P-271. Contact Patterns of United States Health Care Workers at Quaternary Health Center: Stability of contacts during the post-pandemic era
Authors: Pischel Lauren , Aguolu Obianuju G , Ahmed Noureen , Campbell Melissa , Borg Ryan C , Duckwall Chelsea , Willebrand Kathryn , Paintsil Elliott E , Muenker M Catherine , Malik Amyn , Kiti Moses C , Jenness Samuel , Lopman Ben , Belsky Justin , Martinello Richard A , Yildirim Inci , Ko Albert I , Omer Saad 
Published: January 2025

Abstract

Background
We lack understanding of how health care workers’ (HCWs) contacts change over time or in response to pandemics. This study describes the social contact patterns of HCWs in a large United States health care system via standardized social contact diaries.
Mean number of total contacts over time (Jan 2021-May 2022):
The mean contacts noted with dark-blue line with 95% confidence intervals (95%CI) in dark gray. The dashed black line shows the linear regression of contacts over time. The-axis is interrupted as the study was closed in June and July 2021.

Methods
Inpatient and outpatient HCWs enrolled from October 2020 to June 2022. Participants completed a monthly survey of all contacts during a single representative working day selected by the participant. Direct contact was defined as being within 2 meters of another person. Indirect contact was defined as being in the same room but more than 2 meters. In June 2022, participants completed a 2-day individual-level contact diary. We generated age-stratified contact matrices. Contacts were described by contact type, duration and contact relationship. Number and duration of contacts by job were compared by chi-squared test and number of contacts over time by linear regression.
Average contacts of health care worker with all individuals
The individual tiles color and numeric fill denote the average number of contacts per HCW of that age range with a contact of that age range. A horizontal marginal histogram shows the age break down of HCW participants and a vertical marginal histogram shows the resulting distribution of contact’s ages.

Results
360 HCWs enrolled, 95 completed 1 or more monthly contact diary and 88 completed the intensive 2-day diary. The total number of contacts was stable over time (β0.14, p 0.20, Fig.1). HCWs reported direct contacts with less than 5 patients, 5-9 patients, 10-19 patients or 20 more patients, 50%, 29%,15% or 6% of the time respectively. HCWs reported direct contact with less than 5 other HCWs, 6-10 HCWs, 11-20 or 21 or more 19%, 39%, 27 % or 15% of the time respectively. In the June 2022, a total of 2,550 contacts were reported, 1,592 (62%) were with HCWs, and 570 (22%) with patients. Social workers, rehab/transport and doctors were more likely to have contact with 20 or more patients vs. other professions. Nurses, imaging technologists and rehab/transport were more likely to spend 20 minutes or more with patients vs. other professions. Contact matrices were not age assortative with HCWs having similar contacts across all working ages (Fig. 2). HCWs’ physical contacts focused on extremes of age (Fig. 3). Contact type varied by job with nearly all groups having more contacts with colleagues than patients (Fig, 4).
Average physical contacts of HCWs per day: The
The individual tiles color and numeric fill denote the average number of physical contacts per HCW of that age range with a contact of that age range. A horizontal marginal histogram shows the age break down of HCW participants and a vertical marginal histogram plot the resulting distribution of contact’s ages.

Conclusion
HCW contacts concentrated in their work environment and most contacts were focused in the working-age population. These contacts were stable over time even in the COVID-19 pandemic response. HCWs were 2.8 time more likely to contact HCWs than patients.
Number of contacts of 2 days by participant job and contact individual
Grouped box plots show the number of contacts over the 2-day intensive diary by HCW job (x-axis) and the HCWs relationship with the contact (e.g. colleague, patient or other).

Disclosures
Lauren Pischel, MD, Auxa Health: Advisor/Consultant Amyn Malik, MBBS, MPH, PhD, Analysis Group, Inc: Former Employee. We consulted with Pharma and Biotech on different research studies Ben Lopman, PhD, Epidemiological Research and Methods, LLC: Advisor/Consultant|Hillevax, Inc: Advisor/Consultant Albert I. Ko, MD, Merck: Grant/Research Support|Regeneron: Grant/Research Support Saad Omer, MBBS MPH PhD, Meta: Advisor/Consultant|Meta: Grant/Research Support