Objective: Background: Cases Reports: Conclusions: Unusual clinical course High-frequency percussive ventilation (HFPV) is a method that combines mechanical ventilation with high-fre-quency oscillatory ventilation. This report describes 3 cases of patients with severe COVID-19 pneumonia who received intermittent adjunctive treatment with HFPV at a single center without requiring admission to the Intensive Care Unit (ICU). Case 1 was a 60-year-old woman admitted to the hospital 14 days after the onset of SARS-CoV-2 infection symptoms, and cases 2 and 3 were men aged 65 and 72 years who were admitted to the hospital 10 days after the onset of SARS-CoV-2 infection symptoms. All 3 patients presented with clinical deterioration accom-panied by worsening lung lesions on computed tomography (CT) scans after 21 days from the onset of symp-toms. SARS-CoV-2 infection was confirmed in all patients by real-time reverse transcription-polymerase chain reaction (RT-PCR) assay from nasal swabs. All 3 patients had impending respiratory failure when non-invasive intermittent HFPV therapy was initiated. After therapy, the patients had significant clinical improvement and visibly decreased lung lesions on followup CT scans performed 4-6 days later. The 3 cases described in this report showed that the use of intermittent adjunctive treatment with HFPV in patients with severe pneumonia due to infection with SARS-CoV-2 improved lung function and may have prevent-ed clinical deterioration. However, recommendations on the use of intermittent HFPV as an adjunctive treatment in COVID-19 pneumonia requires large-scale controlled clinical studies. In the pandemic context, with a shortage of ICU beds, avoiding ICU admission by using adjunctive therapies on the ward is a useful option.