Excess mortality in Latvia in association with COVID-19 in 2020

During the COVID-19 pandemic, the measure of excess mortality is used to assess the pandemic's total impact on crude mortality. Excess mortality captures not only COVID-19 confirmed death but also undiagnosed or not reported COVID-19 death and death from other causes that are attributable to the overall crisis conditions. The study analyzed the changes in the crude-mortality per 100,000 population in Latvia in 2020 compared to the average mortality rates during the previous five years, i.e., 2015–2019. All-cause monthly and COVID-19 monthly mortality data were obtained from the Causes of Death database from the Centre for Disease Prevention and Control. Excess mortality was calculated using monthly and cumulative monthly mortality differences with P-score. Both monthly excess mortality (differences in mortality rates per month) and cumulative monthly excess mortality (differences in cumulative mortality rates per month) were calculated. Positive excess mortality indicates that the observed mortality is higher than expected. The study was implemented within the State Research Program VPP-COVID-2020/1-0011. The first COVID-19 death in Latvia was registered in April 2020. Since May 2020, positive excess mortality in the following months was observed. Excess of cumulative monthly mortality remained negative until November 2020; however, since March, the constant reduction in cumulative monthly differences occurred, and in December, the cumulative monthly excess mortality was positive. In May, June, August, and September, less than 10% of excess mortality was attributed to COVID-19 mortality. In July, 45%, in October, 30%, more than 70% of excess mortality was related to COVID-19 mortality in November and December. Findings of excess mortality suggest the cause-of-death structure should be studied in detail by investigating the trends of cause-specific mortality rates contributing to all-cause mortality changes in Latvia.