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3 Lessons from the emergence of the SARS-CoV-2 Delta variant

The emergence of the SARS-CoV-2 Delta variant highlights the importance of widespread vaccination and the ongoing need for accurate testing.

New variants can quickly change the public health situation

Positive developments related to the pandemic situation between the end of 2020 and early 2021 generated a great deal of hope. Multiple vaccines were starting to become available and by March 8, 2021, the CDC declared that fully vaccinated people could gather indoors without wearing masks.1 At that time, many believed that the worst of the pandemic was in the past. However, the emergence of the SARS-CoV-2 Delta variant significantly impacted the public health situation across much of the United States, with the CDC issuing new masking guidance and urging more people to become vaccinated in a July 27, 2021, announcement.2

As we now know, the Delta variant is ~2x more contagious than previous variants,2-5 which has led to very rapid spread in areas with low vaccination rates.5 In the United States, the 7-day moving average of reported cases increased from ~12,000 in late June to ~60,000 by July 27.2 One of the main lessons the medical community can learn from the rapid spread of the Delta variant is how quickly a new variant can change the local public health situation from in to out of control. So how can we stop the emergence of new variants, one or more of which may be worse than Delta?

Stopping the emergence of new variants requires controlling disease spread

As with many viruses, the emergence of SARS-CoV-2 variants is the result of random errors introduced into the viral genome during replication.6 The best way to reduce the emergence of new variants is to limit virus replication by limiting transmission.7

Variants are expected. The best way to slow the emergence of new variants is to reduce the spread of infection by taking measures to protect yourself, including getting a COVID-19 vaccine when available.7

Until vaccination rates increase sufficiently to limit transmission, SARS-CoV-2 testing will continue to be needed

Despite the effectiveness of vaccines in reducing the risk of death from SARS-CoV-2 and limiting disease spread, vaccine hesitancy remains a challenge.8,9 Given a vaccination level of ~55% of the total population in the United States,10 it seems plausible that we may see additional outbreaks from new variants, although Delta is the only variant of concern currently in the United States.11

In addition, many scientists believe that COVID-19 is here to stay, becoming an endemic disease.12,13 Whether COVID-19, during its transition to endemicity, becomes a milder disease and/or a disease of the young,12,13 diagnostic testing will most likely continue to be an important tool for ensuring public health.

The Talis One™ Instrument Delivers Accurate Molecular Testing at the Point of Care

The Talis One COVID-19 Test System is conducted on the Talis One instrument which is designed to easily fit into a variety of care settings. The instrument is built to maximize health outcomes in the face of infectious disease threats, with an assay menu that will expand to include sexual and women’s health tests in the near future.

Learn more about the Talis One COVID-19 Test System

References

  1. CDC. CDC Museum COVID-19 Timeline. Centers for Disease Control and Prevention. Published August 4, 2021. Accessed August 23, 2021. https://www.cdc.gov/museum/timeline/covid19.html
  2. CDC. Coronavirus Disease 2019 (COVID-19). Delta Variant: What We Know About the Science. Centers for Disease Control and Prevention. Published February 11, 2020. Accessed September 24, 2021. https://www.cdc.gov/coronavirus/2019-ncov/variants/delta-variant.html
  3. Li B, Deng A, Li K, et al. Viral Infection and Transmission in a Large, Well-Traced Outbreak Caused by the SARS-CoV-2 Delta Variant.; 2021:2021.07.07.21260122. doi:10.1101/2021.07.07.21260122
  4. Wang Y, Chen R, Hu F, et al. Transmission, viral kinetics and clinical characteristics of the emergent SARS-CoV-2 Delta VOC in Guangzhou, China. EClinicalMedicine. 2021;40:101129. doi:10.1016/j.eclinm.2021.101129
  5. Bian L, Gao Q, Gao F, et al. Impact of the Delta variant on vaccine efficacy and response strategies. Expert Rev Vaccines.:1-9. doi:10.1080/14760584.2021.1976153
  6. Chen J, Wang R, Wei G-W. Review of the mechanisms of SARS-CoV-2 evolution and transmission. ArXiv. Published online September 15, 2021:arXiv:2109.08148v1.
  7. CDC. Coronavirus Disease 2019 (COVID-19). What you need to know about variants. Centers for Disease Control and Prevention. Published February 11, 2020. Accessed September 24, 2021. https://www.cdc.gov/coronavirus/2019-ncov/variants/variant.html
  8. Tram KH, Saeed S, Bradley C, et al. Deliberation, Dissent, and Distrust: Understanding Distinct Drivers of Coronavirus Disease 2019 Vaccine Hesitancy in the United States. Clin Infect Dis Off Publ Infect Dis Soc Am. Published online July 16, 2021:ciab633. doi:10.1093/cid/ciab633
  9. Siegler AJ, Luisi N, Hall EW, et al. Trajectory of COVID-19 Vaccine Hesitancy Over Time and Association of Initial Vaccine Hesitancy With Subsequent Vaccination. JAMA Netw Open. 2021;4(9):e2126882. doi:10.1001/jamanetworkopen.2021.26882
  10. CDC. COVID Data Tracker. Centers for Disease Control and Prevention. Published March 28, 2020. Accessed September 24, 2021. https://covid.cdc.gov/covid-data-tracker
  11. CDC. Coronavirus Disease 2019 (COVID-19). SARS-CoV-2 Variant Classifications and Definitions. Centers for Disease Control and Prevention. Published February 11, 2020. Accessed September 24, 2021. https://www.cdc.gov/coronavirus/2019-ncov/variants/variant-info.html
  12. Torjesen I. Covid-19 will become endemic but with decreased potency over time, scientists believe. BMJ. 2021;372:n494. doi:10.1136/bmj.n494
  13. Phillips N. The coronavirus is here to stay — here’s what that means. Nature. 2021;590(7846):382-384. doi:10.1038/d41586-021-00396-2

