The emergence of Omicron less than one year ago represented a big shift in SARS-CoV-2 evolution. The subvariants also don’t seem to pose greater risks that the parent Omicron, says Van Kerkhove. But fortunately, infection from one Omicron subvariant still sufficiently reduces the risk of getting reinfected with another. “WHO only names a variant when it is concerned that additional risks are being created that require new public health action,” Agrawal explains.Ĭurrently, all Omicron sublineages are considered variants of concern because they share similar characteristics: They spread more easily than earlier variants and can dodge previous immunity. “But WHO does not name all variants,” says Anurag Agrawal, the chair of WHO’s Technical Advisory Group for Virus Evolution which makes recommendations on naming variants. In May 2021, WHO began assigning variants of interest and variants of concern letters of the Greek alphabet. When this happens, WHO labels the variant as interesting or concerning.
These mutations can also render authorised therapies ineffective. Others can alter the appearance of the virus, enabling it to dodge immunity from previous infections or vaccines and making it more difficult to detect. Some mutations can help a variant spread more easily or may cause more severe disease. Scientists also believe that Omicron like variants could evolve in people with compromised immune systems where the virus can persist longer while acquiring dozens of new mutations. “The more SARS-CoV-2 circulates, the more it may change,” says Maria Van Kerkhove, the epidemiologist who leads the COVID-19 response at WHO. The viruses that make up that branch are called "variants." Those mutations then create a new branch of the SARS-CoV-2 evolutionary tree.
If the same mutation appears and spreads in unrelated populations, that suggests it offers an advantage to the virus.
These changes, called mutations, are random and usually have no or little consequence for the virus. “A marathon runner does not slow down before the finish line.” SARS-CoV-2 variants are still evolvingĮvery time SARS-CoV-2, the virus that causes COVID-19, replicates during an infection, it can make mistakes and change a little bit. Marion Koopmans, the director of the WHO Collaborating Center for emerging infectious diseases and a member of WHO’s mission to probe the origins of the COVID-19 pandemic says, “The situation is much better than it has been.” But she cautions that with fall and winter approaching, we should remain prepared for another substantial wave. “SARS-CoV-2 evolution is not over,” says Olivier Schwartz, head of the Virus & Immunity Unit at Institut Pasteur, Paris. The coronavirus is continuously evolving and gaining novel mutations to date there have been more than 200 newer Omicron sublineages and their derivatives. While WHO has not anointed any of these recent Omicron derivatives with a Greek letter of their own, experts fear these variants could undermine the new boosters and treatments, leading to a new wave of infections and deaths. nursing home residents have risen nine-fold since the end of April, and by August death rates almost quadrupled in this group, according to the data compiled by the AARP Public Policy Institute and the Scripps Gerontology Center at Miami University in Ohio. In the U.K., symptomatic infections have steadily increased since August 27-the day they hit lowest level this year- according to the ZOE COVID-19 study, an App-based project in which patients enter their symptoms on their phone. Infections over the last three months have been dominated by new sublineages of Omicron: BA.2, BA.2.12.1, BA.4., and BA.5. For the past 10 months the World Health Organisation hasn’t named any new variants, which begs the question: Has the virus stopped evolving? Then in November 2021, Omicron, a vastly different version of the virus emerged. Ten variants with Greek names-Alpha through Mu-killed millions.
Every few months for the first two years of the pandemic the public learned the name of a new coronavirus variant that had emerged and was more adept at infecting us or causing severe disease.
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