XBB.2.3, Prevalence, Structural, Genomic, and Pathogenic Properties.

Abstract

Background: The World Health Organization -WHO- declares the end of COVID-19 pandemic on May 5, 2023, and the contagious and pathogenic XBB.2.3 “Acrux” begins to spread worldwide. XBB.2.3 has a higher transmission rate and greater evasive capacity of immune-generated antibodies and vaccines than the XBB.1.16 strain, the potential to evade all forms of immunity, including those conferred by current booster vaccination or by previous infections, besides that current virus vaccines and their boosters may provide little or no protection against XBB.2.3*. Those infected with XBB.2.3*, are expected to acquire more opportunistic secondary infections that contribute to the severity of the disease and more long-term problems (Post-COVID Syndrome) and a possible increase in the mortality rate.

Aim: The purpose of the manuscript is to present a systematic review on the prevalence, structural, genomic, and pathogenic characteristics of XBB.2.3 and its descendants as of May 31, 2023, emphasizing the symptoms generated in children, adults, and the elderly.

Material and methods: Original scientific articles published in Medline, Pubmed, Science Direct, Web of Science, Scopus, EBSCO and BioMed Central databases, official health organizations (WHO, CDC, ECDEC, DOH Philippines) electronic publications, and specialized media in the subject, were electronically searched to accomplish the aim of the study. Articles published in any language were included from 2020 to present using a variety of keywords in combination. The studies relevant to our review were analysed and compared.

Results and discussion: XBB.2.3 probably originated in India, but is expanding, being detected as early as Europe in mid-January 2023 and as of May 31, 2023, in more than 47 countries, including the United States, India, Philippines and Thailand. XBB.2.3* has five defining mutations; S:D253G (previously found in Lambda and Iota variants), S:P521S (new since XBB family), S:S486P and the unprecedented ORF1a:G2091S, and ORF7a:A13V. S:S486P is probably the responsible of the superior transmissibility of XBB.2.3*, appears to have a 37% rate of infection and hospitalisation, which is 3-8% higher than other sub-variants.

Conclusions: XBB.2.3* SARS-CoV-2 strain has a higher transmission rate than XBB.1.16*, exhibits a greater evasive capacity of immune-generated antibodies and vaccines than XBB.1.16*, and even has the potential to evade all forms of immunity, including those conferred by current booster vaccination or by previous infections. Those infected with XBB.2.3*, are expected to acquire more opportunistic secondary infections that contribute to the severity of the disease and more long-term problems (Post-COVID Syndrome) and a possible increase in the mortality rate. Preliminary data from the study suggest that current virus vaccines and their current boosters may provide little or no protection against XBB.2.3*. The potential consequences of XBB.2.3* underscore the importance of coordinated, proactive and productive efforts to contain its spread.