There’s a lot that we don’t know yet about Omicron, the coronavirus variant that’s powering the latest surge in infections. Reported to the World Health Organization less than a month ago, Omicron was responsible for almost three-fourths of U.S. coronavirus infections by Dec. 20.
It’ll take weeks, maybe months, to collect all the data
for scientists to feel confident giving definitive answers. But Paula Cannon, a virology professor at USC Keck School of Medicine, said we should have a clearer picture in about two weeks.
“We should start to have a sense of whether or not this is going to be an incredibly infectious
but potentially milder version of COVID, or whether it’s incredibly infectious and just as bad as every other version of COVID,” she said.
Here are some of the key questions that researchers are still trying to answer.
Is Omicron as deadly as previous coronavirus variants?
Since emerging in South Africa last month, Omicron has not driven up death rates there — and in fact, the surge in infections is
already fading. And so far in the United States, only one confirmed Omicron-related death had been reported as of Tuesday, claiming the life of an unvaccinated person who’d recovered from a previous bout with COVID-19. But as much as we’d like to believe Omicron will end the pandemic with a whimper, not a bang, health officials don’t have enough data to conclude yet just how virulent the variant may be or why. We do have three preliminary studies — one from South Africa, one from England and one from Scotland — that report a lower hospitalization rate for people infected with Omicron than for those infected with other variants. But researchers also noted that Omicron patients are more likely to have been helped by antibodies from vaccinations or previous infections than was the case during earlier COVID-19 waves, so it’s not an apples-to-apples comparison. Also, many of the early Omicron cases have been among younger people, who are less likely to be hospitalized from COVID-19 in general. Another early study from Hong Kong that hasn’t been peer-reviewed offers one other glimmer of hope, finding that Omicron moves into the lungs much more slowly than earlier versions of the virus. Paula Cannon, a virology professor at USC Keck School of Medicine, said that Omicron seems to be better at replicating in the upper part of the respiratory tract, which is correlated to being more infectious but less likely to cause serious disease. But these are still hypotheses, not solid proof or an explanation of the factors responsible. Why is it spreading so fast?
Early research suggests that Omicron’s mutations have enabled it to circumvent the body’s defenses more effectively and replicate faster. Although those studies still need to be reviewed by independent scientists and corroborated by others, we are at least getting some hints as to the answer.
Still, we don’t understand yet the mechanisms that have enabled Omicron to spread so quickly. Do people with Omicron spew more virus into the air — in other words, would five minutes next to someone infected with Omicron expose you to a higher viral load than five minutes next to someone with the Delta variant? “It appears that it is trending to yes,” said Jasmine Plummer, a research scientist and director at Cedar-Sinai Medical Center. John Beigel, associate director for clinical research in the National Institute of Allergy and Infectious Diseases, said one of the factors is waning protection from the initial vaccines. That’s why it’s important for people to get their boosters. “When we boost, we not only increase the amount of antibodies, but you’re increasing how well the antibodies will bind to the Omicron variant,” Beigel said. How much protection from Omicron will vaccines (and boosters) give?
The data show that fully vaccinated people are vulnerable to being infected by Omicron, just as they’ve been to the Delta variant. Early research also suggests that
boosters are particularly important in protecting against Omicron. But scientists are still exploring what it is about the mutations in the new variant that reduce the effectiveness of antibodies — whether gained through vaccination or a past infection — and how effective the body’s other defenses remain. “The vaccines seem to be holding up against what they’re supposed to do, which is not necessarily, ‘Are you going to test positive on a COVID test?’ But, ‘Are we going to prevent you from getting severe illness and hospitalization?’ Yes,” said Plummer. “What we hope, and we don’t know because the science is so new, is that the symptoms seem to be milder if you’re vaccinated,” she added. Moderna said Monday that in lab tests, even a half-dose of its booster significantly increased the level of antibodies available to defend against Omicron. Pfizer also has stated that lab tests show its booster yielded a dramatic increase in antibodies to fight the variant. Will vaccines need to be retooled for Omicron?
Possibly, but it’s too early to tell whether the current vaccines and boosters will give enough protection or whether we’ll need more frequent booster shots. Top U.S. health officials have expressed faith that the existing vaccines will
continue to offer some shielding, particularly to those who’ve received a booster shot. “We don’t have the clinical data to support that, yet,” Beigel said. “I think that the clinical data is really going to drive the decision of, ‘Do we need to retool the vaccine or not?’” In the meantime, Pfizer began working on an Omicron-specific version of its COVID-19 vaccine on Nov. 25 and is expecting delivery of the new vaccine by March, pending regulatory approval. How will Omicron affect those who are not vaccinated?
