key: cord-0986021-747yrat7
authors: Partridge, David G.; Sori, Alka; Green, Daniel J.; Simpson, Rebecca; Poller, Bozena; Raza, Mohammad; Kaur, Harpreet; Jessop, Helen; Colton, Bethany; Nield, Aileen; Evans, Cariad M.; Lee, Andrew
title: Universal Use of Surgical Masks is Tolerated and Prevents Respiratory Viral Infection in Stem Cell Transplant Recipients
date: 2021-09-17
journal: J Hosp Infect
DOI: 10.1016/j.jhin.2021.09.005
sha: 2ce97e903c97a4d80eaf364382bcdd84a4629b0f
doc_id: 986021
cord_uid: 747yrat7

Prevention of respiratory viral infection in stem cell transplant patients is important due to its high risk of adverse outcome. This single centre, mixed methods study, conducted before the SARS-CoV-2 pandemic, explored the barriers and facilitators to a policy of universal mask wearing by visitors and healthcare workers and examined the impact of the first year of introduction of the policy on respiratory viral infection rates compared to preceding years adjusted for overall incidence. Education around universal mask wearing was highlighted as being particularly important in policy implementation. A statistically significant fall in respiratory viral infection was observed following introduction.

Respiratory viral infections are a major cause of morbidity in stem cell transplant recipients and mortality rates of 6-50% have been reported. [1] In contrast, these pathogens typically cause only mild symptoms in immunocompetent individuals and may therefore be introduced to the hospital unwittingly by health care workers (HCWs) or visitors. Vulnerability of this patient group to nosocomial infection is well recognised with protective isolation in single rooms with appropriate engineering controls and routine use of protective equipment including gloves by staff for direct patient care common to most centres. [2] A previous single centre study demonstrated that universal wearing of surgical facemasks by those in contact with at-risk patients was associated with a reduction in parainfluenza infection compared to both a historical control period and to another neighbouring hospital. [3] Despite this evidence, prior to the onset of the SARS-CoV-2 pandemic, the universal wearing of masks in this high-risk setting was not widely adopted and the underlying reasons for this have not been clearly identified. In this study, we sought to qualitatively assess the barriers to routine adoption of universal mask wearing to assist in its introduction and, subsequently, to validate the infection control benefits of the original study in a further hospital setting.

The emergence of SARS-CoV-2; the disproportionately adverse consequences of infection with it in Haematology patients; [4] and the potential for transmission from asymptomatic or paucisymptomatic individuals including HCWs, make the need for infection control interventions aimed at preventing viral transmission in this vulnerable group of patients an even more urgent priority and one that will remain even after a successful vaccination campaign.

The Haematology department at Sheffield Teaching Hospitals NHS Foundation Trust (STH) provides tertiary level services to over 1 million people in South Yorkshire and North Derbyshire and performs approximately 140 stem cell transplants per year. STH has 12 dedicated positive pressure ventilated lobby protective isolation rooms with HEPA filtered air and en-suite facilities for stem cell transplant recipients. [5] The Virology laboratory at the trust provides diagnostic serology and molecular virology testing for a similar geographical area. All patients with clinical features suggestive of a viral respiratory tract infection are tested for influenza A/B, respiratory syncytial virus (RSV), parainfuenza virus 1-4, human metapneumovirus, seasonal coronavirus, rhinovirus and adenovirus. These tests are performed using an in-house multiplex PCR method validated on the Roche Flow system.

Semi-structured interviews were conducted with transplant patients and healthcare workers from the Haematology transplant ward between June and August 2018. Patients under the age of 18 years, those unable to provide written informed consent and those who were clinically unstable were excluded from the study. The interviews were audio-recorded and transcribed. Thematic analysis was performed manually to assess perception of mask use. Similar themes were identified from both HCW and patient interviews. Education to emphasise the potential benefit of universal mask use and to reduce anxiety surrounding it was described as being especially important in facilitating the introduction of the intervention.

The findings of the qualitative study were discussed with senior nursing and medical staff including the stem cell transplant co-ordinators to ensure that the rationale for the intervention was understood by both patients and HCWs. The supportive responses from interviewed patients were particularly important in facilitating the introduction of universal mask use.

