First and Second Waves of Covid-19: A Comparative Study of the Clinical Presentation and Outcome among Hospitalized Patients in Lagos Nigeria.

Objective: Nigeria experienced many waves of the COVID-19 pandemic. This study compared the clinical presentations and mortality among hospitalized patients during the first and second waves of the pandemic in Lagos State, Nigeria.

Methods: A retrospective cohort study was conducted. Deidentified medical records of laboratory-confirmed COVID-19 patients admitted into 15 isolation centers in Lagos, Nigeria between February 27, 2020, and September 30, 2020 (first wave) and October 1, 2020, and April 30, 2021 (second wave) were reviewed. IBM Statistics version 25 was used for data analysis.

Results: More patients were hospitalized during the first wave of the pandemic. The mean age of patients was higher during the second wave (54.5±15.8 years vs. 42.2±15.5 years, p <0.001). More patients admitted during the second wave had comorbidities (56.0% vs 28.6%, p <0.001), were symptomatic (90.8% vs 52.0%, p <0.001), had severe COVID-19 disease (58.9% vs 25%, p <0.001) and died (14.9% vs 6.4%, p<0.001) compared with the first wave. The odds of death increased with age and severity of COVID-19 disease during the first and second waves.

Conclusion: A higher proportion of the patients admitted in Lagos, Nigeria during the second wave were older, had comorbidities, and had severe COVID-19 disease than the first wave. Despite the fewer hospitalized patients, there were more deaths during the second wave.