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chuka_lisВышла статья- по результатам прошлогоднего рандомизированного контролируемого испытания (РКИ) в Бангладеш, с участием около 340 тыс человек (в десятках их деревень и сотнях живущих в них общин)- которые носили маски (им бесплатно раздавали) и старались соблюдать социальную дистанцию, мотивированные исследователями и лидерами общин (опыт) или вели себя как обычно (контроль).
Ну, в моем понимании, практически невозможно организовать исследование именно РКИ-типа про эффекты использования масок, из-за лимитаций, потому что контроль фактически слабо осуществим (это совсем не то, что лекарство или контролируемая врачом процедура, как и собраный врачом же анамнез, и анализы, при клиническом испытании), и все скатывается в наблюдение и эпидемиологический сбор данных, причем опросниками (тк все осуществляется в период эпидемии же).
В общем, авторы сделали, что могли чтобы это было РКИ прагматического типа, и согласно их данным- ношение хирургических масок способствует снижению частоты симптоматичного ковида, особенно у стариков за 65 (на треть,около 36%, по сравнению с контролем)., и снижает заболеваемость симптоматичным ковидом в обществе на 11%, если дополнительно примерно 30% жителей начинают пользоваться масками (у них продолжительность ношения масок, в общественных местах- период 10 недель, во время эпидемии).
Социальную дистанцию у них там, не смотря на увещевания, все равно никто особо не соблюдал, потому эффекта выявить не удалось.
Our primary outcome is symptomatic seroprevalence for SARS-CoV-2. We also analyzedthe impact of our intervention on mask-wearing, physical distancing, and COVID-like symptoms. We began with 342,126 individuals atbaseline. We were able to collect follow-up symptom data (whether symptomatic or not) from335,382 (98%). Of these, 27,166 (7.9%) reported COVID-like symptoms during the 8-weeksintervention in their village. We attempted to collect blood samples from all symptomatic individ-uals. Of these, 10,952 (40.3%) consented to have blood collected, including 40.8% in the treatmentgroup and 39.9% in the control group We tested 9,977 (91.1%) of the collected blood samples to determineseroprevalence for SARS-CoV-2 IgG antibodies. Mask-wearing was assessed through direct observation in public locations including mosques,markets, the main entrance roads to villages, and tea stalls. Surveillance staff noted whether adultswere wearing any mask or face covering, whether the mask was one distributed by our project(and if so, the color), and whether the mask was worn over both the mouth and nose. The maskdistribution and promotion was conducted by the Bangladeshi NGO GreenVoice, a grassroots orga-nization with a network of volunteers across the country. Household surveys and surveillance wereperformed independently by Innovations for Poverty Action (IPA).Mask-wearing and physical distancing were measured through direct observation. Surveillancestaff were distinct from intervention implementation staff and conducted surveillance in paired in-tervention and control villages. While SARS-CoV-2 transmission is more likely in indoor locations with limited ventilation than outside, ruralBangladeshi villages have few non-residential spaces where people gather, so observations wereconducted outside except at the mosque, where surveillance was conducted inside Symptom reportingThe owner of the household’s primary phone completed surveys by phoneor in-person at weeks 5 and 9 after the start of the intervention. They were asked to report symp-toms experienced by any household member that occurred in the previous week and over the pre-vious month. COVID-like symptoms were defined by whether they were consistent with the WHOCOVID-19 case definition for suspected or probable cases with an epidemiological link We collected capillary blood samples from participants who reportedCOVID-like symptoms during the study period. For the purposes of blood collection, endlinewas defined as 10-12 weeks from the start of the intervention. SARS-CoV-2 testingBlood samples were tested for the presence of IgG antibodies againstSARS-CoV-2 Mask-wearing was 13.3% in control villages and 42.3% in treatment villages. Our regressionadjusted estimate is an increase of 28.8 % e alsorun our analysis separately in mosques, markets, and other locations such as tea stalls, the entranceof restaurants, and the main road in the village. The increase in mask-wearing was largest inmosques (37.0 percentage points), while in all other locations it was 25-29 percentage points. Contrary to concerns that mask-wearing would promote risk compensation,we did not find evidence that our intervention decreases distancing behavior. While we find increases in physical distancing of 5.1 percentage points pooling across alllocations, there was substantial heterogeneity across locations. In markets, individuals becomesubstantially more likely to physically distance (7.4 