Omicron: A spike in COVID-19 cases and potentially different symptoms
First, some background. Omicron (or B.1.1.529) is a new coronavirus variant that was first identified in Botswana and South Africa in November—although later reports showed earlier cases in the Netherlands. The first case in the U.S. was reported on Dec. 1 in California. By Dec. 20, it became the predominant strain in the U.S. Both the WHO and the Centers for Disease Control and Prevention (CDC) have classified Omicron as a “variant of concern.”
The new variant caused an alarming spike in COVID-19 cases in South Africa—cases went from 300 a day in mid-November to 3,000 a day at the end of that month. It’s also been identified in almost 100 other countries.
Early reports from South Africa indicate that most cases have been mild—and that symptoms for this variant may be different. “The reports show that patients in South Africa—many of whom were young—have had severe fatigue, but no loss of taste or smell,” says Lauren Ferrante, MD, a Yale Medicine pulmonologist.
Is Omicron more transmissible—or deadlier—than previous variants?
Two important questions about Omicron are top of mind for scientists, says Dr. Murray.
The first is how transmissible the new variant is compared to Delta, previous variants like Alpha and Beta, and the original virus. “What’s going to be critically important is whether, in areas where Omicron exists, it will become the dominant strain as Delta did,” Dr. Murray says.
Based on early data from South Africa, the United Kingdom, and Denmark, Grubaugh says Omicron is expected to outcompete Delta and will likely become the predominant variant strain in most places, as it is in the U.S.
But questions remain about what makes it more transmissible and how quickly it could rise to dominance, he adds.
The second question is whether Omicron is more likely than Delta or other variants to cause severe disease—if most infections continue to turn out to be mild, rapid transmission would be less of a threat, he says.
Do current vaccines protect against Omicron?
There is a third—and likely most important—question that has to do with how protective the existing vaccines will be against the new variant, says Dr. Murray.
There’s a key distinguishing factor for Omicron. Unlike Delta and other coronavirus variants, this one carries an abundance of mutations—about 50 in all, including 26 that are unique to the variant—and more than 30 on the spike protein, which is the viral protein that vaccines train the immune system to recognize and attack.
Grubaugh says some of Omicron’s enhanced transmissibility may come from its ability to evade some immune responses, especially in people who were previously infected, but not vaccinated. Scientists also want to know if these mutations indicate a possible reduction in the effectiveness of the COVID-19 vaccines and certain monoclonal antibody treatments, and if they are a sign that Omicron is a more contagious form of the virus.
“We don’t really know how the mutations work together. Not everything is additive,” Grubaugh says. But, again, it’s too early to speculate about the possibilities, he adds. “We really need to be careful and let the data speak for itself as it becomes available.”
Grubaugh says there is some preliminary laboratory data to show that antibodies generated from vaccines are less effective at neutralizing Omicron, although some of that loss can be restored with booster shots. In mid-December, an early real-world study from South Africa showed the Pfizer-BioNTech vaccine to be 33% effective at preventing infection and 70% effective at preventing hospitalization.
But experts caution that South Africa has a different population than the U.S.—with more young people and high levels of prior infection—and more data will be needed to better understand the variant. That study was conducted by Discovery Health, the country’s largest private health insurance administrator, and it has not been published or peer-reviewed.
What are scientists doing to prepare for Omicron?
The good news is that experts are in a better position to prepare for Omicron than they were a year ago, when Alpha, the first coronavirus variant to be identified, surfaced in Great Britain. “At that time, we didn’t have a very robust genomic surveillance system,” Grubaugh says. “Now, we have things in place.”
The three companies producing vaccines for the U.S.—Pfizer-BioNTech, Moderna, and Johnson & Johnson—have all started work on Omicron-specific vaccines. Meanwhile, the CDC has been monitoring variants continuously. It reports that the U.S. variant surveillance system has reliably detected new variants, so it expects to quickly identify new cases of Omicron here in the U.S.
What you can do to protect yourself from Omicron
One thing people should do is stay calm, Grubaugh says, adding that the behind-the-scenes work to prepare for an Omicron worst-case scenario is necessary even if the variant turns out to be less of a threat than anyone anticipates. “The intent behind these preparations is not to scare people; it’s to do what we need to do to be prepared,” he says.
People also need to understand that variants like Omicron are a natural part of the progression of the virus, Grubaugh adds. “The fact that there is a new variant isn’t surprising,” he says. “Delta was never going to be the last variant—and Omicron is not going to be the last one. As long as there is a COVID-19 outbreak somewhere in the world, there is going to be something new that emerges.”
Both Grubaugh and Dr. Murray say the best way to prevent new variants is to get vaccinated, because if more people are vaccinated, it decreases the opportunity for the virus to spread and mutate. If you haven’t gotten your vaccine and booster shot yet, the CDC has endorsed choosing the Moderna and Pfizer-BioNTech vaccines.
In response to Omicron, the CDC is also urging everyone 18 and older to get a COVID-19 booster shot when they are eligible. Teenagers ages 16 or 17 may also get the Pfizer-BioNTech booster, which the FDA authorized for that age group in December 2021.
Meanwhile, because Delta still remains a threat in the U.S., experts continue to recommend protecting against that variant by maintaining infection prevention strategies such as wearing a mask in public indoor settings in areas of substantial or high community transmission, washing hands frequently, and physical distancing from other people.