In biological terms, a mutation occurs when a cell’s genetic code is altered. This change can affect the way a cell behaves. In addition to living cells, viruses (which are not alive) have the potential to mutate. All viruses contain genetic material, in the form of RNA or DNA. COVID-19 is an RNA-based virus that, because of mutations, has evolved into several notable new strains over the course of the COVID-19 pandemic, including the Omicron variant. Understanding mutations is helpful in understanding how COVID-19 may develop as the pandemic continues.
Mutations occur when there is an error in the copying of genetic material; the mutation (or error) will then continue to replicate. There are two major classes of mutations in living cells:
Hereditary Mutations — Also known as germline mutations, these mutations are inherited from one or both parents. The mutations are present in almost all cells and are part of the organism’s makeup. The mutations are passed by germ cells (egg and/or sperm cells) to the offspring.
Acquired Mutations — Also known as somatic mutations, these mutations are not genetic, which means they cannot be passed between generations. Environmental factors, such as UV radiation or tobacco, can cause mutations in cells that then continue to replicate. This can result in diseases such as cancer.
Mutations can have many different effects. One common effect is nothing. These mutations are referred to as neutral mutations and have neither a positive nor a negative effect on genetic material. Some mutations are fixed before they can cause any effect at all — there are repair mechanisms that can catch copying errors and fix them before they have a chance to replicate. Sometimes they are not fixed, as is common in viruses, but still have no clinical impact.
Mutations can also have beneficial or harmful effects, in terms of how they help an organism survive.
COVID-19 is an RNA-based virus. This means that its genetic information is encoded in RNA, rather than DNA. Mutation rates are typically higher in RNA-based viruses. A virus does not have cells; rather, it is a particle referred to as a virion. Virions are bundles of genetic material inside a protein shell called a capsid. RNA is less organized than DNA and has a very limited ability to edit mistakes in replication.
Like other viruses, COVID-19 invades a host cell, connecting with spike proteins and then beginning to replicate its own RNA when it is in the host cell. COVID-19 mutates frequently because there is rapid replication of the virus over time in a large population, providing more opportunities for mutations to occur. The more the virus is transmitted and spreads, the more it needs to replicate, and the more it needs to replicate, the more opportunities it has to produce a mutation that is advantageous for its survival and thus persists. This means that there is a greater chance for “beneficial” mutations (that is, mutations that are beneficial to the virus and help it survive, invade a host more effectively, and reproduce more quickly).
It is almost impossible for scientists to determine exactly how often the COVID-19 virus mutates, but they have determined that COVID-19 genetic mutations occur approximately every 11 days.
Viruses constantly change through mutation. A virus that has one or more new mutations is considered a variant. Many variants do not thrive, and many disappear unnoticed. When mutations occur in the COVID-19 virus’s RNA that make the virus more transmissible or affect its severity, scientists and medical experts take note and track the new variant’s spread. Currently, the CDC (U.S. Centers for Disease Control and Prevention) has identified two variants of the virus (SARS-CoV-2) that causes COVID-19 as variants of concern: the Delta variant and the Omicron variant.
COVID-19 genetic mutations are taking place in millions of hosts around the world. The fact that COVID-19 is so widespread and has infected so many people has allowed COVID-19 to rapidly mutate and create numerous variants.
Mutations are random, so it’s not really possible to predict how and when they will occur. It is possible that future mutations of COVID-19 will lead to strains that are more contagious or cause more severe illness, or will impact the virus’s ability to transmit and/or the possibility to resist antibodies. Being fully vaccinated (which includes getting a booster shot as recommended) is the best way to protect yourself against COVID-19 (including any future variants thereof), as well as a crucial step in preventing the spread of the disease.
Typically, the biological evolutionary trajectory for viruses is toward a strain that is easily transmissible, so it can infect enough hosts to survive and propagate, but less deadly, so it does not kill off its host with itself (which would negatively affect the virus’s ability to spread effectively). In the future, many medical experts expect COVID-19 to settle into a sort of endemic seasonal virus that is easily transmissible but not as deadly. We have seen this evolution in other viruses in the past, such as the flu.
COVID-19 is not the first virus of its kind. The virus that causes COVID-19, SARS-CoV-2, is actually the fifth coronavirus to settle into what is expected to be an endemic existence. The other four types of coronaviruses tend to show up as mild colds and have been plaguing humans for decades or even longer. Right now, with variants of various levels of concern appearing, it is hard to determine whether COVID-19 will develop into a milder illness like the “common cold” or be a comparatively more serious threat to health, like the flu.
Vaccines are still the best possible protection against COVID-19. Scientists are working hard to keep up with the virus’s mutations and the variants they can cause. Vaccines are typically designed to produce immune responses that target areas of a virus that are less likely to mutate. Some of the new variants have shown to be more resistant to vaccines and antibodies, while still being very effective at preventing severe and life-threatening symptoms. (Keep in mind that there is more to immune response than antibodies — T-cells, for instance, also play a role in a body’s ability to ward off illness.) Research into new COVID-19 variants and the efficiency of vaccines is continuously being done, and this research may show that new vaccines will be necessary. The body’s immunity also naturally wanes over time, so it is not only variants that bring about the need for new or repeated vaccinations.
In the meantime, staying up-to-date on vaccines and following all recommended precautions (such as masking in public places and frequent hand washing) is the best way to prevent illness from COVID-19.
Carbon Health’s medical content is reviewed and approved by healthcare professionals before it is published. But note that our knowledge and understanding of COVID-19 are developing and changing very rapidly; if you have questions or concerns about COVID-19 precautions, treatments, and vaccinations, please talk to your healthcare provider.