percentage points). There was no physicaldistancing practiced in any mosque, in either treatment or control villages, probably as a result ofthe strong religious norm of standing shoulder-to-shoulder when praying. mong the 335,382 participants who completed symptom sur-veys, 27,166 (8.1%) reported experiencing COVID-like illnesses during the study period. Moreparticipants in the control villages reported incident COVID-like illnesses (n=13,893, 8.6%) com-pared with participants in the intervention villages (n=13,273, 7.6%). Over one-third (40.3%) ofsymptomatic participants agreed to blood collection. Omitting symptomatic participants who didnot consent to blood collection, symptomatic seroprevalence was 0.76% in control villages and0.68% in the intervention villages. we estimate a roughly 10% decline in symp-tomatic seroprevalence in the treatment group (adjusted prevalence ratio (aPR) = 0.91 [0.82, 1.00])for a 29 percentage point increase in mask wearing over 8 weeks. We find clear evidence that surgical maskslead to a relative reduction in symptomatic seroprevalence of 11.2% For cloth masks, we find an imprecisezero, although the confidence interval includes the point estimate for surgical masks We find clear evidence that the intervention reduced symptoms: we estimate a reduction of11.9% (adjusted prevalence ratio 0.88 [0.83,0.93]; control group prevalence = 8.59%; treatmentgroup prevalence = 7.60%). Additionally, when we look separately by cloth and surgical masks,we find that the intervention led to a reduction in COVID-like symptoms under either mask type(p=0.000 for surgical,p=0.048 for cloth), Our intervention combined multiple distinct elements: we provided people with free masks; weprovided information about why mask-wearing is important; we had mask promoters reinforcethe importance of mask-wearing by stopping individuals in public places who were not wearing masks, reminding them about the importance of mask-wearing, and giving them a mask if theydid not have one; we partnered with local leaders to encourage mask-wearing at mosques andmarkets; and in some villages we provided a variety of reminders and commitment devices as wellas incentives for village leaders. We find no evidence that the impact of the intervention attenuates over the 10 weeks. In the414 villages for which we have 10 weeks of surveillance, the point estimates are slightly smallerin week 10 (a 23.3 percentage point increase) than week 1 (30.4 percentage points), although thisdifference is not statistically significant. We additionally conducted a follow-up surveillance 5 months after the start of the intervention(20-27 weeks, depending on the wave). Mask-wearing had declined to 14.1% in the control groupand 22.4% in the intervention group In surgical mask villages, weobserve a 23.0% decline in symptomatic seroprevalence among individuals aged 50-60 (adjustedprevalence ratio of 0.77 [0.59,0.95]) and a 34.7% decline among individuals aged 60+ (p=0.001)(adjusted prevalence ratio of 0.65 [0.46, 0.85]). We present results from a cluster-randomized controlled trial of a scalable intervention designed toincrease mask-wearing and reduce cases of COVID-19. Our estimates suggest that mask-wearingincreased by 28.8 percentage points, corresponding to an estimated 51,347 additional adults wear-ing masks in intervention villages, and this effect was persistent even after active mask promotionwas discontinued. The intervention led to a 9.3% reduction in symptomatic SARS-CoV-2 sero-prevalence (which corresponds to a 103 fewer symptomatic seropositives) and an 11.9% reductionin the prevalence of COVID-like symptoms, corresponding to 1,587 fewer people reporting thesesymptoms.9The effects were substantially larger (and more precisely estimated) in communitieswhere we distributed surgical masks, consistent with their greater filtration efficiency measuredin the laboratory (manuscript forthcoming). In villages randomized to receive surgical masks, therelative reduction in symptomatic seroprevalence was 11% overall, 23% among individuals aged50-60, and 35% among those over 60.We found clear evidence that surgical masks are effective in reducing symptomatic seropreva-lence of SARS-CoV-2; while cloth masks clearly reduce symptoms, we cannot reject that they havezero or only a small impact on symptomatic SARS-CoV-2 infections (perhaps reducing symptomsof other respiratory diseases). In summary, we found that mask distribution, role modeling, and promotion in a LMIC settingincreased mask-wearing and physical distancing, leading to lower illness, particularly in olderadults. We find stronger support for the use of surgical masks than cloth masks to prevent COVID-19. Whether people with respiratory symptoms should generally wear masks to prevent respiratoryvirus transmission—including for viruses other than SARS-CoV-2—is an important area for futureresearch. Our findings suggest that such a policy may benefit public health.
