Clinical characteristics and outcome of influenza virus infection among adults hospitalized with severe COVID-19: a retrospective cohort study from Wuhan, China

Abstract

Background Coronavirus disease 2019 (COVID-19) is an emerging infectious disease that rapidly spreads worldwide and co-infection of COVID-19 and influenza may occur in some cases. We aimed to describe clinical features and outcomes of severe COVID-19 patients with co-infection of influenza virus. Methods Retrospective cohort study was performed and a total of 140 patients with severe COVID-19 were enrolled in designated wards of Sino-French New City Branch of Tongji Hospital between Feb 8th and March 15th in Wuhan city, Hubei province, China. The demographic, clinical features, laboratory indices, treatment and outcomes of these patients were collected. Results Of 140 severe COVID-19 hospitalized patients, including 73 patients (52.14%) with median age 62 years were influenza virus IgM-positive and 67 patients (47.86%) with median age 66 years were influenza virus IgM-negative. 76 (54.4%) of severe COVID-19 patients were males. Chronic comorbidities consisting mainly of hypertension (45.3%), diabetes (15.8%), chronic respiratory disease (7.2%), cardiovascular disease (5.8%), malignancy (4.3%) and chronic kidney disease (2.2%). Clinical features, including fever (≥38 °C), chill, cough, chest pain, dyspnea, diarrhea and fatigue or myalgia were collected. Fatigue or myalgia was less found in COVID-19 patients with IgM-positive (33.3% vs 50/7%, P = 0.0375). Higher proportion of prolonged activated partial thromboplastin time (APTT) > 42 s was observed in COVID-19 patients with influenza virus IgM-negative (43.8% vs 23.6%, P = 0.0127). Severe COVID-19 Patients with influenza virus IgM positive have a higher cumulative survivor rate than that of patients with influenza virus IgM negative (Log-rank P = 0.0308). Considering age is a potential confounding variable, difference in age was adjusted between different influenza virus IgM status groups, the HR was 0.29 (95% CI, 0.081–1.100). Similarly, difference in gender was adjusted as above, the HR was 0.262 (95% CI, 0.072–0.952) in the COX regression model. Conclusions Influenza virus IgM positive may be associated with decreasing in-hospital death.

The role of respiratory co-infection with influenza or respiratory syncytial virus in the clinical severity of COVID-19 patients: A systematic review and meta-analysis

“…After excluding low-quality studies, a similar meta-estimate was observed (Figure S2, panel B in the Online Supplementary Document ). Results from two high-quality studies [ 19 , 25 ] using multivariable models were consistent with our meta-estimates although another high-quality study [ 17 ] showed no significant difference in receiving mechanical ventilation between the two groups.…”

“…The total number of SARS-CoV-2 patients co-infected with influenza/RSV and mono-infected patients per study ranged from 22 to 4501. Nine studies were mainly conducted in Asia, six of which were from China [ 16 , 17 , 21 - 23 , 25 ]. For viral detection method, SARS-CoV-2 was detected using PCR for all studies whereas influenza and / or RSV co-infection was confirmed by PCR, serological testing, or antigen assays.…”

“…The quality assessment of included studies is provided in Table S1 in the Online Supplementary Document . Four studies [ 16 , 17 , 19 , 25 ] were assessed as high-quality and they used multivariate statistical methods to account for common confounders such as age, sex, and comorbidities. The basic characteristics of the included studies are available in Table 1 .…”

“…Six studies [ 17 , 19 , 22 , 24 , 25 , 27 ] reported mechanical ventilation as an outcome (all but one [ 27 ] on influenza and two studies [ 22 , 27 ] on RSV co-infection).…”

The importance of influenza vaccination during the COVID‐19 pandemic

“… 10 Of the few reports, some suggest no difference in the clinical course of dually infected patients compared with those infected with SARS‐CoV‐2 alone; however, both improved and worse outcomes have been reported. 11 , 12 , 13 , 14 From a clinical and public health perspective, the burden on healthcare systems due to epidemics of either virus alone, let alone overlapping epidemics, remains a credible threat. Thus, without intervention, the potential of a ‘syndemic’—a term coined to describe twin synergistic epidemics—due to the cocirculation of influenza and COVID‐19 is a serious reality, especially as public health and social measures are relaxed.…”