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SARS-CoV-2 Omicron BA.4, Omicron BA.5.2.1, and x-ray irradiated Omicron BA.4 available through NCPV

Severe acute respiratory syndrome-related coronavirus 2 (SARS-CoV-2) Omicron BA.4 (NCPV 2209291v), (Nextclade PANGO lineage BA.4, Nextstrain clade 22A, and clade GRA on GISAID) and  x-ray irradiated product (NCPV 2210281v) is available through NCPV. As discussed in previous newsletters (NCPV News January 2020) the irradiation process inactivates the virus the whilst antigenic structures remain intact.

Live SARS-CoV-2 Omicron BA.5.2.1 (NCPV 2210071v) is also available. This falls under the Nextclade PANGO lineage BA.5.2.1, Nextstrain clade 22B, and clade GRA on GISAID.

Both BA.4 and BA.5.2.1 are more contagious sub-lineages of BA.2 (Chen et al, 2022) and were detected in the beginning of 2022 in South Africa (Mohapatra et al, 2022). BA.5 was designated as a variant of concern (VOC) in the UK in May (UKHSA, 2023), and by June infections started to rise (WHO, 2022). Just a month later, in July, it had become the dominant variant, which at this point was responsible for half of the world’s cases according to available surveillance and collected sequences by GISAID (WHO, 2022).

These NCPV accessions are iconic Omicron sub-lineages and will prove essential to scientists engaging in SARS-CoV-2 Omicron studies. Both have the defining amino acid changes: L452R and F486V in the spike receptor binding domain (RBD), making them far more transmissible than previous Omicron variants (Tegally et al, 2022). At the time, the variants evaded immunity provided by both previous infection and vaccination, requiring updated lateral flow tests (LFTs), vaccines and monoclonal antibody (mAb) therapeutics (Altarawneh et al, 2022; Bruel et al, 2022; Cao et al, 2022; Ng et al, 2022; Zhou et al, 2023).

Conveniently, the novel x-ray irradiated Omicron BA.4 NCPV batch allows scientists to carry out work at a lower containment level. In the United Kingdom, work can be carried out at Advisory Committee on Dangerous Pathogens containment level 2 (ACDP CL2) instead of containment level 3 (ACDP CL3). It is also pivotal as a positive control in assays and diagnostic and serologic tests.

Transmission electron micrograph o fx-ray irradiated SARS-CoV-2 Omicron BA.4

Image provided by Microbial Imaging, Porton, UKHSA.



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Written by Teresa Ramalho,

December 2023