Millica Phiri
Emergency Operation Center, Zambia National Public Health Institute, Lusaka, Zambia; Incident Management System, Zambia National Public Health Institute, Lusaka, Zambia
Tadatsugu Imamura
Japan International Cooperation Agency, Tokyo, Japan; Center for Postgraduate Education and Training, National Center for Child Health and Development, Tokyo, Japan
Patrick Sakubita
Emergency Operation Center, Zambia National Public Health Institute, Lusaka, Zambia; Incident Management System, Zambia National Public Health Institute, Lusaka, Zambia
Nelia Langa
Emergency Operation Center, Zambia National Public Health Institute, Lusaka, Zambia; Incident Management System, Zambia National Public Health Institute, Lusaka, Zambia
Moses Mulenga
Emergency Operation Center, Zambia National Public Health Institute, Lusaka, Zambia; Incident Management System, Zambia National Public Health Institute, Lusaka, Zambia
Marian Matipa Mulenga
Emergency Operation Center, Zambia National Public Health Institute, Lusaka, Zambia; Incident Management System, Zambia National Public Health Institute, Lusaka, Zambia
George Kapapi
Emergency Operation Center, Zambia National Public Health Institute, Lusaka, Zambia; Incident Management System, Zambia National Public Health Institute, Lusaka, Zambia
Michael Mwamba
Emergency Operation Center, Zambia National Public Health Institute, Lusaka, Zambia; Incident Management System, Zambia National Public Health Institute, Lusaka, Zambia
Jane Nalwimba
Emergency Operation Center, Zambia National Public Health Institute, Lusaka, Zambia; Incident Management System, Zambia National Public Health Institute, Lusaka, Zambia
Deborah Tembo
Emergency Operation Center, Zambia National Public Health Institute, Lusaka, Zambia; Incident Management System, Zambia National Public Health Institute, Lusaka, Zambia
Kingsley Keembe
Emergency Operation Center, Zambia National Public Health Institute, Lusaka, Zambia; Incident Management System, Zambia National Public Health Institute, Lusaka, Zambia
Karen Moompizho
Emergency Operation Center, Zambia National Public Health Institute, Lusaka, Zambia; Incident Management System, Zambia National Public Health Institute, Lusaka, Zambia
Nkomba Kayeyi
Incident Management System, Zambia National Public Health Institute, Lusaka, Zambia
William Ngosa
Incident Management System, Zambia National Public Health Institute, Lusaka, Zambia
Davie Simwaba
Incident Management System, Zambia National Public Health Institute, Lusaka, Zambia
Paul Msanzya Zulu
Incident Management System, Zambia National Public Health Institute, Lusaka, Zambia
Fred Kapaya
Incident Management System, Zambia National Public Health Institute, Lusaka, Zambia
Raymond Hamoonga
Incident Management System, Zambia National Public Health Institute, Lusaka, Zambia
Mazyanga Lucy Mazaba
Incident Management System, Zambia National Public Health Institute, Lusaka, Zambia
Nyambe Sinyange
Incident Management System, Zambia National Public Health Institute, Lusaka, Zambia
Muzala Kapina
Incident Management System, Zambia National Public Health Institute, Lusaka, Zambia
Chie Nagata
Center for Postgraduate Education and Training, National Center for Child Health and Development, Tokyo, Japan
Nathan Kapata
Incident Management System, Zambia National Public Health Institute, Lusaka, Zambia
Akira Ishiguro
Center for Postgraduate Education and Training, National Center for Child Health and Development, Tokyo, Japan
Victor Mukonka
Incident Management System, Zambia National Public Health Institute, Lusaka, Zambia
Abstract
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.
