The Texas Coronavirus Antibody REsponse Survey (CARES) seeks to understand the human antibody response to SARS-CoV-2, the virus that causes COVID-19.

Enrollment goal has been met >

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as of October 3, 2021

In the attached report, we are sharing with you our key findings, and we expect more to come. We will continue to keep you updated as we move forward with Texas CARES programming, with you as a partner. This project continues because of your dedication to the Texas community and to the health of our fellow Texans.

  • Overall, we estimate that three-quarters of Texans have SARS-CoV-2 antibodies, generated either from a prior natural infection or from a vaccine, and therefore possess some level of protection from COVID-19.
  • Antibody levels seem to peak about 120 days after infection and then decrease, though they remain detectable after 275 to 500 days.
  • Unvaccinated individuals with a previous infection have lower levels of antibodies to the spike protein compared to fully vaccinated individuals.
  • More than a third of children had antibodies to the virus, and of those, 50.8% reported never having had symptoms.

The state of Texas continues to experience diverse population and economic growth that reflects what the nation may look like in the future. Texas sees significant health disparities across our rural/urban areas and within our communities. Texas CARES was designed to help us learn more from you about how SARS-CoV-2 has impacted our state.


Texas CARES, we have reached our initial enrollment goal! Thank you!

  • If you've already enrolled, please make sure to complete your blood draw - remember that this is a marathon and not a sprint. 
  • Already completed your first blood draw? We are continuing the second and third ones for all enrolled participants, so watch for reminders.
  • We completed the first milepost, but there is a lot of "race" left, and we still need your help before we reach the finish line to understand antibodies. 
  • And if you're curious about what we are learning, check out our website to access the public dashboard, and learn more about COVID-19 antibodies in Texas and possible opportunities for continuing participation in the program.

For participants who are currently enrolled in Texas CARES, you will need to: 

  1. Choose a clinical pathology lab site where you will go to have your blood drawn for your 3 antibody tests. To find a CPL site convenient to you, visit https://www.cpllabs.com/locations/. Once on the CPL webpage, scroll all the way down to the bottom to enter your zip code. Please be sure to bring your ID to your CPL visits. No appointment is needed.
  2. While at your first antibody test (T1), your attending clinician at the CPL may verify that you completed the initial consent form and survey. Please note that appointments are walk-in, but please check location hours at https://www.cpllabs.com/locations/.
  3. Mark your calendar for a reminder for your next antibody test as you leave the clinic. The survey team will send reminder texts for T2 and T3 survey links 90 days after your results are received.
  4. For T2 and T3, you will also be asked to complete an additional survey.

The results of your antibody test will be texted to you after each CPL visit. You can access a full report on CPL’s portal after you receive the text message from Texas CARES. If your results are not loaded in the portal, please call the Sonic MyAccess customer service group at 512.339.1275.

Your test results and survey responses are protected by HIPAA regulations, just like your health records. Individual results will not be shared with your employer, professional organizations or any other stakeholders. 

For more information, you can review a list of our most frequently asked questions


What is Texas CARES?

The Texas Coronavirus Antibody REsponse Survey, or Texas CARES, is a survey that will help us better understand the human antibody response to SARS-CoV-2, the virus that causes COVID-19. Survey participants will help us measure things like how many people in the survey have COVID-19 antibodies, and how long those antibodies last. 

How does it work?

To identify what percent of the Texas population has antibodies in their blood, we will use two serology tests, also known as antibody tests. One serology test, called the total antibody test, will look for antibodies in the blood made in response to natural SARS-CoV-2 infection. A separate serology test called the Roche S-test will also be used to test for the presence of spike-protein antibodies, which are the antibodies arising from natural infection or vaccination against COVID-19. Serology results are especially important for detecting previous infections in people who had few or no symptoms.

We will review the results of the serology tests, along with responses to a series of surveys that help us understand what things could contribute to people's differences in COVID-19 symptoms and diagnosis.

Data collection and analysis

Since the project started, we've been working on distilling the data into a format that's easy to read and easy to understand. While the data collection isn't complete, the information we do have has been placed into the Texas CARES dashboard. You can view more information about the data, including considerations for its limitations, on the dashboard webpage


Click the image to view an up-to-date version of the dashboard.

What are the survey's goals?

We will focus on several key goals:  

  • Estimate how many people in Texas have been infected with SARS-CoV-2.
  • Estimate how many people have been vaccinated for SARS-CoV-2 and develop antibodies.  
  • How long COVID-19 antibodies last in someone's system. 
  • Identify the characteristics of people who develop COVID-19 antibodies. 
  • Identify the characteristics of people who never develop COVID-19 antibodies.

Why does it matter?

