Estimating excess mortalities due to the COVID-19 pandemic in Lusaka, Ndola, and Kitwe urban districts in Zambia using burial records data

Abstract Introduction The true mortality impact of the COVID-19 pandemic is difficult to estimate at the national level due to limitations in testing, surveillance, and accurate attribution of cause of death. Therefore, developed nations have used estimates of excess mortality during the pandemic as an objective indicator based on historic national death registration data. This could not be estimated in developing African nations, including Zambia, due to incomplete death registration data hence the true impact of the pandemic in these regions remains potentially underestimated. Since the pandemic primarily concentrated in large cities, this study utilises burial records from Lusaka, Ndola, and Kitwe urban districts in Zambia to estimate COVID-19-associated excess mortalities. Methodology Linear and Negative Binomial Regression were applied on burial permits data, some dating back to 2011, to estimate monthly expected all-cause mortalities and corresponding excess mortalities during the 2020 - 2021 pandemic period. Pearson’s correlation and multivariate linear regression were also used to corroborate excess mortalities with COVID-19 incidence and other meteorological parameters. Results Kitwe and Ndola had substantial gaps in burial records while Lusaka had minimal gaps. On average, Kitwe recorded no excess mortalities while Lusaka and Ndola recorded significant excess mortalities with overall 3,484 (P-score 11.1%) and 378 (P-score 6.1%) excess deaths respectively. This translates to an estimated 3.5 for Lusaka and 1.5 for Ndola COVID-19 deaths undercount ratio. Excess mortality positively correlated with COVID-19 incidence (P < 0.05) suggesting that it was caused by the pandemic and negatively correlated with temperature after controlling for average relative humidity and average hours of sunshine (P < 0.05). Discussion and conclusion The findings of this study show that the mortality impact of COVID-19 was underestimated in Zambia and this may apply to other African nations. It further shows that pandemic excess mortalities can be tracked in African urban centres that have complete burial records data.