key: cord-0724703-500myn1l authors: Wu, Ping; Lu, Wanrong; He, Liang; Meng, Yifan; Wu, Peng; Ding, Wencheng; Ma, Ke; Liu, Jia title: COVID-19 Patients with Recent Influenza A/B Infection: A Retrospective Study date: 2020-05-28 journal: J Infect DOI: 10.1016/j.jinf.2020.05.050 sha: 4c3d46fbfcd77fc44a51834e66c64bacf5a641c0 doc_id: 724703 cord_uid: 500myn1l nan We read with the interest the recent paper by Chen et al. who described the clinical progression of 249 patients with coronavirus disease 2019 (COVID-19). 1 As the author mentioned, some factors, such as age and CD4 T cell counts, would be associated with intensive care units (ICU) admission. In addition, the application of host-directed therapy and early control of viral replication might be crucial for improving the prognosis of COVID-19. We are interested in investigating the potential risk factors associated with the progression and prognosis of COVID-19. To date, cases of severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2) and influenza A co-infection have been reported in COVID-19 patients. [2] [3] [4] We suspected that the recent infection with influenza among COVID-19 patients might affect disease prognosis and progression to some extent. The high specificity and the sensitivity of Immunoglobulin M (IgM) assays suggest that IgM is a reliable biomarker for the surveillance of recent influenza infection. 5, 6 Here, we reported that recent infection of influenza A/B and produce specific IgM in COVID-19 might be a common phenomenon, and influenza IgM status could be the significant factor associated with clinical outcomes and prognosis of COVID-19. 4.8%, 67/1386). The A IgM + / B IgM + group was not included as we identified no such cases. In Figure 1 , in terms of the clinical outcome, the mortality rates of the A IgM + / B IgMgroup and A IgM -/ B IgM + group were lower than that of the A IgM -/ B IgMgroup. Figure 1 also indicates that the A IgM -/B IgMgroup had the highest rate of severe cases among the three groups. Statistically significant differences existed across the different groups when considering mortality (P = 0.0008) and severe illness rates (P < 0.0001). To further explore the relationship between the influenza A/B IgM status and clinical outcome and illness severity among the COVID-19 patients, we established univariate analysis and multivariate analysis models (Table 1) . For the univariate analysis, we found that sex, age, and comorbidities were significant cofactors among mortality and severe illness. The A IgM + / B IgMgroup has showed lower risk of mortality (OR =0.514, 95%CI: 0.360-0.732) and severe illness (OR =0.511, 95% CI:0.408-0.640). For multivariate analysis, after adjustment for cofactors, patients in the A IgM + / B IgMgroup were less likely to die than patients in the A IgM -/ B IgMgroup (OR = 0.671, 95% CI: 0.463-0.973). However, the mortality rate of the A IgM -/ B IgM + group was not statistically different from that of the A IgM -/ B IgMgroup according to the adjusted model (OR = 0.903, 95% CI: 0.359-2.272). Furthermore, our analysis also indicated that a similar trend was also observed in severe/non-severe analysis. The A IgM + /B IgMgroup had a lower rate of severe illness than the A IgM -/B IgM -group (OR = 0.601, 95% CI: 0.476-0.760), whereas no such difference was found for the A IgM -/B IgM + group (OR = 0.968, 95% CI: 0.563-1.665). In the analysis, older age, male gender, and comorbidities were more prone to poor outcomes and progression, which were consistent with previous studies. 1, 9 Therefore, in the multivariate analysis, we adjusted these cofactors. We found that COVID-19 patients positive for influenza A IgM had a lower risk of mortality and severe illness compared with those showing negative A/B IgM status. However, these trends were not significant differences between A IgM -/ B IgM + group and A IgM -/ B IgMgroup. The reason for better prognosis and clinical outcome in influenza A IgM + COVID-19 patients is likely complicated, but could be due to potential interactions between influenza A and SARS-Cov-2, or because IgM + is a marker of patient functional immune status. However, the second hypothesis cannot fully explain why these protective effects were not observed among influenza B IgM + COVID-19 patients. Due to the suddenness of the COVID-19 pandemic outbreak, more studies are needed to confirm these findings. Clinical progression of patients with COVID-19 in Shanghai Co-infection with SARS-CoV-2 and influenza A virus Co-infection of Coronavirus Disease 2019 and Influenza A: A Report from Iran Co-infection with SARS-CoV-2 and Influenza A Virus in Patient with Pneumonia Early adaptive humoral immune responses and virus clearance in humans recently infected with pandemic 2009 H1N1 influenza virus Serum IgM antibody and influenza A infection Clinical features of patients infected with 2019 novel coronavirus in Wuhan Compassionate Use of Remdesivir for Patients with Severe Covid-19 Clinical characteristics of 140 patients infected with SARS-CoV-2 in Wuhan Abbreviations: A IgM, influenza A IgM; B IgM, influenza B IgM; OR, odds ratio; 95%CI, 95% confidence interval We would like to show our great respect to all the workers and volunteers in the fight against COVID-19, especially to the medical workers who work with the authors on the frontline. All authors have declared there is no competing interest exists. This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.