Project description:Until now, there are more than two hundred million confirmed cases of COVID-19 including more than seven million deaths. Clinical trials of all three vaccines authorized for use in the UK (Pfizer–BioNTech, Oxford–AstraZeneca, and Moderna) have reported high vaccine efficacy. This rapid systematic review was initiated because no systematic review had been conducted to determine the safety and efficacy of AstraZeneca ChAdOx1 nCoV-19 vaccine. Evidence acquisition: A systematic search in the following platforms: PubMed, Google Scholar, Scopus, WOS, and MEDLINE databases for all articles in the English language regarding safety and efficacy of SARS-CoV-2 vaccine ChAdOx1 nCoV-19 was performed. Papers published up to end of June were included. Evidence synthesis: Out of 477 retrieved articles, fifteen are included. All the selected articles are concerned with evaluation of AstraZeneca ChAdOx1 nCoV-19 vaccine. Three of them discussed the effectiveness of ChAdOx1 nCoV-19 vaccine, while thirteen (one is common with the group of the effectiveness) measured the adverse effects associated with the vaccine. Because thrombosis was recorded as a serious adverse effect developed after ChAdOx1 nCoV-19 vaccination, it was emphasized in a special group to be analyzed separately. In conclusion: the main message of selected papers was that the value of ChAdOx1 nCoV-19 vaccination to provide critical protection should be considered higher compared to the significant worldwide burden of the emerging COVID-19 infection. No causal relations were found to link cases- having thrombotic adverse reactions to the vaccine. Supplementary Information The online version contains supplementary material available at 10.1186/s43168-021-00109-3.
Project description:SARS-CoV-2 vaccine ChAdOx1 nCoV-19 (AstraZeneca) causes a thromboembolic complication termed vaccine-induced immune thrombotic thrombocytopenia (VITT). Using biophysical techniques, mouse models, and analysis of VITT patient samples, we identified determinants of this vaccine-induced adverse reaction. Super-resolution microscopy visualized vaccine components forming antigenic complexes with platelet factor 4 (PF4) on platelet surfaces to which anti-PF4 antibodies obtained from VITT patients bound. PF4/vaccine complex formation was charge-driven and increased by addition of DNA. Proteomics identified substantial amounts of virus production-derived T-REx HEK293 proteins in the ethylenediaminetetraacetic acid (EDTA)-containing vaccine. Injected vaccine increased vascular leakage in mice, leading to systemic dissemination of vaccine components known to stimulate immune responses. Together, PF4/vaccine complex formation and the vaccine-stimulated proinflammatory milieu trigger a pronounced B-cell response that results in the formation of high-avidity anti-PF4 antibodies in VITT patients. The resulting high-titer anti-PF4 antibodies potently activated platelets in the presence of PF4 or DNA and polyphosphate polyanions. Anti-PF4 VITT patient antibodies also stimulated neutrophils to release neutrophil extracellular traps (NETs) in a platelet PF4-dependent manner. Biomarkers of procoagulant NETs were elevated in VITT patient serum, and NETs were visualized in abundance by immunohistochemistry in cerebral vein thrombi obtained from VITT patients. Together, vaccine-induced PF4/adenovirus aggregates and proinflammatory reactions stimulate pathologic anti-PF4 antibody production that drives thrombosis in VITT. The data support a 2-step mechanism underlying VITT that resembles the pathogenesis of (autoimmune) heparin-induced thrombocytopenia.
Project description:Background there are very few reports of COVID-19 vaccine related multiple sclerosis (MS) relapses. Here we report our first case of ChAdOx1 nCoV-19 Corona virus vaccine related MS relapse. Case presentation a 24- year- old lady doctor, who had taken ChAdOx1 nCoV-19 Corona virus vaccine got a relapse after seven days of the last dose (second) of the vaccine. Relapse was in the form of paresthesias involving her left upper and lower limbs and Lhermitte's phenomena. She responded fairly well to a short course of steroids. Conclusions this case highlights the importance of counselling MS patients regarding the potential for relapse pre-vaccination and closely monitoring MS patients who are administered the ChAdOx1 nCoV-19 Corona Virus vaccine for any relapse.
Project description:ChAdOx1 nCov-19 and Ad26.COV2.S are approved vaccines inducing protective immunity against SARS-CoV-2 infection in humans by expressing the Spike protein of SARS-CoV-2. We analyzed protein content and protein composition of ChAdOx1 nCov-19 and Ad26.COV2.S by biochemical methods and by mass spectrometry. Four out of four tested lots of ChAdOx1 nCoV-19 contained significantly higher than expected levels of host cell proteins (HCPs) and of free viral proteins. The most abundant contaminating HCPs belonged to the heat-shock protein and cytoskeletal protein families. The HCP content exceeded the 400 ng specification limit per vaccine dose, as set by the European Medicines Agency (EMA) for this vaccine, by at least 25-fold and the manufacturer's batch-release data in some of the lots by several hundred-fold. In contrast, three tested lots of the Ad26.COV2.S vaccine contained only very low amounts of HCPs. As shown for Ad26.COV2.S production of clinical grade adenovirus vaccines of high purity is feasible at an industrial scale. Correspondingly, purification procedures of the ChAdOx1 nCov-19 vaccine should be modified to remove protein impurities as good as possible. Our data also indicate that standard quality assays, as they are used in the manufacturing of proteins, have to be adapted for vectored vaccines.
