Influenza co-infection associated with severity and mortality in COVID-19 patients

Virol J. 2021 Jun 14;18(1):127. doi: 10.1186/s12985-021-01594-0.

Abstract

Background: In COVID-19 patients, undetected co-infections may have severe clinical implications associated with increased hospitalization, varied treatment approaches and mortality. Therefore, we investigated the implications of viral and bacterial co-infection in COVID-19 clinical outcomes.

Methods: Nasopharyngeal samples were obtained from 48 COVID-19 patients (29% ICU and 71% non-ICU) and screened for the presence of 24 respiratory pathogens using six multiplex PCR panels.

Results: We found evidence of co-infection in 34 COVID-19 patients (71%). Influenza A H1N1 (n = 17), Chlamydia pneumoniae (n = 13) and human adenovirus (n = 10) were the most commonly detected pathogens. Viral co-infection was associated with increased ICU admission (r = 0.1) and higher mortality (OR 1.78, CI = 0.38-8.28) compared to bacterial co-infections (OR 0.44, CI = 0.08-2.45). Two thirds of COVID-19 critically ill patients who died, had a co-infection; and Influenza A H1N1 was the only pathogen for which a direct relationship with mortality was seen (r = 0.2).

Conclusions: Our study highlights the importance of screening for co-infecting viruses in COVID-19 patients, that could be the leading cause of disease severity and death. Given the high prevalence of Influenza co-infection in our study, increased coverage of flu vaccination is encouraged to mitigate the transmission of influenza virus during the on-going COVID-19 pandemic and reduce the risk of severe outcome and mortality.

Keywords: COVID-19; Co-infection; Influenza A H1N1; Mortality; SARS-CoV-2.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Bacterial Infections / epidemiology
  • Bacterial Infections / mortality
  • Bacterial Infections / pathology
  • COVID-19 / epidemiology
  • COVID-19 / mortality*
  • COVID-19 / pathology
  • Coinfection / epidemiology
  • Coinfection / mortality*
  • Coinfection / pathology
  • Female
  • Hospitalization
  • Humans
  • Influenza A Virus, H1N1 Subtype / isolation & purification
  • Influenza, Human / epidemiology
  • Influenza, Human / mortality*
  • Influenza, Human / pathology
  • Intensive Care Units
  • Male
  • Middle Aged
  • Nasopharynx / microbiology
  • Nasopharynx / virology
  • Prevalence
  • SARS-CoV-2 / isolation & purification
  • Saudi Arabia / epidemiology