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Physical interventions to interrupt or reduce the spread of respiratory viruses: systematic review.

Jefferson T, Del Mar C, Dooley L, Ferroni E, Al-Ansary LA, Bawazeer GA, van Driel ML, Foxlee R, Rivetti A - BMJ (2009)

Bottom Line: The incremental effect of adding virucidals or antiseptics to normal handwashing to reduce respiratory disease remains uncertain.Evidence was limited for social distancing being effective, especially if related to risk of exposure-that is, the higher the risk the longer the distancing period.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.

View Article: PubMed Central - PubMed

Affiliation: Acute Respiratory Infections Group, Cochrane Collaboration, Rome, Italy. jefferson.tom@gmail.com

ABSTRACT

Objective: To review systematically the evidence of effectiveness of physical interventions to interrupt or reduce the spread of respiratory viruses.

Data sources: Cochrane Library, Medline, OldMedline, Embase, and CINAHL, without restrictions on language or publication. Data selection Studies of any intervention to prevent the transmission of respiratory viruses (isolation, quarantine, social distancing, barriers, personal protection, and hygiene). A search of study designs included randomised trials, cohort, case-control, crossover, before and after, and time series studies. After scanning of the titles, abstracts and full text articles as a first filter, a standardised form was used to assess the eligibility of the remainder. Risk of bias of randomised studies was assessed for generation of the allocation sequence, allocation concealment, blinding, and follow-up. Non-randomised studies were assessed for the presence of potential confounders and classified as being at low, medium, or high risk of bias.

Data synthesis: 58 papers of 59 studies were included. The quality of the studies was poor for all four randomised controlled trials and most cluster randomised controlled trials; the observational studies were of mixed quality. Meta-analysis of six case-control studies suggested that physical measures are highly effective in preventing the spread of severe acute respiratory syndrome: handwashing more than 10 times daily (odds ratio 0.45, 95% confidence interval 0.36 to 0.57; number needed to treat=4, 95% confidence interval 3.65 to 5.52), wearing masks (0.32, 0.25 to 0.40; NNT=6, 4.54 to 8.03), wearing N95 masks (0.09, 0.03 to 0.30; NNT=3, 2.37 to 4.06), wearing gloves (0.43, 0.29 to 0.65; NNT=5, 4.15 to 15.41), wearing gowns (0.23, 0.14 to 0.37; NNT=5, 3.37 to 7.12), and handwashing, masks, gloves, and gowns combined (0.09, 0.02 to 0.35; NNT=3, 2.66 to 4.97). The combination was also effective in interrupting the spread of influenza within households. The highest quality cluster randomised trials suggested that spread of respiratory viruses can be prevented by hygienic measures in younger children and within households. Evidence that the more uncomfortable and expensive N95 masks were superior to simple surgical masks was limited, but they caused skin irritation. The incremental effect of adding virucidals or antiseptics to normal handwashing to reduce respiratory disease remains uncertain. Global measures, such as screening at entry ports, were not properly evaluated. Evidence was limited for social distancing being effective, especially if related to risk of exposure-that is, the higher the risk the longer the distancing period.

Conclusion: Routine long term implementation of some of the measures to interrupt or reduce the spread of respiratory viruses might be difficult. 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.

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Related in: MedlinePlus

Effect of frequent handwashing or wearing masks, gloves, or gowns on prevention of cases of severe acute respiratory syndrome
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Related In: Results  -  Collection

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fig1: Effect of frequent handwashing or wearing masks, gloves, or gowns on prevention of cases of severe acute respiratory syndrome

Mentions: Six of the seven case-control studies assessed the impact of public health measures to curb the spread of severe acute respiratory syndrome during February to June 2003 in China, Singapore, and Vietnam. Homogeneity of case definition, agent, settings, and outcomes allowed meta-analysis (table 2, figure). Binary data were pooled; as none of the comparisons showed significant heterogeneity, a fixed effects model was used. Although continuous data were often available, the variables were different and measured in different units, with standard deviations usually missing, which made meta-analysis impossible. Studies reported that disinfection of living quarters was highly effective in preventing the spread of severe acute respiratory syndrome (odds ratio 0.30, 95% confidence interval 0.23 to 0.39)32; handwashing for a minimum of 11 times daily prevented most cases (0.45, 0.36 to 0.57; all six studies),32 33 34 35 37 38 wearing simple masks was highly effective (0.32, 0.25 to 0.40; five studies),32 33 34 35 38 wearing N95 masks was even more effective (0.09, 0.03 to 0.30; two studies)33 37, wearing gloves was effective (0.43, 0.29 to 0.65; three studies),33 35 37 wearing gowns was also effective (0.23, 0.14 to 0.37; four studies),33 35 37 38 and all approaches combined achieved high effectiveness (0.09, 0.02 to 0.35; two studies).33 37 All studies selected cases from hospitals, except one32 which chose cases of probable severe acute respiratory syndrome reported to the Department of Health in Hong Kong. A seventh case-control study36 assessed the impact of environmental, administrative, and host factors in 86 wards in 21 hospitals in Guangzhou and 38 wards in five hospitals in Hong Kong during the severe acute respiratory syndrome pandemic. Six significant risk factors were identified: minimum distance between beds of 1 m or less (odds ratio 6.94, 1.68 to 28.75), availability of washing or changing facilities for staff (0.12, 0.02 to 0.97), whether resuscitation was ever done on the ward (3.81, 1.04 to 13.87), whether staff worked while they had symptoms (10.55, 2.28 to 48.87), whether any index patient or the first patient with severe acute respiratory syndrome admitted to a ward required oxygen therapy (4.30, 1.00 to 18.43), and whether any index patients required bilevel positive airway pressure ventilation (11.82, 1.97 to 70.80).


