January 27, 2022

The Uncertainties of the Omicron Variant

The first case of the new coronavirus variant, Omicron, also known as B.1.1.529, was detected in southern Africa this month. Just a few weeks ago, South Africa, where the most Omicron infections have been detected, was recording around three hundred coronavirus cases a day—one of its lowest averages of the pandemic. Since then, cases have soared. Nearly five thousand South Africans now test positive for the virus on average each day, the country’s test-positivity rate has increased nearly fivefold, and the number of COVID hospitalizations in Gauteng province, where the variant was first identified, has almost quadrupled. It’s not yet clear how much of the surge is due to Omicron, but preliminary evidence suggests that it has played a role. Last week, just a day after South African officials reported its emergence, the World Health Organization declared Omicron its fifth “variant of concern.” So far in the pandemic, that’s the fastest the W.H.O. has moved from detection to classification.

The W.H.O. raised the alarm based largely on the variant’s numerous, worrying genetic changes. Omicron boasts some fifty mutations—far more than Delta—including around thirty on its spike protein, which the virus uses to enter cells. (Delta, by contrast, has just ten unique spike mutations.) Some of these mutations have previously been found on other variants, and are linked to enhanced transmissibility and immunity evasion. But at least twenty-six are unique to Omicron—they’ve never been seen before—and we don’t know what they do. In a sense, Omicron is the virus’s promising new recruit: it has a number of notable attributes on paper. Whether it becomes the pandemic’s most fearsome player remains to be seen.

With any new coronavirus variant, we want to understand three basic questions: Is it more transmissible? Does it cause more severe disease? And can it skirt our immune systems? There’s often a delay between when a new variant is detected and when we have a clear understanding of its epidemiological significance. Omicron is no exception, and we don’t yet know how the variant performs in any of these domains. Given its rapid spread in South Africa—and the fact that it shares mutations with Delta—Omicron is probably extremely contagious. But new variants generally haven’t inflicted more punishing illness. With Omicron, early anecdotal evidence suggests that many infections have been mild, and that severe cases have affected mainly unvaccinated people. (Only one in four South Africans are fully immunized.)

On the third question—whether Omicron will cause more reinfections and breakthrough cases—it’s similarly too early to say. But there is reason for concern. COVID vaccines are based on the spike protein in the original Wuhan strain of the virus; they use a model of it to prepare our immune systems for a coronavirus invasion. The abundance of mutations on Omicron’s spike protein suggests that the variant might render our current vaccines meaningfully less effective. On the other hand, it’s far from clear how Omicron’s mutations will unite to change its immune-evasion capabilities. The impact of any given mutation depends, in part, on the other mutations present; sometimes viruses pay a price for adding new ones. You might put together a basketball team stacked with all-stars—but a conflict between the two best players still could sink its chances. Scientists are already examining how effectively the blood of immunized people neutralizes Omicron in the lab; real-world studies of vaccine effectiveness against the new variant are also in the works. We’ll know much more about how it behaves in the coming weeks.

Many political leaders aren’t waiting to act. Immediately after the W.H.O. declaration, countries rushed to institute travel restrictions. Japan, Israel, and Morocco banned all foreign visitors. The U.S., the U.K., Australia, and many European countries restricted travel from South Africa and other countries in the region, which may compound the economic challenges faced by the continent. South Africa should be praised for detecting and promptly reporting the new variant, but its vigilance and transparency has come with a cost. “Perhaps our scientists’ ability to trace some of these variants has been our biggest weakness,” Lindiwe Sisulu, South Africa’s tourism minister, said. “We’re finding ourselves punished for the work that we do.” To encourage other nations to step forward in the future, the global response should include support and resources for South Africa as it struggles to contain its outbreak.

Travel restrictions may temporarily slow the spread of Omicron, but it is already on the loose. The variant has been detected in at least nineteen countries, including Portugal, Israel, Canada, and Australia. Almost certainly it is already in the United States. “It’s not going to be possible to keep this infection out of the country,” Anthony Fauci, the nation’s top infectious-disease expert, told the Times, on Friday. “The question is: Can you slow it down?” Doing so will require more than travel bans. A comprehensive approach must include bolstering the nation’s testing and genomic-surveillance infrastructure; insuring rapid access to the new COVID pills; and doing all we can to increase rates of vaccination and booster shots. The current COVID vaccines will likely offer protection against Omicron, as they have with all prior variants. Still, in the event that there’s a significant decrease in their effectiveness, Pfizer and Moderna are preparing Omicron-specific formulations. The Food and Drug Administration has indicated that it will require only small trials, confirming safety and immunogenicity, to authorize boosters against new variants. At this point in the pandemic, we know how to play the game.

The emergence of Omicron would seem to mark another chapter in the viral story: a new variant has arrived and threatens to upend our fragile equilibrium yet again. But, from another perspective, little has changed. Despite the many unknowns swirling around Omicron, two things were true before its discovery and will remain true in the coming months. The first is that, like all forms of the coronavirus, Omicron will affect various populations differently. In a likely scenario, nations with high immunization rates will remain reasonably well protected as the variant circulates; those which built a “Delta wall” will find that it keeps Omicron at bay, too. This is especially true in countries that have high vaccination rates among older people and others at particular risk for severe COVID-19. Meanwhile, low-income countries—where only six per cent of people have received even one dose of a COVID vaccine—could face devastating surges, as Omicron and Delta rip through the population. (The U.S., for all its wealth, remains in an in-between state: forty per cent of Americans have not been fully vaccinated, let alone received a booster shot.)

A second unavoidable truth is that we must intensify our efforts to immunize the world. Every major coronavirus variant—Alpha, Beta, Gamma, Delta, and now Omicron—has arisen in a country with rampant viral spread. The most important step we can take to protect against this and future variants is to vaccinate as many people as quickly as possible, both in the U.S. and around the world. In a press briefing on Monday, the President told the nation that Omicron is “a cause for concern, not a cause for panic.” He’s right, although “concern” might not be the right word. Above all, it’s a cause for action.


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