The Effectiveness of SARS-CoV-2 Vaccination in Preventing Severe Illness and Death - Real-world Data from a Cohort of Patients Hospitalized with COVID-19.

Background: While long-term studies on the correlates of protection, vaccine effectiveness, and enhanced surveillance are awaited for SARS-CoV-2 vaccine, studies on breakthrough infections help understand the nature and course of this illness among vaccinated individuals and guide in public health preparedness. This study aims to compare the differences in the hospitalization outcomes SARS-CoV-2 infection of fully vaccinated individuals with with those of unvaccinated and partially vaccinated individuals. Materials and Methods: Single institution observational cohort study. This study compared the differences in clinical, biochemical parameters and the hospitalization outcomes of 53 fully vaccinated individuals with those of unvaccinated (1464) and partially vaccinated (231) individuals, among a cohort of 2,080 individuals hospitalized with SARS-CoV-2 infection. Descriptive statistics and propensity-score weighted multivariate logistic regression analysis adjusting for clinical and laboratory parameters were used to compare the differences and to identify factors associated with outcomes. Results: Completing the course of vaccination protected individuals from developing severe COVID-19 as evidenced by lower proportions of those with hypoxia, abnormal levels of inflammatory markers, requiring ventilatory support, and death compared to unvaccinated and partially vaccinated individuals. There were no differences in these outcomes among patients who received either vaccine type approved in India. Conclusions: Efforts should be made to improve the vaccination rates as a timely measure to prepare for the upcoming waves of this highly transmissible pandemic. Vaccination rates of the communities may also guide in the planning of the health needs and appropriate use of medical resources.

Silent Hypoxia in Coronavirus disease-2019: Is it more dangerous? -A retrospective cohort study.

Background: Hypoxia in patients with COVID-19 is one of the strongest predictors of mortality. Silent hypoxia is characterised by the presence of hypoxia without dyspnoea. Silent hypoxia has been shown to affect the outcome in previous studies. Methods: This was a retrospective study of a cohort of patients with SARS-CoV-2 infection who were hypoxic at presentation. Clinical, laboratory and treatment parameters in patients with silent hypoxia and dyspnoeic hypoxia were compared. Multivariate logistic regression models were fitted to identify the factors predicting mortality. Results: Among 2080 patients with COVID-19 admitted to our hospital, 811 patients were hypoxic with SpO2 <94% at the time of presentation. Among them, 174 (21.45%) did not have dyspnoea since the onset of COVID-19 symptoms. Further, 5.2% of patients were completely asymptomatic for COVID-19 and were found to be hypoxic only on pulse oximetry. The case fatality rate in patients with silent hypoxia was 45.4% as compared to 40.03% in dyspnoeic hypoxic patients (P = 0.202). The odds ratio of death was 1.1 (95% CI: 0.41-2.97) in the patients with silent hypoxia after adjusting for baseline characteristics, laboratory parameters, treatment and in-hospital complications, which did not reach statistical significance (P = 0.851). Conclusion: Silent hypoxia may be the only presenting feature of COVID-19. As the case fatality rate is comparable between silent and dyspnoeic hypoxia, it should be recognised early and treated as aggressively. Because home isolation is recommended in patients with COVID-19, it is essential to use pulse oximetry in the home setting to identify these patients.

Clinical features, demography, and predictors of outcomes of SARS-CoV-2 infection at a tertiary care hospital in India: A cohort study.

BACKGROUND: The "second wave" of the COVID-19 pandemic hit India from early April 2021 to June 2021. We describe the clinical features, treatment trends, and baseline laboratory parameters of a cohort of patients with SARS-CoV-2 infection and their association with the outcome. METHODS: This was a retrospective cohort study. Multivariate logistic regression models were fitted to identify clinical and biochemical predictors of developing hypoxia, deterioration during the hospital stay, and death. RESULTS: A total of 2080 patients were included. The case fatality rate was 19.5%. Among the survivors, the median duration of hospital stay was 8 (5-11) days. Out of 853 (42.3%%) of patients who had COVID-19 acute respiratory distress syndrome at presentation, 340 (39.9%) died. Patients aged >45 years had higher odds of death as compared to the 18-44 years age group. Vaccination reduced the odds of death by 40% (odds ratio [OR] [95% confidence interval [CI]]: 0.6 [0.4-0.9], P = 0.032). Patients with hyper inflammation at baseline as suggested by leukocytosis (OR [95% CI]: 2.1 [1.5-3.1], P < 0.001), raised d-dimer >500 mg/dL (OR [95% CI]: 3.2 [2.2-4.7], P < 0.001), and raised C-reactive peptide >0.5 mg/L (OR [95% CI]: 3.7 [2.2-13], P = 0.037) had higher odds of death. Patients who were admitted in the 2nd week had lower odds and those admitted in the 3rd week had higher odds of death. CONCLUSION: This study shows that vaccination status and early admission during the inflammatory phase can change the course of illness of these patients. Improving vaccination rates and early admission of patients with moderate and severe COVID-19 can improve the outcomes.