An in-depth appraisal of clinico-biochemical and radiological findings of COVID-19 patients during the COVID-19 pandemic in a dedicated COVID Care Hospital in Eastern India and its outcome in relation to the COVAXIN vaccination status: A 2-year study.

Introduction: COVID-19 pandemic hit Odisha province from April 2020 to December 2020, then from April 2021 to August 2021 and from February 2022 to April 2022 as the first, second, and third waves, respectively, with the most severe form witnessed during the second wave. Kalinga Institute of Medical Sciences hospital in Odisha was declared a Dedicated COVID Hospital (DCH) during those three waves and witnessed 9485 cases of admissions among which there were 1214 deaths. COVAXIN vaccination of the vulnerable population was launched in February 2021 onwards. This study has been done to know the clinic-biochemical profiles, radiologic findings of COVID-19 admitted patients, the predictors of mortality in the second wave, and clinical outcomes in the three waves in relation to COVAXIN vaccination status.

Material And Methods: This was a serial three-round retrospective study from the electronic medical records using multistage random sampling where we collected and critically analyzed the demographic, and all the relevant possible health data of the cases that consist of 514 cases admitted in three waves. The data from death certificates among the 555 cases in the second wave have been analyzed to conclude predictors of mortality.

Results: Mortality increased with age, male gender, comorbidities, and raised C-reactive protein level. High NL ratio, extent of pulmonary involvement. There was a wide variation in incidence and spectrum of illness starting from 79% incidence of mild symptomatic in the initial and third wave, but remained in the range of 35-65% in the second wave, respectively, and the most noticeable symptomatic illness was that of the upper respiratory tract. In fulminant cases, the mode of presentations was severe pneumonia and acute respiratory distress syndrome. Males were more sufferers than females. Children had better outcomes compared to adults. COVID-associated coagulopathy had a normal platelet count. Subsequently, in 2021 year onwards vaccination of the vulnerable population was launched in a phased manner that changed the dynamics of the disease outcome by better survival chances despite intercurrent COVID infection by induction of herd immunity. On the contrary, there was a higher prevalence of serious illness among non-vaccinated individuals. While the cases continued during the second wave of the pandemic, long COVID became a clinical entity of symptomatic that persisted or recurred among the COVID illness recovered cases after reverse transcriptase polymerase chain reaction results for COVID-19 became negative. The symptoms consisted of fatigue, cough, dyspnea as pulmonary manifestations and extra-pulmonary involvement of the cardiac, renal, and central nervous systems and the pulmonary imaging features consisted of interstitial pneumonia, consolidation, cavity pattern, and prone to microbial infection. These events lead to morbidity and admission. Coinciding with the vaccination of all population of Odisha province with the first dose of the vaccine by around the period of the first quarter of 2022, there was a new variant named Omicron responsible in the third wave, in which the majority of the admitted cases had.mild upper respiratory illness. This was not as lethal as its predecessors due to its lower propensity to invade the lungs and blood vessels.

Conclusion: Immune dysregulation plays a central role in the pathogenesis of the manifestations. Vaccine-induced protection and the induction of herd immunity played a proactive role in the waning of the severity of clinical presentations.