The Omicron COVID-19 Variant: Here's What We Know So Far

by Elizabeth Broadbent
Originally Published: 
Andriy Onufriyenko/Getty Images

Each new COVID-19 variant sends us into a doom spiral. It’s driven by three key questions: Is it more transmissible than earlier variants? Will it make us sicker than previous variants? And perhaps most importantly, Will our vaccines work as effectively against it? For most variants, that doom spiral has come to nothing. But first alpha, then delta had enough mutations that strengthened transmissibility (how easily the virus passes from one person to another), made people sicker, and in the case of delta, also seemed to evade our vaccines at a higher rate. Now the WHO has named omicron a “variant of concern,” calling “the overall global risk related to the new VOC Omicron… very high.”

That’s epidemiologist-speak for “We’re freaking out.”

But it’s a little more nuanced than scientists at the WHO throwing their papers in the air and shouting that the sky is falling. Omicron’s dangerous. Here’s what we know.

It Has A Lot Of Mutations

Science time: remember, mRNA vaccines work by teaching our cells to produce a spike protein — the same spike protein found on a COVID-19 virus. Our immune cells recognize that spike protein as foreign and produce antibodies to combat it. When our immune system sees a similar spike protein on a real COVID-19 virus, it attacks. Delta has 18 mutations on its spike protein. Omicron has a staggering 34.

Generally, the more mutations, the more worrisome. But it also depends where those mutations happen, and seeing them on that spike protein sends scientists running scared. Vaccines train our bodies to defeat COVID based on its spike protein profile. Before our antibodies can fight COVID, they have to recognize a COVID virus’s spike protein. If that viral cell has too many mutations in the right place — what epidemiologists call the “receptor-binding domain,” our antibodies won’t recognize it as COVID. When that happens, our vaccines stop working.

Omicron has multiple mutations on that all-important receptor-binding domain which make it more likely, the WHO thinks, to cause breakthrough infections in those who have been vaccinated or previously infected.

Some of its mutations also seem related in increased transmissibility. And real-world experience bears that out.

“We have seen these mutations in other strains, in twos and threes, and each time they were a little harder to neutralize but didn’t spread particularly well,” Benjamin Neuman, a virologist at Texas A&M University, said to The Washington Post. “Now, all together? It’s a complete black box.”

But It Has To Outcompete Delta…

For omicron to pose a real danger, it must be more contagious than delta. Unfortunately, virologists say it “seems likely to be more transmissible than delta, including among vaccinated people.” They predict our vaccines will be less effective against omicron, leading to more breakthrough infections, symptomatic or not, and spreading the disease more widely. Moderna CEO Stéphane Bancel threw markets into a panic when he told The Financial Times that existing vaccines would not be as effective against omicron as they are against existing variants. There could be, he said, “a material drop” in effectiveness against omicron. “I just don’t know how much, because we need to wait for the data,” he said. “But all the scientists I’ve talked to … [say], ‘This is not going to be good.'”

Omicron is outcompeting delta; it has increased transmissibility; and our vaccines are less effective at beating it. But it’ll be about two weeks, says Bancel, before we know more about exactly vaccines work against it.

There Is Some Good News About Omicron

Following the cardinal rule of epidemiology — when the virologists freak out, you listen — everyone’s scrambling to sequence, track, and study omicron, and we should have more information in the next few weeks as scientists track its spread and determine its transmissibility rates, its rate of breakthrough infections, and the severity of infections it causes in both vaccinated and unvaccinated individuals.

But viruses that kills their hosts too quickly don’t spread effectively. So far, omicron doesn’t seem to cause more severe illness than other variants. South African virologist Barry Schoub says omicron cases there (where it was first sequenced) have tended to be “mild or moderate… That’s a good sign. But let me stress it is early days.” Severe cases of omicron “have been concentrated among people who are not fully vaccinated,” head of an intensive care unit in South Africa’s Soweto, Dr. Rudo Mathivha, tells The New York Times. Israeli health official Dr. Sharon Alroy-Preis told the press that vaccinated people only seemed to become “slightly ill” from omicron. And the Times’ own Carl Zimmer agreed that, “For now, there’s no evidence that omicron causes more severe disease than previous variants.”

Of course, we’re terrified about our vaccine efficacy. But Dr. Raghib Ali, an epidemiologist at the University of Cambridge, has reassuring words for us over Twitter:

“Omicron is like the song ‘One Piece at a Time’ by Johnny Cash, where he puts together a car from stolen bits of lots of different cars. It is made of mutations that were somewhat successful separately in other variants, but together it is hard to say more than it looks weird,” Benjamin Neuman, a virologist at Texas A&M University, told The Washington Post. So while we highly suspect it will be more transmissible and evade our immune response more effectively (bad news), omicron doesn’t seem as if it will cause higher rates of severe illness and death than previous variants (good news).

Bottom line: Vaccinated individuals will be more likely to become infected, and the virus will be more easily spread. However, a COVID vaccine wasn’t manufactured to stop COVID infection. It was meant to stop COVID from causing severe illness and death. Omicron may overtake delta. It may infect more vaccinated people, and its faster spread among unvaccinated populations could be a disaster for those without access to vaccines. Omicron is a call for nations like the US to ship out whatever vaccines we can to countries that need them.

Virologists are hitting the panic button. But until we know exactly how transmissible omicron is, and how effective it has become at evading our vaccines, it’s too early for us to do the same.

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