An increased risk of both venous and arterial thromboembolism was noted in reports from SARS-CoV-2-infected patients in China and has been confirmed in autopsy findings from patients who experienced sudden death. Myeloproliferative Neoplasms (MPNs), which encompass polycythemia vera, essential thrombocythemia and primary myelofibrosis, are thrombophilic disorders with a natural propensity to thrombosis that is fuelled by the intrinsic activation of inflammatory cytokines. It therefore follows that an underlying diagnosis of MPN may increase the risk of worse clinical outcomes and death during periods of active Covid-19 disease. This ambispective, observational study aims to elucidate the key factors which affect the clinical course of patients with MPN who develop Covid-19 disease.

This is an European multicenter observational study that will include around 550 MPN patients with a confirmed diagnosis of Covid-19 will be followed for at least one month. Detailed information on the clinical characteristics of these patients and their disease outcomes will be retrospectively and prospectively collected in a specific eCRF, including MPN characteristics, treatment and comorbidities pre-Covid-19, time of Covid-19 diagnosis, drugs/device used for the treatment of Covid-19, any change in MPN therapy, antithrombotic prophylaxis employed during the period of infection and - for hospitalised patients only - key blood and laboratory parameters. A particular focus will be on exploring final outcomes for patients in this study, most notably the incidence of fatal and non-fatal thrombotic events. Statistical analyses will also be performed looking for any independent factors that can significantly predict patient outcomes after Covid-19 diagnosis.

Ultimately, this project will provide important insights into disease severity and progression in patients with MPN and Covid-19 and uncover the key clinical factors which drive outcomes and mortality. Results may help clinicians better understand how patient characteristics and management decisions can impact on disease trajectory when MPN and Covid-19 collide.

Inclusion Criteria:

• Age > 18 years
• Confirmed diagnosed of MPN according to WHO criteria
• Diagnosis of COVID-19 based by the positivity of oropharyngeal swab performed between 15 February 2020 up to 15 February 2022
• Signed informed consent

Exclusion Criteria:

• None

Patients with Myeloproliferative Neoplasm (Polycythemia Vera, Essential Polycythemia, Myelofibrosis) diagnosed with COVID-19 between 15 February 2020 and 15 February 2022

Each participant can visualize its own data on eCRF after the completion patient's electronic data form.