Use of non‐pharmaceutical interventions to reduce the transmission of influenza in adults: A systematic review

Abstract

During seasonal influenza epidemics and pandemics, virus transmission causes significant public health concern. Reduction of viral transmission by non-pharmaceutical interventions (NPI) has a significant appeal and is often recommended. However, the efficacy of such interventions is unclear. A systematic literature review was undertaken to identify and evaluate the published literature on NPI efficacy to prevent human transmission of influenza virus in adults. Reviewers assessed the quality of eligible studies utilizing the Critical Appraisal Skills Programme for bias and the Scottish Intercollegiate Guidelines Network for methodological quality. Studies were assessed for risk of bias domains of random sequence generation, allocation concealment, attribution bias, selective reporting and blinding. Relevant citations of 2247 were reduced to 100 for full-text evaluation. Only seven met all selection criteria and pooled analysis was not feasible. Of the seven studies, two were randomized controlled trials (RCT) and five were cluster RCT. The main NPI studied were disinfection and hygiene; barriers; and combined NPI. However, these seven RCT had significant design flaws. Only two studies used laboratory confirmed influenza and poor statistical power was a major problem. Positive significant interventions included professional oral hygiene intervention in the elderly and hand washing. Despite the potential for NPI in preventing influenza transmission, there is very limited data available. Hand washing and dental hygiene may be useful, but other interventions have not been fully assessed. Properly designed studies evaluating large populations including ‘at risk’ patients and in a variety of communities are needed.

Respiratory Infections in the U.S. Military: Recent Experience and Control

“…At least two recent civilian-based, well-controlled studies have shown the efficacy of HW measures in decreasing influenza virus contamination of household surfaces, with a concomitant decrease in the number of influenza cases in Bangkok, Thailand (653,654). Consistent with these studies and with the concept of decreases in virus load and transmissibility via fomites, HW and HH practices have been found to provide a 55% reduction in the risk of transmission of respiratory viruses, including influenza viruses, in three recent large systematic reviews in the literature (642,643,714). Additionally, two recent studies of school-age populations have shown that HH interventions can reduce ILI and laboratory-confirmed influenza infection (655,656).…”

Effectiveness of vaccination and wearing masks on seasonal influenza in Matsumoto City, Japan, in the 2014/2015 season: An observational study among all elementary schoolchildren

“…These results may explain why seasonal influenza is not always controlled, despite implementation of hand washing and water gargling in school settings. Thus, because NPIs have been considered a single category, interpretation of efficacy was difficult (Aiello et al, 2010a, Aiello et al, 2012, Cowling et al, 2009, Simmerman et al, 2011, Smith et al, 2015), suggesting that NPIs should be evaluated individually. However, because this study was cross-sectional in design, cause-and-effect relationships could not be determined.…”

“…In addition, combinations of NPIs with pharmaceutical intervention may be more effective than either alone. However, studies assessing the effectiveness of NPIs have yielded inconsistent results (Aiello et al, 2010a, Smith et al, 2015), which may be caused by poor statistical power due to sample size or selection bias. Alternatively, randomized controlled trials may not always reflect the natural setting of an influenza epidemic.…”

Evidence-Based, Cost-Effective Interventions To Suppress The COVID-19 Pandemic: A Systematic Review

“…Overall, they were the best performing intervention across populations, settings, and threats. Similarly, in a narrative review, MacIntyre et al (2015) drew on evidence from randomized community trials to conclude that face masks do provide protection against infection in various community settings, subject to compliance and early use. Differences in publication date, search strategy, and study selection criteria may explain the discrepancies among these reviews.…”