Abstract
PurposeGargling with tea has protective effects against influenza infection and upper respiratory tract infection (URTI). To evaluate if tea and tea catechin consumption has the same protective effects as gargling with tea, we performed a systematic review and meta-analysis.MethodsWe performed a comprehensive literature search using the PubMed, Cochrane Library, Web of Science, and Ichu-shi Web databases. The search provided six randomized controlled trials (RCTs) and four prospective cohort studies (n = 3748). The quality of each trial or study was evaluated according to the Cochrane risk-of-bias tool or Newcastle–Ottawa Scale. We collected data from publications meeting the search criteria and conducted a meta-analysis of the effect of tea gargling and tea catechin consumption for preventing URTI using a random effects model.ResultsTea gargling and tea catechin consumption had significant preventive effects against URTI (risk ratio [RR] = 0.74, 95% confidence interval [CI] 0.64–0.87). In sub-analyses, a significant preventive effect was observed by study type (prospective cohort study: RR = 0.67, 95% CI 0.50–0.91; RCT: RR = 0.79, 95% CI 0.66–0.94) and disease type (influenza: RR = 0.69, 95% CI 0.58–0.84; acute URTI: RR = 0.78, 95% CI 0.62–0.98). Both gargling with tea and consuming tea catechins effectively protected against URTI (tea and tea catechins consumption: RR = 0.68, 95% CI 0.52–0.87; tea gargling: RR = 0.83, 95% CI 0.72–0.96).ConclusionOur findings suggest that tea gargling and tea catechin consumption may have preventive effects against influenza infection and URTI. The potential effectiveness of these actions as non-pharmaceutical interventions, however, requires further investigation.
Highlights
Recent pandemics involving influenza [1], severe acute respiratory syndrome-coronavirus (SARS-CoV) [2], and SARS-CoV-2 (COVID-19) [3] have substantially increased global interest in preventive measures against infectious diseases
Experimental evidence and largescale randomized controlled trials (RCTs) demonstrating the efficacy of hand washing [11] led the World Health Organization (WHO) to consistently recommend this Non-pharmaceutical interventions (NPIs) for infectious upper respiratory disease prevention [5]
We collected, evaluated, and analyzed published RCTs and prospective cohort studies that quantitatively evaluated the effects of gargling or consuming tea or tea catechins to reduce the risk of viral respiratory infection, without placing any limits on the subject population
Summary
Recent pandemics involving influenza [1], severe acute respiratory syndrome-coronavirus (SARS-CoV) [2], and SARS-CoV-2 (COVID-19) [3] have substantially increased global interest in preventive measures against infectious diseases. Limited evidence for the effects of gargling and mouthwash to reduce respiratory virus infection has been published, and the efficacy of these measures is not well accepted [16]. While these NPIs are potentially promising public health interventions, validation of their effects is needed. Combining these interventions might strengthen their preventive effects, thereby reducing the severity and delaying the peak of epidemics (e.g., influenza) in the early stages
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
