Associated factors of respiratory co-infection of COVID-19 and the impact of co-infection on SARS-CoV-2 viral load

Introduction: Emerging evidence indicates that severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infected individuals are at an increased risk for co-infections. This retrospective study aims to expand the knowledge of associated factors of respiratory co-infection in SARS-CoV-2 positivity. Methodology: A retrospective study was conducted to recruit fifty-five patients with laboratory-confirmed SARS-CoV-2 positivity. We additionally tested 29 other respiratory pathogens using RT-PCR assay for the same specimens tested for laboratory-confirmed SARS-CoV-2. Both univariate and multivariate analysis were performed to identify independent factors for co-infection. Cox regression was conducted to detect the association between co-infection and viral load after controlling other related factors. Results: Among all the fifty-five COVID-19 patients, the rate of co-infection with at least one other respiratory pathogen was 76.4% (42/55). The rate of bacterial co-infections was 83.3% (35/42), among which Streptococcus pneumonia was the most common co-infection. Over 70% of neutrophils proportion (OR: 4.563; 95% CI: 1.116-18.648) was an independently associated factor for bacterial co-infection, whereas fever (OR: 4.506; 95% CI: 1.044-19.441) and chest tightness (OR: 0.106; 95% CI: 0.015-0.743) for viral co-infection. The strongest promotion of SARS-CoV-2 viral decreasing load was detected from co-infection of only viruses (HR: 4.039; 95% CI: 1.238-13.177), and the weakest was found from co-infection of only bacteria (HR: 2.909; 95% CI: 1.308-6.472). Conclusions: Various co-infections variously promote SARS-CoV-2 viral decreasing load. Timely identification of co-infections aggressively contributes to COVID-19 patient management.