Aspiration pneumonia after SARS-CoV-2 Omicron infection frequently induced physical functional decline in Japan

<b>Introduction.</b> Nursing and healthcare-associated pneumonia (NHCAP) mainly occurs in older people whose physical functions have declined, and it is the most common type of pneumonia in Japan, a super-ageing society. In older people who meet NHCAP criteria, respiratory tract infections are often accompanied by aspiration pneumonia.<b>Gap statement.</b> The SARS-CoV-2 Omicron variant frequently causes aspiration pneumonia and has induced a decline in physical function.<b>Aim.</b> To clarify functional outcomes at 1 year after hospital discharge in SARS-CoV-2 Omicron-related NHCAP cases.<b>Methodology.</b> We compared the functional outcomes between 259 patients with primary SARS-CoV-2 pneumonia and 223 patients with aspiration pneumonia.<b>Results.</b> Functional decline rates for calculating the Barthel index at the time of hospital discharge were higher in the aspiration pneumonia group than the primary SARS-CoV-2 pneumonia group [114 patients (51.6%) vs 70 patients (27.0%), <i>P</i><0.0001]. Of 114 patients with aspiration pneumonia who had a decline in physical function at the time of hospital discharge, 91 (79.8%) still showed functional decline 1 year later. In contrast, 9.3% of patients had functional decline at 1 year after hospital discharge in the primary SARS-CoV-2 pneumonia group, which was significantly lower than in the aspiration pneumonia group.<b>Conclusions.</b> The Omicron variant showed decreased infectivity in the lungs and was less pathogenic compared with the Delta and former variants. However, physicians should recommend SARS-CoV-2 vaccination and non-pharmaceutical interventions, depending on the presence or absence of applicable criteria for NHCAP, even when the predominant strain is the Omicron variant.