Tracking Omicron: Why The Variant Is So Infectious

According to the most recent CDC data released on Christmas, Omicron accounted for 58.6% of all positive COVID-19 cases nationwide.
Posted at 8:47 PM, Jan 04, 2022

In less than one month, the Omicron variant has gone from being first detected in the U.S. to its dominant variant circulating.

Over the holidays, the variant caused canceled flights, filled hospitals and kept many families from seeing each other for a second year in a row. And as of Christmas, the CDC's most recent day of data shows the Omicron variant of COVID-19 accounted for 59% of current cases in the US.

"This current virus - the Omicron variant - has about 50 mutations; more than 30 in the spike protein domain, which is more mutations than we've seen in any of the coronavirus variants so far," said Dr. Phil Stahel, Chief Medical Officer at the Medical Center of Aurora in Colorado.

For comparison, Delta had around 13 mutations, and Dr. Sthael says that means our body's antibodies have a more difficult time recognizing COVID as COVID. It's the main reason why Omicron is 20 times more transmissible than the original strain of COVID-19 and 2.5 times as transmissible as Delta, even if you are vaccinated.

"Omicron, the receptor binding domain, has mutated so much that is has less affinity in terms of the antibodies from the vaccine recognizing it, so therefore the answer is the booster shot because you will overwhelm the virus with the quantity of the immune response even if there is not a perfect match," Dr. Stahel said.

A study out of Denmark shows people with the booster were 56% less likely to become infected by Omicron if a member in their household had it compared to people who only had two doses of the vaccine. But going deeper, the vaccine does appear to do a great job of preventing serious infection. Researchers in South Africa found that even though Omicron's mutations allow it to circumvent the vaccine's antibodies easily, it does a poor job at escaping T-cells, our body's second line of defense that prevents serious infection. 

The kicker though: current data suggests that only applies to people who have been infected in the last three months or are vaccinated.

"We may still get the virus, we may still get sick, we may be miserable for a few days, but it is no longer a catastrophe," Dr. Stahel said. "We will not be admitted to hospitals, and we will not die from SARS-COVID-2."

Dr. Stahel says until we reach herd immunity with COVID, Omicron still poses more of a significant risk of serious health issues and death in those who are unvaccinated compared to those who are.