The COVID-19 pandemic reshaped mortality across the world, but official COVID-19 death counts often tell only part of the story. In countries where reporting practices differ or health systems are under strain, many pandemic-related deaths may be hidden in other causes. Understanding the true impact of the pandemic therefore requires looking beyond COVID-19 itself. In this new working paper, Ekaterina Degtiareva, whose PhD research is based at the Leverhulme Centre for Demographic Science (LCDS), together with Sergey Timonin, Andrea Tilstra (LCDS), and José Manuel Aburto, provide the first detailed cause-specific analysis of excess mortality in Russia during 2020–2021.
Using national weekly and regional monthly mortality data, the study applies compositional generalised additive models to estimate excess mortality by cause, age, and sex, and then across regions. The authors estimate over one million excess deaths in Russia during the pandemic—almost twice the number officially attributed to COVID-19 . Crucially, they show that this gap is largely explained by increases in cardiovascular mortality, which account for around 60% of non-COVID excess deaths . This pattern suggests that many COVID-19 deaths may have been misclassified, while others reflect indirect effects such as disrupted healthcare.
The analysis also reveals stark inequalities. Excess mortality varied widely across regions and demographic groups: women experienced particularly high mortality at older ages, while men saw substantial excess deaths at working ages. Two major mortality waves, in late 2020 and late 2021, drove much of the overall burden.
The study highlights how institutional factors, such as death certification practices, healthcare capacity, and public trust, shape how pandemic mortality is recorded and understood. By combining detailed cause-of-death data with compositional modelling, the work provides a clearer picture of the pandemic’s true toll and underscores the importance of mortality surveillance for public health policy.
Find the working paper here https://medrxiv.org/cgi/content/short/2026.03.23.26349084v1
