Top US scientist Anthony Fauci said Omicron is "almost certainly" not more severe than the Delta variant.
Preliminary data about the new Omicron COVID-19 variant is starting to emerge which could give us a clearer understanding of the symptoms and their effects.
The World Health Organization (WHO) has said the Omicron variant is likely to spread further and poses a "very high" global risk. The health agency has also called it a "variant of concern".
Scientists and experts are keeping a sharp eye on data from South Africa, where the variant was first reported.
Early data published in a new British study, which analysed entries made by the UK public in an app, suggests that symptoms of the variant could be easily mistaken for an everyday illness like a cold.
The Zoe Covid Study looked at symptoms in COVID-19 cases in London in particular, recorded over two separate weeks in October and December. Similarities with the Delta variant were detected, with the top five symptoms on the app being the following:
- Runny nose
- Sore throat
Another study released on December 14 by South Africa's largest private health insurance administrator, Discovery Health, has said two doses of Pfizer-BioNTech's COVID-19 vaccine appear to have given 70 per cent protection against hospitalisation in South Africa in recent weeks.
The study was based on more than 211,000 positive COVID-19 test results from November 15 to December 7, around 78,000 of which were attributed to Omicron. The 78,000 results are not confirmed Omicron cases, meaning the study is not able to make conclusive findings.
The analysis also shows protection against hospital admission is maintained across all ages, in people from 18 to 79 years, with slightly lower levels of protection for the elderly.
It also showed there was a higher risk of reinfection during the fourth wave than during previous waves and that the risk of hospitalisation among adults diagnosed with COVID-19 was 29 per cent lower than during the country's first wave early last year.
Earlier in December, the South African Medical Research Council released a study that suggests the strain could cause a milder infection than previous variants.
But it cautioned it is still too early to tell if the variant poses a greater risk of death as it was only detected over two weeks ago and there is a small amount of data to go off.
The report details the situation over the last two weeks at the Steve Biko/Tshwane District Hospital Complex in the Gauteng province where the variant was first detected.
The report also revealed that more younger people were being admitted to the hospital with COVID-19 Omicron infections, but this could be related to lower rates of vaccination among such age groups in South Africa.
The report's main findings were that the majority of patients were not oxygen-dependent and that most of the patients in the COVID-19 wards were "incidental Covid admissions," having had another medical or surgical reason for admission to the hospital.
'Very mild symptoms'
The findings of the report coincide with those of a doctor in South Africa, who was one of the first to suspect the different coronavirus strain. Dr Angelique Coetzee said the symptoms of the Omicron variant are mild and could be treated at home.
Coetzee, a private practitioner and chair of the South African Medical Association, told Reuters that on November 18, she noticed seven patients at her clinic who had symptoms different from the dominant Delta variant, albeit "very mild".
She treated around 30 patients and said the most common feature appeared to be tiredness.
How do Omicron symptoms differ?
Fatigue was one of the main symptoms her patients were reporting, Dr Coetzee said.
Other symptoms were a mild headache, body aches, and a scratchy throat.
But she said unlike the Delta variant, patients have so far not reported a loss of taste or smell. There was also no major drop in oxygen levels.
How was Omicron discovered?
Coetzee said a patient at her clinic on 18 November reported being "extremely fatigued" for two days with body aches and headache.
"Symptoms at that stage were very much related to normal viral infection. And because we haven't seen COVID-19 for the past eight to 10 weeks, we decided to test," she said. It then turned out the patient and his family were positive.
More patients came in on the same day with similar symptoms, which was when she realised there was "something else going on".
Since then, she's seen two to three patients a day.
"We have seen a lot of Delta patients during the third wave. And this doesn't fit in the clinical picture," she said, adding she alerted NICD on the same day with the clinical results.
"Most of them are seeing very, very mild symptoms and none of them so far have admitted patients to surgeries. We have been able to treat these patients conservatively at home," she said.
Who has been affected?
Coetzee said her experience was treating people who are 40 or younger and that almost half of the patients with Omicron symptoms that she treated were not vaccinated.
But she warns that the effects of the omicron variant in elderly patients are unknown.
Should we be worried about Omicron?
So far, there have only been a small number of cases reported around the world. It has been detected in several southern African countries as well as some in the US, UK, Belgium, the Netherlands, and Hong Kong.
But what worries scientists is how quickly the new variant can spread.
The first case was detected on November 9 and last week three-quarters of the cases registered in South Africa - about 3,000 after a period with very few infections - are due to this variant.
But the main unknown surrounding this variant is its multiple mutations. Some are worrisome, according to the WHO. This is mainly because of the risk of reinfection.
South African scientists have said it contains more than 30 mutations to the spike protein, which is the component of the virus that binds to cells. This is significantly more mutations than the Delta variant.
Scientists are concerned as the spike protein mutations could make this new variant more transmissible and it’s also possible the new variant may reduce the effectiveness of the available diagnostics, drugs and vaccines.
"Depending on these characteristics, there could be future surges of Covid-19, which could have severe consequences, depending on a number of factors including where surges may take place. The overall global risk related to the new VOC [variant of concern] Omicron is assessed as very high," the WHO said.
It said in its report that it is "a highly divergent variant with a high number of mutations... some of which are concerning and may be associated with immune escape potential and higher transmissibility".
How do you know if you have contracted Omicron?
According to the WHO, several labs have indicated that for one widely used PCR test, one of the three target genes is not detected (called S gene dropout or S gene target failure) and this test can therefore be used as a marker for this variant, pending sequencing confirmation.
The health agency said that using this approach, this variant has been detected at faster rates than previous surges in infection, suggesting that this variant may have a growth advantage.