key: cord-0805477-mor77puj
authors: Faury, Hélène; Courboulès, Camille; Payen, Mathilde; Jary, Aude; Hausfater, Pierre; Luyt, CharlesEdouard; Dres, Martin; Pourcher, Valérie; Abdi, Basma; Wirden, Marc; Calvez, Vincent; Marcelin, Anne-Geneviève; Boutolleau, David; Burrel, Sonia
title: Medical Features of COVID-19 and Influenza Infection: A Comparative Study in Paris, France
date: 2020-08-14
journal: Journal of Infection
DOI: 10.1016/j.jinf.2020.08.017
sha: b84ccc72ec1f96c19b9f7627ae6e415d996eaa1b
doc_id: 805477
cord_uid: mor77puj

• COVID-19 and influenza patients share overweight as a risk factor for severe infection; • Higher death rate was reported in COVID-19 group than in influenza group; • COVID-19 patients developed preferentially secondary respiratory failure; • Older age and diabetes were confirmed as major contributing death risk factors in COVID-19.

-COVID-19 and influenza patients share overweight as a risk factor for severe infection -Higher death rate was reported in COVID-19 group than in influenza group -COVID-19 patients developed preferentially secondary respiratory failure -Older age and diabetes were confirmed as major contributing death risk factors in COVID-19

Medical Features of COVID-19 and Influenza Infection: We would like to share our findings for SARS-CoV-2 and influenza virus infections as virus co-circulation is likely to occur in future 2 . It is important to facilitate differential diagnosis. We therefore conducted a retrospective study to further explore specific features and to better characterize risk factors for severe illness.

This retrospective study included 200 inpatients from the Pitié-Salpêtrière University Hospital (Paris, France) with SARS-CoV-2 (n=100, 'COVID-19 group') or influenza (n=100, 'influenza group') laboratory-confirmed infections on respiratory specimens between January 1 st -March 25 th , 2020.

Patients with complete baseline clinical and biological available data were consecutively included. The study was approved by the Comité Ethique de la Recherche of Sorbonne University (approval number CER 2020-44). Demographic, biological, treatment, and clinical outcome data were extracted from medical records using a standardized form. We collected date of symptom onset, comorbidities, radiographic findings upon admission, and relevant data concerning hospital courses (overall duration of stay, and transfer in intensive care unit [ICU] and supportive care ward). Clinical outcomes were monitored up to April 11 th , final date of follow-up.

Overweight/obesity was defined as body mass index (BMI) >25kg/m 2 .

Variables are presented as 'median' (interquartile ranges; IQR) or 'number of' (%). We used the with diabetes, hypertension, and overweight/obesity as most common comorbidities. However, influenza patients were more likely to have chronic pulmonary diseases (p=0.01).

Overweight/obesity rate (p=0.02) and median BMI (p=0.04) were significantly higher in COVID-19. At the time of diagnosis, the most frequent symptoms were fever (p=0.63) and cough (p=1.00) in both groups. COVID-19 patients complained more significantly about fatigue, faintness, diarrhea, and anosmia/ageusia. Conversely, sputum production (p=0.0001) and nasal congestion (p=0.02) were reported most frequently in influenza. The frequency of patients presenting with respiratory failure were similar in both groups (around 10.0%). However, secondary respiratory failure were only observed in COVID-19 (21%; p<0.0001). COVID-19 patients experienced more often acute kidney failure (p=0.048) and pulmonary embolism (p=0.03). Heart congestion was more frequent in influenza (p=0.003). Notably, ground-glass opacities showed a trend towards higher frequency in COVID-19 patients, although not statistically significant (p=0.06). Conversely, pulmonary nodules were much more observed in influenza (p=0.001). Influenza patients had statistically higher levels of white blood cells, neutrophils, platelets, sodium, troponin, albumin than COVID-19 patients (Table 1 ). Both groups exhibited lymphocytopenia (around 80% of patients) (data not shown), however no significant median value difference was observed.

The median time from illness onset to admission was 4 [1-6] and 2 [0-4] days for COVID-19 and influenza, respectively (p=0.02, Figure 1 ). COVID-19 patients more frequently required hospitalization (p=0.001) (data not shown). Noteworthy, the median duration of overall hospital stay was significantly longer for COVID-19 than for influenza (10 [4-17] and 4 [1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] days, respectively, p<0.0001). Overall, COVID-19 patients more frequently required oxygen therapy (p=0.002) ( Table 1 ). The median duration between onset of symptoms and aggravation was 7 (5-10) and 4 (2.5-6) days in COVID-19 and influenza groups, respectively (p<0.0001) (data not shown). Clinical worsening was linked to a higher ICU rate admission among COVID patients Table 6 ).

To the best of our knowledge, this study is the largest case series to date comparing COVID-19 and influenza. COVID-19 patients more frequently reported dry cough, asthenia, diarrhea, anosmia/ageusia, and clinical worsening around 7 days after symptom onset, as previously described [3] [4] [5] [6] . As previously reported, radiologic findings showed that ground-glass opacity was more common in COVID-19 3 , however it could be also observed during influenza 5,6 . We reported more severe cases requiring oxygenation therapy, a higher death rate, and a longer hospital stay in COVID-19 group. Moreover, COVID-19 patients also experienced disease aggravation around 7 days post-symptom onset, as previously reported 3, 6 . Both infection may evolve to respiratory failure 3,5,6 , however, COVID-19 patients developed preferentially secondary respiratory failure.

Interestingly, inflammation marker levels were significantly higher in severe COVID-19 cases. It is well established that SARS-CoV-2 triggers an excessive harmful proinflammatory response 7 promoting thrombotic events as pulmonary embolism 8 . In our study, pulmonary embolism was only reported during COVID-19 (p=0.03). COVID-19 and influenza patients commonly share overweight/obesity as risk factor for severe infection 9 . As previously reported, pre-existing hypertension and diabetes were additionally associated with a higher risk to develop severe COVID-19. Similarly, our study also confirmed older age and diabetes as major contributing death risk factors in COVID-19 3, 10 . To conclude, we described similarities but also differences between COVID-19 and influenza, thereby providing some guidance for healthcare management.

HF and MP had the idea for and designed the study. HF, MP, CC, and SB and had full access to the collected data and take responsibility for the integrity of the data and the accuracy of the data analysis. PH, CEL, MD, and VP assessed the accuracy of clinical data. HF, CC, and AJ processed statistical data. HF, CC, MP, DB, and SB drafted the paper. All authors critically revised the manuscript for intellectual content and gave final approval for the submitted version.

We acknowledge all healthcare workers involved in the diagnosis and treatment of patients.

None.

We declare no competing interests. 

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