Medically reviewed by Susan Kerrigan, MD and Marianne Madsen
Viruses mutate. It’s their modus operandi. The mutation process of some viruses–like the common cold–is so fast that by the time we are immune to one variant, it has created many others to which we lack immunity. Not all variant strains persist. Some emerge and then disappear, while others stay around for an extended period.
How does COVID-19 mutate?
COVID-19 is caused by a virus called SARS-CoV-2. Like all viruses, the coronavirus disease cannot survive unless it can infect a new host. Once a host has been exposed to the coronavirus, it begins the process of viral replication. This process involves the virus infecting the host’s cells and hijacking the cell’s machinery to produce more virus copies.
As with any attempt to clone an original strain, mistakes can occur. The new copies may end up not being exact copies of the original SARS-CoV-2 virus. These mistakes happen quite often, and when they do, it is called a virus mutation. Most mutations don’t cause any major changes to the virus. But when they do, they can change the way the virus operates, including how infectious it is, the type of illness it causes, and how our immune systems react to the virus. These viral mutations make up the SARS-CoV-2 variants.
Variant Classification
The Centers for Disease Control and Prevention (CDC) has a three-tiered classification system to assess the impact of viral variants.
- Variant of Interest: The variant might lead to an outbreak but hasn’t yet become widespread.
- Variant of Concern: This type of variant shows evidence of becoming more easily transmissible with an increased risk of severe disease.
- Variant of High Consequence: The variant reduces the effectiveness of treatment and the existing vaccines.
COVID-19 Variants
The COVID-19 virus has seen several mutations emerge since the original virus was discovered. None of the current or previous variants have been classified as a variant of high consequence by the CDC. However, they do currently list four COVID-19 virus variants as being variants of concern. They are Alpha, Beta, Gamma, and Delta, which is now the dominant variant of coronavirus. Another six variants are listed as being variants of interest.
What Causes the COVID-19 Virus to Mutate?
According to the World Health Organization (WHO), the process by which a virus mutates and creates variants can be explained quite easily. The more a virus circulates in a population, the more opportunity it has to spread. The more opportunity it has to spread, the more chance it has to replicate. With an increase in virus replication comes an increased opportunity for mutations of previous strains to occur and, with them, new variants.
How To Prevent COVID-19 Variants
The way to prevent COVID-19 virus variants is to reduce the virus’s opportunity to spread and mutate. COVID-19 vaccinations are considered the best overall way to protect you from catching a coronavirus and preventing severe illness. The more people who are vaccinated, the less opportunity the virus has to spread. While the COVID-19 vaccine won’t make it impossible to be infected or to pass the virus to someone else, a recent study showed that the risk of viral transmission would be lower than an unvaccinated person.
Whatever your vaccination status, the current recommendations issued by the WHO and CDC to reduce transmission can stop the spread of the virus and its mutation into variants at the source. These include washing hands frequently, wearing a mask or face covering, practicing social distancing, providing good ventilation, and avoiding crowded places.
References
- VDH: Variants of the Virus that Causes COVID-19
- CDC: SARS-CoV-2 Variant Classifications and Definitions
- WHO: The effects of virus variants on COVID-19 vaccines
- New England Journal of Medicine: Prevention and Attenuation of Covid-19 with the BNT162b2 and mRNA-1273 Vaccines
- COVID Variants on the Horizon