[First wave of the COVID-19 pandemic in Navarre, Spain, February-June 2020].

Background The COVID-19 pandemic was declared in 2020. The shortage of diagnostic tests limited monitoring of the first wave of the pandemic. This study estimates and describes the wave in Navarre (Spain). Methods Enhanced epidemiological surveillance, seroepidemiological survey estimates and mortality registries were used to characterise the first wave of the COVID-19 pandemic from February to June 2020 in Navarre. Results A total of 10,358 persons (1.6?% of population) were confirmed with COVID-19, 1,943 cases were hospitalized (3 per 1,000 inhabitants), 139 were admitted to the ICU (21 per 100,000 inhabitants), and 529 people died from confirmed COVID-19 (80 per 100,000). Mortality increased exponentially with age, exceeding 1?% in people over 85 years. 58?% of deaths occurred amongst nursing home residents. The mortality registry received reporting of 733 confirmed or probable COVID-19 deaths, while the excess deaths during this period were 613 (20.9?%) concentrated from mid-March to the end of April. It is estimated that, at the end of June, 6.7?% (n?=?44,000) of the population had detectable antibodies against SARS-CoV-2 and 10.3?% had had the infection. The estimates of SARS-CoV-2 infection incidence increased sharply in the first half of March and decreased quickly during the home lockdown in the second half of March. Conclusions The first wave of the pandemic produced a high number of cases, hospitalizations and deaths in Navarre in a few weeks. The pronounced decrease of SARS-CoV-2 infections during the home lockdown suggests considerable efficacy and impact of this measure for transmission control.