Bacterial co-infection and secondary infection in patients with COVID-19: a living rapid review and meta-analysis

Clin Microbiol Infect. 2020 Dec;26(12):1622-1629. doi: 10.1016/j.cmi.2020.07.016. Epub 2020 Jul 22.


Background: Bacterial co-pathogens are commonly identified in viral respiratory infections and are important causes of morbidity and mortality. The prevalence of bacterial infection in patients infected with SARS-CoV-2 is not well understood.

Aims: To determine the prevalence of bacterial co-infection (at presentation) and secondary infection (after presentation) in patients with COVID-19.

Sources: We performed a systematic search of MEDLINE, OVID Epub and EMBASE databases for English language literature from 2019 to April 16, 2020. Studies were included if they (a) evaluated patients with confirmed COVID-19 and (b) reported the prevalence of acute bacterial infection.

Content: Data were extracted by a single reviewer and cross-checked by a second reviewer. The main outcome was the proportion of COVID-19 patients with an acute bacterial infection. Any bacteria detected from non-respiratory-tract or non-bloodstream sources were excluded. Of 1308 studies screened, 24 were eligible and included in the rapid review representing 3338 patients with COVID-19 evaluated for acute bacterial infection. In the meta-analysis, bacterial co-infection (estimated on presentation) was identified in 3.5% of patients (95%CI 0.4-6.7%) and secondary bacterial infection in 14.3% of patients (95%CI 9.6-18.9%). The overall proportion of COVID-19 patients with bacterial infection was 6.9% (95%CI 4.3-9.5%). Bacterial infection was more common in critically ill patients (8.1%, 95%CI 2.3-13.8%). The majority of patients with COVID-19 received antibiotics (71.9%, 95%CI 56.1 to 87.7%).

Implications: Bacterial co-infection is relatively infrequent in hospitalized patients with COVID-19. The majority of these patients may not require empirical antibacterial treatment.

Keywords: Bacterial infections; COVID-19; Co-infection; Living review; Secondary infection.

Publication types

  • Meta-Analysis
  • Systematic Review

MeSH terms

  • Asia / epidemiology
  • Bacteria / classification
  • Bacteria / isolation & purification
  • Bacteria / pathogenicity
  • Bacterial Infections / epidemiology*
  • Bacterial Infections / microbiology
  • COVID-19 / complications*
  • COVID-19 / microbiology*
  • Coinfection / epidemiology*
  • Coinfection / microbiology
  • Coinfection / virology
  • Critical Illness / epidemiology
  • Data Management
  • Female
  • Humans
  • Male
  • Pandemics
  • Prevalence
  • Respiratory Tract Infections
  • United States / epidemiology