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

Abstract

Introduction. 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. Gap statement. The SARS-CoV-2 Omicron variant frequently causes aspiration pneumonia and has induced a decline in physical function. Aim. To clarify functional outcomes at 1 year after hospital discharge in SARS-CoV-2 Omicron-related NHCAP cases. Methodology. We compared the functional outcomes between 259 patients with primary SARS-CoV-2 pneumonia and 223 patients with aspiration pneumonia. Results. 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%), P<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. Conclusions. 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.