COVID-19 in the Netherlands: lessons from a nationwide query of dutch autopsy, histology, and cytology pathological reports.

Since the onset of the COVID-19 pandemic, autopsies have played a valuable role in understanding the pathophysiology of COVID-19. In this study, we have analyzed COVID-19-related pathology reports from autopsies, histology, and cytology on a nationwide level. Pathology reports from all 43 pathology laboratories in the Netherlands stating "COVID," "Corona," and/or "SARS" were queried from the Dutch Nationwide Pathology Database (Palga). Consecutive reports of the included patients were also retrieved. Out of 5065 entries, a total of 1833 eligible COVID-19-related pathology reports between January 2020 and June 2021 were included in this collection of reports. Lung histopathology reports reflected differences in the severity of abnormalities (acute diffuse alveolar damage, alveolar histiocytes, and thrombi during the first three pandemic waves (Wuhan variant) versus the fourth wave (alpha variant)). Autopsy reports from 2020 state significantly shorter disease duration and younger age of death compared to autopsy reports from 2021. All reports together reflected a more granular pathology with comorbidities such as chronic histiocytic intervillositis, perniosis, and thrombi found in a variety of organs (lungs, kidneys, and small and large intestines). This nationwide overview of pathology reports provides data related to deaths as well as comorbidities in a clinical setting of COVID-19. Certain findings reported in SARS-CoV-infected lungs and placentas were also reported in post-COVID-19 tissue of the same kind. Consecutive reports after the earliest reports with COVID-19 allowed for follow-up reports. These follow-up reports can help with post-viral studies regarding long-term effects of COVID-19 as well as identifying the effects of different SARS-CoV-2 variants.