Antibiotic Use, Bacterial Co-Infection, and Antimicrobial Resistance in Adults Hospitalized with COVID-19, Influenza, or RSV: A Systematic Review and Meta-Analysis.

BACKGROUND

Adults hospitalized with COVID-19, influenza A/B, or respiratory syncytial virus (RSV) frequently receive empirical antibiotics, but antibiotic prescribing, confirmed bacterial co-infection, antimicrobial resistance (AMR), and outcomes have not been jointly synthesized across these infections.

METHODS

We conducted a PRISMA 2020 systematic review and meta-analysis of 39 studies including 839,531 hospitalized adults. Random-effects models with Freeman-Tukey double-arcsine transformation pooled prevalence estimates; sensitivity and publication-bias analyses were performed where appropriate.

RESULTS

Pooled antibiotic use was 62.56% (95% CI, 53.75-70.97%) for COVID-19, 57.48% (25.76-86.09%) for influenza A/B, and 76.03% (67.62-83.53%) for RSV, with very high heterogeneity. Confirmed bacterial co-infection was lower: 5.31% (3.43-7.56%), 18.66% (9.98-29.30%), and 24.36% (18.53-30.70%), respectively. Prescribing-to-confirmed infection ratios ranged from 3.0 to 46.2. AMR evidence was restricted to COVID-19 studies and was dominated by carbapenem-resistant Gram-negative organisms, mainly in secondary, ICU-associated, or healthcare-associated infections. Confirmed bacterial complications were associated with ICU admission, longer hospitalization, and higher mortality.

CONCLUSIONS

Antibiotic prescribing exceeded confirmed bacterial infection across all viral groups, but estimates require cautious interpretation due to heterogeneity, diagnostic uncertainty, observational evidence, and the absence of low-risk-of-bias studies. The evidence base was dominated by COVID-19 cohorts, while influenza A/B and RSV data, especially virus-specific AMR evidence, remain limited. COVID-19-specific AMR findings should not be generalized to influenza A/B or RSV. Virus-specific stewardship should prioritize rapid diagnostics, systematic sampling, reassessment, and de-escalation when bacterial infection is not confirmed.