Characterizing the third wave of COVID-19: An analysis from the National Clinical Registry of COVID-19.

Background & objectives: Data from the National Clinical Registry for COVID-19 (NCRC) were analyzed with an aim to describe the clinical characteristics, course and outcomes of patients hospitalized with COVID-19 in the third wave of the pandemic and compare them with patients admitted earlier. Methods: The NCRC, launched in September 2020, is a multicentre observational initiative, which provided the platform for the current investigation. Demographic, clinical, treatment and outcome data of hospitalized COVID-19 patients were captured in an electronic data portal from 38 hospitals across India. Patients enrolled during December 16, 2021 to January 17, 2022 were considered representative of the third wave of COVID-19 and compared with those registered during November 15 to December 15, 2021, representative of the tail end of the second wave. Results: Between November 15, 2021 and January 17, 2022, 3230 patients were recruited in NCRC. Patients admitted in the third wave were significantly younger than those admitted earlier (46.7±20.5 vs. 54.6±18 yr). The patients admitted in the third wave had a lower requirement of drugs including steroids, interleukin (IL)-6 inhibitors and remdesivir as well as lower oxygen supplementation and mechanical ventilation. They had improved hospital outcomes with significantly lower in-hospital mortality (11.2 vs. 15.1%). The outcomes were better among the fully vaccinated when compared to the unvaccinated or partially vaccinated. Interpretation & conclusions: The pattern of illness and outcomes were observed to be different in the third wave compared to the last wave. Hospitalized patients were younger with fewer comorbidities, decreased symptoms and improved outcomes, with fully vaccinated patients faring better than the unvaccinated and partially vaccinated ones.