Co-Infections in People with COVID-19: A Systematic Review and Meta-Analysis

Abstract

Background: In previous influenza pandemics, bacterial co-infections have been a major cause of mortality. The significance of co-infecting pathogens in COVID-19 is unknown. Methods: We systematically searched for studies of any design which reported numeric data on co-infections in patients with confirmed COVID-19 published from 1 January 2020 to 17 April 2020. The main outcome was the proportion of patients who had a bacterial, fungal or viral co-infection. We included patients of all ages, in all settings. Pooled estimates were derived using random effects meta-analysis where appropriate. The protocol is registered on PROSPERO (CRD4202040178398). Findings: Our search retrieved 1188 records with 30 eligible for inclusion. From 18 studies, the pooled proportion of hospitalised COVID-19 patients with a bacterial co-infection was 7% (95% CI 3-12%, n=2183, I2 =92∙2%). Subgroup analysis indicated a higher proportion of ICU patients with bacterial co-infections than patients in mixed ward/ICU settings (14%, 95% CI 5-26, I2 =74∙7% versus 4%, 95% CI 1-9, I2 = 91∙7%). The commonest bacteria were Mycoplasma pneumonia, Pseudomonas aeruginosa and Haemophilus influenzae. The pooled proportion with a viral co-infection was 3% (95% CI 1-6, n=1014, 16 studies, I2 =62∙3%), with Respiratory Syncytial Virus and influenza A the commonest. Ascertainment of outcomes was a potential cause of bias in most studies as many patients remained hospitalised at censor date. Interpretation: A low proportion of patients with COVID-19 have a bacterial co-infection; much less than in previous influenza pandemics. These findings do not support the routine use of antibiotics in the management of confirmed COVID-19 infection. Funding Statement: LL and VB are funded by the National Institute for Health Research (NIHR) Nottingham Biomedical Research Centre, UK. Declaration of Interests: LL, BL and VB declare no competing interests. WSL’s institution has received unrestricted investigated-initiated research funding from Pfizer for an unrelated pneumonia cohort study in which he is the Chief Investigator.