Early research has shown that unvaccinated people are, predictably, more vulnerable to infection by Omicron — just like with previous coronaviruses
— and more vulnerable to serious cases of COVID-19. But it’s too soon to say whether Omicron preys on unvaccinated people to a greater degree than other variants. Are there different symptoms?
anecdotal evidence that the main symptoms of Omicron are nasal congestion, dry cough and fatigue. This is a departure from the fever and loss of taste and smell seen with other variants. But researchers need more data to confirm any differences and explain why they exist. Will medicines that work on other variants work the same with Omicron?
Doctors are warning that
two antibody drugs from Regeneron and Eli Lilly, which have been the go-to treatments for early COVID-19, will be less potent against Omicron. The drugmakers say that they can quickly develop new versions with Omicron-targeting antibodies, but they aren’t expected to launch for at least several months. Pfizer has confirmed that its newly authorized COVID-19 treatment pill, Paxlovid, retained its potency against the Omicron. Unlike the antibody drugs, Paxlovid doesn’t target coronavirus’ spike protein, which is where Omicron’s mutations are concentrated. Another newly authorized antiviral pill from Merck, called molnupiravir, is also expected to work against Omicron. Is there an increased risk of reinfection?
Preliminary evidence suggests yes, Omicron is more likely to cause repeat infections than earlier variants, according to the World Health Organization. Just as vaccine-induced antibodies seem to be less effective because of mutations in Omicron’s spike protein, the same appears to be true for antibodies generated from a past infection.
The researchers from Imperial College London have estimated that compared with the Delta variant, Omicron is 5.4 times more likely to cause a reinfection. Will the prevention measures we’ve been taking throughout the pandemic (masking, social distancing) work as well with Omicron?
The answer depends on why Omicron spreads more readily than its predecessors. In other words, we don’t know yet.
Even so, experts urge us to continue doing all the same things to curtain viral spread. Barbara Ferrer, the director of the Los Angeles County Department of Public Health, advises everyone to: Wear a mask when you’re indoors in a public place or with people outside of your household. Get tested when you’re going to be in high-risk situations for you or those around you, or if you’ve been exposed to a coronavirus-positive person or have symptoms yourself. What do we know about outdoor transmissibility? Does that not provide the same risk mitigation it used to?
So far, it appears that there’s still a lower risk of getting infected if you are outdoors because there’s less ability for viral particles to accumulate, Plummer said.
But we won’t know how the outdoor risk of Omicron compares with other variants until data are collected from outdoor events, Cannon said. “What I can’t do is take a group of 10 people, make them sit in my back garden and blow Delta at them and then blow Omicron at them and say, ‘Aha! Omicron is more or less infectious.’” “There’s not going to be an absolute risk-free approach to this,” Beigel said. “But you take the measures that are within your risk tolerance, and you try to minimize the amount of risk that you’re taking.” Does Omicron affect people in different age groups differently?
Early reports from
South Africa and Scotland showed that most new Omicron cases were reported in people in their 20s and 30s, and they had mild symptoms. But there are other factors that could help explain that phenomenon. For example, South Africa’s median age is 27.6, almost a decade younger than the median age in the U.S. Public Health Scotland officials said the age profile could reflect “early detection of a large number of cases in events that typically attract people in these age groups.” Younger people are also less likely to be vaccinated, and thus more likely to become infected with any coronavirus variant. “I don’t think we have the granularity to really say, ‘Is this behaving different than other strains we’ve seen in different age groups?’” Beigel said. How long will this Omicron surge last?
Time will tell, but the rapid rise and fall of Omicron case counts in South Africa gives some people hope that this wave could be short-lived.
“Omicron is burning very fast and very bright; the curve of new infections is going up incredibly steeply. And there’s an expectation it will probably come down equally steeply,” Cannon said. She advised returning for the next month to the precautions we took before we had vaccines. ”I’m thinking that January might be a good month to cancel my gym subscription and not eat out,” she said. “But then by February, we’ll be kind of back to where we are currently. That’s my hope.” Will the spread of Omicron increase the odds of an even more transmissible (or nastier in some other way) variant?
At this point we have little more than history to guide us, and we’ve seen previous viruses mutate in both directions —
more benign and more deadly. Plummer reminds us that we knew new variants could keep cropping up as long as there were people with active coronavirus infections. The best way to combat the effects of these variants is to have more people get vaccinated, including with the most recent booster shots, she said.
This report was written by Times staff writers Salma Loum, Madalyn Amato, Karen Garcia, Ada Tseng and Jon Healey. The Times Utility Journalism Team works to publish information that can solve problems, answer questions and help with decision making.