WEST PALM BEACH, Fla. — Health experts continue to learn more about the omicron variant of COVID-19 since it was first detected in South Africa in late November of last year.
The new variant has spread across the U.S. at a staggering speed since the first case was detected in California on Dec. 1.
Omicron became the dominant strain in the U.S., bypassing the highly-contagious delta variant, by Dec. 20.
According to the most recent CDC data released on Christmas, omicron accounted for 58.6% of all positive COVID-19 cases nationwide.
MORE: Omicron spreading quickly in Florida
Below are five things to know about omicron as it causes a dramatic spike in coronavirus cases in the U.S. and around the world:
1. Why is omicron spreading faster than the delta variant?
Infectious disease experts continue to analyze how this strain of the virus transmits compared to other variants of the virus.
Researchers say omicron is 20 times more transmissible than the original strain of COVID-19 and two-and-a-half times as transmissible as delta, even if you are vaccinated.
Omicron has about 50 mutations compared to delta's 13 mutations, causing our antibodies to have a more difficult time recognizing COVID.
2. Is it less deadly than delta?
Dr. Robert Redfield, the former director of the Centers for Disease Control and Prevention, said COVID-19 will continue to evolve, becoming more transmissible but less likely to cause serious illness or death.
"(The) delta (variant), that virus replicates in the upper and lower respiratory tract in the lungs. It causes a lot of lung disease, and many of the 800,000 deaths that we've had have died because of pulmonary insufficiency," Redfield said. "Omicron doesn't replicate very well in the lungs. It replicates up above the neck in the oral pharynx and in the sinuses. And as a consequence, we're not seeing as much of the serious pulmonary disease."
Recent data shows that the U.S. case rate is climbing much higher but not hospitalization rates.
Redfield said last week that the virus is still serious enough to cause hospitalization and death among those vulnerable to COVID-19.
He also said people need higher immunity to protect against omicron, which is why so many vaccinated people and those with prior infections are testing positive again.
Dr. Anthony Fauci has agreed with this assessment.
"All indications point to having a less severity of omicron versus delta," Fauci said last Wednesday.
3. Which type of COVID test is most accurate when detecting omicron?
Officials at a laboratory in St. Lucie County told WPTV that antigen tests struggle to detect the omicron variant.
Scientists at Dynix Diagnostix in Fort Pierce believe false negatives could be contributing to the spread of COVID-19.
Rob Toher, the chief operating officer at Dynix Diagnostix, said polymerase chain reaction tests (PCR) are superior compared to the rapid antigen test when it comes to the new omicron variant.
Federal health officials agreed with that assessment, saying last weekthat several popular rapid COVID-19 antigen tests still work to detect omicron cases but have a "reduced sensitivity" in early studies.
4. What is the best defense against omicron?
Despite the virus being very contagious, doctors say getting a booster shot continues to be the best way to avoid serious issues from omicron.
The FDA on Monday approved Pfizer's vaccine booster shot for kids as young as 12.
The CDC announced Tuesday that those who got the Pfizer vaccine should now seek a booster shot five months after their second shot, instead of six months.
A study out of Denmark showed people with a COVID-19 booster shot 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.
Medical Analyst Dr. Leana Wen told CNN last month that a cloth mask isn't the best defense against omicron.
"Cloth masks are little more than facial decorations. There's no place for them in light of omicron," Wen told CNN.
She suggested that people wear at least a three-ply surgical mask, which is a disposable mask that can be found at most drugstores and some grocery and retail stores.
The CDC continues to recommend wearing a mask in public indoor settings in areas of substantial or high community transmission, regardless of vaccination status.
The CDC also has a link that provides advice about masks for people who want to learn more about what type of mask is right for them depending on their circumstances.
However, the CDC has not updated its guidance on masks since the omicron variant began.
Frequent hand washing, limiting indoor settings as much as most possible and avoiding close contact with people exposed to COVID-19.
The CDC announced on Dec. 27 that people with COVID-19 should isolate for five days. If they are asymptomatic or their symptoms are resolving (without fever for 24 hours), follow that by five days of wearing a mask when around others to minimize the risk of infecting people they encounter.
MORE: Where the CDC stands with isolation, quarantine and booster shot recommendations
5. When will COVID cases subside in the U.S.?
Fauci offered some encouraging news last Wednesday, telling CNBC that he believed that the latest wave of the coronavirus pandemic may hit its peak in the U.S. by the end of January.
Omicron cases have already subsided in South Africa, more than a month after it was first detected there.
"It certainly peaked pretty quickly in South Africa," Fauci told CNBC. "I would imagine, given the size of our country and the diversity of vaccination versus not vaccination, that it likely will be more than a couple of weeks, probably by the end of January," Fauci said.