Thermo Fisher Scientific confirmed that its polymerase chain reaction (PCR) TaqPath Covid-19 Combo Kit and TaqPath Covid-19 CE-IVD RTPCT Kit which test for the presence of SARS-CoV-2, are not impacted by the emerging B.1.1.529, or Omicron variant, enabling accurate test results.

The Omicron variant, which was designated a variant of concern by the World Health Organization (WHO), has more than 30 mutations in the spike protein alone. The WHO has reported that preliminary evidence suggests an increased risk of transmission compared to other variants of concern. This designation and information are leading to renewed travel restrictions and research to examine the variant's impact on efficacy of existing vaccines and tests. The WHO and European Centres for Disease Control have both reported that using S-gene target failure (SGTF) of the PCR assays as a proxy for the variant helped to identify Omicron. Cases of the variant were first identified in South Africa and have now been reported in at least a dozen countries around the world. 

The TaqPath Covid-19 assays detect SARS-CoV-2 infections by identifying the presence of three gene targets from the orf1a/b, S, and N regions of the virus. By surveying across multiple genes, the test can report accurate results even in the case where one of the targets is impacted by a mutation. While the S gene target in the test is impacted in the presence of Omicron variant mutations, the orf1a/b and N gene targets in the TaqPath Covid-19 tests have been determined to not be impacted by any of the mutations in the Omicron variant, based on assessment of sequences in the GISAID public database. As a result, the overall accuracy of the TaqPath Covid-19 assays is not impacted.

The Omicron variant has been found to include the 69-70del mutation of the S gene, first identified as a mutation in the Alpha variant. This mutation causes a dropout of the S-gene target in results from the TaqPath test, which could indicate to clinicians and researchers a possible Omicron variant infection. Confirmation must then be performed by sequencing the sample.

"The Thermo Fisher test allowed us to detect cases that may contain the new variant by identifying samples exhibiting S-gene dropout," said Tulio de Oliveira, director of the Centre for Epidemic Response and Innovation (CERI), Stellenbosch University and UKZN, South Africa. "This early identification is very important in helping us track and understand the spread of the B.1.1.529 variant to South Africa and the world."