Omicron<br />On November 26, 2021, the World Health Organization (WHO) announced a new severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variant Omicron (B.1.1.529), as a variant of concern (VOC). This variant carries an unusually high number of mutations, 32, on the spike (S) protein, the main antigenic target of antibodies generated by either infections or vaccination. In comparison, the devastating Delta variant has only 5 S protein mutations, which posed a high potential global risk and has spread internationally.<br />The mutations on the Omicron variant are widely distributed on multiple proteins of SARS-CoV-2 such as NSP3, NSP4, NSP5, NSP6, NSP12, NSP14, S protein, envelope protein, membrane protein, and nucleocapsid protein. The focus is the mutations on the S protein receptor-binding domain (RBD) for the potential impact on infectivity and antibody resistance caused by this new variant.<br /><br />It is estimated that it will take at least 2–3 weeks to appropriately assess the neutralizing capacity of our current interventions (vaccines and convalescent plasma) through in vitro testing and longer to determine in vivo protection. Some of the mutations are in spike protein regions that are immune‐dominant and thought to be important in antibody‐mediated host defense. Other mutations are in domains that are targeted by T cell‐mediated host defense. Scientists from South Africa have shared their belief that prior infection with COVID‐19 provides relatively little immune protection against subsequent infection with the Omicron variant. Fortunately most of the anecdotally reported Omicron cases thus far have had relatively mild symptoms and clinical manifestations. Vaccine manufacturers rapidly launched major efforts to create mRNA vaccines modified to be effective against the Omicron variant, but it is too early to be able to assess the immune response and/or protective efficacy.<br /> The Omicron variant may become a dark period that includes a global surge or it may be a false alarm that quickly fades from memory. Either way, our actions now must be the same to ensure success in both scenarios. (1) Vaccinate the globe: The Omicron variant highlights the need to vaccinate the world which requires looking beyond our individual nations. (2) Clear and transparent communication: This must occur frequently between the scientific community and the public and in an equitable manner<br /> <br /><br /><br />Fig: Omicron variant mutations Panel A shows the RA of Spike signature mutations and high prevalent mutations in OFR1a and ORF1b. Panel B shows the RA of Omicron variant mutations in ORF1a and ORF1b and signature mutations in structural proteins E, M, and N. Please note ORF1b:P314L corresponds to nsp12 mutation nsp12:P323L. Panel C shows the phylogenetic relationship among different SARS-CoV-2 variants.<br /><br />References<br />1- Kannan, S. R., Spratt, A. N., Sharma, K., Chand, H. S., Byrareddy, S. N., & Singh, K. (2022). Omicron SARS-CoV-2 variant: Unique features and their impact on pre-existing antibodies. Journal of autoimmunity, 126, 102779. https://doi.org/10.1016/j.jaut.2021.102779<br /><br />