Partial relief at Tor Vergata Polyclinic in Rome, where a suspected case of the new Omicron variant of Sars-CoV-2 was later revealed to be not Omicron, but an atypical delta type. Experts from the Capitoline facility are urging people to keep their attention high for the risk of misleading diagnostic test results, such as Omicron. An unvaccinated patient admitted to the respiratory unit at the Tor Vergata Clinic – reads a note – was positive for the first time on the molecular test as of November 25 on two targets (gene E and RDRP/S), but several times negative for gene N Then he tested positive for the Delta AY.4 variant with a double atypical deletion.”
“The intuition of Professor Paola Rogliani, who is treating the patient – confirms from Tor Vergata, Professor of Microbiology and Clinical Microbiology, Francesca Seccherini Silberstein – was to order the sequence for a suspected atypical variant, such as the new Omicron. Thanks to the collaboration between the virology unit at the dispensary. The sample was processed and sequenced in less than 48 hours thanks to the work of the team, notably Maria Concetta Bellucci and young university graduates Greta Marchegani and Daniel Stella, under the supervision of Sandro Greely, Head of the Department of Virology in the Department of Experimental Medicine at the University of Tor Vergata. It has to be SARS-CoV-2 virus with a delta strain variant AY.4. On closer examination, a non-repetitive deletion at position 214-215 of the nucleocapsid was identified by Muhammad Al-Khatib, which could lead to a partially negative diagnostic test result.As in 4, the Omicron variant also has an atypical deletion in the N gene that deserves attention, as it may have repercussions in the outcome and interpretation of diagnostic tests.”
“This aspect,” or rather the potential implications of Sars-CoV-2 atypical variants on diagnostic tests, continues Ceccherini Silberstein, “will be investigated as soon as possible by collaborative studies within the recently funded European research project EuCare: European groups of patients and schools. To strengthen the response to epidemics, led by Italy, dedicated to clarifying some of the crucial and most controversial aspects of the Covid-19 epidemic, such as “the impact of variables in serological and / or molecular tests and vaccines currently in use”.