Excess deaths in Spain during the first year of the COVID–19 pandemic outbreak from age/sex–adjusted death rates

O bjectives Assess the impact of the illness designated COVID–19 during the first year of pandemic outbreak in Spain through age/sex–specific death rates. S tudy design Age/sex–specific weeekly deaths in Spain were retrieved from Eurostat. Spanish resident population was obtained from the National Statistics Office. M ethods Generalized linear Poisson regressions were used to compute the contrafactual expected rates after one year (52 weeks or 364 days) of the pandemic onset. From this one–year age/sex–specific and age/sex–adjusted mortality excess rates were deduced. R esults For the past continued 13 years one–year age/sex–adjusted death rates had not been as high as the rate observed on February 28th, 2021. The excess death rate was estimated as 1.790×10 −3 (95 % confidence interval, 1.773×10 −3 to 1.808×10 −3 ; P −score = 20.2 % and z −score = 11.4) with an unbiased standard deviation of the residuals equal to 157×10 −6 . This made 84 849 excess deaths (84 008 to 85 690). Sex disaggregation resulted in 44 887 (44 470 to 45 303) male excess deaths and 39 947 (39 524 to 40 371) female excess deaths. C onclusion With 73 571 COVID–19 deaths and 9772 COVID–19 suspected deaths that occurred in nursing homes during the spring of 2020 it is only 1496 excess deaths (1.8 %, a z −score of 0.2) that remains unattributed. The infection rate during the first year of the pandemic is estimated in 16 % of population after comparing the ENE–COVID seroprevalence, the excess deaths at the end of the spring 2020 and the excess deaths at the end of the first year of the pandemic.