[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.