Evolution, Vaccine Development and World Prevalence of SARS-CoV-2 as of October 31, 2024

Abstract

Background: SARS-CoV-2 is the etiological agent responsible for the Coronavirus Disease 2019 (COVID-19).

The virus it has a high mutation rate that generates a rapid and constant appearance of new viral variants that have spread rapidly around the world. By improving the virus ability to bind to the ACE2 cell receptor, and icrease the evasion of antibodies, monoclonal antibody treatments or vaccines to combat it, mutations in viral S-protein is to blame for its high rate of spread.

This review intended for to highlight the functional virus classification used by the WHO, PANGO, GISAID and Nextrain, the major findings related to the rate of spread, the S-protein mutations linked to the decrease host immune responses elicited by prior SARS-CoV-2 infections and by the protection induced by vaccination.

Aim: The purpose of the manuscript is to perform a systematic review on the SARS-CoV-2 virus evolution, structural, genomic, pathogenic characteristics, prevalence and COVID-19 vaccine development as of October 31, 2024.

Material and Methods: Original scientific articles published in Medline, Pubmed, Science Direct, Web of Science, Scopus, EBSCO and BioMed Central databases, official health organizations (World Health Organization, U.S. Centers for Disease Control and Prevention, European Centre for Disease Prevention and Control, The Africa Centres for Disease Control and Prevention) 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 January 1, 2024, to October 31, 2024, using a variety of keywords in combination. The studies relevant to our review were analyzed and compared.

Results and Discussion: SARS-CoV-2 evolve at least between hosts and within hosts.

Because the continuous evolution at the inter-host level, there are variants that evolve within individual hosts, either as they reproduce generation after generation during a persistent infection, or by recombination between two variants that infect the same host simultaneously.

SARS-CoV-2 variants derived from intrahost evolution or recombination, might not compete well against variants that had been evolving among hosts all along, but there have been several cases where only a few additional mutations made their descendants extremely successful.

These include recombinant XBB lineages such as XBB.1.5, XBB.1.16, EG.5, and EG.5.1, and more recently JN.1^*, a descendent of BA.2.86.

Recently the FliRT and FluQE Variants are globally increasing in prevalence, mainly in Japan, Australia, United States and other countries.

The increased prevalence or KP.3.1.1 and XEC variants is observed globally and in USA as of Ocober 26, 2024.

The next COVID-19 vaccine update will focus on JN.1, a variant that has already largely disappeared, which is likely to be replaced by variants with other mutations.

The current COVID-19 vaccines present high but heterogenous levels of protection, with decreasing protective effects for vaccines based on traditional technologies as SARS-CoV-2 variants emerged over time. The actual mRNA vaccines offered substantially higher and more consistent protection.

Conclusions: The evolution of SARS-CoV-2 has developed in the emergence of new mutant strains, some exhibiting enhanced transmissibility, immune evasion capabilities, and reduced vaccine efficacy.

Actually, KP.3.1.1 and XEC are the globally prevalent SARS-CoV-2 variants which exhibit an increase in their binding to human cell receptors but a decreased virulence.

There is no known broad estimate of the duration of protection offered by SARS-CoV-2 vaccines against COVID-19 disease, which varies not only by disease status and type, but also by circulating variants.

Current mRNA vaccines against COVID-19 have shown high effectiveness against severe disease, even after six months of the application of the primary series, improving after a booster dose.