What is the Deltacron Variant?
Since its initial emergence in December 2019, SARS-CoV-2 has posed various challenges by continuously mutating itself into different variants throughout the course of the pandemic. Following investigations by a laboratory in Cyprus, virologists from L’Institut Pasteur in Paris have sequenced the genome of a novel variant of SARS-CoV-2. Informally referred to as “Deltacron”, the novel variant appears to be in circulation since early January. Although it was initially considered by many experts as a product of contamination between samples of Omicron and Delta in the laboratory, the presence of Deltacron has subsequently been confirmed by several analyses of the sequences from various authentic sources around the world. In a media briefing on March 9, the World Health Organization (WHO) addressed Deltacron as a new variant of SARS-CoV-2 and identified the virus as a recombinant strain that combines mutations from both the Delta (AY.4) and the Omicron (BA.1) variants. While much remains unknown about the exact epidemiological characteristics of the Deltacron variant, efforts to determine the potential impact of the strain for the future of the pandemic has accelerated. Read along to learn more about the Deltacron variant, its emergence, prevalence, and characteristics, along with its potential impact on the performance of vaccines and diagnostic tests currently in use.
How has the Deltacron variant emerged?
The World Health Organization (WHO) has identified the Deltacron variant as a recombinant virus which combines mutations from Delta (AY.4) and Omicron (BA.1) strains of SARS-CoV-2. Genetic recombination is a relatively common phenomenon for many viruses, including human coronaviruses. Recombinant viruses emerge through the co-infection of the same host cell by multiple variants. When multiple strains of a virus simultaneously infect and replicate within a single host cell, they may exchange parts of their genome and acquire mutations from one another. Among the 36 amino acid mutations located in the spike (S) protein of the Deltacron variant, 27 mutations were found in Omicron, five were found in Delta, while the rest were shared by both Omicron and Delta. Altogether, the Deltacron variant combines nearly the full-length spike protein of the Omicron variant with the backbone of the Delta variant.
How common is the Deltacron variant?
There are no recent updates on the number of cases infected with the Deltacron variant. According to data by GISAID, as of April 4, the variant has been identified in various countries in Europe, such as France (74), Denmark (8), Netherlands (3), Belgium (3), and Germany (3) with low to moderate prevalence.
What are the symptoms of the Deltacron variant?
So far, no evidence has been found to suggest that infections with the Deltacron variant presents with any unique symptoms. It has been reported that potential cases infected with the Deltacron variant have presented with symptoms similar to those observed with other variants, such as sore throat, headache, runny nose, loss of taste/smell, and fever. Further, no deaths have been recorded so far among patients infected with the Deltacron variant.
What are the risks associated with the Deltacron variant?
Experts largely agree that it may be too early to conclude whether there are significant differences between the viral characteristics and behavior of the Deltacron and other versions of SARS-CoV-2, including the Omicron and Delta variants. Researchers worldwide are working on tissue culture experiments to investigate the impact of Deltacron on human cells and compare it to the impact of Delta and Omicron variants. However, given that the variant has not so far caused any evident spikes in infections or deaths, experts suggest that Deltacron is unlikely to outcompete the Delta or Omicron variants. Emphasizing that Deltacron has Omicron’s characteristic spike protein, experts also predict that the variant could partially evade vaccine-induced or infection-induced immunity and cause reinfections. Likewise, it is expected for Deltacron to exhibit a level of transmissibility and pathogenicity similar to that of Omicron, which means that while the variant could easily spread among people, it is unlikely to infect lung cells and cause severe disease. Finally, even though the similarity between the virion structures of Deltacron and the Delta variant has caused some concern regarding the risks posed by the recombinant, antibodies and other immune responses generated against Omicron is expected to offer significant protection against infections with Deltacron.
How effective are the current vaccines against the Deltacron variant?
Data on the ability of Deltacron to evade immunity is scarce, and the exact impact of the delta-derived spike mutations on its replication and pathogenesis remains unclear. Still, one study by Evans et al. (2022) has found no impairment in neutralization resistance or enhanced sensitivity to serum obtained during the Delta wave, reporting that the Deltacron variant may retain the strong resistance characterizing other Omicron subvariants.
Although the continuous emergence of variants and subvariants has generated significant concern over the efficacy and durability of vaccine-induced and infection-induced immunity, experts agree that vaccination remains the most potent strategy against SARS-CoV-2. Regardless of the variant, keeping up to date with vaccines and boosters is known to provide substantial protection against severe disease and death. A second generation of COVID-19 vaccines utilizing multiple strains, engineered proteins, self-amplifying RNA, and protein nanoparticles have also been under development to enhance the efficacy and durability of vaccine-induced immunity against the emerging variants of SARS-CoV-2.
How accurate are the current diagnostic test kits in the detection of the Deltacron variant?
While much about the Deltacron variant remains unknown, there is currently no evidence to suggest that the mutations observed in the Deltacron variant has significant impact on the specificity, or overall accuracy of the diagnostic tests in use. The performance of molecular testing and antigen-based testing in the detection of the Deltacron variant is expected to be on par with that observed with other strains of Omicron. Successfully detecting various strains of the virus including the Delta and Omicron strains, our RapidFor™ SARS-CoV-2 Rapid Antigen Test Kits deliver quick and highly accurate results with flexible sample options.
References
Evans, J. P., Qu, P., Zeng, C., Zheng, Y. M., Carlin, C., Bednash, J. S., Lozanski, G., Mallampalli, R. K., Saif, L. J., Oltz, E. M., Mohler, P. J., Gumina, R. J., & Liu, S. L. (2022a, June 16). Neutralization of the SARS-CoV-2 Deltacron and BA.3 Variants. New England Journal of Medicine, 386(24), 2340–2342. https://doi.org/10.1056/nejmc2205019
Evans, J. P., Qu, P., Zeng, C., Zheng, Y. M., Carlin, C., Bednash, J. S., Lozanski, G., Mallampalli, R. K., Saif, L. J., Oltz, E. M., Mohler, P. J., Gumina, R. J., & Liu, S. L. (2022b, June 16). Neutralization of the SARS-CoV-2 Deltacron and BA.3 Variants. New England Journal of Medicine, 386(24), 2340–2342. https://doi.org/10.1056/nejmc2205019
Farheen, S., Araf, Y., Tang, Y., & Zheng, C. (2022, July 22). The Deltacron conundrum: Its origin and potential health risks. Journal of Medical Virology, 94(11), 5096–5102. https://doi.org/10.1002/jmv.27990
GISAID – hCov19 Variants. (n.d.). GISAID. Retrieved October 14, 2022, from https://gisaid.org/hcov19-variants/
