Healthcare-associated infection impact with bioaerosol treatment and COVID-19 mitigation measures

Abstract

Background: The real-world impact of breathing zone air purification and coronavirus disease 2019 (COVID-19) mitigation measures on healthcare-associated infections is not well documented. Engineering solutions to treat airborne transmission of disease may yield results in controlled test chambers or single rooms, but have not been reported on hospital-wide applications, and the impact of COVID-19 mitigation measures on healthcare-associated infection rates is unknown.

Aim: To determine the impact of hospital-wide bioaerosol treatment and COVID-19 mitigation measures on clinical outcomes.

Methods: The impact of the step-wise addition of air disinfection technology and COVID-19 mitigation measures to standard multi-modal infection control on particle counts, viral and bacterial bioburden, and healthcare-associated infection rates was investigated in a 124-bed hospital (>100,000 patient-days over 30 months).

Findings and conclusion: The addition of air disinfection technology and COVID-19 mitigation measures reduced airborne ultrafine particles, altered hospital bioburden, and reduced healthcare-associated infections from 11.9 to 6.6 (per 1000 patient-days) and from 6.6 to 1.0 (per 1000 patient-days), respectively (P<0.0001, R²=0.86). No single technology, tool or procedure will eliminate healthcare-associated infections, but the addition of a ubiquitous facility-wide engineering solution at limited expense and with no alteration to patient, visitor or staff traffic or workflow patterns reduced infections by 45%. A similar impact was documented with the addition of comprehensive, restrictive, and labour- and material-intensive COVID-19 mitigation measures. To the authors' knowledge, this is the first direct comparison between traditional infection control, an engineering solution and COVID-19 mitigation measures.

Keywords: Aerosol transmission; Aerosolization; COVID-19; Disease transmission; Engineering; Healthcare-associated infections.

Figure 1

Mechanism of action of the ACTIVE Particle Control system. Particulate pollutants, viruses, bacteria and allergens enter the conditioning phase and exit with a net-neutral charge. The technology-accelerated collisions result in particle agglomeration. The larger coagulated particles and their increased mass are subject to air currents that deliver the same to the collector media. Once collected, the highly defined high voltage field induces oxidative stress killing or inactivates any biological material.

Figure 2

Progressive infection control methods. Standard infection control procedures were in place in 2018. ACTIVE Particle Control technology was implemented in late February 2019, and comprehensive coronavirus disease 2019 (COVID-19) restriction and mitigation measures were implemented in late February 2020.

Figure 3

Roof-top placement of ACTIVE Particle Control units. ACTIVE Particle Control devices were placed within roof-top air-handling units. The entire complex is covered, with the exception of one patient unit (identified in orange).

Figure 4

Healthcare-associated infection rates. Baseline mean healthcare-associated infection (HAI) rate with standard infection control (IC) was 11.9/1000 patient-days; this reduced to 6.7/1000 patient-days after implementation of the ACTIVE Particle Control (APC) system (P<0.0001), and 1.0/1000 patient-days after implementation of comprehensive COVID-19 restriction and mitigation measures (P<0.0001). Analysis of variance (with and without Bonferroni multiple comparisons): P<0.0001. With each additional infection prevention measure, 86% of the variation in HAI rate was due to the mitigation procedure (R²=0.86).