Systematic review of post-acute sequelae (≥4 weeks) in adults following non-COVID respiratory viral infections (RVIs), including influenza, RSV, and HMPV, covering observational studies published January 2004–August 2025.
Across 13 studies (n=631,863), influenza was most studied and consistently linked to long-term pulmonary dysfunction, reduced diffusion capacity, dyspnoea, fatigue, and lower quality of life; two RSV cohorts (n=1,553 and n=471) showed predominantly cardiovascular sequelae; one HMPV cohort (n=92) found persistent symptoms in 55% of adults at 90–270 days, most often dyspnoea, fatigue, and cough.
Evidence is fragmented due to inconsistent study designs, limited pathogen coverage, and low certainty of evidence (GRADE); no meta-analysis was possible due to heterogeneity; findings may be skewed toward severe infections.
Clinicians should be aware that non-COVID respiratory viruses—especially influenza, RSV, and HMPV—can cause multi-organ post-acute sequelae, warranting structured follow-up after severe infection. Standardised, prospective monitoring protocols are needed, as current evidence is insufficient to guide specific pathogen-targeted post-acute care.