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Addressing Healthcare disparities in the US with Point-of-Care Testing

Healthcare disparities in the US have become strikingly apparent throughout the COVID-19 pandemic, affecting historically underserved populations (e.g., lower-income households, Black and Minority Americans, immigrants, people with disabilities, rural populations, etc.). Point-of-care (POC) testing can help. To reduce the spread of infections and bring health equity forward, we need to take a closer look at POC testing and how to get it to communities that need it most.

Healthcare disparities in the US at the point of care

The rapidity of spread and mortality associated with the COVID-19 pandemic has shined a light on health disparities in the US. COVID-19 infection is higher among groups already affected by health disparities across age, race, ethnicity, language, income, and living conditions.1 Since the beginning of the pandemic, the top-third of vulnerable counties (defined by the COVID-19 vulnerability Index) have seen 21% more cases and 47% more deaths than the bottom-third of vulnerable counties, despite receiving 27% fewer tests.2 3

One study found that transportation barriers are associated with significantly higher odds of a positive COVID-19 test, which suggests a greater risk of disease exposure associated with reliance on public transit and/or shared rides, or it may suggest inadequate access to health care, including timely COVID-19 testing.1 What’s more, COVID-19 has shifted the utilization of the American healthcare system where individuals are delaying or forgoing care—which can have serious and life-threatening health consequences. By June 2020, over 40% of U.S. adults reported that they delayed health care due to COVID-19 concerns.4

Adding to these challenges is the threat of false negative COVID-19 test results, which could potentially lead to positive case clusters.5 6 When false negatives are suspected, individuals have to leave the facility and wait for their reflex testing results to become available. Ideally, individuals awaiting reflex testing results (as well as those who receive a positive COVID-19 test result) will quarantine, but this is not always possible, especially for those relying on public transportation and living in overcrowded housing facilities.

Minimizing the time it takes to get accurate results and being able to communicate those results to patients quickly is paramount for minimizing community spread and delivering proper treatment. This supports the need for rapid and reliable testing, as well as in-visit test-to-answer POC workflows—especially for communities that have been shown to have less access to medical care and are less inclined to use telehealth service.

What Point-of-Care Diagnostic Tests Should Look Like

To drive health equity forward, we need diagnostic testing to be more accessible and reliable for underserved populations.

Point-of-care diagnostics should enable rapid and effective test-to-treat workflows all in one visit

Because underserved populations are more likely to miss appointments due to transportation and are more likely to have limited access to telehealth,7-10 it is imperative that these individuals get the information and treatment they need while they are in the testing facility. To confidently make treatment decisions during the same visit, point of care diagnostic tests should be sensitive without compromising speed and operational efficiency.

