Prevention of influenza

Abstract

There are several Cochrane reviews of the relevant evidence relating to different aspects of the prevention and treatment of influenza. Two abstracts on this topic are presented below. The full texts of these reviews are available free of charge from: http://cochrane.bvsalud.org/portal/php/index.php?lang=pt. SELECTION CRITERIA:We scanned 2300 titles, excluded 2162 and retrieved the full papers of 138 trials, including 49 papers of 51 studies. The quality of three randomised controlled trials (RCTs) was poor; as were most cluster RCTs. The observational studies were of mixed quality. We were only able to meta-analyse case-control data. We searched for any interventions to prevent viral transmission of respiratory viruses (isolation, quarantine, social distancing, barriers, personal protection and hygiene). Study design included RCTs, cohort studies, casecontrol studies, cross-over studies, before-after, and time series studies. Data collection and analysis: We scanned the titles, abstracts and full text articles using a standardised form to assess eligibility.RCTs were assessed according to randomisation method, allocation generation, concealment, blinding, and follow up. Non-RCTs were assessed for the presence of potential confounders and classified as low, medium, and high risk of bias. MAIN RESULTS:The highest quality cluster RCTs suggest respiratory virus spread can be prevented by hygienic measures around younger children.Additional benefit from reduced transmission from children to other household members is broadly supported in results of other study designs, where the potential for confounding is greater. The six case-control studies suggested that implementing barriers to transmission, isolation, and hygienic measures are effective at containing respiratory virus epidemics. We found limited evidence that the more uncomfortable and expensive N95 masks were superior to simple surgical masks. The incremental effect of adding virucidals or antiseptics to normal handwashing to decrease respiratory disease remains uncertain. The lack of proper evaluation of globalmeasures such as screening at entry ports and social distancing prevent firm conclusions about these measures. AUTHORS' CONCLUSIONS:Many simple and probably low-cost interventions would be useful for reducing the transmission of epidemic respiratory viruses.Routine long-term implementation of some of the measures assessed might be difficult without the threat of a looming epidemic.