We are proud to share the reports published by Public Health England who have demonstrated successful inactivation of SARS-CoV-2 using our 3 virusPHIX™ products:

virusPHIX+™
Our original formulation, developed for PCR testing on swab and saliva samples

PHE Inactivation study
Triplicate samples of tissue culture fluid containing 5% (v/v) foetal calf serum, spiked with SARS-CoV-2 were treated with virusPHIX+™ for indicated contact time/s or mock-treated in triplicate with an equivalent volume of PBS. All samples were then subjected to a purification step to remove cytotoxic buffer components. PBS-treated samples were subjected to the same purification procedure in parallel.

Test 1: Purified samples were immediately titrated on Vero E6 cells to establish virus titre. This test is quantitative and reports the titre of virus in each treatment condition in TCID50 per ml. Reduction in virus titre following treatment is given as the difference between the mean log10 TCID50/ml for treated conditions and the PBS control.

Test 2: In parallel, purified samples were seeded onto Vero E6 monolayers to amplify any remaining virus over the course of up to four serial passages. Virus amplification over each passage was detected by visual (microscopic) examination of monolayers for cytopathic effect, and confirmed by SARS-CoV-2-specific real-time PCR. This test is qualitative and reports either the presence or absence of virus amplification. This test may detect levels of virus that are below the detection limit of the titration assay (test 1) due to a greater sample plating volume and the opportunity for any virus present to amplify over serial passages.

Results

 

Download the PHE report here: https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/937439/HCM-CoV2-034-v2_virusPHIX_TCF__5_.pdf

Additional independent studies also show SARS-CoV-2 inactivation and 1 month RNA stability at room temperature

A recent study from the Roslin Institute in Edinburgh, UK concluded that virusPHIX+™ inactivates SARS-CoV-2 in as little as 10 minutes when treated at a 1:1 sample to reagent ratio at room temperature. Under these conditions, a 10log6 reduction in SARS-CoV-2 virus titre was recorded.

Another independent study by Qnostics UK demonstrated that virusPHIX+™ stabilises SARS-CoV-2 virus RNA for at least 33 days at 20°C. Sputum samples spiked with SARS-CoV-2 RNA were analysed over 33 days, and the Ct value was compared with virusPHIX+™ treated samples and control (no stabiliser added):

Independent study by Qnostics UK demonstrated that virusPHIX+™ stabilises SARS-CoV-2 virus RNA for at least 33 days at 20°C. Sputum samples spiked with SARS-CoV-2 RNA were analysed over 33 days, and the Ct value was compared with virusPHIX+™ treated samples and control (no stabiliser added)

Independent study by Qnostics UK demonstrated that virusPHIX+™ stabilises SARS-CoV-2 virus RNA for at least 33 days at 20°C. Sputum samples spiked with SARS-CoV-2 RNA were analysed over 33 days, and the Ct value was compared with virusPHIX+™ treated samples and control (no stabiliser added)

Find out more about virusPHIX+™ here

virusPHIX-LV™
Lower viscosity formulation, optimised for automated liquid handling platforms (Ortho, Hamilton, Tecan)

PHE Inactivation Study
PHE evaluated the reduction in virus titre SARS-CoV-2 spiked samples (tissue culture fluid). Samples were treated with virusPHIX-LV™ at a 1:10 ratio at room temperature. Triplicate samples were treated with test buffer for indicated contact time/s or mock-treated in triplicate with an equivalent volume of PBS. All samples were then diluted two-fold to reduce product viscosity and subjected to a purification step to remove cytotoxic buffer components. PBS-treated samples were subjected to the same dilution and purification procedure in parallel. Purified samples were titrated on Vero E6 cells to establish virus titre. This test is quantitative and reports the titre of virus in each treatment condition in TCID50 per ml. Reduction in virus titre following treatment is given as the difference between the mean log10 TCID50/ml for treated conditions and the PBS control:

Download the PHE report here:
https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/937388/HCM-CoV2-055-v1_VirusPHIX-LV_TCF__1_.pdf

Find out more about virusPHIX-LV™ here

virusPHIX-P9™
Compatible with both swab/saliva samples, and recommended when it is necessary to add sample directly into an RT-LAMP, LamPORE or RT-PCR assay without RNA purification*.

*virusPHIX-P9™ has been demonstrated to be directly compatible with LAMP assays, please contact us for further information.

PHE Inactivation Study
PHE evaluated the reduction in virus titre SARS-CoV-2 spiked samples (tissue culture fluid). Samples were treated with virusPHIX-P9™ at a 1:3 ratio at room temperature. Triplicate samples were treated with test buffer for indicated contact time/s or mock-treated in triplicate with an equivalent volume of PBS. All samples were then diluted two-fold to reduce product viscosity and subjected to a purification step to remove cytotoxic buffer components. PBS-treated samples were subjected to the same dilution and purification procedure in parallel. Purified samples were titrated on Vero E6 cells to establish virus titre. This test is quantitative and reports the titre of virus in each treatment condition in TCID50 per ml. Reduction in virus titre following treatment is given as the difference between the mean log10 TCID50/ml for treated conditions and the PBS control:

Download the PHE report here: https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/953552/HCM-CoV2-059-v1_VirusPHIX-P9_TCF.pdf

Find out more about virusPHIX-P9™ here

About virusPHIX™

virusPHIX™ is a novel RNA stabiliser and virus inactivation medium based on technology developed by RNAssist Limited (Cambridge, UK). It has shown to stabilise RNA for up to 1 year at 20°C, and has successfully inactivated all tested viruses and bacteria to date. Unlike other virus transport mediums, virusPHIX™ does not contain guanidine, a highly toxic substance than can produce hydrogen cyanide when mixed with household cleaning products such as bleach. virusPHIX™ is a completely non-toxic, non-volatile reagent that can be used safely in a home testing environment and shipped for PCR analysis. The virusPHIX™ range of products are manufactured and sold worldwide by Rapid Labs Limited (Colchester, UK). With over 200 evaluators around the world, virusPHIX™ is a popular choice for RNA stabilisation thanks to its compatibility with most front-end RNA purification kits.

For more information about using virusPHIX™ for SARS-CoV-2, please get in touch to discuss your requirements and we will be happy to advise on the best formulation to suit your needs.

rnassist@rapidlabs.co.uk