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Different pattern of the second outbreak of COVID-19 in Marseille, France

Our take —

This study provides an overview of key differences among COVID-19 patients presenting at Institut Méditerranée Infection during the first wave (March 3 – April 27, 2020) and first part of the second wave (June 15 – August 15, 2020) of the pandemic in Marseille, France’s second largest city. Persons presenting at the facility were tested for SARS-CoV-2 using PCR irrespective of symptoms. Cases in the first period were more likely to be older. However, caution should be taken when interpreting these results, as demographic data analyzed included the peak of the first wave (early April) of COVID-19 in the country, while data analyzed for the second wave did not include its peak (which occurred after August) and thus, may not reflect the complete picture of COVID-19 cases detected in the entire second wave. In addition, while mortality rate was 1.1% for cases identified between March 3 and April 27, and 0.1% between June 15 and August 15, analysis of additional data showed mortality rate of 0.8% for the period June 15 to September 30. Continuous monitoring of regional trends and outcomes in COVID-19 cases is needed to inform prevention and control efforts, as well as planning for healthcare needs.

Study design

Retrospective Cohort

Study population and setting

The study compared differences among COVID-19 patients seen at Institut Méditerranée Infection, a university hospital dedicated to research in infectious and tropical diseases, during the first wave (March – April 2020) and second wave (June – August 2020) of the pandemic in Marseille, France. From early March, the hospital tested everyone presenting at its facility without regard to symptoms. COVID-19 treatment at both time periods included use of hydroxychloroquine and/or azithromycin.

Summary of Main Findings

From March 3 to April 27, 3737 COVID-19 cases were identified, while 768 cases were identified from June 15 to August 15. Cases identified from March 3 to April 27 were more likely to be older (45.3 years vs. 39.2 years), hospitalized (18% vs. 10.7%), and transferred to the ICU (1.8% vs. 0.9%). They were also less likely to be male (45.6% vs. 52.6%). There was no significant difference in prevalence of loss of taste or loss of smell between patients identified from March 3 to April 27, and those identified from June 15 to August 15. However, patients in the first wave had higher lymphocyte and platelet counts, fibrinogen and D-dimer levels than those in the second wave. Viral load was higher among patients in the second wave. The overall mortality rate was 1.1% for cases identified from March 3 to April 27. Overall mortality was 0.1% from June 15 to August 15. Additional data was collected up to September 30 for 3557 patients (of whom 33 died), raising the total mortality from June 15 to September 30 to 0.8%. However, demographic characteristics were not described for these additional patients.

Study Strengths

Individuals presenting to the facility underwent SARS-CoV-2 PCR testing regardless of symptomatology.

Limitations

While data analyzed included the peak of the first wave (early April 2020) of COVID-19 in the country, data analyzed on demographic and clinical factors for the second wave only captured the first part of the second wave (June – August), but did not include its peak (which occurred after August). No indication that analyses were adjusted for confounding.

Value added

Highlights key differences in demographic and clinical characteristics of COVID-19 patients at Institut Méditerranée Infection in Marseille, France, during the first wave and first part of the second wave of the COVID-19 pandemic in the country.

This review was posted on: 22 March 2021