A comparative analysis of the second and third wave of the Covid-19 pandemic: an experience from a tertiary care hospital in Western India

• Published in: Journal of medical microbiology Vol. 72; no. 5
• Main Authors: Swami, Anjali, Mohanty, Ankita, Jamwal, Ashima, Turbadkar, Dilip, Baveja, Sujata, Shastri, Jayanthi, Chitalia, Vidushi
• Format: Journal Article
• Language: English
• Published: England 01.05.2023
• Subjects: COVID-19 - epidemiology; Humans; India - epidemiology; Pandemics; Retrospective Studies; SARS-CoV-2 - genetics; Tertiary Care Centers; India; diagnosis; surveillance; variants; Covid-19; pandemic
• ISSN: 0022-2615; 1473-5644
• DOI: 10.1099/jmm.0.001685

As the world was still recovering from the 2020 pandemic, the devastating impact of Covid-19 driven by the Delta variant shook the world in 2021. As the second wave was declining, there was an unusual surge in Covid-19 positive cases by the end of 2021 which led to global concern about the change in virus characteristics. Whole genome sequencing is critical for understanding a rapidly progressing pandemic. . To provide an insight into the major differences encountered in the changing characteristics between the second and third waves of the pandemic at a tertiary care hospital in India. A retrospective observational cohort analysis was conducted on Covid-positive patients during the second wave of the Covid-19 pandemic (from March 2021 to April 2021) and the third wave of the Covid-19 pandemic (from December 2021 to January 2022). Out of 303 Covid-19 positive cases, 52 samples were tested by whole genome sequencing during the second wave and 108 during the third wave. A decline of 18.5 % was observed in the case fatality rate from the second wave to the third wave. There was a 5 % decline in the number of patients admitted with ARDS and a 16.3 % decline in the number of patients with co-morbidities.In total, 51.9 percent of cases were due to the Delta variant during the second wave and 95 percent due to the Omicron variant during the third wave. We found that 36.5 % of Covid-positive patients during the second wave had been vaccinated compared to 40 % in the third wave. Whole genome sequencing of clinical samples from a wide range of individuals during a viral epidemic will enable us to develop a more rapid public health response to new variants and identify the required vaccine modifications more quickly.