mariPOC antigen testing designed to escape strain variations

written byJanne Koskinen

posted onJanuary 14, 2021

The expected has happened. The SARS-CoV-2 causing COVID-19 disease has mutated, as typical for coronaviruses. The new strains are not only spreading more effectively, but they also may be missed by PCR based tests. The U.S. Food and Drug Administration (FDA) warns health care providers to be aware that genetic variants of SARS-CoV-2 arise regularly and false negative test results can occur.

FDA is alerting that false negative results may occur with any molecular test for the detection of SARS-CoV-2 if a mutation occurs in the part of the virus’ genome assessed by that test. This is because molecular tests look for a specific sequence, and it is basic text book biology knowledge that sequence changes are faster on genetic level than on protein level. Reports from test developers to FDA showed reduced analytical sensitivity associated with certain SARS-CoV-2 molecular tests. The prevalence of new genetic variants are increasing and it may lead to increasing amount of cases going undetected.

The FDA believes the risk of these mutations impacting clinical sensitivity is low, but new mutations are on the way.

mariPOC antigen tests including SARS-CoV-2 have been designed in a more sophisticated and wise manner. These tests detect the infectious virus directly by targeting conserved epitopes of conserved antigens, typically nucleoprotein. The design makes the tests robust against strain variation. For example, mariPOC SARS-CoV-2 test detects so conserved epitope that even SARS-CoV-1 from 2003 is detected, and hence most likely any new strain variant that might rise in the years to come. Another example is our influenza A virus test which recognizes seasonal influenza viruses, as well as, potentially pandemic avian influenzas. mariPOC is always ready to fight new pandemics caused by new viruses in these species.