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How is the Omicron variant different and why are scientists so concerned?

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CANMORE, ALTA. -

Scientists around the world are racing to learn more about the newly discovered B.1.1.529 coronavirus variant, now known as Omicron, to see how it compares to other variants of concern.

The important questions 鈥 like how transmissible it is, how good it is at evading immunity from vaccines or past illness, and whether it causes more severe illness 鈥 remain to be answered.

While some scientists say it will be weeks before we get a clear picture of how Omicron will impact the pandemic, the World Health Organization (WHO) said Wednesday it expects to have more information on the transmissibility of the variant within days.

What we do know about this variant is that it contains more than 30 mutations in the spike protein, which allows it to bind to human cells and gain entry to the body 鈥 a factor that has elevated concerns for some scientists.

WHAT IS A MUTATION?

First, it鈥檚 important to remember that mutations to SARS-CoV-2, the virus that causes COVID-19, have been expected since the early days of the pandemic. That鈥檚 because mutations always arise as viruses spread 鈥 it鈥檚 how they ensure their own survival.

, SARS-CoV-2 gains access to our cells using its 鈥渃orona鈥 鈥 a layer of protein spikes that fit into our cells like a lock and key 鈥 where it makes copies of its genomes.

But during that process, errors are inevitably introduced into the code, causing a mutation or variant.

Sometimes those mutations are harmless. But other times, like in the case of the Delta variant, the virus can change to become more transmissible or cause more severe illness.

鈥淲hat we have seen with other viruses is, over time, they mutate in various ways. And one of the ways that they can mutate is to actually get a little bit less severe because there's a bit of a fitness cost to the virus,鈥 Dr. Susy Hota, infectious disease expert at Toronto鈥檚 University Health Network told CTV鈥檚 Your Morning Wednesday.

鈥淚f it starts to kill off its hosts a little bit too early, it just won't replicate. And that's the goal of a virus, is to make more copies of itself and persist over time.鈥

Hota notes that COVID-19 has held its advantage with previous variants because it tends to have infections that last for quite a while, giving it plenty of opportunity to spread from person to person.

WHAT DO WE KNOW ABOUT OMICRON鈥橲 MUTATION?

The variant鈥檚 genome, in total, has around 50 mutations, including those in the spike protein, according to the British Medical Journal (BMJ). Scientists say it hasn鈥檛 directly evolved from the Delta variant and contains characteristic changes found in the Alpha, Beta, Gamma and Delta variants.

鈥淭his variant carries some changes we鈥檝e seen previously in other variants but never altogether in one virus. It also has novel mutations that we鈥檝e not seen before,鈥 Lawrence Young, a virologist and professor of molecular oncology at Warwick Medical School, told the BMJ .

Another distinguishing note is that one of Omicron鈥檚 mutations leads to 鈥淪 gene target failure鈥 鈥 also referred to as 鈥淪 gene dropout鈥 鈥 meaning one of several areas of the gene that are targeted by PCR testing gives a false negative.

鈥淚n one PCR test, three different genes are monitored. However, one of the S gene targets is not detected due to the mutations,鈥 Chris Richardson, Microbiology and Immunology professor at the University of Dalhousie, .

鈥淭his is called S gene dropout or S gene target failure, which is actually helpful and is diagnostic of omicron. The dropout is a marker for this variant.鈥

According to the World Health Organization (WHO), than previous surges in infection using this approach.

But researchers in South Africa first sounded the alarm over the B.1.1.529 variant after finding more than 30 mutations in the spike protein 鈥 a far greater number than what we鈥檝e seen with any other variant.

Because the spike protein is the target of antibodies that our immune system produces to fight COVID-19, a high number of mutations raises concerns that Omicron may be able to evade the antibodies produced by a previous COVID-19 infection or vaccination.

鈥淭he spike protein of the virus is really important for entry into cells, as well as targets for antibodies that help to control infections. So, it's possible, scientifically, looking at the virus that it could be more transmissible than what we've seen so far,鈥 Hota explained.

鈥淚t also could result in what we call immune evasion 鈥 in other words, your immune system may not be able to control it as well, so you may be susceptible to more reinfections or vaccines maybe a little less effective.鈥

But Hota says these are merely hypotheses and we should be careful not to draw any conclusions from speculation or anecdotal reports about the severity of illness or transmissibility of Omicron at this stage.

鈥淚 think we need to see it in a larger number of people to get a good sense of how it compares to what we've seen so far with COVID 19,鈥 she said.

WHAT ARE SOME OF THE SYMPTOMS?

For the most part, scientists and researchers believe it will be another two weeks before they will be able to understand how efficiently Omicron can spread and how severe the symptoms of infection are.

Dr. Angelique Coetzee, chair of South African Medical Association and one of the first doctors to suspect a new variant in the country, that most patients have experienced 鈥渧ery mild鈥 symptoms, including fatigue, body aches and headache. Most patients were treated at home, she added.

Unlike the Delta variant, Coetzee said that there haven鈥檛 been any reports of a loss of taste or smell and there has not been a drop in oxygen levels.

On Tuesday, White House medical adviser Dr. Anthony Fauci told reporters that Omicron is 鈥渁lmost certainly鈥 less severe than Delta, but could be more transmissible.

鈥淚t appears that with the cases that are seen, we are not seeing a very severe profile of the disease,鈥 he said.

Willem Hanekom, director of the Africa Health Research Institute, on Monday that early data suggests that Omicron may be escaping immunity, but that most cases have been mild.

The that there is 鈥渘o information to suggest that symptoms associated with Omicron are different from those from other variants,鈥 though it had also reported hospitalizations are on the rise in South Africa.

Scientists also expressedconcern about how Omicron may affect infants. Hospitals in Tshwane, South Africa reported that 52 of their 452 COVID-19 patients were under the age of two, a higher number than any other age group.

Not all the infections have been linked to Omicron and some experts have said it is not yet time to be concerned with Omicron鈥檚 impact on children, however.

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