CVS Health study captures emergence of SARS-CoV-2 variants

A CVS Health study conducted by its Clinical Trial Services organization under contract to the US Department of Health and Human Services¹ provided early insights and signals on what was happening with the COVID-19 pandemic in large parts of the country over a nine-month period. While the contract ended Dec. 31, 2021, the infrastructure that was in place enabled CVS Health to  continue its analyses for another two weeks as the Omicron variant moved across the US. Data is limited to COVID-19 test results collected at CVS Retail locations (over a 9-month period (April 2021 – February 2022) and patient self-reported registration data that accompanies these tests.

Registration included the request for information on previous vaccination prior to the time of testing.² CVS Health did not capture data on booster vaccinations, hospitalizations or emergency department visits in this population. Since CVS Health only captured data at the time of testing (which was in an ambulatory setting), progression and severity of symptoms could not be estimated from those who tested positive.

CVS Health’s powerful analytics engine was used to analyze COVID-19 test data related to breakthrough infections in people previously fully vaccinated for COVID-19.³ The data consists of a broad representation of the US population, including diverse populations by age, race, ethnicity, gender, and self-reported health conditions covering 35 states and the District of Columbia. Trends and patterns in the data provide population-level indicators of immunity to infection by showing differences in infection rates between those who are unvaccinated and those who report to be fully vaccinated. (Figure 1) Furthermore, the data allow for early identification of locations with increases in infections due to the emergence of new variants, like Delta and Omicron.

Figure 1: Proportion of COVID-19 Test Positivity Among Persons Tested at CVS Health Retail Locations in the US by Vaccination Status, April 25, 2021-February 5, 2022

Figure 1 line chart shows proportion of COVID-19 test positivity among persons tested at CVS Health Retail Locations in the US by vaccination status between April 25, 2021 and February 5, 2022. Y-axis indicates positivity rate ranging from 0 to 35.1% and X-axis indicates the timeline over the course of the study period. The unvaccinated positivity rate graph line slopes down to a minimum point of 5.7% in June followed by a steep upward climb until August. It moves back downward until November and then a steady climb until January where it reached a maximum level of 35.1%. It then began to decline steadily thereafter. The self-reported fully vaccinated positive graph line shows a steady line at about 0.8% until early July. The graph line then climbs to approximately 5% until early August where it generally flattens out until November 8. It begins to climb to a maximum point of 26.3% in early January 2022. Following that peak, the line generally makes a steady decline. Breakthrough infections are defined as positive COVID-19 test results by PCR or Antigen testing in CVS Health Retail testing locations >7 days post fully vaccinated (99% of all breakthroughs happen >14 days post fully vaccinated). Fully vaccinated defined as 2 doses of an mRNA vaccine or 1 dose of the non-mRNA vaccine. This data contains product and vaccine eligible populations as described in the eligibility timeline outlined in the following COVD-19 Vaccine Timeline: Eligibility & Restrictions publication (https://www.doh.wa.gov/Portals/1/Documents/1600/coronavirus/348-862-VaccineTimeline.pdf)

We have observed that throughout the course of the pandemic, the results of analyses of CVS Health data mirrored other scientific studies and observations that often took longer to gather and analyze.  In some cases, the data signaled the potential of a variant prior to recognition that the variant was in the United States.  At a minimum, the pattern observed in the CVS Health data mirrors the CDC reports on the emergence of the variants.⁴

While these data show that the current vaccines have been very effective in preventing COVID-19 in all age groups, it also appears to show breakthrough infections as an early signal of a possible new variant that was starting to drive higher infection rates. What followed as early as July 2, 2021 and then again on November 8, 2021 demonstrated a marked increase in the amount of people developing COVID-19 symptoms and infections in people who had received some or all of the respective initial recommended doses of a COVID-19 vaccine. Both of these timepoints appear to represent early indicators of Delta and Omicron, respectively, affecting the US population.

This study demonstrates the value of near real-time tracking of testing results in the community, as offered by CVS Health data analysis, as a valuable additional insight into the evolution of the pandemic, the emergence of variants, and protection from infection due to vaccines. As mentioned previously, this study did not look to evaluate severity of disease, frequency of severe disease that may require hospitalization or emergency department visits, or the ability of currently available COVID-19 vaccines to prevent severe disease.