Not only will test-to-treat workflows at the point of care help detect disease and deliver proper care earlier, but it can help minimize health care expenses due to missed appointments and hospitalization. This approach is stressed in the Sexually Transmitted Infections National Strategic Plan (2021-2025), where several objectives are discussed to ensure continuity of care. The plan touches on expanding personnel training to enhance screening, testing, and treatment capabilities within a single facility, specialized programs, and integrated and collaborative approaches in settings that serve communities disproportionately affected by STIs, HIV, and viral hepatitis.11

The Talis Solution: A sample-to-answer test with central-lab quality sensitivity

  • The Talis One COVID-19 test enables quick and secure collection of samples for infectious disease testing
  • Talis One provides lab-quality molecular diagnostic results by utilizing innovative nucleic acid amplification technology integrated with solid-phase nucleic acid purification
  • Compared with up to several days of wait time for lab-run tests with similar accuracy, the Talis One solution delivers clear results in less than 30 mins

Point-of-care diagnostics should be flexible enough to adapt to different environments and different communities

Point-of-care locations can range from large pop-up centers in rural areas and places of work to metropolitan mobile clinics. Each community is unique, and POC tests need to be adaptable to the specific needs of the community. The instruments being used to detect SARS-CoV-2 should be space efficient for multiple types of facilities and, ideally, flexible enough to test for multiple infectious diseases and disease variants that are prevalent in the community being tested. This can save time for both the individual and the testing facility.

As suggested by the Office of the Assistant Secretary of Health (OASH) and Office of Minority Health (OMH), to expand access to communities that are unable to access traditional testing sites, the federal government should partner with test kit manufacturers to develop SARS-CoV-2 test kits that are flexible enough to be used at the point of care or at-home and should establish and enforce policies that require public and private health insurance to cover SARS-CoV-2 testing to minimize financial barriers.12

The Talis Solution:

  • Talis One is a complete, cost-effective solution that has potential for menu expansion to infectious diseases in respiratory and women’s health
  • With its small footprint and streamlined sample-to-answer workflow, Talis One can be used in a variety of point-of-care settings, enabling easy and broad access to testing for patients

Point-of-care diagnostics should be easy-to-implement and easy-to-use

Adopting new healthcare technologies is resource intensive—requiring a substantial amount of time for implementation and training. With healthcare personnel shortages increasing in underserved areas,13 it can be difficult to maintain an efficient operational workflow, or worse, patients cannot get the tests they need because there aren’t enough people to perform them. POC testing needs to be easy to implement and intuitive so that facilities can get up and running as quickly as possible and maintain efficiency through personnel changes.

The Talis Solution:

  • Talis One’s user-centric workflow makes it easy to quickly begin testing in a variety of CLIA- waived healthcare settings
  • Talis provides on-demand support and training including access to educational resources and implementation guides

Point-of-care diagnostics should have features that streamline reporting and communication to patients, labs and governing bodies

Timely reporting is essential for sharing results, monitoring where outbreaks occur, tracking the incidence and prevalence of infection, and evaluating the impact of interventions. Not only can it help determine if a newly placed mobile clinic is effective and quickly get test results to patients, but it also enables proper allocation of critical resources to those in greatest need.

The Talis Solution:

  • Talis One has cloud connectivity that easily integrates with LIS and EMR systems
  • Results from the Talis One molecular tests are delivered as easy-to-understand reports
  • With sample-to-answer workflow, Talis One enables caregivers to communicate results to patients within 30 minutes

Moving Towards Health Equity with Point-of-Care Testing

With the CDC planning to invest $2.25 Billion to address COVID-19-related health disparities and advance health equity among populations that are at high-risk and underserved,14 there is no better time than now to evaluate and adopt a new POC testing solution.

To ensure there is timely and equitable access to testing with rapid return of results in communities disproportionately affected by COVID-19, we need to consider the recommendations outlined by the CDC:1 5

  • Use a social vulnerability index16 to help select testing sites
  • Review the groups to prioritize for screening testing
  • Carefully consider the different types of SARS-CoV-2 tests when planning for diagnostic or screening use

By providing easy access to actionable results at the point-of-care in public health settings, the Talis One molecular testing solution empowers you to quickly and confidently diagnose infections, promote safety and peace of mind for your patients, and ultimately combat healthcare disparities in the US.

