Vaxzevria and mRNA COVID-19 vaccines showed similar and favourable safety profiles in a population-based cohort study of over a million people

AstraZenecaIn a large real-world study, data published as a pre-print on The Lancet server from over one million individuals assessed the incidence rates of blood clotting disorders of thromboembolism and thrombocytopenia, including the very rare thrombosis with thrombocytopenia (TTS) following vaccination with an mRNA vaccine or Vaxzevria, and compared them with expected rates in a general population and in people with COVID-19.

Safety profiles of Vaxzevria, and the mRNA-based vaccine were similar and overall favourable. Very rare clotting disorders (TTS) were observed with both vaccines but these were in line with what would be expected in the general population and lower than in those diagnosed with COVID-19.(1) Follow-up time was not sufficient to report rates after two doses of Vaxzevria, though other studies have shown rates of rare blood clotting events to be lower after a second dose.(2)

Regardless of the vaccine used, the increase in rates of thrombosis among persons infected with COVID-19 was far higher than among those vaccinated. Rates of venous thromboembolism were eight times higher after a diagnosis of COVID-19 infection compared with the expected rate.

Sir Mene Pangalos, Executive Vice President, BioPharmaceuticals R&D, said: "This real-world study offers further evidence of the favourable benefit:risk profile of Vaxzeria and demonstrates the critical role all COVID-19 vaccines are playing in combatting the pandemic."

The analysis included 945,941 mRNA participants (778,534 with two doses), 426,272 Vaxzevria participants, conducted between 27 December 2020 and 19 May 2021. It also included 222,710 COVID-19 participants identified between 1 September 2020 and 1 March 2021, and 4,570,149 background participants as of 1 January 2017 from a public health database held in Catalonia, Spain.

The results are in line with recent reports in the Medicines and Healthcare products Regulatory Agency (MHRA) Yellow Card Report, the UK system for collecting and monitoring information on safety concerns, which also show low rates of TTS after a second dose.(2)

No specific risk factors or definitive cause for TTS following COVID-19 vaccination have been identified and AstraZeneca continues to perform and support ongoing investigations of potential mechanisms. Furthermore, these very rare events can be managed when symptoms are identified and treated appropriately.(3)

About Vaxzevria, formerly AZD1222

Vaxzevria was co-invented by the University of Oxford and its spin-out company, Vaccitech. It uses a replication-deficient chimpanzee viral vector based on a weakened version of a common cold virus (adenovirus) that causes infections in chimpanzees and contains the genetic material of the SARS-CoV-2 virus spike protein. After vaccination, the surface spike protein is produced, priming the immune system to attack the SARS-CoV-2 virus if it later infects the body.

The vaccine has been granted a conditional marketing authorisation or emergency use in more than 80 countries across six continents. More than 800 million doses of COVID-19 Vaccine AstraZeneca have been supplied to more than 170 countries worldwide, including more than 100 countries through the COVAX Facility.

About AstraZeneca

AstraZeneca (LSE/STO/Nasdaq: AZN) is a global, science-led biopharmaceutical company that focuses on the discovery, development, and commercialisation of prescription medicines in Oncology, Rare Diseases and BioPharmaceuticals, including Cardiovascular, Renal & Metabolism, and Respiratory & Immunology. Based in Cambridge, UK, AstraZeneca operates in over 100 countries and its innovative medicines are used by millions of patients worldwide.

1. Burn, E (2021) Thromboembolic events and thrombosis with thrombocytopenia after COVID-19 infection and vaccination in Catalonia, Spain. Pre-print Online: https://papers.ssrn.com/sol3/papers.cfm?abstract_id=3886421
2. Bhuyan P., et al., (2021) Thrombosis with thrombocytopenia after second AZD1222 dose: a global safety database analysis of rare cases. The Lancet. Published Online: https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(21)01693-7/fulltext
3. MHRA. Coronavirus vaccine - weekly summary of Yellow Card reporting - GOV.UK 1 July Update. Available at: https://www.gov.uk/government/publications/coronavirus-covid-19-vaccine-adverse-reactions/coronavirus-vaccine-summary-of-yellow-card-reporting
4. Bussel, J.B., et al. (2021) Thrombosis with Thrombocytopenia Syndrome (also termed Vaccine-induced Thrombotic Thrombocytopenia): https://www.hematology.org/covid-19/vaccine-induced-immune-thrombotic-thrombocytopenia

Most Popular Now

SK bioscience and GSK start Phase 3 trial of adjuv…

SK bioscience (SK) and GlaxoSmithKline plc (GSK) today announced the initiation of a Phase 3 clinical study of SK's COVID-19 vaccine candidate, GBP510, in combination wit...

No serious health effects linked to mRNA COVID-19 …

Federal and Kaiser Permanente researchers combing the health records of 6.2 million patients found no serious health effects that could be linked to the 2 mRNA COVID-19 v...

Blood vessels produce growth factor that promotes …

Blood vessels supply tumors with nutrients and, on the other hand, enable cancer cells to spread throughout the body. The settlement of circulating tumor cells in a dista...

First-in-human clinical trial for a vaccine to tre…

The first patients have been enrolled in a phase 1 randomized placebo-controlled clinical trial to study a therapeutic vaccine for opioid use disorder developed by resear...

Sandoz strengthens pipeline by entering into agree…

Sandoz, a Novartis division, today announced that it has entered into a commercialization agreement with Bio-Thera Solutions, Ltd. for biosimilar bevacizumab (BAT1706). B...

Pfizer and BioNTech submit a variation to EMA with…

Pfizer Inc. (NYSE: PFE) and BioNTech SE (Nasdaq: BNTX) announced that they submitted a variation to the European Medicines Agency (EMA) requesting to update the Condition...

A drug costing less than €2 a day helps in the tre…

Metoprolol, a drug widely used to treat cardiovascular disease, is beneficial when administered to COVID-19patients. This is the finding of a study by investigators at th...

Rheumatoid arthritis treated with implanted cells …

With a goal of developing rheumatoid arthritis therapies with minimal side effects, researchers at Washington University School of Medicine in St. Louis have genetically ...

NIH scientists build a cellular blueprint of multi…

Chronic lesions with inflamed rims, or "smoldering" plaques, in the brains of people with multiple sclerosis (MS) have been linked to more aggressive and disabling forms ...

Scientific evidence to date on COVID-19 vaccine ef…

An expert review by an international group of scientists, including some at the WHO and FDA, concludes that, even for the delta variant, vaccine efficacy against severe C...

How a plant virus could protect and save your lung…

Using a virus that grows in black-eyed pea plants, nanoengineers at the University of California San Diego developed a new treatment that could keep metastatic cancers at...

COVID-19 nasal vaccine candidate effective at prev…

Breathe in, breathe out. That’s how easy it is for SARS-CoV-2, the virus that causes COVID-19, to enter your nose. And though remarkable progress has been made in develop...