Objectives: The Omicron variant–mediated COVID-19 wave is responsible for a global tsunami of cases. There is scarce data about the clinical and epidemiological characteristic analyses of the third wave. We present the data of COVID-19 patients from Mumbai region during the early third wave by taking S-gene target failure (SGTF) as a proxy for probable Omicron cases. Methods: We collected retrospective data of RT-PCR-confirmed (COVID-19) patients, and measured the proportion of possible Omicron cases by SGTF. We segregated and analyzed the clinical and lab data of patients with outcomes such as differing symptoms, vaccination coverage, previous infection, and travel history. We also performed a trend analysis of Mumbai’s COVID-19 data before and during the third wave. Results: All patients had mild clinical symptoms while few were asymptomatic. Myalgia was more significantly present in SGTF/Omicron cases compared to non-SGTF/Delta patients. Out of the total 101 COVID-positive individuals, 94 individuals (93%) had taken two doses of COVID vaccine. Among these 94 individuals, 9 (8.9%) had been previously infected with COVID 19 in the first or second waves. 77.7% of the previously infected were now infected with Omicron variant and only 22.3% by a non-Omicron variant. Conclusion: Rapid rise and fall during the third wave in Mumbai was due to Omicron cases gradually replacing Delta. The overall milder clinical spectrum in both Omicron and Delta cases imply that vaccines might not be effective against re-infection but can attenuate disease severity and mortality, as evident by high coverage of vaccination in the country.

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Optical coherence tomography (OCT) is an evolving medical imaging technology that offers in vivo cross-sectional, sub-surface images in real-time. OCT has become popular in the medical as well as non-medical fields. The technique extensively uses for food industry, dentistry, dermatology, and ophthalmology. The technique is non-invasive and works on the Michelson interferometry principle, i.e., dependent on back reflections of the signal and its interference. The objective is to develop an algorithm for signal processing to construct an OCT image and then to enhance the quality of the image using image processing techniques like filtering. The image construction was primarily based on the Fourier transform (FT) of the dataset obtained by data acquisition. This FT could be performed rapidly with the extensively used algorithm of fast Fourier transform (FFT). The depth-wise information could be extracted from each A-scan, i.e., axial scan and also the B-scan was obtained from the A-scan to see the structure of sample. The maximum penetration depth achieved with proposed system was 2.82mm for 1024 data points. First and second layer of leaf were getting at thickness of 1mm and 1.6mm, respectively. A-scans for Human fingertip gave its first, second and third layer was at a thickness of 0.75mm, 0.9mm and 1.6mm, respectively. A-scans for foam sheet gave its first, second and third layer was at a thickness of 0.6mm, 0.75mm, and 0.85mm, respectively.

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