The Centers for Disease Control and Prevention (CDC) reported on Monday that the omicron variant now accounts for nearly 73% of new coronavirus infections in the U.S. That rise is astonishing given that, in the beginning of December, the new variant only made up less than 1% of new infections. This means that the variant has successfully outcompeted the delta variant, ushering in a new stage of the pandemic scientists long feared would arise.
Currently, much of the country is seeing a dramatic increase in the number of COVID-19 cases thanks to omicron. In New York state, new coronavirus cases have increased more than 80% over the last two weeks.
While the country now has to brace for a surge in cases due to a more transmissible variant, it is likely not only unvaccinated people who will be affected. As reported by The New York Times, the country should also prepare for a rise in breakthrough infections, or infections despite vaccination. That is because, as Salon has previously reported, omicron is unique in the sense that compared to previous variants, it has the highest number of mutations reported — mutations that can partially evade vaccine-based immunity.
Indeed, out of nearly 50 mutations observed in the omicron variant compared to the original virus, 32 are in the spike protein, which implicates the virus' ability to attach and gain entry into human cells.
But that doesn't mean the vaccines don't provide some protection; rather, they are still overwhelmingly effective at preventing severe cases and death. Still, omicron's rapid rise leaves one big, open-ended question: How severe is the disease caused by omicron? And can we expect a rise in hospitalizations and deaths, or can we just expect many (albeit mild) infections?
According to the CDC, the omicron variant is now the dominant strain of COVID-19 in the U.S. Nearly three out of four new infections are from this mutant virus — an increase by sixfold from where omicron infections stood last week, and an even more startling figure considering the first reported case of omicron in the U.S. was less than a month ago.
Scientists have made remarkable strides in understanding the origin and spread of COVID-19, which is part of what makes the omicron variant so shocking: its origins are perplexing, as it didn't stem from other recent prominent strains like the delta variant. The confusion around its origins creates added hurdles in terms of treating it.
Besides its incredible virulence, here's why the omicron variant is so scary: Omicron has 30 mutations located near its spike protein, which are the thorn-like protrusions on the SARS-CoV-2 virus' central sphere. Because the existing mRNA COVID-19 vaccines are designed to train the immune system to recognize those spines as intruders, mutations on the spike proteins may help the virus evade the body's attempts to defend itself, and perhaps partially evade existing vaccine-based immunity.
So how did omicron rack up so many mutations on its spike proteins, without any intermediate steps of evolution through other variants? Scientists have theories about how that happened, though none are comforting.
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