To Determine the Clinical Efficacy of COVID Vaccine in Post Vaccinated Individuals with Severe Pneumonia in Preventing ICU Mortality in a COVID Designated Tertiary Care Centre: A Retrospective Study

Abstract

Background: The "Severe Acute Respiratory Syndrome Coronavirus 2 disease has caused globally a challenging and threatening pandemic (COVID-19), with massive health and economic losses [1]. In India national vaccination campaigns kick started officially on January 16, 2021, and the vaccines were prioritized for frontline workers and susceptible groups. Individual vaccination can prevent or minimise a number of outcomes, including lab confirmed infection, symptomatic illness, infectivity rate, or a combination of these [2-3]. India had initially approved two vaccines under the trade name Covishield and Covaxin against COVID.
Aim: Demonstrate the efficacy of a single / two -dose schedule of COVID vaccine in the prevention of ICU mortality.
Methods: In this retrospective study, we included all COVID 19 confirmed patients who were admitted in covid designated ICU from March 15 to July 31 2021. Demographic, clinical, laboratory and radiological data were collected from all patients received in ICU. Primary outcome was to assess the mortality outcome in vaccinated COVID patients. Secondary outcome measured were to find an association between severity of the pneumonia and comorbidities, PaO2/Fio2 ratio, Neutrophil lymphocyte ratio, D dimer and CT severity score.
Results: 319 patients were enrolled in the study. 252 patients were not vaccinated.59 had received the first dose and 8 patients had received both the doses. The mortality among vaccinated patients were less compared to nonvaccinated and significant (p value 0.030). Mortality among single and double dose vaccinated patients couldn’t be made out because only 8 patients had received both the doses. Among the demographic profile, difference in age between vaccinated and unvaccinated was statistically significant. (64.39 ±11.916/ 54.18±14.124 p<.001. Among comorbidities hypertension, diabetes, obesity was associated with significant mortality. Admission saturation and mean PaO2/FiO2 ratio were high among vaccinated and significant. Neutrophil lymphocyte ratio, D dimer CT severity score were high among non vaccinated compared to vaccinated. There is no difference in mode of oxygen delivery in both vaccinated and non vaccinated patient. Days of ICU stayal was less among vaccinated.
Conclusion: Effectiveness of vaccine against SARS-CoV-2 infection after the first dose of immunisation is convincingly evident. However second dose of immunization should be continued to attain total protection.