Variant of Interest vs Variant of Concern – What’s the Difference?

As the Sars-COV-2 virus continues to spread across the globe, the World Health Organization has readily identified four COVID ‘variants of concern’: alpha, beta, gamma, and delta. As of late, the delta variant has proven to be particularly transmissible, hitting the United States with an additional mutation now classified as the delta AY42 variant. In addition to these variants of concern, other variants are also being monitored under the title ‘variants of interest’ including variants eta, iota, kappa, and lambda, mu, along with 12 additional variants that have surfaced across the world.

With so many variants, it can be confusing to determine what classifies one a concern over the other.


What makes a variant ‘of interest’?

A VOI typically refers to specific genetic markers that have been associated with changes to receptor binding. This implies that variants of interest may be more difficult to treat, be at risk for more severe symptoms, or have a heightened rate of transmission. However, these specific strains may appear in isolated regional cases and have yet to spread outside to other countries. Although, the WHO agrees to continue to monitor their development.

What makes a variant ‘of concern’?

VOC‘s express similar attributes as ‘variants of interest’ but are more likely to be responsible for greater disease severity across the globe. At a higher risk for hospitalizations, these variants express more significant antibody responses and may produce a higher rate of infection or viral load. Furthermore, physicians may face increased difficulty in treatment as these strains show reduced effectiveness in pharmaceutical interventions or vaccines. Additionally, they are considered more highly transmissible making it easier to cross regional boundaries.

Because viruses so frequently mutate and evolve, scientists will continue to closely monitor both ‘variants of concern’ and ‘variants of interest’ in the Sars-COV-2 virus.

To note, many mutations are inconsequential to the virus’s impact on disease, whereas others can also effectively interrupt the virus’s ability to replicate or proliferate. Though, when a mutation threatens to become a dominant strain, as is the case with Delta, a ‘variant of interest’ is elevated to one of concern.

If you’d like to learn more about the current list of COVID-19 variants, visit the World Health Organization here variant page for more information.

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