Project description:Recent reports of thrombosis following AstraZeneca COVID-19 vaccine in young females (<55 years-old) led to temporary suspension and urgent investigation by the European Medicines Agency (EMA) that concluded that vaccine benefits still outweigh its side effects (SEs). Therefore, this study aims to provide early independent evidence on the vaccine SEs' prevalence and their potential risk factors; a cross-sectional survey-based study was carried out between February and March 2021 in Germany and Czech Republic among healthcare workers who recently received the AstraZeneca COVID-19 vaccine. The study used a validated self-administered questionnaire composed of twenty-eight multiple-choice items covering demographic variables, medical anamneses, and local, systemic, oral, and skin related SEs of the vaccine. Out of the ninety-two included participants, 77.2% were females and 79.3% were from Germany. Their mean age was 35.37 ± 12.62 (19-64) years-old, 15.2% had chronic illnesses and 22.8% were receiving medical treatments. Overall, 94.6% of the participants reported at least one SE. The most common local SE was injection site pain (72.8%), and the most common systemic SEs were fatigue (73.9%), muscle pain (55.4%), chills (48.9%), feeling unwell (46.7%), nausea (45.7%), and headache (29.3%). The vast majority (91.9%) resolved within 1-3 days, and the below 35 years-old group was the least affected age group. The SEs' frequency was insignificantly higher in females and previously infected participants; the vaccine safety for the elderly was supported by the early findings of this study. Chronic illnesses and medical treatments were not associated with an increased risk of SE incidence and frequency. No blood disorder SEs were reported in our sample. Further independent studies are highly required to evaluate the safety of the AstraZeneca vaccine and to explore whether gender or previous infection could be associated with the vaccine SEs.
Project description:Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) emerged in December 20191,2 and is responsible for the coronavirus disease 2019 (COVID-19) pandemic3. Vaccines are an essential countermeasure and are urgently needed to control the pandemic4. Here we show that the adenovirus-vector-based vaccine ChAdOx1 nCoV-19, which encodes the spike protein of SARS-CoV-2, is immunogenic in mice and elicites a robust humoral and cell-mediated response. This response was predominantly mediated by type-1 T helper cells, as demonstrated by the profiling of the IgG subclass and the expression of cytokines. Vaccination with ChAdOx1 nCoV-19 (using either a prime-only or a prime-boost regimen) induced a balanced humoral and cellular immune response of type-1 and type-2 T helper cells in rhesus macaques. We observed a significantly reduced viral load in the bronchoalveolar lavage fluid and lower respiratory tract tissue of vaccinated rhesus macaques that were challenged with SARS-CoV-2 compared with control animals, and no pneumonia was observed in vaccinated SARS-CoV-2-infected animals. However, there was no difference in nasal shedding between vaccinated and control SARS-CoV-2-infected macaques. Notably, we found no evidence of immune-enhanced disease after viral challenge in vaccinated SARS-CoV-2-infected animals. The safety, immunogenicity and efficacy profiles of ChAdOx1 nCoV-19 against symptomatic PCR-positive COVID-19 disease will now be assessed in randomized controlled clinical trials in humans.
Project description:BackgroundAssessment of the safety and efficacy of vaccines against the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in different populations is essential, as is investigation of the efficacy of the vaccines against emerging SARS-CoV-2 variants of concern, including the B.1.351 (501Y.V2) variant first identified in South Africa.MethodsWe conducted a multicenter, double-blind, randomized, controlled trial to assess the safety and efficacy of the ChAdOx1 nCoV-19 vaccine (AZD1222) in people not infected with the human immunodeficiency virus (HIV) in South Africa. Participants 18 to less than 65 years of age were assigned in a 1:1 ratio to receive two doses of vaccine containing 5×1010 viral particles or placebo (0.9% sodium chloride solution) 21 to 35 days apart. Serum samples obtained from 25 participants after the second dose were tested by pseudovirus and live-virus neutralization assays against the original D614G virus and the B.1.351 variant. The primary end points were safety and efficacy of the vaccine against laboratory-confirmed symptomatic coronavirus 2019 illness (Covid-19) more than 14 days after the second dose.ResultsBetween June 24 and November 9, 2020, we enrolled 2026 HIV-negative adults (median age, 30 years); 1010 and 1011 participants received at least one dose of placebo or vaccine, respectively. Both the pseudovirus and the live-virus neutralization assays showed greater resistance to the B.1.351 variant in serum samples obtained from vaccine recipients than in samples from placebo recipients. In the primary end-point analysis, mild-to-moderate Covid-19 developed in 23 of 717 placebo recipients (3.2%) and in 19 of 750 vaccine recipients (2.5%), for an efficacy of 21.9% (95% confidence interval [CI], -49.9 to 59.8). Among the 42 participants with Covid-19, 39 cases (95.1% of 41 with sequencing data) were caused by the B.1.351 variant; vaccine efficacy against this variant, analyzed as a secondary end point, was 10.4% (95% CI, -76.8 to 54.8). The incidence of serious adverse events was balanced between the vaccine and placebo groups.ConclusionsA two-dose regimen of the ChAdOx1 nCoV-19 vaccine did not show protection against mild-to-moderate Covid-19 due to the B.1.351 variant. (Funded by the Bill and Melinda Gates Foundation and others; ClinicalTrials.gov number, NCT04444674; Pan African Clinical Trials Registry number, PACTR202006922165132).