Influenza Viral Infection is a High-Risk Factor for Developing Coronavirus Disease 2019 (COVID-19)

Abstract

Coronavirus disease 2019 (COVID-19) is caused by infection with the 2019 novel coronavirus 2 (2019-nCoV, now referred to as SARS-CoV-2). COVID-19 has become a global pandemic since its outbreak at the end of Dec 2019. COVID-19 could lead to severe acute respiratory disease, especially to those who have reduced immunity. Binding of the viral Spike protein (S) to its receptor ACE2 (Angiotensin Converting Enzyme 2) on the surface of target cells has been proven to be key for virus entry and infection. Although ACE2 expression in the respiratory system is necessary for pneumonia infection by SARS-CoV-2, the regulation of ACE2 gene expression remains poorly investigated, especially for patients that are in pre-pathological conditions. Here, by analyzing The Gene Expression Omnibus (GEO) database, we investigated the expression regulation of ACE2 in various kinds of primary epithelial cells from the respiratory system after influenza A or respiratory Syncytial Virus (RSV) infection. Our analyses reveal that infection of influenza A, RSV or influenza vaccines greatly increased ACE2 expression, suggesting that influenza viral infection could represent a high risk factor for developing COVID-19. We also found that the regulatory effect of influenza A virus on ACE2 expression is associated with activation of the interferon beta-induced pathway and viral RNA-activated host response. Together, our data provide a theoretical framework for clinical classification for SARS-CoV-2 infection susceptibility and could be used for future prevention and therapy treatment for COVID-19.

Impact of early phase COVID-19 precautionary behaviors on seasonal influenza in Hong Kong: A time-series modeling approach

“…Many studies warned that repeated COVID-19 outbreaks are expected to happen and the number of infections and deaths could become even worse during winter (1)(2)(3)(4)(5). Besides the relaxation of social distancing during winter holidays, seasonal influenza, which commonly circulates during wintertime, may facilitate the transmission and mortality of COVID-19 if both severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and influenza virus spread at the same time (6)(7)(8)(9). In fact, many places have seen surges in COVID-19 infections in 2020/2021 winter (10)(11)(12).…”