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References

  1. Rozenfeld, Yelena, et al. “A model of disparities: risk factors associated with COVID-19 infection.” International journal for equity in health 19.1 (2020): 1-10.
  2. Bringing Greater Precision to the COVID-19 Response. (2020, December). Retrieved July 01, 2021, from https://precisionforcovid.org/ccvi
  3. Smittenaar, P., Stewart, N., Sutermaster, S., Coome, L., Dibner-Dunlap, A., Jain, M., … & Sgaier, S. K. (2021). A COVID-19 Community Vulnerability Index to drive precision policy in the US. medRxiv.
  4. Czeisler, Mark É., et al. “Delay or avoidance of medical care because of COVID-19–related concerns—United States, June 2020.” Morbidity and mortality weekly report 69.36 (2020): 1250.
  5. False negative rate of COVID-19 PCR testing: A discordant testing analysis. (2021, January 9). Retrieved July 01, 2021, from https://virologyj.biomedcentral.com/articles/10.1186/s12985-021-01489-0
  6. Cao G, Tang S, Yang D, Shi W, Wang X, Wang H, et al. The potential transmission of SARS-CoV-2 from patients with negative RT-PCR swab tests to others: two related clusters of COVID-19 outbreak. Jpn J Infect Dis. 2020. https://doi.org/10.7883/yoken.JJID.2020.165.
  7. Samuels, R. C., Ward, V. L., Melvin, P., Macht-Greenberg, M., Wenren, L. M., Yi, J., … & Cox, J. E. (2015). Missed appointments: factors contributing to high no-show rates in an urban pediatrics primary care clinic. Clinical pediatrics, 54(10), 976-982.
  8. Fischer, S. H., Ray, K. N., Mehrotra, A., Bloom, E. L., & Uscher-Pines, L. (2020). Prevalence and characteristics of Telehealth utilization in the United States. JAMA network open, 3(10), e2022302-e2022302.
  9. Pierce, R. P., & Stevermer, J. J. (2020). Disparities in use of telehealth at the onset of the COVID-19 public health emergency. Journal of telemedicine and telecare, 1357633X20963893.
  10. Vogels, E. (2021, June 22). Digital divide persists even as Americans with lower incomes make gains in tech adoption. Retrieved July 01, 2021, from https://www.pewresearch.org/fact-tank/2021/06/22/digital-divide-persists-even-as-americans-with-lower-incomes-make-gains-in-tech-adoption/
  11. U.S. Department of Health and Human Services. 2020. Sexually Transmitted Infections National Strategic Plan for the United States: 2021–2025. Washington, DC.
  12. COVID-19 Health Equity Task Force: Long COVID, PPE, Testing and Therapeutics Subcommittee Interim Recommendations. (2021, June 25). Retrieved July 01, 2021, from https://www.minorityhealth.hhs.gov/Assets/PDF/June-COVID19HETFSubcommitteesRecommendations-062521-508.pdf
  13. Malayala, Srikrishna Varun, et al. “Primary care shortage in medically underserved and health provider shortage areas: Lessons from Delaware, USA.” Journal of Primary Care & Community Health 12 (2021): 2150132721994018.
  14. CDC announces $2.25 billion to address Covid-19 health disparities in communities that are at high-risk and underserved. (2021, March 17). Retrieved July 01, 2021, from https://www.cdc.gov/media/releases/2021/p0317-COVID-19-Health-Disparities.html
  15. Overview of Testing for SARS-CoV-2 (COVID-19). (2021, March 17). Retrieved July 01, 2021, from https://www.cdc.gov/coronavirus/2019-ncov/hcp/testing-overview.html
  16. CDC/ATSDR Social Vulnerability Index. (2021, April 28). Retrieved July 01, 2021, from https://www.atsdr.cdc.gov/placeandhealth/svi/index.html

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Put the Talis One solution to work for you. Connect with us for information about our products and company updates.

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SARS-COV-2 Variants and Their Impact on Molecular Tests

As new variants of SARS-CoV-2 arise, they can impact diagnostic testing, potentially resulting in false negative results. To confidently make treatment decisions, achieve best-possible patient outcomes, and drive operational and clinical efficiency in a point-of-care setting, you need highly sensitive, rapid molecular tests capable of detecting all existing and emerging SARS-CoV-2 variants.

Which SARS-CoV-2 Tests Are Susceptible to False Negatives?

Molecular tests are straightforward to design for pathogen detection because they are largely based on an RNA sequence. However, viruses that rapidly evolve, such as SARS-CoV-2, can influence test sensitivity based on the sequence of the variant, the design of the test and the prevalence of the variant in the population.

Earlier this year, the FDA identified four EUA-authorized molecular tests that could be impacted by SARS-CoV-2 genetic variants, such as the B.1.1.7 variant that has been associated with an increased risk of transmission.1-2

It is important to be aware that genetic variants are expected to continue to emerge in SARS-CoV-2, which can threaten the sensitivity of virtually any molecular test. This is due to the possibility that one of the targets is driving the sensitivity, so that even if the others still match perfectly the sensitivity can be reduced based on a mutation in a single target. By choosing a test that uses multiple genetic targets, a test will be less likely to be impacted by increased prevalence of genetic variants.3

How To Know If SARS-CoV-2 Variants Impact Your Molecular Test?


