Abstract

Martin Maïdadi Foudi, Célestin Godwe, Emilande Guichet, Nicolas Fernandez Nuñez, Guy-Roland Awoundza, Nadine Lamare, Marie Amougou Atsama, Marcel Tongo, Onana Boyomo, Wifred Mbacham, Ahidjo Ayouba, Martine Peerters, Eric Delaporte and Charles Kouanfack*

Omicron is the most mutated SARS-CoV-2 variant; its high transmissibility and immune evasion ability have raised global concerns. We reported here the first identification of BA.5.2.1 Sub-lineage of Omicron variant in two fully vaccinated patients in Cameroon. We used DICOV-MOC/I MULTIPLEX RT-PCR and CovidSeq on Illumina ISeq100 respectively for the screening of SARS-CoV-2 mutations and whole-genome sequencing. We detected antibodies to Spike (SP) and Nucleocapsid (NC) proteins from ancestral and Omicron SARS-COV-2 strains using a multiplex Luminex-based assay on a MagPix platform. On the 15th of June 2022, two patients (Cases 1 and 2) presented at CREMER laboratory in Yaoundé for COVID-19 test. Nasopharyngeal Swab RT-PCR results were positive with Treshold Cycle of 16.7 and 19.3 for both the cases respectively. Mutations screening revealed the presence of K417N and L452 mutations for Case 1 and a single K417N mutation detected for Case 2. We obtained two full-length of SARS-CoV2 genome. Phylogenetic analysis showed that the two strains belonged to the BA.5.2.1 sublineage of Omicron. Serological analysis of Case 1 plasma collected 25 days after the onset of symptoms showed high levels of antibodies against SP and NC of ancestral and Omicron variants.