Omicron COVID-19 Variant Symptoms, Transmission, Vaccines Efficacy And Other Details

Earlier this week, the World Health Organization (WHO) classified a new strain of SARS-CoV-2, circulating in South Africa, as a 'variant of concern'. This strain is named Omicron [1].

On Monday, the Network for Genomics Surveillance in South Africa (NGS-SA) identified the variant. It identified a group of SARS-CoV-2 viruses that belonged to the lineage B.1.1.529. Initial indications suggest that this variant may even be more infectious than the highly infectious Delta variant. Current vaccines may be less effective in protecting against it.

Omicron COVID-19 Variant: Everything You Need To Know

1. Where was the new covid-19 variant discovered?

Scientists in South Africa detected a small number of B.1.1.529 variants in samples taken between 14 November and 16 November.

In an announcement made on Wednesday, South African scientists sequenced more genomes, informed the government of their concern, and requested the World Health Organization (WHO) to convene its technical working group on virus evolution on Friday [2].

About 100 cases of the variant have been identified in the country, mostly in Gauteng, its most populous province.

2. Where else has the Omicron variant been detected?

Early signs from diagnostic laboratories suggest that the virus has spread rapidly in Gauteng and may already be present in the other eight provinces of South Africa. South Africa's daily infection rate nearly doubled on Thursday to 2,465 [3].

3. Why are scientists concerned about the Omicron variant?

"We are concerned that this new variant may pose a substantial threat to public health," said Javid. According to Sajid Javid, UK Health Secretary, this variant appears to be more transmissible than Delta, and current vaccines may be less effective in combating it.

The B.1.1.529 variant is of major concern, as it reveals an exceptionally high mutation rate. It has been detected in several confirmed cases of Coronavirus infection in South Africa. In addition, the Beta variant was detected and described as being very unstable and potentially dangerous [4][5].

Over the last two weeks, there has been a four-fold increase in new cases reported in South Africa, coinciding with the emergence of B.1.1.529.

4. Why are Omicron mutations different?

Taking a look at the mutation profile of the new variant, the NGS-SA has concluded that B.1.1.529 has a very unusual array of mutations, including 30 located in the region that encodes the spike protein, which is responsible for the virus entering human cells [6].

It has been pointed out that some of the mutations are well-characterised and have a known phenotypic impact, affecting transmissibility and immune evasion. In addition, alpha and Delta variants have already been detected with some of these mutations. However, at this point, the significance of these mutations is not clear.

The NGS-SA has indicated that a cluster of mutations, known as H655Y + N679K + P681H, is associated with more efficient cell entry, indicating a greater likelihood of viral transmission [7].

There is also a deletion, NSSP6, similar to the deletions found in the Alpha, Beta, Gamma, and Lambda variants. NGS-SA suggests that this may be associated with evasion of innate immunity and could result in increased transmissibility [8].

5. Are Omicron symptoms different?

According to the National Institute for Communicable Diseases (NICD) of South Africa, "no unusual symptoms" have been reported following infection with B.1.1.529. However, the study highlights that, as with other infectious variants such as Delta, some individuals are asymptomatic [9].

6. Are vaccines effective against the Omicron variant?

Omicron's epidemiological and clinical correlation cannot be fully established. Scientists are unable to establish a direct causal link between the illness and any outbreak. South Africa has begun to examine the immune escape properties of B.1.1.529 in a laboratory environment. In addition, this will provide insight into the effectiveness of current vaccines. The organisation has also developed a system for monitoring hospitalisation and outcome related to B.1.1.529 in real-time. By examining the data, it will be possible to determine whether the mutation is associated with disease severity or affects the effectiveness of therapeutic medicines administered in hospitals [10].

7. How many cases of the Omicron variant have been detected in the UK?

In the UK, no cases of the new B.1.1.529 variant have been reported.

On A Final Note...

The WHO said that its technical advisory group met to review the new variant and declared it a variant of concern. Thus, Omicron has been demonstrated to be associated with one or more of the following changes, such as an increase in transmissibility and decreasing efficacy of diagnostics, vaccines, and therapeutics.

As the new variant indicates, the pandemic is far from over. Covid-appropriate behaviour will be crucial for breaking the chain of transmission, including masking, social distancing, adequate ventilation of shared areas, frequent hand-washing and surface sanitisation.