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Context: SARS-CoV-2 virus causes COVID-19 by infecting nasal and oral cavities primarily by attaching its spike proteins to ACE 2 receptors expressed in epithelial cells. Aim: This study was done to evaluate the micronucleated cell count, metanuclear abnormalities, and genotoxic factor in exfoliated buccal mucosal cell among the COVID-19 suspected patients. Settings and Design: This cross-sectional study was conducted at AIIMS, Mangalagiri, between August and October 2022. Methods: One hundred COVID-19 suspected patients were recruited for this study after obtaining informed and written consent; buccal smear was obtained and stained for papanicolaou test (PAP). The PAP-stained slides were analyzed for micronuclei (MN), pyknotic, karyolytic, and karyorrhexic cell count, respectively. Based on their reverse transcription-polymerase chain reaction (RT-PCR) report, the patients were grouped into COVID-19 positive and negative groups. Statistical Analysis: The genotoxicity factor was calculated using the micronucleated cell count from both the groups using mean and standard deviation. Results: The MN, micronucleated cell, pyknotic, karyolitic, and karyorrhexic cell count in COVID-19 positive patients were 24.12, 15.24, 3.08, 2.88 and 4.40, respectively, than COVID-19 negative patients 5.69, 8.17, 1.08, 1.00 and 2.43, respectively. The genotoxicity factor for SARS-CoV-2 was 2.68 which is a positive genotoxic effect on buccal mucosal cells. Conclusion: SARS-CoV-2 increases the expression of micronucleated cells, pyknotic cells, karyolytic cells, and karyorhexic cells and concludes SARS-CoV-2 is having cytogenotoxic effect on the buccal mucosal cells. This can be used as a reliable marker in identifying the early carcinogenic effects of virus causing COVID-19. [ABSTRACT FROM AUTHOR]

COVID-19 pandemic has been a global health emergency due to its association with severe pneumonia and high rate of mortality. In the current study, we reported the direct evidence for the variable level of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus infection on several types of oral epithelial cells isolated from the aspirated oropharyngeal and bronchoalveolar secretions of severely infected and intubated patients using cytology, confocal based immunofluorescence imaging (IF), scanning electron microscope (SEM) and transmission electron microscopic (TEM) studies. Cytological analysis showed the presence of keratinised and non-keratinised oral epithelial cells with viral inclusion bodies in stratum granulosum and intermedium cells. IF imaging using SARS-CoV-2 spike protein specific antibody confirmed the presence of virus inside the stratum spinosum/granulosum (keratinised) and stratum intermedium/superficial cells (non-keratinised). No SARS-CoV-2 viruses were seen in stratum corneum cells. SEM analysis also confirms the absence of virus like structure on stratum corneum surface while viruses like structure were seen on the stratum spinosum/granulosum/stratum/intermedium and stratum superficial cells. This advanced microscopic study confirms directly that the virus tends to infect and multiply in the metabolically active or sub-basal cells of oral epithelium and absent in the inactive keratinised stratum corneum from shedding zones of oral mucosa. [ABSTRACT FROM AUTHOR]