The coronavirus disease MESHD 2019 (COVID-19) pandemic is causing a huge toll on individuals, families, communities and societies across the world. Currently, whether wearing facemasks in public should be a measure to prevent transmission TRANS of severe acute respiratory syndrome MESHD coronavirus-2 (SARS-CoV-2) remains contraversial.1 This is largely because there have been no randomized controlled trials (RCTs) for coronavirus to directly support this. However, lessons may be taken from published RCTs examining influenza-like illness (ILI).2,3 Recent studies suggested that SARS-CoV-2 shares similar transmission TRANS route with influenza virus,4 and the incidence of community transmission TRANS of SARS-CoV-2 in individuals with ILI is high.5 Therefore, we undertook this meta-analysis of RCTs examining the efficacy of wearing facemasks to prevent ILI in community settings, irrespective of confirmatory testing for the causative virus. We undertook a systematic literature search for RCTs related to facemasks and ILI between 1966 and April 2020 using PUBMED, EMBASE, and Cochrane library. RCTs undertaken in community (not hospital) settings comparing wearing and not wearing facemasks for ILI were included. Incidence of ILI (e.g., fever MESHD fever HP, cough MESHD cough HP, headache MESHD headache HP, sore throat, aches or pains MESHD pains HP in muscles or joints) was estimated per group. Relative risk (RR) and 95% confidence interval (CI) were calculated. We screened 899 related abstracts and eventually included 8 RCTs (Figure S1). Basic characteristics and quality of included RCTs are listed in Supplement. Participants wearing facemasks had a significantly lower risk of developing ILI than those not wearing facemasks (pooled RR=0.81, 95% CI: 0.70-0.95) and there was no heterogeneity (Figure 1). The decreased risk of ILI was more pronounced if everyone wore facemask irrespective of whether they were infected or not (RR=0.77, 95% CI: 0.65-0.91), compared to those wearing facemasks when infected (RR=0.95, 95% CI: 0.58-1.56) or uninfected (RR=1.26, 95% CI: 0.69-2.31). This study shows that wearing facemasks, irrespective of infection MESHD status, is effective in preventing ILI spread in the community. This situation mirrors what is happening now in public settings where we do not know who has been infected and who has not. Although there are no RCTs of facemasks for SARS-CoV-2, as with other simple measures such as social distancing and handwashing, these data support the recommendation to wear facemasks in public to further reduce transmission TRANS of SARS-CoV-2 and flatten the curve of this pandemic, especially when social distancing is impractical, such as shopping, or travelling TRANS with public transport for work that cannot be done from home.