Clinical Comparison of COVID Waves 2–5. An Inpatient Retrospective Comparative Analysis From Karachi, Pakistan

Category	Detail
Condition	COVID-19 infection caused by SARS-CoV-2
Key Mechanisms	SARS-CoV-2 binds to ACE2 receptors in various organs; different variants (Beta, B.1.1.7, Delta, Omicron) influence disease severity and outcomes
Target Population	Adult inpatients (>16 years) with PCR-confirmed COVID-19 admitted to a specialized infectious diseases hospital in Karachi, Pakistan
Care Setting	Inpatient hospital setting at Sindh Infectious Diseases Hospital & Research Center

Wave 2 had the highest discharge rate (81%) and lowest mortality (18.9%) among waves 2 to 5.
Wave 4 (Delta variant) showed the highest disease severity with predominant severe COVID on admission (79.4%), highest intubation (27.1%), septic shock (24.3%), disease progression (50.8%), and mortality (42.5%).
Wave 5 (Omicron variant) involved mostly elderly patients with mild disease (22.4%), high comorbidity prevalence (84.6%), and increased acute kidney injury (29.2%).

Implement supportive care tailored to disease severity, including oxygen therapy and mechanical ventilation as needed.
Monitor and manage complications such as cytokine release syndrome, septic shock, and acute kidney injury.
Vaccination rollout is critical to reduce severity and mortality.

Monitor for disease progression, especially in severe cases (notably in wave 4).
Regularly assess for organ dysfunction including respiratory failure and acute kidney injury.
Track clinical parameters to identify cytokine release syndrome.

Advanced age and presence of comorbidities increase risk of severe disease and complications.
Emergence of more virulent variants (e.g., Delta) correlates with higher mortality and severity.
Delayed or inadequate treatment may worsen outcomes.

Adult hospitalized COVID-19 patients in Karachi during waves 2 to 5

Mortality and severity varied by wave and variant; vaccination and emerging therapies contributed to improved survival post-wave 2.

Early identification and classification of disease severity on admission to optimize resource allocation.
Close monitoring for cytokine release syndrome and septic shock, especially during waves with higher severity.
Prioritize vaccination to reduce disease severity and mortality.
Adapt clinical management protocols according to predominant circulating variant and observed clinical patterns.

Clinical Scorecard: Comparative Clinical Analysis of COVID-19 Waves 2 to 5: A Retrospective Study of Inpatient Data from Karachi, Pakistan