The data offer a rare bit of good news. Still, hospitalizations are likely to increase simply because the variant is so contagious.
By Carl Zimmer and Emily Anthes
Three separate teams of scientists on two continents have found that Omicron infections more often result in mild illness than earlier variants of the coronavirus, offering hope that the current surge may not be quite as catastrophic as feared despite skyrocketing caseloads.
The researchers examined Omicron’s course through populations in South Africa, Scotland and England. The results in each setting, while still preliminary, all suggested that the variant was less likely to send people in hospitals.
“Given that this is everywhere and given that it’s going to be so transmissible, anything that would lower severity is going to be better,” said Natalie Dean, a biostatistician at Emory University in Atlanta.
Since the discovery of the Omicron variant in southern Africa in November, scientists have struggled to learn whether it causes more severe illness compared with other variants — and if so, in whom.
The new research suggests that the variant may have biological features that make it somewhat less dangerous than Delta, the variant that dominated the world from summer till now.
But Omicron’s lowered risk of hospitalization in all three countries also appears to be due in large part to immunity in those populations. Many of the infected already had protection against severe disease, either because of previous infections or vaccinations.
While the new research is heartening, experts warn that the surge coming to many countries still may flood hospitals with Omicron cases, simply because the variant spreads so much more easily than previous versions of the coronavirus.
“I don’t want to be alarmist, but I don’t think that you can let your guard down,” said Christina Ramirez, a biostatistician at the University of California, Los Angeles.
Americans should take rapid tests before holiday events and should gather outside, open windows or find other ways to improve ventilation, Dr. Ramirez said.
While Omicron may be causing milder disease on average, it’s also spreading faster than any variant yet. It is now the dominant variant in the United States, Europe and many other regions of the world.
Yet encouraging news came from South Africa on Wednesday, suggesting that these surges may not last as long as previous ones. Omicron has fueled a record number of daily new cases, but officials reported on Wednesday that the wave of infections may have peaked.
As infections in the United States rose to 154,000 daily cases on average over the past week, federal health officials added a defense against the rising threat to hospitals. The Food and Drug Administration authorized the first pill to treat Covid-19 on Wednesday, offering a highly effective treatment against severe illness.