A large clinical trial presented at ESCMID Global 2026 has found that improving oral hygiene in hospital patients is associated with a significant reduction in non-ventilator-associated hospital-acquired pneumonia (NV-HAP), a common healthcare-associated infection (1).

NV-HAP develops at least 48 hours after admission in patients who are not on mechanical ventilation and is associated with longer hospital stays, increased healthcare costs, and higher mortality.

The Hospital Acquired Pneumonia Prevention (HAPPEN) study included 8,870 patients across nine hospital wards in Australia. Researchers introduced a structured oral care program, providing patients with toothbrushes, toothpaste, and education, alongside staff training to improve delivery of care.

Following implementation, the proportion of patients receiving oral hygiene increased from 15.9 percent to 61.5 percent. This was associated with a reduction in NV-HAP cases from 1.00 to 0.41 per 100 admission days at risk – an approximate 60 percent decrease.

From a diagnostic perspective, NV-HAP can be difficult to identify. Diagnosis typically relies on a combination of clinical features, imaging, and microbiological testing, but presentations can be non-specific, particularly in older or medically complex patients. This can lead to underdiagnosis or inconsistent reporting.

The findings are consistent with current understanding of NV-HAP pathogenesis. In many cases, infection occurs when bacteria from the patient’s own oral cavity are aspirated into the lungs. Improving oral hygiene may reduce this microbial burden and lower infection risk.

The study highlights how prevention strategies may influence the types and frequency of infections detected in clinical samples, as well as demand for microbiological testing. Although oral care is included in some clinical guidelines, supporting evidence has been limited. These findings provide data from a large hospital population and may help inform infection prevention strategies.

Overall, the study indicates that routine oral hygiene may contribute to reducing hospital-acquired infections and supports the need for consistent implementation and monitoring in clinical practice.

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