OMICRON COVID-19 VARIANT – WHAT WE KNOW SO FAR

Dr Anup R Warrier, Senior Consultant – Infectious Diseases, Aster Hospitals – India  

Omicron – the newest variant of the novel coronavirus has taken the world by storm. First discovered in South Africa, variant B.1.1.529 is believed to be extremely contagious. With the sudden increase in the number of COVID patients in South Africa, experts have come to believe that the new variant has a high rate of transmission. The WHO has said that it will take weeks to understand how the variant may affect diagnostics, therapeutics and vaccines.

What is the current situation?

The World Health Organization (WHO) has stated that B.1.1.529 is a variant of concern. Experts consider this rapid change from 'variant of interest' (VoI) to 'variant of concern' (VoC) is important, since the difference between the two is significant. As compared to variant of interest, variant of concern is linked to "an increase in transmissibility or  more severe disease (e.g., increased hospitalizations or deaths), significant reduction in neutralization by antibodies generated during previous infection or vaccination, reduced effectiveness of treatments or vaccines, or diagnostic detection failures," as per the Centre for Disease Control and Prevention (CDC). Experts in South Africa have stated that Omicron causes only mild illnesses based on the clinical spectrum , although the infection rates continue to be high. 

The new variant could ‘escape’ the antibodies induced by present vaccines 

Omicron, the new variant of COVID-19 virus, has multiple mutations that have altered significantly in the spike protein and ACE receptor binding sites. This means it could have increased transmission potential (affecting more persons than the Delta after similar exposure) or/and increased severity of disease. It also means that it could escape the antibodies induced by present vaccination and monoclonal antibody cocktail.
The spike proteins of the coronavirus play a major role in its entry into our cells. They bind to a protein found on the surface of human cells - the ACE-2 receptor - and use that as a point of entry. Most of the COVID vaccines target the spike proteins to produce an immune response. The antibodies we produce as a result are very specific and recognize only spike proteins structure. So, if the spike protein is mutated, its structure changes and it becomes difficult for the antibodies vaccination to detect the new structure, allowing the variants to ‘escape’. However, the stimulation of the T-cell response that helps in prevention of severe disease is expected to be largely unaltered. 

Is the new variant more dangerous than the Delta variant?

While some of Omicron's genetic changes may seem worrisome, it remains unclear whether they pose a threat to public health. Some earlier variants, such as the beta variant, initially alarmed scientists, but ultimately did not spread. Preliminary evidence suggests the strain has an increased risk of reinfection, according to the WHO. However, so far there is no indication that the variant causes more severe disease.

Prevention continues to be the key

As the holiday season has already approached, it is imperative that we all follow the basics that we have been for the last 18 months - 

• Maintain social distancing in public spaces
• Continue to wear a mask to increase protection when you're outdoor and in crowded places 
• Wash your hands regularly or sanitize them as a routine