Pre-Vaccination Anti-Severe Acute Respiratory Syndrome Coronavirus 2 Antibody Seroprevalence in Workers at Three Japanese Hospitals.

BACKGROUND: Antibody testing is essential for accurately estimating the number of people infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). This study aimed to investigate the influence of background factors on seroprevalence by testing for anti-SARS-CoV-2 antibodies in blood samples obtained from the staff of three hospitals. METHODS: This cross-sectional observational study was conducted from June 8 to July 4, 2020, as part of a mandatory health examination. Leftover blood samples collected during the health examinations at each hospital were used to test for the presence of anti-SARS-CoV-2 antibodies. The Elecsys Anti-SARS-CoV-2 RUO assay was used for antibody detection. The relationship between staff age, gender, body mass index, blood pressure, work environments with different exposure risks, place of residence, and campus location and seroprevalence was investigated. The data were anonymized prior to analysis. RESULTS: A total of 3,677 individuals were included in the study, comprising 2,554 females (69.5%) and 1,123 males (30.5%). Anti-SARS-CoV-2 antibody (immunoglobulin G) was detected in 13 participants (0.35%). Seroprevalence was slightly higher in males than females (0.62% vs. 0.23%, P=0.08). By occupation, anti-SARS-CoV-2 antibodies were found in 6 (0.75%) physicians, 6 (0.31%) nurses, and one individual (0.11%) in the medical personnel group, with slightly higher levels in physicians. No significant difference was noted in the seroprevalence in terms of all background factors. CONCLUSIONS: Our study shows that the background factors do not impact seropositivity rates. Thorough daily infection control and adherence to recommended health guidelines were found to reduce infection risk.

Assessment of contamination using an ATP bioluminescence assay on doorknobs in a university-affiliated hospital in Japan.

BACKGROUND: Doorknobs are inevitable points of hand contact. We monitored doorknob contamination in a university hospital using an ATP bioluminescence assay and stamp agar method. We selected grip-, lever-, push-, insert-, and two-pull-type doorknobs in staff lavatories and break rooms, a linen closet, dirty utility rooms, a newborn care unit, clinical lavatories and examination rooms, dressing rooms for radiological tests, and lavatories for health examination, as monitoring points in wards and clinics. Sequential monitoring with an ATP assay (six times) and culture (once) were performed at the same time of day in autumn, winter, and summer. We provided contamination data to appropriate healthcare providers and housekeepers, and queried the staff regarding decontamination of doorknobs. RESULTS: When comparing ATP values on the same type of doorknobs, significant differences in contamination were demonstrated among several clinical rooms and several rooms in wards during all three seasons. No correlation was observed between ATP values on clinical-examination-room doorknobs and outpatient numbers, or between ATP values at any monitoring point and microbial colony-forming units. ATP values on clinical-examination-room doorknobs were reduced after cleaning according to instructions. CONCLUSIONS: ATP assay is useful for measuring baseline doorknob contamination in clinical rooms. Our findings confirm the need to improve routine decontamination in clinical departments. We need to analyze further the relationship between hospital-acquired infections and doorknob contamination, as assessed by ATP assay in clinics.