The emergence of the alternative omicron, contributed to the increase in the incidence of SARS-CoV-2 infection in the world. This strain has been shown to increase the risk of reinfection as well as infection despite full immunization. by more than 37 mutations in the S protein. Compared to the original SARS-CoV-2 discovered in Wuhan, this variant is more easily transmitted by respiratory droplets.
Currently, the Omikron variant is distinguished from other SARS-CoV-2 strains using the method Targeted damage to the S protein gene.. Because there is a mutation (deletion) in the Omikron S protein gene, standard PCR tests do not detect it. This phenomenon is called SGTF (Failure of gene target S) It is used to detect Omikron infection.
Now South African scientists compare the performance Saliva and nasopharyngeal swabs For PCR-dependent detection of Delta and Omikron variants. The researchers collected saliva and nasopharyngeal swabs from 382 asymptomatic patients, who presented to a Cape Town hospital for SARS-CoV-2 testing between August and December 2021. The samples were examined by RT-PCR.
The positive concordance between salivary and pharyngeal smears was estimated at 71% and 100%. In the case of injury to the delta. This means that 100 percent incidence of the delta variant It can be detected by performing an antigen test from the nasopharynx. In case Variant of Omikron The results were surprising – 100%. Tested samples taken from saliva detected the pathogen, compared to 86 percent. Coming from the nasopharynx.
The results showed that if an Omikron variant is suspected, it may be better saliva smearAnd not the nasopharynx. Saliva samples have been shown to contain more viral RNA than nose samples (in the case of Omikron). This may be due to the patterns of removal of this variant from the body (more with the mouth and less with the nose). Other evidence indicates that the recurrence rate of the Omikron variant is significantly higher in the upper respiratory tract than the delta variant.
