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作者：Laurie Barclay, MD  
出處：WebMD醫學新聞

　　September 23, 2009 — 根據9月23日BMJ期刊的一篇系統性回顧報告結果，衛生保健與一些身體方面的方法，可有效降低流感等呼吸道病毒的傳染。
　　
　　義大利羅馬Cochrane Collaboration急性呼吸道感染小組的Tom Jefferson醫師等人寫道，2007年Cochrane回顧顯示，身體方面的介入方式(個人衛生保健、防護物品以及保持距離)相當地有效。不過，目前的流行病介入方式之主流似乎依舊是疫苗和抗病毒藥物，而並無證據支持其廣泛使用，特別是新型H1N1病毒這個似乎相對輕微的威脅。
　　
　　本回顧的目標是評估身體方面介入方式阻斷或減少呼吸道病毒之傳播的效果。回顧者搜尋了Cochrane Library、Medline、OldMedline、Embase以及CINAHL等資料庫中，任何期刊、任何語言、已發表之以身體介入方式預防呼吸道病毒的任何研究。這些介入包括隔離、檢疫、社交距離、防護物、個人保護與衛生保健。
　　
　　符合條件的研究包括隨機試驗、世代研究、案例控制、交叉試驗、前後對照、經時變化研究。回顧者第一次搜尋標題、摘要、全文文獻，採用一個標準格式，以確認這些文獻是否符合需求。接著，藉由評估分派序列之產生、分派之隱藏、單雙盲以及追蹤，以確認隨機試驗的可能取樣偏差。確認可能的干擾因素之後，將非隨機的研究分類為低、中、高偏差風險。
　　
　　回顧者確認了58篇文獻、總共描述了59個符合納入分析的研究。全部共有4篇隨機控制試驗，多數是群組隨機控制試驗，方法學品質不佳。觀察型研究的品質則不均。
　　
　　根據6個案例控制研究的後設分析，身體方面的介入方式對於預防嚴重急性呼吸道症狀的傳染相當有效。
　　
　　介入方式如下：
　　* 每天洗手超過10次(勝算比[OR]為0.45；95%信心區間[CI]為0.36 - 0.57；需治療人數[NNT]為 4；95% CI，3.65 - 5.52)。
　　* 戴外科口罩(OR，0.32；95% CI，0.25 - 0.40；NNT，6；95% CI，4.54 - 8.03)。
　　* 戴N95口罩(OR，0.09；95% CI，0.03 - 0.30；NNT，3；95% CI，2.37 - 4.06)。
　　* 戴手套(OR，0.43；95% CI，0.29 - 0.65；NNT，5；95% CI，4.15 - 15.41)。
　　* 穿著手術衣(OR，0.23；95% CI，0.14 - 0.37；NNT，5；95% CI，3.37 - 7.12)。
　　* 同時有洗手、戴口罩、手套與穿著手術衣(OR，0.09；95% CI，0.02 - 0.35；NNT，3；95% CI，2.66 - 4.97)。
　　
　　同時有洗手、戴口罩、手套與穿著手術衣，也可有效阻斷居家的流感傳染。根據最高品質的群組隨機試驗結果，對於幼童以及家庭，衛生保健方法可以預防呼吸道病毒傳染。
　　
　　戴起來比較不舒適且昂貴的N95口罩比一般外科口罩更有效的證據有限，而且N95會引起皮膚刺激。在一般洗手中添加殺病毒劑或抗菌劑的附加好處並不確定，全球性的方法，如進入港口時篩檢，則未被適當評估。
　　
　　就曝露風險方面來看，保持社交距離似乎是有效的，曝露風險越高，則採取保持社交距離的期間越久，但是證據有限。
　　
　　回顧作者寫道，例行的長期完成一些阻斷或降低呼吸道病毒擴散的方法是有困難的。不過，許多簡單且低價的介入方式可以用來降低流行性呼吸道病毒的傳染。應投資更多資源於研究哪種身體介入方式最有效、可行且具成本效益，以使急性呼吸道傳染的影響減到最小。
　　
　　研究限制包括納入之研究在方法學方面的限制。
　　
　　研究作者結論表示，在高傳染風險的狀況，需採取使用防護物的方法，例如戴手套、手術衣與有過濾裝置的口罩，且隔離可能的案例。最需採行的方法是透過定期的學校衛生保健教育，讓幼童減少傳染。此外，社會上應投資於更舒適且更佳的口罩與防護器具，以增加使用意願。
　　
　　國家健康服務研究發展計畫、澳洲國家健康與醫學研究委員會支持本研究。回顧作者們皆宣告沒有相關財務關係。

Simple Interventions May Reduce Transmission of Epidemic Respiratory Viruses

By Laurie Barclay, MD
Medscape Medical News

September 23, 2009 — Hygiene and physical measures may effectively reduce transmission of respiratory tract viruses including influenza, according to the results of a systematic review reported in the September 23 issue of the BMJ.

