What You Should Know About COVID-19 Variants and Their Classifications

Key Takeaways
  • All viruses evolve over time. And while most changes have little to no impact on the virus’ properties, others may cause increased risk to public health.

  • Key indicators to monitor include transmissibility, disease severity, and how effective vaccines, medicines, or other public health measures work against a variant.

  • The core classifications to be aware of include: variant of concern, variant of interest, variant under monitoring, and variant of high consequence.

The World Health Organization (WHO) has been working with partners, expert networks, national authorities, and researchers in monitoring and assessing the evolution of SARS-CoV-2 since Since 2020.[1] They have created different classifications of COVID variants to help prioritize global monitoring and research, and inform the ongoing response to the COVID-19 pandemic.

Here are the core classifications to be aware of:

A Variant of Concern (VOC) is one that shows . That means it’s more likely to evade protection from vaccines or other treatments. There is also typically a significant reduction in neutralization by antibodies generated during previous infection or vaccination.

A Variant of Interest (VOI) has specific genetic markers that are associated with heightened transmissibility and prevalence or other indicators of emerging public health risks. Multiple public health actions, such as enhanced sequence surveillance or epidemiological investigations, may be required to determine transmissibility, disease severity, and the efficacy of approved or authorized vaccines. VOIs are monitored closely to see if they should be reclassified as a VOC.

A Variant Under Monitoring (VUM) is considered “de-escalated”. It longer meets the criteria to be designated as a VOC or VOI. A VUM was at one point more likely to spread, cause reinfection, or lead to severe illness, but are no longer circulating enough to pose a significant public health risk. Note that the CDC uses another similar classification called Variant Being Monitored (VBM).

A Variant of High Consequence (VOCH) is a variant that shows greater resistance to prevention measures. In the instance of a VOCH, health organizations put together a strategy to prevent or contain transmission. This might mean updating treatments or reformulating vaccines.[2]

How many coronavirus variants are there, and what are their classifications?

Researchers have seen multiple variants of the SARS-CoV-2 coronavirus that are different from the original version first detected in China in 2019. Currently, there are two SARS-CoV-2 VOIs: Lambda and Mu. Alpha, beta, gamma, delta, and omicron variants are classified as VOCs.[3] There are also a handful of formerly monitored variants that are no longer circulating. This information is regularly updated by the WHO and CDC.


  1. Tracking SARS-CoV-2 variants. (2021, May 31). WHO. https://www.who.int/en/activities/tracking-SARS-CoV-2-variants/
  2. Coronavirus Disease 2019 (COVID-19). (2020, February 11). Centers for Disease Control and Prevention. https://www.cdc.gov/coronavirus/2019-ncov/variants/variant-classifications.html
  3. COVID Variants: What You Should Know. (2021). Johns Hopkins Medicine. https://www.hopkinsmedicine.org/health/conditions-and-diseases/coronavirus/a-new-strain-of-coronavirus-what-you-should-know

DISCLAIMER: This article is for general information purposes only, does not constitute medical advice and is not intended to be relied upon for medical diagnosis or treatment. If you are experiencing a medical emergency, dial 911 immediately.