The Omicron variant of the coronavirus has alarmed many scientists due to the sheer variety of genetic mutations it carries — about 50 in all, together with no less than 26 which are distinctive to it. However more does not necessarily mean worse: Mutations generally work collectively to make a virus extra fearsome, however they might additionally cancel each other out.
“In precept, mutations may work in opposition to one another,” mentioned Jesse Bloom, an evolutionary biologist on the Fred Hutchinson Most cancers Analysis Heart in Seattle. “Nevertheless, on this case evolutionary choice is extra prone to result in the unfold of a brand new variant with favorable than unfavorable combos of mutations.”
Nonetheless, this phenomenon, referred to as epistasis, is why scientists are reluctant to take a position on Omicron’s attributes, though particular person mutations within the variant are related to better transmissibility or with a capability to dodge the physique’s immune defenses.
“You will need to get a way of the complete virus,” mentioned Penny Moore, a virologist on the Nationwide Institute for Communicable Ailments in South Africa.
Dr. Moore’s workforce is amongst dozens worldwide attempting to know whether or not present vaccines will work in opposition to Omicron. The researchers are creating synthetic variations of the virus that comprise all of Omicron’s mutations, relatively than making judgments primarily based on a subset of mutations.
It’s a lesson researchers realized final yr, when the Beta variant emerged in South Africa. They estimated that variant’s means to evade immunity primarily based on one specific mutation, E484K. However Beta additionally had two different mutations that turned out to have an effect on sensitivity to vaccines.
“The mix of these three mutations was extra resistance than a virus that contained solely E484K,” Dr. Moore mentioned. Learning the only mutation “turned out to be deceptive.”
Omicron carries a mutation referred to as N501Y, which is believed to permit the virus to bind to human cells extra tightly. This mutation was additionally current within the Alpha variant and was linked to its contagiousness.
“Nonetheless, it ended up being Delta, which doesn’t have that specific mutation, that was extra much more transmissible than Alpha,” Dr. Bloom mentioned. “That’s as a result of Delta had different mutations that improve transmissibility.”
A variant’s contagiousness is dependent upon how nicely the virus binds to receptors on human cells, but in addition on the steadiness of the virus, the place within the airways it replicates and the way a lot of it’s exhaled.
Omicron has a cluster of mutations which are all linked to tighter binding to human cells. “However appearing collectively, they may have a considerably completely different impact,” Dr. Bloom mentioned. For that cause, he added, he can not predict how the variant will act within the physique.
That can require laboratory research, that are underway throughout the globe.