Optimizing and Unifying Infection Control Precautions for Respiratory Viral Infections

The coronavirus disease 2019 (COVID19) pandemic has focused an intense spotlight on respiratory precautions for healthcare workers managing patients with respiratory viral infections. Prevailing wisdom before the pandemic was that most respiratory viruses are transmitted by large respiratory droplets and fomites. These droplets were believed to have a carrying radius of 3–6 feet before rapidly falling to the ground by virtue of gravity. Surgical masks were presumed to provide adequate protection in most situations by providing a barrier between patients’ emissions and the mucous membranes of providers’ mouths and noses. Notwithstanding this framework, the United States Centers for Disease Control and Prevention’s (CDC) infection control guidelines include a hodgepodge of different personal protective equipment recommendations for different respiratory viruses [1]. These span the gamut from respirators, eye protection, gowns, and gloves to care for patients with emerging pathogens such as Middle East Respiratory Syndrome (MERS), avian influenza, and now, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2); surgical masks alone to care for patients with influenza; gloves and gowns alone without masks or eye protection to care for patients with respiratory syncytial virus (RSV); and nothing at all to care for immunocompetent adults with parainfluenza. This curious mix of recommendations appears to be the product of a handful of studies conducted predominantly in the 1980s and 1990s that evaluated the additive benefit of one or more of these precautions against one of these viruses, mostly RSV. None of the cited studies compared infection rates between viruses or provided evidence why one virus should be treated differently from another. Many of the source studies only reported on nosocomial infection rates in patients but did not consider infections in healthcare workers. And almost all the studies focused on pediatric populations. The suitability of these studies to support current infection control recommendations is dubious. For example, 2 key studies are cited to support the use of gloves and gown alone without a mask or eye protection to care for patients with RSV. The first was a quality improvement initiative in a children’s hospital designed to increase providers’ compliance with gloves and gowns over the course of 3 RSV seasons from 1982 to 1985. The investigators reported that an increase in glove and gown use from 39% to 81% of audits was associated with a 3-fold decrease in nosocomial RSV infections [2]. The investigators did not assess whether adding masks and eye protection could further decrease infections and the study only evaluated infections in patients; infections among staff members were not assessed. The second study was a prospective comparison of nosocomial RSV rates among children assigned to wards with different precaution sets over 3 RSV seasons [3]. Nosocomial RSV rates ranged from 26% of patients when using no precautions, 28% with gloves and gowns alone, 19% with cohort nursing alone, and 3% with gloves and gowns combined with cohort nursing. The fact that the only successful strategies included cohort nursing belies the importance of staff as vectors of infection, yet the study did not report on staff infection rates. This study also did not evaluate the marginal benefit of masks and eye protection. Instead, the investigators cited a study that reported that nose and eye protection was associated with striking decreases in both staff and patient infections [4] but explained that they decided not to include nose and eye protectors in their strategies because “they are not popular with clinical staff and are frightening to children” [3]. It is very difficult to reconcile the CDC’s patchwork of legacy recommendations for different respiratory viruses with the wealth of data now demonstrating the primacy of the respiratory route in respiratory viral transmission [5, 6]. It has become evident that the majority Received 05 May 2022; editorial decision 05 May 2022; accepted 06 May 2022; published online 10 May 2022 Correspondence: Michael Klompas, MD, MPH, Department of Population Medicine, 401 Park Drive, Suite 401 E, Boston, MA 02215, USA (mklompas@bwh.harvard.edu). The Journal of Infectious Diseases © The Author(s) 2022. Published by Oxford University Press on behalf of Infectious Diseases Society of America. All rights reserved. For permissions, please e-mail: journals.permissions @oup.com https://doi.org/10.1093/infdis/jiac197