Associations of Government-Mandated Closures and Restrictions With Aggregate Mobility Trends and SARS-CoV-2 Infections in Nigeria
Authors: Daniel O. Erim, Gbemisola A. Oke, Akinyele O. Adisa, Oluwakemi Odukoya, Olalekan A. Ayo-Yusuf, Theodora Nawa Erim, Tina N. Tsafa, Martin M. Meremikwu, Israel T. Agaku
Journal: JAMA Network Open (2021)

<h3>Importance</h3> To prepare for future coronavirus disease 2019 (COVID-19) waves, Nigerian policy makers need insights into community spread of COVID-19 and changes in rates of infection associated with government-mandated closures and restrictions. <h3>Objectives</h3> To measure the association of closures and restrictions with aggregate mobility and the association of mobility with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections and to characterize community spread of COVID-19. <h3>Design, Setting, and Participants</h3> This cross-sectional study used aggregated anonymized mobility data from smartphone users in Nigeria who opted to provide location history (from a pool of up to 40 million individuals) collected between February 27 and July 21, 2020. The analyzed data included daily counts of confirmed SARS-CoV-2 infections and daily changes in aggregate mobility across 6 categories: retail and recreation, grocery and pharmacy, parks, transit stations, workplaces, and residential. Closures and restrictions were initiated on March 30, 2020, and partially eased on May 4, 2020. <h3>Main Outcomes and Measures</h3> Interrupted time series were used to measure associations of closures and restrictions with aggregate mobility. Negative binomial regression was used to evaluate associations between confirmed SARS-CoV-2 infections and mobility categories. Averted infections were estimated by subtracting cumulative confirmed infections from estimated infections assuming no closures and restrictions. <h3>Results</h3> Closures and restrictions had negative associations with mean change in daily aggregate mobility in retail and recreation (–46.87 [95% CI, –55.98 to –37.76] percentage points;<i>P</i> &lt; .001), grocery and pharmacy (–28.95 [95% CI, –40.12 to –17.77] percentage points;<i>P</i> &lt; .001), parks (–43.59 [95% CI, –49.89 to –37.30] percentage points;<i>P</i> &lt; .001), transit stations (–47.44 [95% CI, –56.70 to –38.19] percentage points;<i>P</i> &lt; .001), and workplaces (–53.07 [95% CI, –67.75 to –38.39] percentage points;<i>P</i> &lt; .001) and a positive association with mobility in residential areas (24.10 [95% CI, 19.14 to 29.05] percentage points;<i>P</i> &lt; .001). Most of these changes reversed after closures and restrictions were partially eased (retail and recreation: 14.63 [95% CI, 10.95 to 18.30] percentage points;<i>P</i> &lt; .001; grocery and pharmacy: 15.29 [95% CI, 10.90 to 19.67] percentage points;<i>P</i> &lt; .001; parks: 6.48 [95% CI, 3.98 to 8.99] percentage points;<i>P</i> &lt; .001; transit stations: 17.93 [95% CI, 14.03 to 21.83] percentage points;<i>P</i> &lt; .001; residential: –5.59 [95% CI, –9.08 to –2.09] percentage points;<i>P</i> = .002). Additionally, every percentage point increase in aggregate mobility was associated with higher incidences of SARS-CoV-2 infection in residential areas (incidence rate ratio [IRR], 1.03 [95% CI, 1.00 to 1.07];<i>P</i> = .04), transit stations (IRR, 1.02 [95% CI, 1.00 to 1.03];<i>P</i> = .008), and workplaces (IRR, 1.01 [95% CI, 1.00 to 1.02];<i>P</i> = .04). Lastly, closures and restrictions may have been associated with averting up to 5.8 million SARS-CoV-2 infections over the study period. <h3>Conclusions and Relevance</h3> In this cross-sectional study, closures and restrictions had significant associations with aggregate mobility and were associated with decreased SARS-CoV-2 infections. These findings suggest that future anticontagion measures need better infection control and contact tracing in residential areas, transit stations, and workplaces.