The clinical correlates of vaccine-induced immune thrombotic thrombocytopenia after immunisation with adenovirus vector-based SARS-CoV-2 vaccines

Cardiovascular Sequelae of the COVID-19 Vaccines

Vaccines against COVID-19 present a key tool in lowering the morbidity, mortality, and transmission of the disease, but they also present a strongly controversial topic. As a result, the adverse effects of the vaccine have been under scrutiny by the public eye. A comprehensive summary of the cardiovascular (CV) adverse effects of COVID-19 vaccines is vital for clinical recognition of rare adverse events, determining the public health implications, and creating a base for future research. In May 2023, a search was conducted in the PubMed and Cochrane databases to identify literature on CV complications resulting from the COVID-19 vaccine. All articles with relevant data and discussion regarding adverse effects of the COVID-19 vaccines were included in the review. In total, 4419 articles were screened, and 166 articles were included in the review. The vaccine-associated CV adverse events encompassed the following conditions: myocarditis, pericarditis, acute coronary syndrome, stress cardiomyopathy, hypertension, isolated tachycardia, myocardial infarction (MI) with nonobstructive coronary arteries (MINOCA), cardiac arrest, vaccine-induced thrombotic thrombocytopenia (VITT), MI, cerebral venous thrombosis (CVT), deep vein thrombosis (DVT), pulmonary embolism (PE), and other venous thrombotic disorders. Among these, myocarditis and thrombosis, especially VITT, emerged as the most frequently cited complications in the reviewed literature. Ranges of incidences for the following were recorded among the reviewed articles: myocarditis: 2 to 17 per million, VITT: 3-10 per million, CVST: 2.6-10 per million, MI: 3-4 per million. COVID-19 vaccines entail the potential for adverse events, although at low incidence, some of which exhibit notable severity. These adverse events exhibit demographic specificity and vaccine-specific profiles. The adverse events reviewed are uniformly acute in nature. The existing body of evidence offers limited support for the assertion that COVID-19 vaccines may elevate the baseline risk of CV events in the long term. However, the available research on effects greater than six months is scarce.

The impact of Gam-COVID-Vac, an Adv5/Adv26 COVID-19 vaccine, on the biomarkers of endothelial function, coagulation and platelet activation

COVID-19 vaccines have played a critical role in controlling the COVID-19 pandemic. Although overall considered safe, COVID-19 vaccination has been associated with rare but severe thrombotic events, occurring mainly in the context of adenoviral vectored vaccines. A better understanding of mechanisms underlying vaccine-induced hypercoagulability and prothrombotic state is needed to improve vaccine safety profile. We assessed changes to the biomarkers of endothelial function (endothelin, ET-1), coagulation (thrombomodulin, THBD and plasminogen activator inhibitor, PAI) and platelet activation (platelet activating factor, PAF, and platelet factor 4 IgG antibody, PF4 IgG) within a three-week period after the first (prime) and second (boost) doses of Gam-Covid-Vac, an AdV5/AdV26-vectored COVID-19 vaccine. Blood plasma collected from vaccinees (n = 58) was assayed using ELISA assays. Participants were stratified by prior COVID-19 exposure based on their baseline SARS-CoV-2-specific serology results. We observed a significant post-prime increase in circulating ET-1, with levels sustained after the boost dose compared to baseline. ET-1 elevation following dose 2 was most pronounced in vaccinees without prior COVID-19 exposure. Prior COVID-19 was also associated with a mild increase in post-dose 1 PAI. Vaccination was associated with elevated ET-1 up to day 21 after the second vaccine dose, while no marked alterations to other biomarkers, including PF4 IgG, were seen. A role of persistent endothelial activation following COVID-19 vaccination warrants further investigation.

Aboriginal peoples' perspectives about COVID-19 vaccines and motivations to seek vaccination: a qualitative study

INTRODUCTION

Aboriginal and Torres Strait Islander (Aboriginal) people compared with non-Aboriginal people in Australia have higher rates of chronic conditions. These conditions increase the risk of poorer health outcomes if infected with COVID-19, highlighting the importance of COVID-19 vaccination. This study examined what Aboriginal people think about COVID-19 vaccines, reasons why they were vaccinated or not vaccinated and factors involved in receiving COVID-19 vaccination.

METHODS

We used a participatory peer researcher method to interview 35 Aboriginal people aged 15-80 years living in Western Sydney, Australia. Local Aboriginal people who had ties with the community conducted the interviews. The questions and analyses were framed using the WHO's Behavioural and Social Drivers of COVID-19 model. Interviews occurred between February 2021 and March 2021. Peer researchers were paid for their time in training and to conduct the interviews and each participant received $50.

RESULTS

Reasons why participants would seek vaccination included: to protect themselves from infection and severe illness, to protect others in their community, to travel again and to return to 'normal life'. Reasons why some participants were hesitant about being vaccinated included: fear of vaccine side effects; negative stories on social media; and distrust in Australian governments and medical institutions. Aboriginal people preferred to access COVID-19 vaccination through their local Aboriginal Health Service or a general practitioner they already knew.

CONCLUSION

Achieving high vaccination rates in Aboriginal communities is possible if vaccination programmes are delivered through trusted general practitioners or Aboriginal Health Services.

Fighting Fire with Fire: Immunogenicity of Viral Vectored Vaccines against COVID-19

The persistent expansion of the coronavirus disease 2019 (COVID-19) global pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) requires the rapid development of safe and effective countermeasures to reduce transmission, morbidity, and mortality. Several highly efficacious vaccines are actively being deployed around the globe to expedite mass vaccination and control of COVID-19. Notably, viral vectored vaccines (VVVs) are among the first to be approved for global distribution and use. In this review, we examine the humoral, cellular, and innate immune responses elicited by viral vectors, and the immune correlates of protection against COVID-19 in preclinical and clinical studies. We also discuss the durability and breadth of immune response induced by VVVs and boosters. Finally, we present challenges associated with VVVs and offer solutions for overcoming certain limitations of current vaccine regimens. Collectively, this review provides the rationale for expanding the portfolio of VVVs against SARS-CoV-2.