Right from my home town!
Your daily reminder that masks are useless
[TW]1435293355039150080[/TW]
was there a control county
here is a study across villages in Bangladesh that had control villages
https://www.poverty-action.org/site..._RCT____Symptomatic_Seropositivity_083121.pdf
Background: Mask usage remains low across many parts of the world during the COVID19 pandemic, and strategies to increase mask-wearing remain untested. Our objectives were
to identify strategies that can persistently increase mask-wearing and assess the impact of
increasing mask-wearing on symptomatic SARS-CoV-2 infections.
Methods: We conducted a cluster-randomized trial of community-level mask promotion in
rural Bangladesh from November 2020 to April 2021 (N=600 villages, N=342,126 adults).
We cross-randomized mask promotion strategies at the village and household level, including
cloth vs. surgical masks. All intervention arms received free masks, information on the importance of masking, role modeling by community leaders, and in-person reminders for 8 weeks.
The control group did not receive any interventions. Neither participants nor field staff were
blinded to intervention assignment. Outcomes included symptomatic SARS-CoV-2 seroprevalence (primary) and prevalence of proper mask-wearing, physical distancing, and symptoms
consistent with COVID-19 (secondary). Mask-wearing and physical distancing were assessed
through direct observation at least weekly at mosques, markets, the main entrance roads to
villages, and tea stalls. At 5 and 9 weeks follow-up, we surveyed all reachable participants
about COVID-related symptoms. Blood samples collected at 10-12 weeks of follow-up for
symptomatic individuals were analyzed for SARS-CoV-2 IgG antibodies.
Results: There were 178,288 individuals in the intervention group and 163,838 individuals
in the control group. The intervention increased proper mask-wearing from 13.3% in control
villages (N=806,547 observations) to 42.3% in treatment villages (N=797,715 observations)
(adjusted percentage point difference = 0.29 [0.27, 0.31]). This tripling of mask usage was sustained during the intervention period and two weeks after. Physical distancing increased from
24.1% in control villages to 29.2% in treatment villages (adjusted percentage point difference
= 0.05 [0.04, 0.06]). After 5 months, the impact of the intervention faded, but mask-wearing
remained 10 percentage points higher in the intervention group.
The proportion of individuals with COVID-like symptoms was 7.62% (N=13,273) in the
intervention arm and 8.62% (N=13,893) in the control arm. Blood samples were collected
from N=10,952 consenting, symptomatic individuals.
Adjusting for baseline covariates, the
2
intervention reduced symptomatic seroprevalence by 9.3% (adjusted prevalence ratio (aPR) =
0.91 [0.82, 1.00]; control prevalence 0.76%; treatment prevalence 0.68%). I
n villages randomized to surgical masks (n = 200), the relative reduction was 11.2% overall (aPR = 0.89 [0.78,
1.00]) and 34.7% among individuals 60+ (aPR = 0.65 [0.46, 0.85]). No adverse events were
reported.
Conclusions: Our intervention demonstrates a scalable and effective method to promote mask
adoption and reduce symptomatic SARS-CoV-2 infections.