Mary Wilson
Well-known member
Published: 09 November 2022
DOI https://doi.org/10.1038/s41541-022-00569-8
Alessandra Buoninfante, Arno Andeweg, Alexander T. Baker, Mitesh Borad, Nigel Crawford, Jean-Michel Dogné, David Garcia-Azorin, Andreas Greinacher, Rita Helfand, Anders Hviid, Stefan Kochanek, Marta López-Fauqued, Ishac Nazy, Anand Padmanabhan, Sue Pavord, Daniel Prieto-Alhambra, Huyen Tran, Ulla Wandel Liminga & Marco Cavaleri
... Vaccines have been pivotal to prevent infectious diseases and have shown their immense public health value in reducing morbidity and mortality associated with transmissible diseases. Following the WHO declaration of the COVID-19 pandemic[SUP]1[/SUP] caused by the SARS-COV-2 virus, a global effort was made to develop vaccines against COVID-19, with a number of those being approved in expedited manner in the European Union (EU)[SUP]2[/SUP] and worldwide. Following the approval and rapid roll-out of adenovirus vector COVID-19 vaccines, very rare cases of thromboembolic events with low platelet counts were reported among people vaccinated with ChAdOx1-S AstraZeneca and Ad26.COV2.S Janssen COVID-19 vaccines, Vaxzevria and JCOVDEN, respectively, initially in Austria and Denmark[SUP]3[/SUP] and subsequently all over Europe. These cases emerged also in North America[SUP]4[/SUP] and Australia[SUP]5[/SUP]. Vaccinees affected by thrombosis with thrombocytopenia manifested severe cases of thrombosis, including unusual sites such as cerebral venous sinus thrombosis, splanchnic vein thrombosis, as well as arterial thrombosis, concomitant with thrombocytopenia, and often presence of anti-platelet factor 4 (PF4) antibodies. In addition, high mortality rates in those patients were observed[SUP]6[/SUP]. This syndrome named ‘thrombosis with thrombocytopenia syndrome’ (TTS) or when TTS is not better accounted for by another cause and anti-PF4 antibodies are present, is referred as vaccine-induced immune thrombotic thrombocytopenia (VITT), a newly identified very rare adverse reaction that in the majority of individuals occurs within the first three weeks following vaccination with the first dose of COVID-19 adenovirus vector vaccines. Estimations of the incidence of TTS range from 3.2 to 16.1 cases per million doses for Vaxzevria and 1.7 to 3.7 cases per million doses for JCOVDEN[SUP]7[/SUP]. Reporting rates of Convidencia, an adenovirus type 5-based vector vaccine, are 0.0081 cases per million vaccinees[SUP]8[/SUP]. It has been suggested that TTS/VITT occurs more frequently after the ChAdOx1-S AstraZeneca then after Ad26.COV2.S Janssen COVID-19 vaccines. However, differences in the frequency of use of these vaccines and differences in the surveillance methods across the world make it difficult to draw definite conclusions. As more cases of TTS post vaccination emerged, researchers and relevant stakeholders began to study the disease mechanism underlying this rare adverse event.
https://www.nature.com/articles/s41541-022-00569-8#citeas
DOI https://doi.org/10.1038/s41541-022-00569-8
Alessandra Buoninfante, Arno Andeweg, Alexander T. Baker, Mitesh Borad, Nigel Crawford, Jean-Michel Dogné, David Garcia-Azorin, Andreas Greinacher, Rita Helfand, Anders Hviid, Stefan Kochanek, Marta López-Fauqued, Ishac Nazy, Anand Padmanabhan, Sue Pavord, Daniel Prieto-Alhambra, Huyen Tran, Ulla Wandel Liminga & Marco Cavaleri
... Vaccines have been pivotal to prevent infectious diseases and have shown their immense public health value in reducing morbidity and mortality associated with transmissible diseases. Following the WHO declaration of the COVID-19 pandemic[SUP]1[/SUP] caused by the SARS-COV-2 virus, a global effort was made to develop vaccines against COVID-19, with a number of those being approved in expedited manner in the European Union (EU)[SUP]2[/SUP] and worldwide. Following the approval and rapid roll-out of adenovirus vector COVID-19 vaccines, very rare cases of thromboembolic events with low platelet counts were reported among people vaccinated with ChAdOx1-S AstraZeneca and Ad26.COV2.S Janssen COVID-19 vaccines, Vaxzevria and JCOVDEN, respectively, initially in Austria and Denmark[SUP]3[/SUP] and subsequently all over Europe. These cases emerged also in North America[SUP]4[/SUP] and Australia[SUP]5[/SUP]. Vaccinees affected by thrombosis with thrombocytopenia manifested severe cases of thrombosis, including unusual sites such as cerebral venous sinus thrombosis, splanchnic vein thrombosis, as well as arterial thrombosis, concomitant with thrombocytopenia, and often presence of anti-platelet factor 4 (PF4) antibodies. In addition, high mortality rates in those patients were observed[SUP]6[/SUP]. This syndrome named ‘thrombosis with thrombocytopenia syndrome’ (TTS) or when TTS is not better accounted for by another cause and anti-PF4 antibodies are present, is referred as vaccine-induced immune thrombotic thrombocytopenia (VITT), a newly identified very rare adverse reaction that in the majority of individuals occurs within the first three weeks following vaccination with the first dose of COVID-19 adenovirus vector vaccines. Estimations of the incidence of TTS range from 3.2 to 16.1 cases per million doses for Vaxzevria and 1.7 to 3.7 cases per million doses for JCOVDEN[SUP]7[/SUP]. Reporting rates of Convidencia, an adenovirus type 5-based vector vaccine, are 0.0081 cases per million vaccinees[SUP]8[/SUP]. It has been suggested that TTS/VITT occurs more frequently after the ChAdOx1-S AstraZeneca then after Ad26.COV2.S Janssen COVID-19 vaccines. However, differences in the frequency of use of these vaccines and differences in the surveillance methods across the world make it difficult to draw definite conclusions. As more cases of TTS post vaccination emerged, researchers and relevant stakeholders began to study the disease mechanism underlying this rare adverse event.
https://www.nature.com/articles/s41541-022-00569-8#citeas