We still know very little about how COVID-19 antibodies work across Texas. People with antibodies to COVID-19 may have an immune response to a future infection, but we don’t have enough evidence to support that idea. We do not know if the antibodies will provide someone with any immunity, or even partial protection, from getting infected again. Even if antibodies do provide immunity, we don’t know the amount of antibodies needed for protection, how long that protection might last, or if people with antibodies can still infect others.

Your participation in this survey will provide us with the data that may help answer these questions, which can in turn inform local and state policies. In other words, you are helping Texas in the effort to combat COVID-19 at a local, state and national level. 


What do volunteers have to do?

If you sign up to be a part of Texas CARES you will receive three free antibody tests. These will include both the total antibody test and Roche S-test looking for spike protein. We are working with local labs across Texas to make it convenient for you to enroll and complete your test. After each test, you will receive your results in a confidential and timely manner.  You will also be asked to complete three brief online surveys over time about your health, household and community.

Essentially, volunteers can help in three ways:

  • Complete the 1stdraw
  • Help understand how antibodies respond over time and complete the 2ndand 3rd draw
  • Make a plan, bring a friend & follow, like and share on social media

For more information, including how to interpret the results of your antibody tests, you can review a list of our most frequently asked questions





Timeline with steps as described in the paragraph below


What's the process like? 

Participants will need to complete a brief initial survey that will help us better understand your health and the environmental factors that affect it. The survey should take less than 10 minutes to complete. You will receive a confirmation text message containing your order number and will also be asked to visit a CPL lab or participating clinic where a phlebotomist will draw blood for your first antibody test, which we will call "T1." You will receive a text message once your results are available. You can access your full results report by signing up for your Sonic MyAccess account at www.cpllabs.com/sonicmyaccess or texting “CPL” to 66349 

Three to four months after your T1, you will receive the link to a brief five-minute survey in a reminder text message. Upon completion of the survey, you will receive a confirmation text message with your order number and next steps to return to a CPL lab or participating health clinic where a phlebotomist will draw blood for your second antibody test (T2). You will receive the results of your T2 as soon as they are available. 

Six to seven months after your T1, you will receive a link to your final ten-minute survey in a reminder text message. Upon completion of the survey, you will receive a confirmation text message with your order number and next steps to return to a CPL lab or participating health clinic where a phlebotomist will draw blood for your third antibody test (T3). You will also complete a ten-minute survey during this stage. You will receive the results of your T3 as soon as they are available. 



Who is eligible to participate in the survey?

All Texans (ages 5-80) are eligible to participate. Texas CARES is looking at how different people's experiences with COVID-19, including whether or not they show symptoms, may impact their antibody response. We also want to understand how antibodies and the immunity they might provide is developing across the state, especially with vaccine distribution underway. Individuals who have tested positive, negative, or have never been tested for COVID-19 at all are welcome to participate, regardless of vaccination status.

*We want to include children 5-17 years to ensure that we understand how children may develop immunity, may have been asymptomatic (no symptoms) and have antibodies that are helping them stay healthy. It is important that we have children in the project as they will be returning to school, may be exposed at different levels and may be asymptomatic. Children will have their blood drawn by certified phlebotomists who have experience working with children.


Why are we focusing on these groups?

Texas is a big and diverse state. It is important that all Texans feel invited and welcome to participate and that Texas CARES reflects the geographic and cultural diversity of the State. This will allow us to better understand COVID-19 antibodies and how they impact Texans across different age groups and communities. 



In the classroom

Helping educators teach their students about pandemic response

Texas CARES has developed specialized curriculum sets to support educators who want to teach their students about pandemic response. More detailed information about the curriculum, as well as downloadable lesson plans, are available on the Texas CARES curriculum page.

Lesson plans are available for the following groups, and is aligned to the Health, Science, and Math TEKS for each respective grade range. 

  • Grades K-2
  • Grades 3-5
  • Grades 6-8
  • Grades 9-12


Who is managing the survey? 

Texas CARES is managed by a collaborative team from the University of Texas Health Science Center at Houston (UTHealth) School of Public Health, in partnership with Texas DSHS, CPL, and the UT System. 

Team members from UTHealth School of Public Health include: 

Dr. Eric Boerwinkle 

Dr. Stacia DeSantis

Dr. Steven Kelder

Dr. Bill Kohl III

Dr. Sarah Messiah

Dr. Michael Swartz 

Dr. Melissa Valerio-Shewmaker

Dr. Ashraf Yaseen



Who can I contact if I have questions?

Answers to frequently asked questions can be found here. You can contact the Texas CARES team at TexasCARES@uth.tmc.edu or 713-500-9441. Email is preferred to minimize response time. 

This project has been approved by the UTHealth Committee for Protection of Human Subjects, IRB# HSC-SPH-20-0825.   

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