Experts Discuss Practical Strategies for Respiratory Viruses
By Kelly M. Pyrek
In a recent SHEA-sponsored town hall,“ Respiratory Viruses in Healthcare: Practical Strategies & Persistent Questions,” experts explored the current respiratory virus epidemiology in the U. S., reviewed important papers and issues, and provided insights into transmission prevention and control.
During the event, moderator Thomas Talbot, MD, MPH, professor of medicine in the Division of Infectious Diseases and chief hospital epidemiologist at Vanderbilt University Medical Center, reviewed several pertinent studies. The first, conducted by Williams, et al.( 2025), addressed the risk-mitigation ability of shared room ventilation and filtration on SARS-CoV-2 transmission. As the authors explain,“ Admission to shared hospital rooms are a risk factor of healthcare-associated( HA) SARS-CoV-2. Quantifying the impact of engineering controls such as ventilation and filtration is essential to informing resource utilization and infection prevention guidelines.”
This multicenter test-negative study of patients exposed to SARS-CoV-2 in shared rooms across five hospitals was conducted between January and October 2022. Independent variables tested were measured air changes per hour( ACH), presence of any room mechanical ventilation( RMV), or portable high-efficiency particulate air( HEPA) filter. Covariates included facility( number of beds in room, outbreak status of unit), source patient( presence of symptoms, RT-PCR cycle threshold( Ct) value), and exposed patient factors( age, sex, time from last SARS-CoV-2 vaccine, previous SARS-CoV-2 infection, exposure duration). Multi-level logistic mixed models used to estimate the impact of engineering controls on transmission. Among 468 exposed patients, secondary attack rate was 26.3 percent( range 7.5 to 33.3 percent across hospitals). In multi-variable analysis, increased ACH was associated with decreased odds of infection( adjusted odds ratio( aOR) 0.88, 95 % CI 0.78-1.00; p =. 046) as were exposure duration and Ct value of source patient. Presence of RMV was also associated with decreased odds of infection( aOR 0.51, 95 % CI 0.27-0.95; p =. 034) while use of portable HEPA filter was not significant( aOR 0.58, 95 % CI 0.26-1.31; p =. 18).
The authors concluded,“ Improved ventilation was independently associated with lower odds of SARS-CoV-2 infection among exposed roommates. Ensuring RMV is present and optimizing ACH may significantly mitigate the risk of HA-SARS-CoV-2. Future prospective studies should assess optimal ACH thresholds and the impact of portable HEPA filters.”
“ This is a nice study and something we may not have been as focused on in terms of ventilation and filtration showing that as you have increased air exchanges in a room per hour, you had a reduced secondary attack rate of SARS,” Talbot commented.“ Things like HEPA filtration did not have an impact as far as transmission; mechanical ventilation of a source patient was protective as you’ d expect, a little bit more of a closed respiratory circuit that would not spread in the environment as well.”
In the second study Talbot discussed, Srinivasa, et al.( 2025) investigated the transmission dynamics of common healthcare-associated respiratory virus infections, performing retrospective whole genome sequencing( WGS) surveillance at one pediatric and two adult teaching hospitals. From Jan. 2, 2018, to Jan. 4, 2020, nasal swab specimens positive for rhinovirus, influenza, human metapneumovirus( HMPV), or respiratory syncytial virus( RSV) from patients hospitalized for more than three days were sequenced on Illumina platform. High-quality genomes were assessed for genetic relatedness using more than three single nucleotide polymorphisms( SNPs) cutoff, except for rhinovirus( 10 SNPs). Patient health records were reviewed for genetically related clusters to identify epidemiological connections.
The authors collected 436 viral specimens from 359 patients: rhinovirus( n = 291), influenza( n = 50), HMPV( n = 47), and RSV( n = 48). Of these, 55 percent( 197 / 359 patients) were from pediatric hospitals and 45 percent from adult hospitals. Patients ranged in age from 14 days to 93 years, 61 percent were male, and 74 percent were white. WGS was performed on 61.2 percent( 178 / 291) rhinovirus, 78 percent( 39 / 50) influenza, 92 percent( 44 / 48) RSV, and all HMPV specimens. Among high-quality genomes, we identified 14 genetically related clusters involving 36 patients, ranging in size from two to five patients. They identified common epidemiological links for 53 percent( 19 / 36) of
SHEA Town Hall Panelists:
Tom Talbot
Marci Drees
Katie Passaretti
Chris Nyquist
Jane Siegel
24 • www. healthcarehygienemagazine. com • march-april 2026