A total of 412 and 138 stem cell transplants were undertaken on the unit in the pre-and postintervention periods respectively, of which 122 (29.6%) and 37 (26.8%) were allogeneic (table 1). 

This study demonstrated that universal wearing of fluid-resistant surgical masks by care providers is associated with a significant reduction in the incidence of respiratory viral infection in patients undergoing stem cell transplant. This mirrors the findings of Sung et al. [3] who demonstrated a reduction in respiratory viral infection incidence from 10.3% to 4.4% in HSCT recipients at their unit following the introduction of universal mask wearing. The reduction in infections diagnosed as inpatients was particularly marked, consistent with the location of the intervention but raising a question as to whether further benefit could be gained through advising mask use and other protective measures for patients following discharge both in the community and at outpatient visits.

Previous randomised controlled trials examining the impact of surgical mask use in community settings have not demonstrated an association with reduced respiratory viral infection risk when worn by either index case, contact or both [7] but the impact may be greater in stem cell transplant recipients due to their motivation and the ability to target education on a well-defined patient cohort. Further encouragement of patient mask-wearing when outside their room or visiting other departments may also provide additional benefit and has become routine during the SARS-CoV-2 pandemic.

Stem cell transplant recipients are particularly vulnerable to respiratory viral infection and this susceptibility to infection confers a responsibility on healthcare providers to use any means necessary to prevent nosocomial transmission. HCW-to-patient transmission is a particular concern in this context as viruses such as parainfluenza usually cause very minor symptoms in the healthy but can be devastating in the immunocompromised. Despite this concern, there are a number of barriers to the universal use of masks and these were explored by the qualitative aspect of our study. Not surprisingly concerns about communication difficulties, both verbal and non-verbal were dominant themes as was concern about emotional detachment. These findings are consistent with those of a recent systematic review of potential adverse impacts of mask use. [8] Importantly though, it was felt by both HCWs and patients that these barriers were surmountable through education if a reduction in pathogen transmission could be demonstrated. It is also likely that the barriers will reduce J o u r n a l P r e -p r o o f somewhat following the SARS-CoV-2 pandemic, in which mask use has been normalised both within and outside the hospital but many of the challenges identified remain.

Study size and incidence limited the ability to draw conclusions about relative impact of the intervention on different viruses and whether the impact is lessened in those with a greater potential for transmission via the airborne route. However, it should be noted that while this has been shown to dominate in rhinovirus transmission, this was the only individual pathogen for which a statistically significant reduction in incidence was seen. The impact of mask wearing by the source of droplet nuclei may be greater than that obtained by the potential recipient wearing a mask with the same filtration capacity due to the effect of evaporation and particle size reduction. [9, 10] The results appear to demonstrate no impact on RSV transmission but it should be noted that 3 of the 5 cases of RSV in the post-intervention period occurred after the patients had been discharged from hospital and may reflect community acquisition.

Limitations of this study were its single centre nature; that analysis of only one year of postintervention infections was possible due to the COVID-19 pandemic; and the absence of monitoring of compliance with the mask use policy. However, it is of unique relevance at the current time as it demonstrates the benefit of type IIR fluid resistant surgical mask wearing in the prevention of viral infection as a single intervention added to the existing precautions taken on the ward.

As we emerge from the pandemic phase, SARS-CoV-2 is likely to persist in the population and join other, more longstanding, viruses in exacting a particularly severe toll on the most vulnerable patients. This study demonstrates that for such patients, universal mask use is an acceptable and effective intervention to prevent nosocomial respiratory viral disease. and the adjusted Pre-intervention rate per 100 SCT recipients (7 th column of data).

Respiratory Virus Infections of the Stem Cell Transplant Recipient and the Hematologic Malignancy Patient

Infection Control and Isolation Procedures

Universal Mask Usage for Reduction of Respiratory Viral Infections After Stem Cell Transplant: A Prospective Trial

COVID-19 and stem cell transplantation; results from an EBMT and GETH multicenter prospective survey

Department of Health. Health Building Note 04-01. Supplement 1: Isolation facilities for infectious patients in acute settings

R: A language and environment for statistical computing. R Foundation for Statistical Computing

Masks for Prevention of Respiratory Virus Infections, Including SARS-CoV-2, in Health Care and Community Settings : A Living Rapid Review

Downsides of face masks and possible mitigation strategies: A systematic review and meta-analysis

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