Surgical Mask Usage Reduces the Incidence of Parainfluenza Virus 3 in Recipients of Stem Cell Transplantation

• Published in: Blood 2012-11, Vol.120 (21), p.462-462
• Main Authors: Sung, Anthony D., Sung, Julia A.M., Corbet, Kelly, Broadwater, Gloria, Hars, Vera, Zanter, Ashley, Chao, Nelson J., Horwitz, Mitchell E.
• Format: Article
• Language: English
• ISSN: 0006-4971; 1528-0020
• DOI: 10.1182/blood.V120.21.462.462

Abstract 462 Respiratory viral infections (RVI) are frequent complications of hematopoietic stem cell transplantation (HSCT). Parainfluenza virus 3 (PIV3) in particular affects patients after HSCT, spreads nosocomially, and is associated with increased morbidity and mortality. Given the absence of proven effective treatments, prevention is key. However, surveillance and isolation of infected patients have been insufficient, likely foiled by asymptomatic viral shedding. Requiring all individuals with direct patient contact to wear a surgical mask is a simple and inexpensive intervention that may reduce droplet exposure by asymptomatic shedders and limit nosocomial spread. Prompted by recurrent clusters of PIV3 affecting our adult HSCT program, we performed an institutional review board approved prospective observational study to assess the impact of surgical mask usage. Between January 10, 2010-January 9, 2012 (mask period), all individuals with direct patient contact, including caregivers, visitors, and medical staff, were required to wear a surgical mask when within 3 feet of a patient, regardless of suspicion of RVI. This continued until the patient returned to their primary residence following completion of HSCT. The primary endpoint was the incidence of RVI compared to the control period of December 1, 2003-November 30, 2009 (pre-mask period). A brief washout period (December 1, 2009-January 9, 2010) allowed for training and implementation. Standard infection prevention precautions including strict hand washing were in place during both the pre-mask and mask periods. RVI (influenza A and B, PIV 1, 2, and 3, adenovirus, and respiratory syncytial virus (RSV)) were documented by positive culture, polymerase chain reaction, or direct fluorescence antibody testing from respiratory specimens. Metapneumovirus was excluded as our lab only started testing for it February 2011. Secondary endpoints include clusters of RVI, defined as 3 or more infections in a 30-day period, and death from RVI. The study was designed to detect a 40% reduction in the incidence of RVI with 90% power. During the six-year pre-mask period, 920 patients received HSCTs. During the two-year mask period, 454 patients received HSCTs. In the pre-mask and mask groups, mean age was 50 and 54 (t-test p