As countries around the world react to Omicron, scientists are working to understand this new COVID-19 variant and what it might mean for our collective pandemic response.
This weekend, the World Health Organization (WHO) declared the B.1.1.529 variant, first identified in South Africa, as a SARS-CoV-2 “variant of concern” and renamed it Omicron.
It has since been detected in Australia, Belgium, Botswana, Britain, Denmark, Germany, Hong Kong, Israel, Italy, the Netherlands, France, Canada and South Africa.
Many countries have imposed travel bans or curbs on southern Africa in attempts to stem the spread. The Australian government has temporarily banned non-citizens from nine countries in the sub-region from entering Australia, and required Australians who have been in those countries to undergo 14 days of quarantine.
All international arrivals into New South Wales and Victoria must quarantine for 72 hours.
So, what does this all mean, and how concerned should we be about Omicron?
While all viruses, including that which causes COVID-19, change over time, the WHO says some changes may affect the virus’ properties, such as how easily it spreads (transmissibility), the associated severity of disease or the performance of vaccines, therapeutics or other public health measures.
A variant becomes a “variant of concern”, when it shows one or more of these changes.
Omicron joins the globally-dominant Delta variant in this category, along with its weaker rivals Alpha, Beta and Gamma.
As scientists work to learn more about Omicron and the degree of change, experts are joining the Australian government to call for calm.
Where did Omicron come from?
South African scientists first detected the new variant, but it remains unclear where it first arose.
It was first reported to the WHO from South Africa on 24 November.
The first known confirmed Omicron infection was from a specimen collected on 9 November. In recent weeks, infections in South Africa have increased steeply, coinciding with the detection.
South African Health Minister Joe Phaahla has said the variant was linked to an "exponential rise" of cases in the last few days although experts are still trying to determine if the new variant is actually responsible.
Why are scientists concerned about this variant?
Professor Catherine Bennett, chair of epidemiology at Deakin University, said Omicron stands out due its large number of mutations, some of which are concerning.
“They’re describing more than 50 mutations - 30 of those in the protein spike, and 10 in the particular area of the spike where the vaccines are targeted,” she told SBS News.
“So there are a number of questions about how this would impact its infectiousness, but also how protective our vaccines would be.”
She said these mutations, coupled with the reported rise in cases in South Africa, has prompted questions about the threat the new variant might pose.
“We’re still learning to understand it,” she said. “We’re still [in] early days, so it’s important that we try and contain the spread until we further understand this particular new variant.”
Professor Alexandra Martiniuk, an epidemiology professor at the University of Sydney, said while mutations are not new “and don’t necessarily mean anything in particular”, some appear to be in regions of concern.
“It has been deemed a variant of concern, so we have some concern, but we just don’t have enough data to know how concerned,” she told SBS News.
Chief Health Officer Dr Paul Kelly said the level of concern relates to “the degree of change” that has so far been detected.
“What we do know absolutely - and this is another thing that's changed in the last two years - is an ability to find and describe a genome of the virus very quickly, and then to translate that into a model which demonstrates how different it might be compared with other previous viruses,” he said on Monday.
“Just to be very clear, this is still SARS-CoV-2. It's not a new virus. It is a change of that particular virus … the main thing is that degree of change is probably what's made people concerned.”
Is it more transmissible than other variants?
When it comes to the question of viral transmission, Professor Kelly said it is clear Omicron transmits between people.
“Is it more or less infectious than other strains? The information from South Africa is that it has replaced Delta as the major, possibly the only, virus circulating in that country, quite quickly,” he said.
“So, it is transmitting, at least as well as Delta. That seems clear.”
The WHO has reported a rise in the number of people testing positive in areas where the new variant has been found. It said it’s not yet clear whether Omicron is more transmissible than other variants.
“Preliminary data suggests there are increasing rates of hospitalisation in South Africa, but this may be due to increasing overall numbers of people becoming infected, rather than a result of specific infection,” it said on Sunday.
Professor Martiniuk said the rise in cases does not necessarily amount to Omicron being more transmissible.
“South Africa was in an opening up period and coming into summer, but they had a low vaccination rate. So, an increase in cases was what one would have expected to happen - even under a Delta scenario,” she said.
Professor Bennett also acknowledged South Africa has - for various reasons - a different population and vaccination profile compared to other parts of the world, such as Australia, where rates are much higher.
Does it cause more severe disease?
Again, it’s still too early to tell. But according to the South African Medical Association, preliminary evidence in initial Omicron cases has suggested its infection profile is mild.
Dr Angelique Coetzee, a private practitioner and association chair, was one of the first to suspect the new variant among patients. She told Reuters symptoms were so far mild and could be treated at home. She said unlike Delta, patients had not reported loss of smell or taste and there had been no major drop in oxygen levels with the new variant.
A South African doctor who was one of the first to suspect a different coronavirus strain among patients said that symptoms of the Omicron variant so far were mild and could be treated at home https://t.co/bBxkqYphXw pic.twitter.com/dmi3s6GeAA
But Professor Bennett said it is understood reporting from initial cases was mainly in university students, who would be expected to have a more mild disease.
Professor Martiniuk agreed, noting it will take a few weeks before data on disease severity comes through.
“We will need to wait a few weeks to understand whether increases in hospitalisations or deaths are being seen, and whether those are due to Omicron, or whether they're due to the increasing Delta waves which we were seeing in many parts of the world,” she said.
Will our current COVID-19 vaccines be effective against it?
Perhaps the biggest question remains how current vaccines will protect against the new variant, and whether it might be resistant to antibodies that have been developed. Experts say at this stage, it remains too early to say.
Professor Kelly said there is no evidence that COVID-19 vaccines are less effective against Omicron.
"We have no evidence of that and Pfizer and Moderna can move quickly if that was to come to pass, to make a specific vaccine. That's a major advantage," he said.
Federal Health Minister Greg Hunt said he had spoken with the chief executives of Pfizer and Moderna Australia in the past 24 hours.
"I confirmed that, as our contract had already prepared for variants, that if there were a requirement for a change, they are ready and we are ready," he said on Monday.
"And both have said, 'Yes, that's exactly as the contract set out'."
Professor Bennett said we’ll have a better picture of the virus in a couple of weeks.
In the meantime, Professor Kelly urged Australians to be “alert, not alarmed”.
Minister Hunt said Australia is “as well prepared as any nation in the world”.
“We know that from some of the highest vaccination rates, some of the lowest rates of loss of life, and one of the most well-prepared and strongest hospital systems in the world,” he said.
Professor Bennett agreed there is no cause for alarm at this stage.
“It’s too early to say, but at this stage, it's important that we do actually pay close attention to what we're learning about this on a daily basis, and we try to keep the virus contained until we understand it better," she said.
Professor Martiniuk said the current actions by governments are a “stop- pause” while scientists gather data.
“We are in a timeframe of data analysis and gathering. But I wouldn't want that to go on for very long, because it does damage to the economies of the exact countries that we want to support,” she said.
With additional reporting by AFP and AAP.