"Our 2007 Cochrane review showed that physical interventions (personal hygiene, barriers, and distancing) are highly effective," write Tom Jefferson, MD, from the Acute Respiratory Infections Group, Cochrane Collaboration, in Rome, Italy, and colleagues. "However, the current mainstay of pandemic interventions still seems to be vaccines and antiviral drugs, with no evidence supporting their widespread use, especially against a seemingly mild threat such as the novel H1N1 virus."

The goal of this review was to assess the evidence for efficacy of physical interventions to interrupt or decrease the spread of respiratory tract viruses. The reviewers searched Cochrane Library, Medline, OldMedline, Embase, and CINAHL for studies published in any language or journal regarding any physical intervention to prevent the transmission of respiratory tract viruses. These interventions included isolation, quarantine, social distancing, barriers, personal protection, and hygiene.

Potentially eligible studies included randomized trials, cohort, case-control, crossover, before-and-after, and time series studies. The reviewers first scanned the titles, abstracts, and full-text articles and used a standardized form to determine whether the others were eligible. They then determined potential bias of randomized trials by evaluating generation of the allocation sequence, allocation concealment, blinding, and follow-up. After determination of potential confounders, nonrandomized studies were categorized as having a low, medium, or high risk for bias.

The reviewers identified 58 articles describing 59 studies eligible for inclusion. For all 4 randomized controlled trials and most cluster randomized controlled trials, methodologic quality was poor. The observational studies were of mixed quality.

Physical measures were highly effective in the prevention of transmission of severe acute respiratory syndrome, according to a meta-analysis of 6 case-control studies. The interventions included the following:

Handwashing more than 10 times daily (odds ratio [OR], 0.45; 95% confidence interval [CI], 0.36 - 0.57; number needed to treat [NNT], 4; 95% CI, 3.65 - 5.52).
Wearing surgical masks (OR, 0.32; 95% CI, 0.25 - 0.40; NNT, 6; 95% CI, 4.54 - 8.03).
Wearing N95 masks (OR, 0.09; 95% CI, 0.03 - 0.30; NNT, 3; 95% CI, 2.37 - 4.06).
Wearing gloves (OR, 0.43; 95% CI, 0.29 - 0.65; NNT, 5; 95% CI, 4.15 - 15.41).
Wearing gowns (OR, 0.23; 95% CI, 0.14 - 0.37; NNT, 5; 95% CI, 3.37 - 7.12).
Handwashing, masks, gloves, and gowns combined (OR, 0.09; 95% CI, 0.02 - 0.35; NNT, 3; 95% CI, 2.66 - 4.97).
The combination of handwashing and use of masks, gloves, and gowns also effectively interrupted influenza transmission within households. In younger children and within households, hygienic measures can prevent respiratory tract virus transmission, according to results from the highest-quality cluster randomized trials.

There was limited evidence that the more uncomfortable and expensive N95 masks were more effective than simple surgical masks, but they caused skin irritation. Any additional benefit of adding virucidals or antiseptics to normal handwashing was uncertain, and global measures, such as screening at entry ports, were not properly assessed.

It appeared that social distancing might be effective if used in relationship to the risk for exposure (the higher the risk, the longer the distancing period), but evidence was limited.

"Routine long term implementation of some of the measures to interrupt or reduce the spread of respiratory viruses might be difficult," the review authors write. "However, many simple and low cost interventions reduce the transmission of epidemic respiratory viruses. More resources should be invested into studying which physical interventions are the most effective, flexible, and cost effective means of minimising the impact of acute respiratory tract infections."

Limitations of this study include methodologic limitations of the included studies.

"In situations of high risk of transmission, barrier measures should be implemented such as wearing gloves, gowns, and masks with a filtration apparatus, and isolation of likely cases," the study authors conclude. "Most effort should be concentrated on reducing transmission from young children through regular education at school on hygiene. In addition, society should invest in more comfortable and better designed face masks and barrier apparatus, which would increase compliance with their use."

The National Health Service research and development programme and the National Health and Medical Research Council of Australia supported this study. The review authors have disclosed no relevant financial relationships.

BMJ. 2009;339:b3675.