Application of Portable Air Cleaners to Control the Presence of SARS-CoV-2 Aerosols in Homes of COVID-19 Infected Adults

GEDIMINAS MAINELIS, Nirmala Thomas Myers, Robert Laumbach, Kathleen Black, Pamela Ohman-Strickland, Shahnaz Alimokhtari-V, Alicia Legard, Adriana De Resende, Leonardo Calderón, Frederic T. Lu, Howard Kippen, Rutgers, The State University of New Jersey

     Abstract Number: 467
     Working Group: Aerosol Science of Infectious Diseases: What We Have Learned and Still Need to Know about Transmission, Prevention, and the One Health Concept

Abstract
Individuals with COVID-19 who do not require hospitalization are instructed to self-isolate in their residences. To minimize the secondary attack rates of COVID-19 among household contacts, there is a need to understand the airborne transmission of SARS-CoV-2 within residences. We report on the first naturalistic intervention study to investigate a reduction of such transmission risk using portable air cleaners (PACs) with HEPA filters.

Subjects with confirmed COVID-19 were recruited in the fall/winter of 2020-2021. The PAC was placed in the primary room, where the infected individual was self-isolating. In one 24-hr period, the PAC was operated with a HEPA filter and during the other without a filter ("sham" period), in a randomized order. 24-hr air samples of total aerosols were collected in the primary room and the common room on PTFE filters using open-face filter holders at 10 L/min. Samples were analyzed by RT-PCR for expression of three distinct SARS-CoV-2 genes: N, ORF1ab, and S. Samples were considered positive if any one gene and internal control (MS2 phage) were detected at Ct ≤ 40.

Seventeen individuals completed the entire study. Seven out of sixteen (44%) air samples in primary rooms were positive for SARS-CoV-2 RNA during the sham period. With the PAC operated at its lowest setting (CADR = 263) to minimize noise, positive aerosol samples decreased to four out of sixteen residences (25%) (p=0.229). In addition, a slight decrease in positive aerosol samples was observed in the secondary room.

Thus, our results show that SARS-CoV-2 RNA is common in the home air of COVID-19 patients. As the world confronts both new variants and variability in vaccination rates, our study supports this practical intervention to reduce the presence of viral aerosols in a real-world setting.