As more information emerges about the omicron variant — which has now been detected in five states — public health experts nationwide say the delta variant is still the main threat, The Washington Post reported Dec. 2.
Twelve things to know:
1. If the omicron variant, B.1.1.529, ends up being less concerning than feared, epidemiologists warn that the U.S. — specifically in the Northeast and upper Midwest — will still likely face a winter surge driven by the variant B.1.617.2, or delta, as people travel and gather for the holidays.
2. During a Dec. 3 news briefing, Rochelle Walensky, MD, director of the CDC, said, "We should remember that 99.9 percent of cases in the country right now are from delta." Dr. Walensky also said measures used to counter the delta variant will also be effective slowing the spread of the omicron variant.
3. "Forget about omicron right now," said Eric Topol, MD, director of the Scripps Research Translational Institute in San Diego. "We are not even handling delta well. ... We have the combination of elapsed time, a hyper-contagious variant and relaxed mitigation. It's the perfect storm to have a surge."
4. "I encourage everyone not to be hysterical about what we don't know about omicron, but to be really proactive in controlling what we do know," New Jersey Health Commissioner Judy Persichilli, BSN, RN, said during a Nov. 29 news briefing. "The delta variant is here, it's with us, it's causing increasing trends."
5. A COVID-19 surge at Wyoming, Mich.-based University of Michigan Health-West is in its third month. Data indicates that delta accounts for nearly every infection in Michigan, according to the Post. "It's still wreaking havoc in the community," said Ronald Grifka, MD, the hospital's CMO. "We can't take our eyes off delta, that's for sure."
6. Unlike omicron, scientists know a lot about delta's spread and transmissibility. The variant can be spread by vaccinated individuals with breakthrough infections, and the variant is 50 percent more contagious than the predominant strain seen in the spring of 2020. Some studies cited by the CDC suggest delta cases are more likely to require hospitalization.
7. Highly vaccinated areas have still reported delta surges. "It's just a numbers game: When you have a population that was 75 percent vaccinated, if everyone is exposed to delta as we probably were in some form or fashion, that's a lot of people who are going to get a breakthrough infection," Jennifer Avegno, MD, New Orleans' top public health official, told the Post.
8. As for omicron, the U.S. has identified cases in California, Colorado, Hawaii, Minnesota and New York, as of early Dec. 3.
9. Omicron is at least three times more likely to cause reinfection than variants beta and delta, according to preliminary study findings released by South African scientists Dec. 2. The analysis, published by preprint server medRxiv, examined about 2.8 million COVID-19 samples in South Africa — 35,670 of which were suspected reinfections. Researchers found that omicron has a "substantial ability to evade immunity from prior infection." The paper has yet to be peer-reviewed.
10. It's unclear what level of protection vaccines provide against omicron, though vaccines likely still offer the most effective protection against severe disease and death, said Juliet Pulliam, PhD, epidemiologist in South Africa and one of the study's authors. "Contrary to our expectations and experience with the previous variants, we are now experiencing an increase in the risk of reinfection that exceeds our prior experience," Dr. Pulliam said in a Dec. 2 statement cited by the Post.
11. Omicron cases have surpassed other virus variant cases in South Africa, accounting for 74 percent of the genomes sequenced by the end of November, according to Dec. 3 data from South Africa's National Institute for Communicable Diseases. Delta was previously dominant.
12. Scientists expect to get a clearer idea about omicron's transmissibility and vaccine effectiveness against the mutation in the next week, according to the Post.