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BackgroundIndia experienced the second wave of the COVID-19 pandemic in March 2021, driven by the delta variant. Apprehensions around the usefulness of vaccines against delta variant posed a risk to the vaccination program. Therefore, we estimated the effectiveness of two doses of the ChAdOx1 nCoV-19 (Covishield) vaccine against COVID-19 infection among individuals [≥]45 years in Chennai, India. MethodsA community-based cohort study was conducted from May to September 2021 in a selected geographic area in Chennai, Tamil Nadu. The estimated sample size was 10,232. We enumerated individuals from all eligible households and periodically updated vaccination and COVID-19 infection data. We computed vaccine effectiveness with its 95% confidence interval for two doses of the Covishield vaccine against any COVID-19 infection. ResultsWe enrolled 69,435 individuals, of which 21,793 were above 45 years. Two dose coverage of Covishield in the 18+ and 45+ age group was 18% and 31%, respectively. The overall incidence of COVID-19 infection was 1099 per 100,000 population. The vaccine effectiveness against COVID-19 disease in the [≥]45 age group was 61.3% (95% CI: 43.6 - 73.4) at least two weeks after receiving the second dose of Covishield. Genomic analysis of 74 (28 with two doses, 15 with one dose, and 31 with zero dose) out of the 90 aliquots collected from the 303 COVID-19 positive individuals in the 45+ age group showed delta variants and their sub-lineages. ConclusionWe demonstrated the effectiveness of two doses of the ChAdOx1 vaccine against the delta variant in the general population of Chennai. We recommend similar future studies considering emerging variants and newer vaccines. Two-dose vaccine coverage could be ensured to protect against COVID-19 infection.
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INTRODUCTION: The yield of mycobacteria is shown to be very low in pleural effusions as it is a pauci-bacillary disease. The present study looked at the yield of mycobacterium tuberculosis (MTB) in terms of GeneXpert for acid fast bacilli (AFB) and culture using a medical thoracoscopy guided biopsy and analysed whether the yield increases in more complicated effusions. MATERIALS AND METHODS: This is a retrospective analysis of patients who underwent medical thoracoscopy for tubercular pleural effusions at our institute over the last 5-years. Patients who had no or minimal thin septations were considered as simple effusions and were subjected to semi-rigid thoracoscopy (n = 61). While patients who had multiple loculations and thick septations were considered as complicated effusions and were subjected to rigid thoracoscopy (n = 64). We considered granuloma on a biopsy as the standard for diagnosis of Tuberculosis (TB). Xpert MTB/RIF and The BACTEC MGIT was used for culture. RESULTS: Out 125 patients with granulomatous inflammation on biopsy, 56 (44.8%) were positive for either GeneXpert or culture for MTB. Only GeneXpert was positive in 43 and only culture was positive in 13. Amongst 61 patients with simple effusion, 14 had either GeneXpert for AFB or AFB culture being positive and 9 out of these patients had GeneXpert for MTB detected on biopsy sample. Only culture was positive in 5 patients. In complicated pleural effusion group either GeneXpert or culture for mycobacterium was positive in 42 (65.6%) out of 64 patients. Only GeneXpert was positive in 34 and culture alone was positive in 8 patients. CONCLUSION: The yield of MTB increases as the pleural effusion becomes more complicated. GeneXpert in a biopsy sample is a useful marker for MTB yield especially in a complicated effusion.
