Retrospective study of comparison of clinical severity and outcome of hospitalised COVID-19 patients during the first and second waves of the pandemic in India.

OBJECTIVES: To compare the clinical severity and outcome of hospitalised patients during the two waves of the COVID-19 pandemic in India. SETTING: A tertiary care referral hospital in South India. PARTICIPANTS: Symptomatic SARS CoV-2 reverse transcriptase PCR positive patients presenting to the emergency department during the two waves were recruited. The first wave spanned between April and December 2020 and the second wave between April and May 2021. PRIMARY AND SECONDARY OUTCOME MEASURES: The primary outcome of interest was mortality. Secondary outcomes included illness severity at presentation, need for oxygen therapy, non-invasive ventilation (NIV) and hospital or intensive care unit admission. RESULTS: The mean (SD) age of the 4971 hospitalised patients in the first wave was similar to the 2293 patients in the second wave (52.5±15.4 vs 52.1±15.1 years, p=0.37). When compared with the first wave, during the second wave, a higher proportion of patients presented with critical illness (11% vs 1.1%, p<0.001) and needed supplemental oxygen therapy (n=2092: 42.1% vs n=1459: 63.6%; p<0.001), NIV (n=643; 12.9% vs n=709; 30.9%; p<0.001) or inotropes/vasoactive drugs (n=108; 2.2% vs n=77: 3.4%; p=0.004). Mortality was higher during the second wave (19.2% vs 9.3%; p<0.001). On multivariable regression analysis, age >60 years (risk ratio, RR 2.80; 95% CI 2.12 to 3.70), D-dimer >1000 ng/mL (RR 1.34; 95% CI 1.15 to 1.55), treatment with supplemental oxygen (RR 14.6; 95% CI 8.98 to 23.6) and presentation during the second wave (RR 1.40; 95% CI 1.21 to 1.62) were independently associated with mortality. CONCLUSION: The second wave of the COVID-19 pandemic in India appeared to be associated with more severe presentation and higher mortality when compared with the first wave. Increasing age, elevated D-dimer levels and treatment with supplemental oxygen were independent predictors of mortality.

Impact of prior vaccination with CovishieldTM and Covaxin® on mortality among symptomatic COVID-19 patients during the second wave of the pandemic in South India during April and May 2021: a cohort study.

BACKGROUND: COVID-19 vaccines were authorised for emergency use to mitigate the impact of the pandemic. This study evaluated the effect of prior vaccination with either Oxford Astra Zeneca's Covishield™ or Bharath Biotech's Covaxin® on mortality among symptomatic COVID-19 patients during the second wave of the pandemic in India. METHODOLOGY: In this cohort study comprising of RT-PCR confirmed symptomatic COVID-19 patients presenting during April and May 2021, the effect of prior vaccination on mortality (primary outcome), need for hospitalization, oxygen therapy, non-invasive ventilation (NIV) and intensive care unit (ICU) admission were assessed and expressed as risk ratio (RR) with 95% confidence intervals (CI). RESULTS: The mean (SD) age of the cohort (n = 4183) was 46.3 (15.5) years; 17.9% (748/4183) had received at least one dose of Covishield™ and 4.8% (201/4183) had received Covaxin®. Mortality was 0.2% (95% CI: 0.2% - 0.7%), 3.5% (1.9-5.2%), 6.2% (0.3-12%) and 12.9% (11.8-14.1%) among fully vaccinated (>2 weeks after two doses), partially vaccinated (>2 weeks after one dose or <2 weeks after two doses), indeterminate (<2 weeks after one dose) and unvaccinated patients respectively. The difference in mortality among unvaccinated vs. fully vaccinated was 12.7% (95% CI: 11.4-13.9%), unvaccinated vs. partially vaccinated was 9.4% (7.4-11.4%) and unvaccinated vs. indeterminate vaccinated was 6.8% (0.8-12.7%). On adjusted analysis, as compared to unvaccinated patients, at least one dose of vaccine reduced the need for hospitalization (RR: 0.40; 95% CI: 0.35-0.47), oxygen (0.33; 0.27-0.40), NIV (0.23; 0.17-0.32), ICU admission (0.18; 0.12-0.27) and mortality (0.18; 0.11-0.29). CONCLUSION: Among symptomatic COVID-19 patients, prior vaccination with Covishield ™ or Covaxin® impacted the severity of illness and reduced mortality during a period of widespread delta variant circulation. Full vaccination conferred greater protection than partial vaccination.