Why Respiratory Virus Hospital-acquired Infections Matter

Hospital-acquired infections with respiratory viruses (RV HAIs) are a significant concern because they have serious clinical, public health, and economic consequences, particularly in healthcare settings where vulnerable populations are concentrated.

Share

Hospital patients often have weakened immune systems, chronic lung or heart disease or advanced age or frailty. Respiratory viruses can cause severe disease, complications such as pneumonia and respiratory failure, and even death in these groups.

RV HAIs are associated with longer hospital stays and higher ICU admission rates. In a cohort of 1,700 patients with RV HAI, patients had longer mean lengths of stay (e.g., 21 days vs. 5 days in community-acquired cases). These patients were older, had pre-existing respiratory disorders or were immunosuppressed and faced greater RV HAI risk. They were also likely to exhibit typical respiratory infection symptoms, which could delay diagnosis.

RV HAIs are also associated with significantly higher mortality compared with community-acquired cases, often with several-fold greater risk. Among patients who acquired influenza in hospital, 21.7% died compared with 4% among patients with negative test results. So, roughly 1 in 5 hospital-acquired influenza patients die in hospital, compared with about 1 in 25 in similar hospitalised patients without influenza. The odds of in-hospital death were significantly higher even after adjusting for age and comorbidities.

Respiratory viral infections are often mistaken for bacterial infections, leading to unnecessary antibiotic use, increased antimicrobial resistance and additional side effects and costs to the health system, making them a critical focus for infection control and patient safety.

For policymakers, admissions are a better indicator of harm than case counts alone. Case counts depend heavily on testing availability, health-seeking behaviour and changes in testing policy. Because policy decisions aim to prevent health-system overload, admissions are a direct proxy for system stress. For policymakers, hospital admissions answer the key question: “Is the virus causing enough severe disease to threaten people and the health system?”

However, the healthcare-associated component of admissions is often overlooked. Because surveillance is admission-based, it is easier to report “admissions with respiratory viral infection” than to reliably distinguish community-acquired from healthcare-associated infections in real time.

Classifying an infection as healthcare-associated requires precise timing of symptom onset, reliable testing dates, an understanding of the incubation periods (which vary by virus), and clinical documentation.

In reality, symptoms are often atypical or delayed, and testing is haphazard, frequently occurring days after onset. Patients may have been exposed both in the community and in hospital. To avoid misclassification, and simplify data collection systems usually aggregate all admissions with infection.

Donate to keep TTE going

However, overlooking RV HAIs in surveillance and policy decision-making is a serious mistake, especially in winter, as it leads to systematic underestimation of harm, misjudgement of risk, and missed opportunities for prevention at a time when hospitals are most vulnerable.

In winter, hospitals have high occupancy, respiratory viruses circulate widely in the community, and staff, visitors, and patients create dense transmission networks. Under these conditions, HAI transmission is inevitable and widespread rather than exceptional. Ignoring it falsely treats RV HAIs as marginal when, in reality, they constitute a predictable seasonal burden.

When surveillance ignores them, preventable harm becomes invisible. Poor infection control appears to be due to “inevitable winter pressures”. Accountability is lost, leading to policy complacency rather than improvement.

When RV HAI are ignored, policymakers may erroneously conclude that hospitals are overwhelmed by community transmission. Yet, a substantial share of the winter burden is generated inside healthcare.

In winter, especially, RV HAIs are not background noise; they are a core part of the signal policymakers need to see yet remain blind to. They fall most heavily on those least able to protect themselves: older adults, disabled patients, and long-stay inpatients. Ignoring RV HAIs conceals inequitable harm and undermines commitments to patient safety and fairness - that’s why they matter.

This post was written by two old geezers who know what matters.