Analysis of Thrombotic Adverse Reactions of COVID-19 AstraZeneca Vaccine reported to EudraVigilance database

Abstract

The development of safe, effective, affordable vaccines against COVID-19 remains the cornerstone to mitigating this pandemic. Early December 2020, multiple research groups had designed potential vaccines. From 11 March 2021, several European countries temporarily suspended the use of the Oxford-AstraZeneca vaccine amid reports of blood clot events and death of a vaccinated person, despite the European Medicines Agency and the World Health Organization assurance that there was no indication that vaccination was linked. This study aimed to identify and analyse the thrombotic adverse reactions associated with Oxford-AstraZeneca vaccine. This was a retrospective descriptive study using spontaneous reports submitted to the EudraVigilance database in the period from 17 February to 12 March 2021. There were 54,571 adverse reaction reports of which 28 were associated with thrombotic adverse reactions. Three fatalities were related to Pulmonary Embolism; 1 fatality to Thrombosis. With 17 million people having had the AstraZeneca vaccine, these are extremely rare events. The EMA’s Pharmacovigilance Risk Assessment Committee (18 March 2021) concluded that the vaccine was safe, effective and the benefits outweighed the risks. Conducting further analyses based on more detailed thrombotic adverse event reports, including patients’ characteristics and comorbidities, may enable assessment of the causality with higher specificity.

Safety and Reactogenicity of the ChAdOx1 (AZD1222) COVID-19 Vaccine in Saudi Arabia

“…There had been no reported anaphylactic reactions among AstraZeneca Oxford COVID-19 vaccine recipients (Moghimi, 2021). Previous studies had shown the occurrence of anaphylactic reactions after AstraZeneca COVID-19 vaccine and one study reported thrombotic events at the time when 17 million people were vaccinated (Tobaiqy et al, 2021). There are several limitations of the current study.…”

Insights in ChAdOx1 nCoV-19 vaccine-induced immune thrombotic thrombocytopenia

“…We hypothesized that ChAdOx1 nCoV-19 vaccine induces a proinflammatory "danger signal" that promotes pathologic anti-PF4 antibody production in autoimmune HIT and possibly in VITT. 25,26 Accordingly, we sought to characterize the vaccine composition. Unexpectedly, we found 70-80 µg protein/mL in four independent ChAdOx1 nCoV-19 vaccine lots analyzed.…”

Adverse events and preventive measures related to COVID-19 vaccines

“…7 Safety reports of COVID-19 vaccines demonstrated in previous studies are summarized in Table 1. 7,10,11,[30][31][32][33]…”

“…Interestingly, unlike the mRNA vaccine, the presence of systemic adverse reactions after the second dose did not occur at a higher proportion than that after the first dose. 10,11,32 Another study reported the prophylactic effect of paracetamol on adverse reactions. 33 Although solicited local and systemic adverse reactions were more common in the ChAdOx1 nCoV-19 group than in the control group, prophylactic paracetamol reduced the frequency of adverse reactions, including pain, fever, chills, headache, and malaise.…”

“…35 In a previous study conducted using the EudraVigilance database from February 17, to March 12, 2021, a total of 54,571 adverse reactions were reported, and 28 cases were identified as thromboembolic events. 32 Among the total patients, 19 were female, and two female patients and one male patient died. Most of the thromboembolic events reported were deep vein thrombosis and pulmonary thromboembolism, while there were two cases of pelvic vein thrombosis and one case each of cerebral venous sinus thrombosis, carotid artery thrombosis, and thrombophlebitis.…”