What is a variant?
Like all viruses, SARS-CoV-2 (Covid-19), is constantly mutating as it moves through the population, this action causes variants to emerge. These variants contain mutations (changes) in the RNA of the virus. Most variants from a clinical perspective are inconsequential but are useful in tracking the spread of the virus through the global population.
How does a variant mutate?
SARS-CoV-2 (covid-19) is a Coronavirus, these viruses are known for crown-like spikes on their surfaces called spike proteins. These spike proteins enable the virus to attach to and infect host cells. Mutations in spike proteins can alter the ability of the virus in both inconsequential and consequential ways. Scientists avidly track mutations in Covid-19 spike proteins that increase the ability of the virus to spread, cause more severe illness, evade protective antibodies or detection by testing methods. The U.S. government has established three classifications for monitoring variants: Variant of Interest, Variant of Concern and Variant of High Consequence.
How is diagnostic PCR testing impacted by variants?
In general, most laboratory performed PCR testing is currently unaffected by the identified variants. Testing that is affected are those that utilize a singular gene marker that may be impacted by a variant. In this case it is possible for a variant to go undetected by a diagnostic test method utilizing a singular impacted gene marker. It’s for this reason that Brio ensures that all its partner laboratories are using multiple gene markers to detect Covid-19.
How is rapid PCR testing impacted by variants?
Rapid PCR testing is affected much in that same manner that standard diagnostic PCR tests are impacted. Brio works to ensure that its offering of rapid PCR based testing employs either multiple gene markers or has been proven to detect identified variants through manufacturer verification and testing.
How is rapid antigen testing impacted by variants?
Rapid antigen or Lateral Flow Immunoassay (LFIA) tests function differently than PCR testing, it detects the presence of Spike Proteins in an infected individual. These tests rely on the antigen antibody response to produce a colorimetric marker or line, to indicate if a test is positive for Covid-19. These tests will normally rely on the S1 receptor-binding domain and the nucleocapsid N protein. Most tests on the market today use N protein detection since it has shown to be in higher concentrations than S in infected individuals. Brio’s scientists analyze the impact of each variant on these spiked proteins in coordination with the manufacturer information to ensure the testing offered provides the needed detection for identified variants.
Does standard laboratory PCR and rapid testing identify Covid-19 variants?
No, standard laboratory PCR and rapid testing does not differentiate between the variants ofCovid-19, it simply indicates the presence of an active symptomatic or asymptomatic infection with Covid-19 as a Positive (Detected), or Negative (Not Detected). To determine the presence of a specific variant full genome sequencing of the patient’s specimen must be done.
How does Brio keep track of variant impact on diagnostic testing?
Brio has an extensive process for screening and onboarding partner laboratories and point-of-care tests (rapid). In this process we collect key information on test method, performance and characteristics and catalog it in our laboratory database for reference and tracking. This allows us to easily determine if there is the potential for impact on testing from a specific variant.