Ну, в моем понимании, практически невозможно организовать исследование именно РКИ-типа про эффекты использования масок, из-за лимитаций, потому что контроль фактически слабо осуществим (это совсем не то, что лекарство или контролируемая врачом процедура, как и собраный врачом же анамнез, и анализы, при клиническом испытании), и все скатывается в наблюдение и эпидемиологический сбор данных, причем опросниками (тк все осуществляется в период эпидемии же).
В общем, авторы сделали, что могли чтобы это было РКИ прагматического типа, и согласно их данным- ношение хирургических масок способствует снижению частоты симптоматичного ковида, особенно у стариков за 65 (на треть,около 36%, по сравнению с контролем)., и снижает заболеваемость симптоматичным ковидом в обществе на 11%, если дополнительно примерно 30% жителей начинают пользоваться масками (у них продолжительность ношения масок, в общественных местах- период 10 недель, во время эпидемии).
Социальную дистанцию у них там, не смотря на увещевания, все равно никто особо не соблюдал, потому эффекта выявить не удалось.
Our primary outcome is symptomatic seroprevalence for SARS-CoV-2. We also analyzedthe impact of our intervention on mask-wearing, physical distancing, and COVID-like symptoms. We began with 342,126 individuals atbaseline. We were able to collect follow-up symptom data (whether symptomatic or not) from335,382 (98%). Of these, 27,166 (7.9%) reported COVID-like symptoms during the 8-weeksintervention in their village. We attempted to collect blood samples from all symptomatic individ-uals. Of these, 10,952 (40.3%) consented to have blood collected, including 40.8% in the treatmentgroup and 39.9% in the control group We tested 9,977 (91.1%) of the collected blood samples to determineseroprevalence for SARS-CoV-2 IgG antibodies. Mask-wearing was assessed through direct observation in public locations including mosques,markets, the main entrance roads to villages, and tea stalls. Surveillance staff noted whether adultswere wearing any mask or face covering, whether the mask was one distributed by our project(and if so, the color), and whether the mask was worn over both the mouth and nose. The maskdistribution and promotion was conducted by the Bangladeshi NGO GreenVoice, a grassroots orga-nization with a network of volunteers across the country. Household surveys and surveillance wereperformed independently by Innovations for Poverty Action (IPA).Mask-wearing and physical distancing were measured through direct observation. Surveillancestaff were distinct from intervention implementation staff and conducted surveillance in paired in-tervention and control villages. While SARS-CoV-2 transmission is more likely in indoor locations with limited ventilation than outside, ruralBangladeshi villages have few non-residential spaces where people gather, so observations wereconducted outside except at the mosque, where surveillance was conducted inside Symptom reportingThe owner of the household’s primary phone completed surveys by phoneor in-person at weeks 5 and 9 after the start of the intervention. They were asked to report symp-toms experienced by any household member that occurred in the previous week and over the pre-vious month. COVID-like symptoms were defined by whether they were consistent with the WHOCOVID-19 case definition for suspected or probable cases with an epidemiological link We collected capillary blood samples from participants who reportedCOVID-like symptoms during the study period. For the purposes of blood collection, endlinewas defined as 10-12 weeks from the start of the intervention. SARS-CoV-2 testingBlood samples were tested for the presence of IgG antibodies againstSARS-CoV-2 Mask-wearing was 13.3% in control villages and 42.3% in treatment villages. Our regressionadjusted estimate is an increase of 28.8 % e alsorun our analysis separately in mosques, markets, and other locations such as tea stalls, the entranceof restaurants, and the main road in the village. The increase in mask-wearing was largest inmosques (37.0 percentage points), while in all other locations it was 25-29 percentage points. Contrary to concerns that mask-wearing would promote risk compensation,we did not find evidence that our intervention decreases distancing behavior. While we find increases in physical distancing of 5.1 percentage points pooling across alllocations, there was substantial heterogeneity across locations. In markets, individuals becomesubstantially more likely to physically distance (7.4 percentage points). There was no physicaldistancing practiced in any mosque, in either treatment or control villages, probably as a result ofthe strong religious norm of standing shoulder-to-shoulder when praying. mong the 335,382 participants who completed symptom sur-veys, 27,166 (8.1%) reported experiencing COVID-like illnesses during the study period. Moreparticipants in the control villages reported incident COVID-like illnesses (n=13,893, 8.6%) com-pared with participants in the intervention villages (n=13,273, 7.6%). Over one-third (40.3%) ofsymptomatic participants agreed to blood collection. Omitting symptomatic participants who didnot consent to blood collection, symptomatic seroprevalence was 0.76% in control villages and0.68% in the intervention villages. we estimate a roughly 10% decline in symp-tomatic seroprevalence in the treatment group (adjusted prevalence ratio (aPR) = 0.91 [0.82, 1.00])for a 29 percentage point increase in mask wearing over 8 weeks. We find clear evidence that surgical maskslead to a relative reduction in symptomatic seroprevalence of 11.2% For cloth masks, we find an imprecisezero, although the confidence interval includes the point estimate for surgical masks We find clear evidence that the intervention reduced symptoms: we estimate a reduction of11.9% (adjusted prevalence ratio 0.88 [0.83,0.93]; control group prevalence = 8.59%; treatmentgroup prevalence = 7.60%). Additionally, when we look separately by cloth and surgical masks,we find that the intervention led to a reduction in COVID-like symptoms under either mask type(p=0.000 for surgical,p=0.048 for cloth), Our intervention combined multiple distinct elements: we provided people with free masks; weprovided information about why mask-wearing is important; we had mask promoters reinforcethe importance of mask-wearing by stopping individuals in public places who were not wearing masks, reminding them about the importance of mask-wearing, and giving them a mask if theydid not have one; we partnered with local leaders to encourage mask-wearing at mosques andmarkets; and in some villages we provided a variety of reminders and commitment devices as wellas incentives for village leaders. We find no evidence that the impact of the intervention attenuates over the 10 weeks. In the414 villages for which we have 10 weeks of surveillance, the point estimates are slightly smallerin week 10 (a 23.3 percentage point increase) than week 1 (30.4 percentage points), although thisdifference is not statistically significant. We additionally conducted a follow-up surveillance 5 months after the start of the intervention(20-27 weeks, depending on the wave). Mask-wearing had declined to 14.1% in the control groupand 22.4% in the intervention group In surgical mask villages, weobserve a 23.0% decline in symptomatic seroprevalence among individuals aged 50-60 (adjustedprevalence ratio of 0.77 [0.59,0.95]) and a 34.7% decline among individuals aged 60+ (p=0.001)(adjusted prevalence ratio of 0.65 [0.46, 0.85]). We present results from a cluster-randomized controlled trial of a scalable intervention designed toincrease mask-wearing and reduce cases of COVID-19. Our estimates suggest that mask-wearingincreased by 28.8 percentage points, corresponding to an estimated 51,347 additional adults wear-ing masks in intervention villages, and this effect was persistent even after active mask promotionwas discontinued. The intervention led to a 9.3% reduction in symptomatic SARS-CoV-2 sero-prevalence (which corresponds to a 103 fewer symptomatic seropositives) and an 11.9% reductionin the prevalence of COVID-like symptoms, corresponding to 1,587 fewer people reporting thesesymptoms.9The effects were substantially larger (and more precisely estimated) in communitieswhere we distributed surgical masks, consistent with their greater filtration efficiency measuredin the laboratory (manuscript forthcoming). In villages randomized to receive surgical masks, therelative reduction in symptomatic seroprevalence was 11% overall, 23% among individuals aged50-60, and 35% among those over 60.We found clear evidence that surgical masks are effective in reducing symptomatic seropreva-lence of SARS-CoV-2; while cloth masks clearly reduce symptoms, we cannot reject that they havezero or only a small impact on symptomatic SARS-CoV-2 infections (perhaps reducing symptomsof other respiratory diseases). In summary, we found that mask distribution, role modeling, and promotion in a LMIC settingincreased mask-wearing and physical distancing, leading to lower illness, particularly in olderadults. We find stronger support for the use of surgical masks than cloth masks to prevent COVID-19. Whether people with respiratory symptoms should generally wear masks to prevent respiratoryvirus transmission—including for viruses other than SARS-CoV-2—is an important area for futureresearch. Our findings suggest that such a policy may benefit public health.
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Date: 2021-09-02 01:28 pm (UTC)Спасибо за публикацию!
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Date: 2021-09-02 02:40 pm (UTC)а эпидемиологические есть, и большинство из них о том, что противоэпидемические меры включая макси- помогают бороться с эпидемией.
да и эксперименталные тоже показывают что маски защищают, хоть и не идеально, снижая вирусную нагрузку до 20-90%