Physical interventions to interrupt or reduce the spread of respiratory viruses: systematic review.

Jefferson T, Del Mar C, Dooley L, Ferroni E, Al-Ansary LA, Bawazeer GA, van Driel ML, Foxlee R, Rivetti A - BMJ (2009)

Effect of frequent handwashing or wearing masks, gloves, or gowns on prevention of cases of severe acute respiratory syndrome
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC2749164&req=5

fig1: Effect of frequent handwashing or wearing masks, gloves, or gowns on prevention of cases of severe acute respiratory syndrome
Mentions: Six of the seven case-control studies assessed the impact of public health measures to curb the spread of severe acute respiratory syndrome during February to June 2003 in China, Singapore, and Vietnam. Homogeneity of case definition, agent, settings, and outcomes allowed meta-analysis (table 2, figure). Binary data were pooled; as none of the comparisons showed significant heterogeneity, a fixed effects model was used. Although continuous data were often available, the variables were different and measured in different units, with standard deviations usually missing, which made meta-analysis impossible. Studies reported that disinfection of living quarters was highly effective in preventing the spread of severe acute respiratory syndrome (odds ratio 0.30, 95% confidence interval 0.23 to 0.39)32; handwashing for a minimum of 11 times daily prevented most cases (0.45, 0.36 to 0.57; all six studies),32 33 34 35 37 38 wearing simple masks was highly effective (0.32, 0.25 to 0.40; five studies),32 33 34 35 38 wearing N95 masks was even more effective (0.09, 0.03 to 0.30; two studies)33 37, wearing gloves was effective (0.43, 0.29 to 0.65; three studies),33 35 37 wearing gowns was also effective (0.23, 0.14 to 0.37; four studies),33 35 37 38 and all approaches combined achieved high effectiveness (0.09, 0.02 to 0.35; two studies).33 37 All studies selected cases from hospitals, except one32 which chose cases of probable severe acute respiratory syndrome reported to the Department of Health in Hong Kong. A seventh case-control study36 assessed the impact of environmental, administrative, and host factors in 86 wards in 21 hospitals in Guangzhou and 38 wards in five hospitals in Hong Kong during the severe acute respiratory syndrome pandemic. Six significant risk factors were identified: minimum distance between beds of 1 m or less (odds ratio 6.94, 1.68 to 28.75), availability of washing or changing facilities for staff (0.12, 0.02 to 0.97), whether resuscitation was ever done on the ward (3.81, 1.04 to 13.87), whether staff worked while they had symptoms (10.55, 2.28 to 48.87), whether any index patient or the first patient with severe acute respiratory syndrome admitted to a ward required oxygen therapy (4.30, 1.00 to 18.43), and whether any index patients required bilevel positive airway pressure ventilation (11.82, 1.97 to 70.80).

Bottom Line: The incremental effect of adding virucidals or antiseptics to normal handwashing to reduce respiratory disease remains uncertain.Evidence was limited for social distancing being effective, especially if related to risk of exposure-that is, the higher the risk the longer the distancing period.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.

View Article: PubMed Central - PubMed

Affiliation: Acute Respiratory Infections Group, Cochrane Collaboration, Rome, Italy. jefferson.tom@gmail.com

ABSTRACT

Objective: To review systematically the evidence of effectiveness of physical interventions to interrupt or reduce the spread of respiratory viruses.

Data sources: Cochrane Library, Medline, OldMedline, Embase, and CINAHL, without restrictions on language or publication. Data selection Studies of any intervention to prevent the transmission of respiratory viruses (isolation, quarantine, social distancing, barriers, personal protection, and hygiene). A search of study designs included randomised trials, cohort, case-control, crossover, before and after, and time series studies. After scanning of the titles, abstracts and full text articles as a first filter, a standardised form was used to assess the eligibility of the remainder. Risk of bias of randomised studies was assessed for generation of the allocation sequence, allocation concealment, blinding, and follow-up. Non-randomised studies were assessed for the presence of potential confounders and classified as being at low, medium, or high risk of bias.

Data synthesis: 58 papers of 59 studies were included. The quality of the studies was poor for all four randomised controlled trials and most cluster randomised controlled trials; the observational studies were of mixed quality. Meta-analysis of six case-control studies suggested that physical measures are highly effective in preventing the spread of severe acute respiratory syndrome: handwashing more than 10 times daily (odds ratio 0.45, 95% confidence interval 0.36 to 0.57; number needed to treat=4, 95% confidence interval 3.65 to 5.52), wearing masks (0.32, 0.25 to 0.40; NNT=6, 4.54 to 8.03), wearing N95 masks (0.09, 0.03 to 0.30; NNT=3, 2.37 to 4.06), wearing gloves (0.43, 0.29 to 0.65; NNT=5, 4.15 to 15.41), wearing gowns (0.23, 0.14 to 0.37; NNT=5, 3.37 to 7.12), and handwashing, masks, gloves, and gowns combined (0.09, 0.02 to 0.35; NNT=3, 2.66 to 4.97). The combination was also effective in interrupting the spread of influenza within households. The highest quality cluster randomised trials suggested that spread of respiratory viruses can be prevented by hygienic measures in younger children and within households. Evidence that the more uncomfortable and expensive N95 masks were superior to simple surgical masks was limited, but they caused skin irritation. The incremental effect of adding virucidals or antiseptics to normal handwashing to reduce respiratory disease remains uncertain. Global measures, such as screening at entry ports, were not properly evaluated. Evidence was limited for social distancing being effective, especially if related to risk of exposure-that is, the higher the risk the longer the distancing period.

Conclusion: Routine long term implementation of some of the measures to interrupt or reduce the spread of respiratory viruses might be difficult. 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.

Show MeSH
Related in: MedlinePlus