The United Kingdom, European Union, and Scandinavian countries have reported rare cases of cerebral sinus vein thrombosis (CSVT) and thrombocytopenia in patients who received the AstraZeneca COVID-19 vaccine in the previous 4 to 20 days. It is rare, occurring in anywhere from 1 in every 125,000 to 1 in 1 million people , ; and most of the cases have occurred in women under age 55, although these countries used most of their initial AstraZeneca vaccine supply in this particular age group and may therefore be overrepresented.
The Paul Ehrlich Institute has described that affected individuals in Germany have antibodies that induce massive platelet activation, reducing the platelet count and causing thrombosis. This phenomenon mimics heparin-induced thrombocytopenia (HIT) yet it does not require heparin as a trigger. However, since VIPIT is immune-mediated, an individual with a thrombophilia, a family history of blood clots, or a personal history of arterial or venous clots would likely not be at increased risk of VIPIT. Accordingly, there are no new contraindications to receiving the AstraZeneca vaccine.
In case VIPIT is suspected, the recommended treatment might be similar to that of HIT, this is, intravenous gammaglobulin and non-heparin derived anticoagulants.
 Clinicaltrials.gov. APhase III Randomized, Double-blind, Placebo-controlled Multicenter Study inAdults to Determine the Safety, Efficacy, and Immunogenicity of AZD1222, aNon-replicating ChAdOx1 Vector Vaccine, for the Prevention of COVID-19.[Online] Available at: https://clinicaltrials.gov/ct2/show/NCT04516746?term=NCT04516746&draw=2&rank=1. Last accessed: March2021.
 Pai M, Grill A, Ivers N, etal. Vaccine induced prothrombotic immune thrombocytopenia VIPIT followingAstraZeneca COVID-19 vaccination. Science Briefs of the Ontario COVID-19Science Advisory Table. 2021;1(17).https://doi.org/10.47326/ocsat.2021.02.17.1.0
PINHO AC. COVID-19 VaccineAstraZeneca: benefits still outweigh the risks despite possible link to rare blood clots with low platelets. European Medicines Agency. Published March 18,2021. Accessed March 31, 2021. https://www.ema.europa.eu/en/news/covid-19-vaccine-astrazeneca-benefits-still-outweigh-risks-despite-possible-link-rare-blood-clots
 Updated GTH statement on vaccination with the AstraZeneca COVID-19 vaccine, as of March 22, 2021.Published March 18, 2021. Accessed March 31, 2021. https://gth-online.org/wp-content/uploads/2021/03/GTH_Stellungnahme_AstraZeneca_3_24_2021.pdf