From vaccine effectiveness to transmissibility: What we know about the omicron variant of COVID-19
Nearly two years into the COVID-19 pandemic, the world is going full speed ahead to contain the latest variant, first identified in southern Africa but popping up around the globe.
Effectiveness of COVID vaccines against omicron variant yet to be determined
The World Health Organization named the new version of the virus “omicron” and classified it as a highly transmissible variant of concern, though its actual risks are not yet understood. Early evidence suggests that it poses an increased risk that people who have already had COVID-19 could catch it again, the WHO said. It could take weeks to know whether current vaccines remain effective against it.
Scientists know that omicron is genetically distinct from previous variants, including the beta and delta variants, but they do not know whether these genetic changes actually make it any more transmissible or dangerous. So far, there is no indication the variant causes more severe disease.
Experts are hopeful that vaccines will be at least somewhat effective at preventing serious illness and death — and continue to encourage people to get inoculated.
Peter Openshaw, a professor of experimental medicine at Imperial College London said it was “extremely unlikely” that current vaccines wouldn’t work, noting they are effective against numerous other variants.
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But as the virus continue to spread, countries across the globe are imposing restrictions or bans on travelers from several countries and re-imposing measures such as mask mandates that some hoped were a thing of the past.
Omicron mutations might lead to 'enhanced transmissibility'
Scientists are concerned because the new variant appears to have a high number of mutations — about 30 — in the coronavirus’ spike protein, which could affect how easily it spreads among people.
Sharon Peacock, who has led genetic sequencing of COVID-19 in Britain at the University of Cambridge, said the data so far suggest the new variant has mutations “consistent with enhanced transmissibility,” but said that “the significance of many of the mutations is still not known.”
Lawrence Young, a virologist at the University of Warwick, described omicron as “the most heavily mutated version of the virus we have seen,” including potentially worrying changes never before seen within the same virus.
Variant spike identified in South Africa
In South Africa, Gauteng province — home to Pretoria and the country's largest city of Johannesburg — is the center of the new surge. So far, cases there appear to be mild, according to doctors, and hospital admissions have not spiked.
But experts warn the early round of infections has been among the young and the situation may become more serious if the new surge affects older, unvaccinated South Africans. In all, 41% of those age 18 and over are vaccinated — but young people have been particularly slow to step forward.
Some experts think expanded measures will be needed to curb the spread of the virus.
“I do think that the decision that South Africa is going to have to make is probably around mandatory vaccination,” said Mosa Moshabela, professor of public health at the University of KwaZulu-Natal in Durban.
A new surge — and even a new variant — was long anticipated, but the speed with which omicron hit came as a “shock” to South Africa’s health experts.
While numbers of confirmed cases are still relatively low, they have been increasing at a high rate. The new spike started after some student parties in Pretoria. Numbers quickly jumped from a few hundred cases a day to thousands. South Africa announced 3,220 new cases Saturday, of which 82% are in Gauteng, according to the National Institute for Communicable Diseases. That's still well below the peak of the last wave, when more than 25,000 were confirmed in a day.
As many as 90% of the new cases in Gauteng province are caused by omicron, Tulio de Oliveira, director of the KwaZulu-Natal Research Innovation and Sequencing Platform, said in a tweet, citing the results of diagnostic tests.
Moshabela said, “We did expect that we may see a new or a different variant gaining momentum in the fourth wave. ... We did not really expect to see a variant with the kind of multiplicity of mutations. And that is capable of becoming highly transmissible and escape or evade immunity at the same time. This was really the shock that we had.”
Some COVID-19 variants have died out without severe spread
Even though some of the genetic changes in omicron appear worrying, it’s still unclear whether they will pose a public health threat. Some previous variants, like the beta variant, initially alarmed scientists but didn’t end up spreading very far.
“We don’t know if this new variant could get a toehold in regions where delta is,” Peacock said. “The jury is out on how well this variant will do where there are other variants circulating.”
To date, delta is by far the most predominant form of COVID-19, accounting for more than 99% of sequences submitted to the world’s biggest public database.
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The coronavirus mutates as it spreads and many new variants, including those with worrying genetic changes, often just die out. Scientists monitor COVID-19 sequences for mutations that could make the disease more transmissible or deadly, but they cannot determine that simply by looking at the virus.
Peacock said the variant “may have evolved in someone who was infected but could then not clear the virus, giving the virus the chance to genetically evolve,” in a scenario similar to how experts think the alpha variant — which was first identified in England — also emerged, by mutating in an immune-compromised person.