Background: We aimed to estimate vaccine effectiveness (VE) against COVID-19 mortality, and to explore whether an increased risk in non-COVID-19 mortality exists in the weeks following a COVID-19 vaccine dose. Methods: National registries of causes of death, COVID-19 vaccination and long-term care reimbursements were linked by a unique identifier using data from 1 January 2021 to 31 January 2022. We used Cox regression with calendar time as underlying time scale to, firstly, estimate VE against COVID-19 mortality after primary and first booster vaccination, per month since vaccination and, secondly, estimate risk of non-COVID-19 mortality in the 8 weeks following a first, second or booster dose, adjusting for birth year, sex and country of origin. Results: VE against COVID-19 mortality was >90% for all age groups two months after completion of the primary series. VE gradually decreased thereafter, to around 80% at 7-8 months post-primary series for most groups, and around 60% for elderly receiving a high level of long-term care and for people aged 90+ years. The risk of non-COVID-19 mortality was lower or similar in the 8 weeks following a first booster dose compared to no vaccination, first or second dose, respectively, for all age and long-term care groups. Conclusion: COVID-19 vaccination greatly reduced the risk of COVID-19 mortality and no increased risk of death from other causes was seen at the population level.

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