What is Omicron and what makes it a variant of concern (VoC)?
It is a new variant of SARS-CoV-2 that has recently been reported from South Africa on 24th November 2021 called B.1.1.529 or Omicron (based on Greek alphabets like alpha, beta, delta, etc). This variant has shown a very large number of mutations, especially more than 30 on the viral spike protein, which is the key target of the immune response.
Given the collection of mutations in Omicron, which earlier individually have been associated with increased infectivity and/or immune evasion, and the sudden rise in the number of positive cases in South Africa, the World Health Organization (WHO) has declared Omicron as a Variant of Concern (VoC).
Can the currently used diagnostics methods detect Omicron?
The most accepted and commonly used method of diagnostic for the SARS-CoV- 2 Variant is the RT-PCR method. This method detects specific genes in the virus, such as Spike (S), Enveloped (E) and Nucleocapsid (N), etc. to confirm the presence of the virus. However, in the case of Omicron, as the S gene is heavily mutated, some of the primers may lead to results indicating the absence of the S gene (called S gene drop out). This particular S gene drops out along with the detection of other viral genes could be used as a diagnostic feature of Omicron. However, for final confirmation of the omicron variant genomic sequencing is required.
How concerned should we be about the new VoC?
WHO declares a variant as a VoC after the assessment when there is an increase in transmissibility or detrimental change in COVID-19 epidemiology; or increase in virulence or change in clinical disease presentation; or a decrease in the effectiveness of public health and social measures or available diagnostics, vaccines, therapeutics.
It is important to highlight that Omicron has been declared VoC based on the observed mutations, their predicted features of increased transmission and immune evasion, and preliminary evidence of detrimental change in COVID-19 epidemiology, such as increased reinfections. The definitive evidence for increased remission and immune evasion is awaited.
Also Read:It Looks Like Omicron Causes Milder Illness; Is this How COVID Becomes Endemic?
What precautions should we take?