New variant


During late 2020, the emergence of variants of SARS CoV-2 that posed an increased risk to global public health prompted the characterisation of specific Variants of Interest (VoIs) and Variants of Concern (VoCs). These have been used to prioritise global monitoring and research, and to inform the ongoing response to the COVID-19 pandemic.

HSL testing

As of 31 May 2021, the World Health Organisation (WHO) proposed labels for global SARS CoV-2 VoC and VoI to be used alongside the scientific nomenclature. A SARS CoV-2 VoI becomes a VoC when it has been demonstrated to be associated with one or more of the following changes at a degree of global public health significance:

  • Increase in transmissibility or detrimental change in COVID-19 epidemiology; or
  • Increase in virulence or change in clinical disease presentation; or
  • Decrease in effectiveness of public health and social measures or available diagnostics, vaccines, therapeutics.

With the emergence of the latest VoC, Omicron, it has become increasingly important for hospitals to be aware of the variant the patient is infected with.

This is because the drug used to date to treat specific patients with COVID, such as those at high risk of developing severe COVID disease, does not work on patients infected with the Omicron variant.

Patients infected with the Omicron variant may still be eligible for enrolment into a trial of an alternative monoclonal treatment that has been shown to retain activity against this variant.

Whilst the routine COVID-19 PCR tests can detect a person infected with SARS CoV-2, they cannot determine the specific variant. Further testing such as VoC PCR genotyping or sequencing is required for this.

For this reason, as part of the NHSE remit, HSL has been testing all hospital in-patients to determine the variant they are infected with. This includes the entire London 2 region covering East, North and West Hertfordshire and Central London. We’re providing mutual aid to other hospitals (where capacity allows) to enable appropriate treatment to be given within a five day window. This fast genotyping test can be adapted quickly to detect new variants as they arise.

Whilst the molecular pathology department at the Halo has been concentrating on VoC PCR for hospital patients, our surge laboratory has been testing test and trace samples to help determine the prevalence of the variants in the general population. In addition to this, Molecular pathology at the Halo has been sequencing all positive cases within two days of people entering the country, in order to identify any potential new variants that may arise worldwide.

Our continued efforts have provided significant support for hospitalised patients and UKHSA population surveillance during this ever changing pandemic.