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In the wake of the novel coronavirus that caused the COVID-19 pandemic, concerning variants of SARS-CoV-2 are causing new spikes in case levels in the US1. The number of new daily cases continues to fluctuate, reaching over 100,000 per day in June 20222. Although vaccinations have reduced the likelihood of developing serious disease, sometimes fully vaccinated people remain at risk of infection or reinfection. This is called a “vaccine breakthrough” and means that COVID-19 can still spread through vaccinated populations by evading the body’s immune response3

As long as the disease is not eradicated, SARS-CoV-2, like any other virus, continues to spread and mutate, and people who are vaccinated or have natural immunity still remain at risk of being infected by new variants of SARS-CoV-21. This mutation process can allow for more virulent or more transmissible strains to prosper and spread through the population as weaker or less transmissible variants are phased out due to vaccines and acquired immunity. 


What is a Variant?

All viruses, including SARS-CoV-2, change over time4. Viruses replicate rapidly, and during this process, the genetic code can change due to genetic mutations or viral recombination5. Most of these changes have little impact on the virus’ properties, but some changes can lead to alterations in the virus’ structure. If a set of mutations changes the property of the virus sufficiently, antibodies from our immune system may not “recognize” the new variant and neutralize the threat, and therefore, any preexisting immunity may not work as effectively.


Variants of Concern

Since the ancestral SARS-CoV-2 variant was sequenced in early 2020, there have been several breakthrough mutations that have caused a sudden rise in cases. The WHO defines a variant of concern (VOC) as a variant of the virus that meets one or more of the following changes4:

    • Increase in transmissibility or detrimental change in COVID-19 epidemiology
    • Increase in virulence or change in clinical disease presentation
    • Decrease in effectiveness of public health and social measures or available diagnostics vaccines, therapeutics

Previous circulating VOCs include the Alpha, Beta, Gamma and Delta variants4,6. These variants have all been associated with an increase in cases, transmission and mortality rates6,7. It is possible that these variants may have escaped the immunity that was established from infection with the original SARS-CoV-2 virus or vaccines7.

The Omicron variant has risen to the attention of the public and health officials alike due to its high infection and reinfection rates. This VOC is extensively mutated, which poses a significant threat as it may therefore evade vaccine-induced immunity8. Although Omicron is generally associated with less severe disease, its increased transmissibility has resulted in high numbers of patients being admitted to the hospital, thus putting a large strain on healthcare systems9. Research suggests that the next influx of infections will likely come from sub-variants of Omicron, namely, BA.4 and BA.51. These sub-variants are known to possess significant receptor binding and immune evasion capabilities and are not neutralized as effectively as previous variants by serum from triple vaccinated patients10.


Pandemic Response Lab supports diagnosis

Pandemic Response Lab (PRL) is one of the leading providers of COVID-19 testing and non-diagnostic variant testing in the US. Using a combination of scientific innovation and top-of-the-line robotics, PRL currently has the capacity to process 100,000+ tests per day. Additionally, PRL has delivered 99% of test results in less than 24 hours.

PRL supports the surveillance of SARS-CoV-2 variants across the public and private health sector through performing non-diagnostic, whole genome sequencing. Due to its large-scale workflow, PRL was the first to discover the Beta and Omicron variants in New York state and remains a leader in the challenge to identify and mitigate the spread of SARS-CoV-2 mutations. Learn how you can benefit from PRL’s diagnostic testing and sequencing services by contacting us today.

 

1. CDC. Coronavirus Disease 2019 (COVID-19). Centers for Disease Control and Prevention. Published February 11, 2020. Accessed June 18, 2022. https://www.cdc.gov/coronavirus/2019-ncov/variants/about-variants.html

2. COVID-19 Data Explorer. Our World in Data. Accessed June 18, 2022. https://ourworldindata.org/coronavirus-data-explorer

3. CDC. COVID-19 Vaccination. Centers for Disease Control and Prevention. Published February 11, 2020. Accessed June 18, 2022. https://www.cdc.gov/coronavirus/2019-ncov/vaccines/effectiveness/why-measure-effectiveness/breakthrough-cases.html

4. Tracking SARS-CoV-2 variants. Accessed June 18, 2022. https://www.who.int/activities/tracking-SARS-CoV-2-variants

5. SARS-COV-2 variant classifications and definitions. Centers for Disease Control and Prevention. https://www.cdc.gov/coronavirus/2019-ncov/variants/variant-classifications.html. Published April 26, 2022. Accessed June 27, 2022.

6. Fiolet T, Kherabi Y, MacDonald CJ, Ghosn J, Peiffer-Smadja N. Comparing COVID-19 vaccines for their characteristics, efficacy and effectiveness against SARS-CoV-2 and variants of concern: a narrative review. Clinical Microbiology and Infection. 2022;28(2):202-221. doi:10.1016/j.cmi.2021.10.005

7. Otto SP, Day T, Arino J, et al. The origins and potential future of SARS-CoV-2 variants of concern in the evolving COVID-19 pandemic. Current Biology. 2021;31(14):R918-R929. doi:10.1016/j.cub.2021.06.049

8. Araf Y, Akter F, Tang Y dong, et al. Omicron variant of SARS-CoV-2: Genomics, transmissibility, and responses to current COVID-19 vaccines. Journal of Medical Virology. 2022;94(5):1825-1832. doi:10.1002/jmv.27588

9. Mahase E. Covid-19: What do we know about omicron sublineages? BMJ. 2022;376:o358. doi:10.1136/bmj.o358

10. Tuekprakhon A, Huo J, Nutalai R, et al. Antibody escape of SARS-CoV-2 Omicron BA.4 and BA.5 from vaccine and BA.1 serum. Cell. Published online June 9, 2022. doi:10.1016/j.cell.2022.06.005




 

 

 

 

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