Omicron Variants and What You Need to Know

What is a variant?

The term “variant” refers to a virus that has significant differences from its relatives in terms of infectivity, virulence (the ability to cause disease), or sensitivity to treatment drugs. Currently, scientists have found over 28,000 genetic mutations of the SARS-CoV-2 virus, and based on the level of infectivity and virulence of the virus, the World Health Organization (WHO) has divided the variants into two groups: Variants of Concern (VOIs) and Variants of Concern (VOCs).

• Variants of concern (VOIs): change phenotype or have 1 gene with multiple mutations. VOIs can spread rapidly in the community or across many countries.
• Variants of concern (VOCs): increase transmissibility and even change the epidemiological situation of Covid-19 in many countries related to increased transmissibility, clinical progression, treatment efficacy and vaccine efficacy.

Illustration photo.

Variants of concern (VOCs) noted by WHO globally include:

• Variant B.1.1.7 (Alpha variant): detected in the UK, recorded in 155 countries
• Variant B.1.351 (Beta variant): detected in South Africa, recorded in 111 countries
• P.1 variant (Gamma variant): in Brazil, recorded in 62 countries
• Variant B.1.617 (Delta variant): appeared in India, recorded in 63 countries

New variant Omicron

This variant is identified as B.1.1.529 and has been named the Omicron variant by WHO.

Some scientists believe that Omicron is “flying” in the community because it is much more infectious than previous variants.

Three hypotheses have been proposed for the development of the Omicron variant: (1) It was generated in areas with limited access to medical care and limited epidemiological monitoring of the virus. (2) It may have been developed in immunocompromised populations such as those infected with HIV. (3) Or the virus may have jumped from humans into animal populations, mutated with animal and human variants, and then jumped back to humans.

The Omicron variant is said to have the most mutations among the previously detected variants. Non-synonymous mutations were detected in different protein coding regions of the virus. Of the non-synonymous mutations detected in the S protein coding gene, 43% were found in previous variants including Alpha, Beta, Gamma and Delta. Several point mutations and deletions were also found with varying frequencies in these variants such as NSP4-T492I, NSP6-S106del, NSP6-G107del, NSP12-P323L, N-P13L, N-R203K and N-G204R.

Some of these mutations may reduce the specificity of tests, especially those that use primers for the gene encoding the S protein. Some mutations in the gene encoding the S protein have also been shown in vitro to alter the antigenicity and transmissibility of SARS-CoV-2.

Transmissibility and severity due to the Omicron variant

Studies in South Africa have shown that the Omicron variant is highly contagious, especially among young people. However, it is not yet clear whether the Omicron variant is more contagious than the Delta variant, as the level of transmission depends on many factors.

Preliminary data from South Africa show a high rate of infection with the Omicron variant in young people. Symptoms are generally milder than those reported in other countries with previous VOCs. However, South Africa's data is mainly based on young people with few underlying conditions, so scientists say it is not yet possible to confirm the virulence of this variant.

Protective efficacy of previous exposure to SARS-CoV-2 or vaccination

Some studies have shown that patients can be reinfected with the Omicron variant, but the infection rate and severity of these patients are currently unknown.

The vaccine has been shown to be effective against the Delta variant. Studies have shown that patients infected with the Delta variant tend to have milder symptoms if vaccinated, and that the vaccine is thought to reduce mortality and reduce the severity of the disease. However, there has been no research on the vaccine's ability to protect against the Omicron variant.

Effectiveness of current treatments

According to the World Health Organization (WHO), treatment with corticosteroids and IL-6 receptor blockers is considered the most effective treatment for severe Covid-19 patients, but there are no reports on the effectiveness of this method for the Omicron variant.

Protect yourself against the Omicron variant

Currently, the World Health Organization WHO recommends that individuals still maintain distance when in contact with others, wear masks, open windows for ventilation, avoid closed or crowded spaces, wash hands, cough or sneeze into the elbow or tissue and vaccination is still considered an effective measure to avoid variants of the SARS-CoV-2 virus.

Faculty of Medicine, Dai Nam University