Self-Reported Mask Wearing Greatly Exceeds Directly Observed Use: Urgent Need for Policy Intervention in Kenya

Abstract

BackgroundMany countries in sub-Saharan Africa have so far avoided large outbreaks of COVID-19, perhaps due to the strict lockdown measures that were imposed early in the pandemic. Yet the harsh socio-economic consequences of the lockdowns have led many governments to ease the restrictions in favor of less stringent mitigation strategies. In the absence of concrete plans for widespread vaccination, masks remain one of the few tools available to low-income populations to avoid the spread of SARS-CoV-2 for the foreseeable future.MethodsWe compare mask use data collected through self-reports from phone surveys and direct observations in public spaces from population-representative samples in Ugunja subcounty, a rural setting in Western Kenya. We examine mask use in different situations and compare mask use by gender, age, location, and the riskiness of the activityFindingsWe assess mask use data from 1,960 phone survey respondents and 9,549 direct observations. While only 12% of people admitted in phone interviews to not wearing a mask in public, 90% of people we observed did not have a mask visible (77.7% difference, 95% CI 0.742, 0.802). Self-reported mask use was significantly higher than observed mask use in all scenarios (i.e. in the village, in the market, on public transportation).InterpretationWe find limited compliance with the national government mask mandate in Kenya using directly observed data, but high rates of self-reported mask use. This vast gap suggests that people are aware that mask use is socially desirable, but in practice they do not adopt this behavior.Focusing public policy efforts on improving adoption of mask use via education and behavioral interventions may be needed to improve compliance.FundingWeiss Family Foundation, International Growth Centre

Mask wearing in community settings reduces SARS-CoV-2 transmission

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“…In another wave of surveillance was conducted between June [19][20][21][22]2020 in the same 1,441 locations, and maskwearing dropped to 26%, with 20% wearing masks that covered their mouth and nose and 6% wearing masks improperly. An August 2020 phone survey in rural Kenya found that while 88% of respondents claim to wear masks in public, direct observation revealed that only 10% actually did (34). These observations suggest that mask promotion interventions could be useful in rural areas of low-and middle-income countries (LMIC), home to several billion people at risk for COVID-19.…”

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“…Mask-wearing surveys are still a proxy for actual wearing behaviour, and social desirability bias in survey responses may inflate wearing estimates [43]. In a Kenyan study, the disparity between self-reported wearing and observed wearing was 77% [44]−though this survey was not anonymous, which may have lead to more over-reporting than anonymous surveys such as COVIDNearYou−SurveyMonkey. If data sources over-estimate mask-wearing, then our estimate for the effect of 100% of people wearing masks (most or all of the time) will actually correspond to the effect of less than 100% of people wearing masks.…”