Hand hygiene and facemask use to prevent droplet transmitted viral diseases during air travel: a systematic literature review

Background: Transmission of airborne viral diseases (e.g. influenza A H1N1) takes mainly place in confined spaces including public travel by aircrafts. Adoption of hygiene measures may help to prevent the disease spread in air travel. This review summarizes the evidence on hand hygiene and use of facemask as viral disease prevention measures in aircrafts. Methods: A literature search was performed in PubMed, Scopus, and Web of Science databases up to 10 June 2020, according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses criteria. A PICOS (participants, intervention, comparator, outcome, and study design) approach was used to define the review question. Results: We included four studies, published between 2007 and 2020, all targeting the influenza virus disease, in the qualitative synthesis. Three studies used mathematical models, and two of them single flight models. The fourth was a case-control designed study to tracing an influenza outbreak in two flights during the 2009 influenza A H1N1 pandemic. Unlike the others, this study provided substantial evidence about the risk of not wearing a facemask in the airplane cabin during a flight from New York City to Hong Kong. Interestingly, none of 9 infected passengers compared to 15 (47%) of 32 healthy control passengers wore a mask (odds ratio, 0.0; 95% confidence interval, 0–0.7). In contrast, both case and control passengers appeared to be equally compliant in hand hygiene. Finally, we discussed the practicability of hygiene measures to control and prevent the SARS-CoV-2 transmission in confined air travel-related spaces. Conclusions: Facemask use combined with other hygiene measures may minimize the chance of droplet-transmitted virus (including SARS-CoV-2) spread by air travelers. However, more evidence is necessary before hygiene measures become an integral part of standard procedures in aircrafts.