Clinical outcomes in COVID-19 patients infected with different SARS-CoV-2 variants in Marseille, France

OBJECTIVES: To compare the clinical and epidemiological aspects associated with different predominant lineages circulating in Marseille from March 2020 to January 2021. METHODS: In this single-centre retrospective cohort study, characteristics of patients infected with four different severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants were documented from medical files. The outcome was the occurrence of clinical failure, defined as hospitalization (for outpatients), transfer to the intensive care unit (inpatients) and death (all). RESULTS: A total of 254 patients were infected with clade 20A (20AS), 85 with Marseille-1 (M1V), 190 with Marseille-4 (M4V) and 211 with N501Y (N501YV) variants. 20AS presented a bell-shaped epidemiological curve and nearly disappeared around May 2020. M1V reached a very weak peak, then disappeared after six weeks. M4V appeared in July presented an atypical wave form for 7 months. N501YV has only recently appeared. Compared with 20AS, patients infected with M1V were less likely to report dyspnoea (adjusted odds ratio (OR) 0.50, p 0.04), rhinitis (aOR 0.57, p 0.04) and to be hospitalized (aOR 0.22, p 0.002). Patients infected with M4V were more likely to report fever than those with 20AS and M1V (aOR 2.49, p < 0.0001 and aOR 2.30, p 0.007, respectively) and to be hospitalized than those with M1V (aOR 4.81, p 0.003). Patients infected with N501YV reported lower rate of rhinitis (aOR 0.50, p 0.001) and anosmia (aOR 0.57, p 0.02), compared with those infected with 20AS. A lower rate of hospitalization was associated with N501YV infection compared with 20AS and M4V (aOR 0.33, p < 0.0001 and aOR 0.27, p < 0.0001, respectively). CONCLUSIONS: The four lineages have presentations that differ from one another, epidemiologically and clinically. This supports SARS-CoV-2 genomic surveillance through next-generation sequencing.