Co-infection of SARS-CoV-2 and influenza viruses: A systematic review and meta-analysis

Abstract

We conducted this meta-analysis to determine the proportion of co-infection with influenza viruses in SARS-CoV-2 positive patients and to investigate the severity of COVID-19 in these patients. We included studies with SARS-CoV-2 infection confirmed by qRT-PCR and influenza virus infection (A and/or B) by nucleic acid tests. The proportion of co-infection was compared between children and adults, and between critically ill or deceased patients compared to overall patients. Fifty-four articles were included. The overall proportion of co-infection was 0.7%, 95%CI = [0.4 – 1.3]. Most influenza co-infections were due to the influenza A virus (74.4%). The proportion of co-infection with influenza viruses among children (3.2%, 95% CI = [0.9 – 10.9]) was significantly higher than that in adult patients (0.3%, 95% CI = [0.1 – 1.2]), p-value <0.01. The proportion of co-infection with influenza viruses among critically ill patients tended to be higher than that in overall patients (2.2%, 95% CI = [0.3 – 22.4] versus 0.6%, 95% CI = [0.3 – 1.2], respectively, p-value = 0.22). Screening for pathogens in co-infection, particularly influenza viruses in patients infected with SARS-CoV-2, is necessary. This warrants close surveillance and investigation of the co-incidences and interactions of SARS-CoV-2 and other respiratory viruses, which is facilitated by the expansion of syndromic diagnosis approaches through the use of multiplex PCR assays.

The Host Response to Influenza A Virus Interferes with SARS-CoV-2 Replication during Coinfection

“…Several clinical studies have reported coinfection of SARS-CoV-2 with other viruses, including human immunodeficiency virus (HIV), hepatitis B and C viruses (HBV and HCV, respectively), influenza A and B viruses (IAV and IBV, respectively), and dengue virus (DENV) ( 13 – 19 ). In particular, coinfection with SARS-CoV-2 and IAV was common early in the COVID-19 pandemic, prior to the enforcement of masks and social distancing ( 17 , 20 ). A meta-analysis of published studies from the first 4 months of the pandemic showed viral coinfection with SARS-CoV-2 in 3% of hospitalized COVID-19 patients, with IAV being among the most common coinfecting viruses ( 21 ).…”

Disease of influenza virus and SARS‐CoV‐2 coinfection: Flurona or Flucovid?

“…This happens because the mean incubation and viral shedding times of influenza viruses (2 and 3 days, respectively) are much shorter than those of SARS-CoV-2 (6 and 17 days, respectively). 2 The proportion of coinfection with influenza virus and SARS-CoV-2 among children (3.2%) was remarkably higher than that in adult patients (0.3%), indicating that children are more susceptible to the coinfection. The proportion of coinfection with influenza viruses among critically ill COVID-19 patients (2.2%) was higher than that in overall patients (0.6%), suggesting that coinfection with influenza viruses may aggravate the severity of Indeed, animal studies have shown that simultaneous, or sequential, coinfection by influenza A virus (IAV) and SARS-CoV-2 resulted in more severe weight loss and lung inflammatory damage, as well as increased tissue cytokine/chemokine expression than infection by either IAV or SARS-CoV-2 alone.…”

“…Results from a meta‐analysis of 54 related publications indicated an overall proportion of coinfection with influenza viruses in SARS‐CoV‐2‐positive patients of 0.7%. 2 An over 18‐month period study with 17,011 adults with SARS‐CoV‐2 infection shows 1.3% of coinfection with influenza viruses. 3 However, the actual coinfection rate may be much higher in that some coinfected patients may have undetectable influenza virus at the time SARS‐CoV‐2 infection is diagnosed.…”

“…This happens because the mean incubation and viral shedding times of influenza viruses (2 and 3 days, respectively) are much shorter than those of SARS‐CoV‐2 (6 and 17 days, respectively). 2 …”

“…The proportion of coinfection with influenza viruses among critically ill COVID‐19 patients (2.2%) was higher than that in overall patients (0.6%), suggesting that coinfection with influenza viruses may aggravate the severity of COVID‐19. 2 …”