 cases in Harris County

14-day average of Positivity Rate less than 5%

14-day average of new cases reported in Harris County, outside the city of Houston:

  • Greater than 400 = Red
  • Greater than 200 = Orange
  • Greater than 100 = Yellow

Changing Threat Levels

The indicators used are not on/off switches for threat levels, but will be used by the County in conjunction with health experts to make decisions about policy changes at each level. To move down the ladder of the threat level system, all of the thresholds for these key health indicators must be met. When assessing the virus’s threat to our community and hospital system, the County and public health experts will also consider: 

  • Deaths
  • Transmission rates
  • Medical supply inventory considerations established by the Benchmarks for a Healthy Community for reducing and increasing threat levels
  • As more information and data becomes available, Harris County, working with public health experts, will evaluate metrics and calculations based on current best practices.

The following is additional information about the indicators that will be considered when decreasing the level of threat (Red>Orange>Yellow). Moving the threat level from yellow to green will require widespread deployment of medical countermeasures (vaccine and/or treatment). Additional indicators and timelines are used for increasing the threat level and can be found in the Harris County Benchmarks for a Healthy Community.

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Hospital Population

Why it Matters

  • 14-day flat or decreasing trend in daily COVID-19 hospital population in Harris County.

We must ensure our healthcare system has adequate capacity to treat all cases of COVID-19, including the most severe cases.

We will continue to monitor the daily total of hospital patients in Harris County using data from SETRAC, a regional dashboard, and analyze daily changes in the COVID patient population to see what direction we are heading. As Harris County monitors day-over-day trends, a 14-day flat or decreasing trend will indicate we are moving in the right direction. (If a threat level is moved, this measure will be restarted at zero days.)

  • 14-day flat or decreasing trend in daily COVID-19 ICU population in Harris County.

Hospital ICUs must have the capacity to treat the sickest patients. We will continue to monitor the daily total of COVID-positive and suspected COVID patients in our ICUs and will analyze trends to see what direction we are heading. A 14-day flat or decreasing trend will indicate improvement. (If a threat level is moved, this measure will be restarted at zero days.)

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Hospital Usage

Why it Matters

  • 14-day average of the general population and ICU beds in use by COVID-19 patients in Harris County.
    • Greater than 15%= red
    • Greater than 10%=orange
    • Greater than 5%= yellow

At the height of the COVID-19 pandemic in Harris County, nearly 50 percent of ICU beds were used by COVID patients. In order to ensure that hospital ICUs have adequate capacity to treat the most critically ill COVID patients while caring for patients experiencing a life-threatening crisis or needing critical surgery, the percentage of ICU beds being used for COVID patients must decrease and remain at a manageable level.

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Cases

Why it Matters

  • 14-day flat or decreasing trend in new COVID-19 cases in Harris County

Controlling the rate of COVID-19 transmission will be key to reopening. The number of daily new cases is often the first indicator of the success of stay-at-home measures, social distancing, the avoidance of gatherings, and an adherence to wearing face coverings.

Testing availability can affect the reliability of new case information, but it is still considered an early indicator of the degree of disease transmission. A decreasing trend will indicate the spread of the disease has slowed. (As with other measures, a change in the threat level will trigger a reset of this measure.) Moving between levels should cause a reset in the taking of this measure (meaning that we are looking to see a 14-day flat or decreasing trend after moving from red to orange or orange to yellow).

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Testing

Why it Matters

  • 14-day average of positivity rate of less than 5%

On May 12, 2020, the World Health Organization (WHO) advised governments that before reopening, rates of positivity in testing should remain at 5 percent or lower for at least 14 days.

Positivity rate is a reliable measure for whether or not our testing capacity is sufficient enough to detect a significant number of new cases. If positivity is high, it can indicate uncontrolled community spread, that we are only testing the sick, or a combination of both.

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New Cases in Harris County

Why it Matters

  • 14-day average of new cases reported in Harris County
    • Greater than 400 = Red
    • Greater than 200 = Orange
    • Greater than 100 = Yellow

The CDC and WHO recommend that contact tracing programs be in place before local governments consider easing restrictions. Contact tracing can help to prevent the spread of COVID-19 by interviewing positive patients; identifying their close contacts; interviewing and alerting those contacts to the risk of infection; and instructing those contacts to quarantine or isolate to prevent them from spreading COVID-19 to others.

In order to use contract tracing as a tool to control the spread of the virus, a total number of daily new cases must be at a level that allows contact tracers to quickly trace all cases and contacts.

More Data

In addition to the aforementioned indicators, Harris County looks at a number of measures when considering policies and decisions about the delivery of public health services. These additional measures give a deeper picture of how the virus is affecting our community.

For even more info, see the Harris County Public Health Dashboard Here

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Percent of Weekly Total COVID-19 Cases by Race/Ethnicity

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COVID-19 Cases by Race/Ethnicity

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Percent of Weekly Total COVID-19 Cases by Age

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Harris County COVID-19 Deaths per week and Deaths Per 100k

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Harris County COVID-19 ICU Population and Trend

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Additional Metrics

Epidemiological models such as R0, which estimates the number of people potentially infected by infectious persons, are not foolproof. Reproduction numbers are used to measure the potential spread of a virus. The R number can be useful for predicting growth, but due to inputs that are based on estimates by public health professionals such as the length of time an individual is infectious, there is little consistency between R numbers that are calculated by different entities. Therefore, metrics like R0 are taken collectively with the understanding that while they may validate certain trends, they should not be used as a substitute for actual, on-the-ground numbers. Reproduction numbers can be found here:

https://policylab.chop.edu/covid-lab-mapping-covid-19-your-community

https://ictr.github.io/covid-19-county-R0/

https://sph.uth.edu/dept/bads/covid19-dashboard

http://metrics.covid19-analysis.org/

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