Toothbrushing and flossing can help reduce the risk of pneumonia.Part 2 of the HAPPEN* trial shows a 60-percent reduction in the incidence of non-ventilator–associated hospital-acquired pneumonia (NV-HAP) among hospitalized patients with improved oral hygiene.
In the adjusted analysis, NV-HAP incidence was lower in the intervention group than in the control group (0.70 percent vs 1.1 percent; hazard ratio, 0.40). This translated into an incidence rate ratio [IRR] of 0.41, defined as the total infections per 100 at-risk admission days. [ESCMID Global 2026, abstract O0611]
The estimated effectiveness remained consistent in the sensitivity analyses, including a random intervention effect by trial hospital (IRR, 0.409) and leave-one-cluster-out analyses (IRRs ranged from 0.292 to 0.398).
NV-HAP accounts for most of HAP cases and is the most common healthcare-associated infection, resulting from the aspiration of a patient’s own oropharyngeal material. [Age Ageing 2017;46:352-358]
“However, there are very few prevention strategies or national initiatives and a lack of prospective surveillance in this area, and there have been calls for that for some time,” said lead author Dr Brett Mitchell from Avondale University, New South Wales, Australia, at ESCMID Global 2026.
“Guidelines already recognize the role of oral care in NV-HAP prevention, but there is limited evidence supporting these recommendations,” Mitchell noted in the press release.
HAPPEN Part 2 is a stepped-wedge, randomized controlled trial (RCT) conducted across nine wards (clusters) in three Australian hospitals over 12 months. The clusters were mostly stroke medical units with patients who were at high risk of acquiring NV-HAP. A total of 8,870 patients (mean age 72.5 years, 51.7 percent women) were included. Of these, 4,347 were in wards (intervention group). The remaining participants comprised the control group. At baseline, there were 78 cases of NV-HAP.
The intervention comprised three components: oral care products (toothbrush, toothpaste), educational materials (face-to-face, access to the HAPP trial website), and audit and feedback. The staff was also given access to the educational materials to improve oral care delivery. The control participants received standard of care, with no additional education or access to resources.
The proportion of patients receiving oral care increased from 15.9 percent to 61.5 percent following exposure to the intervention. The audits revealed that oral care was undertaken an average of 1.5 times per day across all clusters.
Part 1 of HAPPEN was a national survey of nurses, as well as focus groups, consumers, government groups, and professional organizations. In this survey, Mitchell and colleagues found that oral care is deprioritized when resources are tight in hospital settings and that barriers to implementation include access to equipment, resources, and training. [Infect Dis Health 2024;29:212-217; Infect Dis Health 2025;30:343-352]
“The solutions proposed [in Part 1] included simple things, such as the provision of products, just-in-time resources, and patient education and awareness. Patients did not know that brushing their teeth in the hospital can help reduce the risk of pneumonia,” Mitchell said. “These helped inform the intervention in [Part 2].”
Mitchell noted that HAPPEN Part 2 is the first and largest multicentre RCT to examine NV-HAP prevention. “We hope this [shows the] value of improving oral care for NV-HAP prevention in hospitalized patients. It is a relatively simple intervention to implement.”
He acknowledged some limitations, including challenges in defining NV-HAP, inaccurate oral care documentation, and the inability to ascertain the quality of oral care.
“The next step is to better understand how structured programmes can be effectively implemented and sustained across hospital wards,” Mitchell noted. Future plans include a cost-effectiveness evaluation, qualitative analysis of patient and clinician experiences, resource review, and a prospective analysis of NV-HAP incidence and mortality.