Consider the patterns of detection
for your specific test. By choosing a test that uses multiple genetic targets, unfamiliar patterns may reveal the presence of new variants without impacting the final result of your test.

Stay up-to-date on emerging SARS-CoV-2 variants4, and their ability to evade detection by specific viral diagnostic tests.

Perform a repeat test. Per FDA recommendations5, consider negative results in combination with clinical observations, patient history and epidemiological information and repeat testing with a different test targeting different genetic regions if COVID-19 is still suspected.

How Do SARS-CoV-2 Molecular Tests Perform at the Point-of-Care?


All molecular tests used at the point-of-care are significantly faster than central-lab molecular tests 

Compared with central lab molecular tests, which may take up to several days, many point-of-care (POC) molecular test results are generated in up to 45 minutes6.

Point-of-care molecular tests integrated with nucleic acid extraction are more sensitive than those without this crucial sample preparation step

Not all POC molecular tests are created equal. There are some that incorporate nucleic acid extraction (e.g., Talis One) and many that do not, and this feature appears to influence the sensitivity of the test.7 Tests integrated with nucleic acid extraction can deliver significantly lower limits of detection (LoD)—with Talis One sensitivity approaching the range of lab-quality tests.7 Confirmatory testing for presumptive negatives may not be required.

Talis One provides rapid and accurate SARS-CoV-2 detection—quickly delivering central lab-quality results at the point of care

At Talis, we strive to use the best technology to bring the precision of lab-based molecular testing to the point-of-care. The Talis One Covid-19 Test System is designed to detect the ORF1ab and N gene (highly conserved regions) to remain sensitive in the presence of new variants and minimize the need for repeat testing. By integrating solid-phase extraction with innovative nucleic acid amplification technology, the Talis One COVID-19 Test System provides a sample-to-answer POC test where clear, actionable, highly sensitive results are generated in less than 30 minutes—helping healthcare providers enhance patient experience and patient outcomes.

Confidently determine who needs to quarantine and be treated to achieve better patient outcomes with the Talis One COVID-19 Test. 

Talis One COVID-19 Test System

Central lab-quality SARS-CoV-2 molecular testing for a variety of care settings—less than 30 minutes from sample to results.

Learn More

References

  1. SARS-CoV-2 Viral Mutations: Impact on COVID-19 Tests. U.S. Food and Drug Administration website. Updated June 3, 2021. Accessed June 25, 2021. https://www.fda.gov/medical-devices/coronavirus-covid-19-and-medical-devices/sars-cov-2-viral-mutations-impact-covid-19-tests
  2. Emergence of SARS-CoV-2 B.1.1.7 Lineage — United States. Centers for Disease Control and Prevention website. Updated January 22, 2021. Accessed June 25, 2021.https://www.cdc.gov/mmwr/volumes/70/wr/mm7003e2.htm
  3. SARS-CoV-2 E Gene Variant Alters Analytical Sensitivity Characteristics of Viral Detection Using a Commercial Reverse Transcription-PCR Assay https://journals.asm.org/doi/full/10.1128/JCM.00075-21 Accessed August 12, 2021
  4. Genetic Variants of SARS-CoV-2 May Lead to False Negative. U.S. Food and Drug Administration website. Updated March 30, 2021. Accessed June 25, 2021. https://www.fda.gov/medical-devices/letters-health-care-providers/genetic-variants-sars-cov-2-may-lead-false-negative-results-molecular-tests-detection-sars-cov-2
  5. Science Brief: Emerging SARS-CoV-2 Variants. Centers for Disease Control and Prevention website. Updated January 28, 2021. Accessed June 25, 2021. https://www.cdc.gov/coronavirus/2019-ncov/science/science-briefs/scientific-brief-emerging-variants.html
  6. Manufacturers’ instructions for use accessed August 12, 2021 at https://www.fda.gov/medical-devices/coronavirus-disease-2019-covid-19-emergency-use-authorizations-medical-devices/in-vitro-diagnostics-euas-molecular-diagnostic-tests-sars-cov-2#individual-molecular
  7. Subsoontorn, P., Lohitnavy, M. & Kongkaew, C. The diagnostic accuracy of isothermal nucleic acid point-of-care tests for human coronaviruses: A systematic review and meta-analysis. Sci Rep 10, 22349 (2020). https://doi.org/10.1038/s41598-020-79237-7 Accessed August 12, 2021

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