NCT04471766.

Study name	Evaluation of locally produced cloth face mask on COVID‐19 and respiratory illnesses prevention at the community level ‐ a cluster‐RCT
Methods	Study type: interventional (clinical trial) Estimated enrolment: 66,000 participants Allocation: randomised Intervention model: parallel assignment Masking: single (outcomes assessor) Primary purpose: prevention
Participants	Ages eligible for study: 10 years and older (child, adult, older adult) Sexes eligible for study: all Accepts healthy volunteers: no Criteria Inclusion criteria: Household resident Age 10 years and older Exclusion criteria: Refusal to participate
Interventions	Experimental: certified cloth face mask plus preventive information Active comparator: information on COVID‐19 prevention
Outcomes	Self‐reported main symptoms of COVID‐19 (3 or more of fever, cough, fatigue, shortness of breath, loss of smell/taste) Consultation for COVID‐19 like illness or reported positive test, or both Self reported COVID‐19 like illness plus hospitalisation or death Any death during the follow‐up period: Reported COVID‐19 like illness (time frame: 4 months' follow‐up) Consultation (time frame: 4 months' follow‐up) Severe illness (time frame: 4 months' follow‐up) Mortality (time frame: 4 months' follow‐up)
Starting date	Estimated study start date: July 2020
Contact information	Amabelia Rodrigues, PhD, 00245966078659; a.rodrigues@bandim.org
Notes	The number of cases of COVID‐19 is still increasing, and transmission of SARS‐CoV‐2 seems to occur mainly through person‐to‐person transmission through respiratory droplets, indirect contact with infected people and surfaces. The use of face masks is recommended as a public health measure, but in many settings only domestic cloth made masks are available to the majority of the people. However, masks can be of different quality, and very little is known about the utility of cloth face masks at the community level. In Bandim Health Project's Health and Demographic Surveillance System we evaluated the effect of providing locally produced cloth face masks on the severity of COVID‐19 like illness and mortality in an urban population. The locally produced cloth mask is made according to a laboratory‐certified model and was provided to the intervention group alongside information of how the risk of transmission can be reduced. The control group received information alone. Follow‐up will be implemented through telephone calls and post epidemic home visits.

ARI: acute respiratory tract infections
GUV: germicidal ultraviolet
ILI: influenza‐like illness
GI: gastrointestinal
n: number
RACF: residential aged care facilities
RCT: randomised controlled trial
SARS: severe acute respiratory syndrome