Room air purifiers may affect RSV incidence among older adults

This article was originally published on Pharmacy Times®.

Findings from a new study assessed the impact of air purification in residential aged care facilities (RACF) versus no air purification and its association with acute respiratory infections (ARIs), including respiratory syncytial virus (RSV).¹

The results show that the use of indoor air purifiers with HEPA-14 filters did not significantly reduce the incidence of ARIs such as RSV among RACF residents. | Image credit: Pratankarnpap – stock.adobe.com

ARIs can have severe consequences for older people, especially those living in RACFs. ARVIs include influenza, COVID-19, rhinovirus, pneumonia and RSV. However, RSV especially poses a significant threat to older adults, as the infection is responsible for up to 160,000 hospitalizations and approximately 10,000 deaths among older adults in the United States each year. Symptoms usually start as a mild cold, but can become more severe in this population.²

“Successful prevention of ARI requires a thorough understanding of the mechanisms of transmission of the pathogen,” the study authors said in a press release.¹ “The risks of inhalational transmission and subsequent infection are related to several factors, including the rate of release and removal of aerosols containing the pathogen, exposure, cumulative dose, and likelihood of infection.”

Despite the increased use of portable air purification devices, the effectiveness of indoor air purification systems with high-efficiency particulate air (HEPA) filters in reducing diseases such as RSV in RACFs is unknown. To evaluate use, investigators conducted a multicenter, double-blind, crossover, randomized clinical trial from April 7 to October 26, 2023, at three RACFs located in Australia. Individuals enrolled in the study were followed up every 2 weeks during the 6-month study period.

The study included 135 people who were divided into a first intervention group (n=70) and a first control group (n=65). Among both groups, 78 people were female and the average age was 85.2 years.

An air purifier with a HEPA-14 filter was placed in the rooms of all individuals in the experimental group, and an air purifier without a HEPA-14 filter was placed in the rooms of all individuals in the control group. Air purifiers have been reported to provide a minimum of 8 air changes per hour during the day and a minimum of 3 air changes per hour at night. According to the study authors, the groups crossed paths after 3 months.

The primary outcome of the study was the incidence of ARI, defined as either infection or absence of infection. However, the infection was divided into influenza, SARS-CoV-2, rhinovirus, RSV or adenovirus. Secondary study outcomes were time to first infection and number of emergency department visits, hospitalizations, and medical examinations due to ARI.

The results showed that in the intention-to-treat analysis, air purifiers with HEPA-14 filters did not reduce the incidence of ARI compared with the control analysis. However, among the 104 people who completed the study, the intervention reduced the incidence of ARI by 35.6% in the control group and by 24% in the intervention group.

The results show that the use of indoor air purifiers with HEPA-14 filters did not significantly reduce the incidence of ARIs such as RSV among RACF residents.

“Although the study results were not statistically significant, they may be clinically important,” the authors said. “There was a reduction in the absolute number of ARIs among participants who used the intervention and completed the study.”