Covid-19 Variants: What You Should Know
By Aleena Kuriakose
Highlights
According to the CDC, there are three categories of Covid-19 variants: variant of interest (VOI), variant of concern (VOC), and variant of high consequence (VOHC).
Evidence suggests the virus has some limitations in its evolution, so there is hope that the vaccines will continue to provide efficacy against the variants.
Introduction
SARS-CoV-2, commonly referred to as Covid-19, was the headliner of the past year. However, attention has been shifting to the emergence and spread of Covid-19 variants, which spread more easily. Several variants have demonstrated significant detrimental effects, including the Delta variant which originated from India and the Lambda variant which originated from Peru. Public health officials and medical officials have been desperately trying to decipher the evolutionary processes involved in the emergence of new variants, what to expect in terms of the future emergence of variants, and what can be done to minimize their impact (Otto et al., 2021).
How does Covid-19 mutate?
Covid-19 is an RNA virus; the RNA mutation rate is higher than the DNA mutation rate. Stuart Ray, M.D., vice chair of medicine for data integrity and analytics, says, it is the nature of RNA viruses to evolve and mutate gradually. “Geographic separation tends to result in genetically distinct variants,” he says. Viruses mutate when there is a change to their genes. Simply, when a virus infects individuals, it attaches to their cells, gets inside them, and replicates their RNA, which helps the virus spread. However, if there is a replication error, the RNA becomes altered and becomes a mutation.
Current Variants
The Centers for Disease Control and Prevention (CDC) classifies variants of SARS-CoV-2 into three categories: variant of interest (VOI), variant of concern (VOC), and variant of high consequence (VOHC).
VOIs aim to observe current variants that are monitored and characterized by federal agencies. These variants possess specific genetic markers that have been correlated with changes to receptor binding, weakened neutralization by antibodies produced against previous infection/vaccination, compromised efficacy of treatments, or predicted increase in spread or disease severity.
VOCs are those that are closely monitored by federal agencies due to indicators of an increase in transmissibility and severity, significant reduction in neutralization by antibodies, and reduced efficacy of treatments. A popular VOC was the delta variant. It was designated as a VOC because of its high transmissibility. As of July 2021, the delta variant is considered the most contagious form of the Covid-19 coronavirus so far.
As for VOHCs, there are currently no variants that rise to that level of high consequence or have clear indication that current prevention measures are ineffective relative to previously spreading variants.
Should We be Concerned about Variants?
The fact that there are variants of Covid-19 is not a surprise to scientists and researchers. Rather, it was expected given that the RNA virus has spread globally, infecting people in many regions. Furthermore, evidence suggests the virus has limitations in its evolution, so there is hope that the vaccines will continue to provide efficacy against variants. However, we must still remain cautious, get vaccinated, adhere to masking regulations, and practice personal hygiene to limit the spread of the virus and ensure safety.
References
Bollinger, R., & Ray, S. (2021, July 23). New variants of coronavirus: What you should know. Johns Hopkins Medicine. https://www.hopkinsmedicine.org/health/conditions-and-diseases/coronavirus/a-new-strain-of-coronavirus-what-you-should-know.
CDC. (2021). Sars-cov-2 variant classifications and definitions. Centers for Disease Control and Prevention. https://www.cdc.gov/coronavirus/2019-ncov/variants/variant-info.html.