Observational study on the characteristics of COVID-19 transmission dynamics during the first wave of the epidemic in Lusaka, Zambia.

Introduction: coronavirus disease 2019 (COVID-19) transmission dynamics in the communities of low- and middle-income countries, particularly sub-Saharan African countries, are still not fully understood. This study aimed to determine the characteristics of COVID-19 secondary transmission during the first wave of the epidemic (March-October 2020) in Lusaka, Zambia. Methods: we conducted an observational study on COVID-19 secondary transmission among residents in Lusaka City, between March 18 and October 30, 2020. We compared the secondary attack rate (SAR) among different environmental settings of contacts and characteristics of primary cases (e.g, demographics, medical conditions) by logistic regression analysis. Results: out of 1862 confirmed cases of COVID-19, 272 primary cases generated 422 secondary cases through 216 secondary transmission events. More contacts and secondary transmissions were reported in planned residential areas than in unplanned residential areas. Households were the most common environmental settings of secondary transmission, representing 76.4% (165/216) of secondary transmission events. The SAR in households was higher than the overall events. None of the environmental settings or host factors of primary cases showed a statistically significant relationship with SAR. Conclusion: of the settings considered, households had the highest incidence of secondary transmission during the first wave in Lusaka, Zambia. The smaller proportion of contacts and secondary transmission in unplanned residential areas might have been due to underreporting of cases, given that those areas are reported to be vulnerable to infectious disease outbreaks. Continuous efforts are warranted to establish measures to suppress COVID-19 transmission in those high-risk environments.

Cross-sectional study of face mask use during the COVID-19 pandemic-Lusaka and Mansa Districts, Zambia, December 2020.

Introduction: coronavirus disease (COVID-19) is primarily spread through respiratory secretions of infected persons, and face mask use has shown to decrease transmission. In Zambia, anecdotal evidence indicates low face mask use among the general population. We objectively assessed face masks use among Lusaka and Mansa residents in December 2020. Methods: we conducted a cross sectional study of face mask usage in Lusaka and Mansa Districts from 16-23 December 2020. A standardized tool was used to visually observe face mask usage and correct face mask usage at various outdoor locations in Lusaka and Mansa. Logistic regression was used to determine association of face mask use and correct face mask use with selected demographic variables. Odds ratios (ORs) and 95% confidence intervals (CIs) were reported. Results: in total, 4070 persons were observed in Lusaka and 1166 Mansa Districts. Face masks usage was 24% in Lusaka and 27% in Mansa. Among the persons wearing face masks, 621 (48%) wore them correctly (52% in Lusaka and 35% in Mansa; p < 0.01 for difference). Being at a health facility (OR: 10.11 [95% CI: 7.99 - 12.81]), shopping mall (OR: 6.38 [95% CI: 5.07 - 8.03]), and school (OR: 2.39 [95% CI: 1.85 - 3.10]) were associated with wearing face masks compared to being at a bus station. Conclusion: face masks usage in public spaces was low in the two districts in Zambia, which might reduce efforts to control COVID-19. Investigating reasons for poor face masks adherence may help formulate effective strategies to increase face masks utilization in Zambia.