A comprehensive analysis of adverse events during clinical trials and over the course of mass vaccinations with the Sputnik V vaccine coronavirus showed that there were no cases of cerebral venous sinus thrombosis (CVST).
All vaccines based on adenoviral vector platform are different and not directly comparable. In particular, AstraZeneca’s ChAdOx1-S vaccine uses chimpanzee adenovirus to deliver the antigen, consisting of S-protein combined with leader sequence of tissue-type plasminogen activator. The vaccine from Johnson&Johnson uses human adenovirus serotype Ad26 and full-length S-protein stabilized by mutations. In addition, it is produced using the PER.C6 cell line (embryonic retinal cells), which is not widely represented among other registered products.
Sputnik V is a two-component vaccine in which adenovirus serotypes 5 and 26 are used. A fragment of tissue-type plasminogen activator is not used, and the antigen insert is an unmodified full-length S-protein. Sputnik V vaccine is produced with the HEK293 cell line, which has long been safely used for the production of biotechnological products.
Thus, all of the above vaccines based on adenoviral vectors have significant differences in their structure and production technology. Therefore, there is no reason and no justification to extrapolate safety data from one vaccine to safety data from other vaccines.
The quality and safety of Sputnik V are, among other things, assured by the fact that, unlike other vaccines, it uses a 4-stage purification technology that includes two stages of chromatography and two stages of tangential flow filtration. This purification technology helps to obtain a highly purified product that goes through mandatory control including the analysis of free DNA presence. In addition, the volume of nucleic acid is several dozen times lower in adenoviral vectors compared to Pfizer and Moderna vaccines (1 to 2 mcg vs 50 to 100 mcg, correspondingly).
A study published in The New England Journal of Medicine on April 9, 2021, discusses that the cause of the thrombosis in some patients vaccinated with other vaccines could be insufficient purification that leads to the emergence of significant quantities of free DNA. Insufficient purification or use of very high doses of target DNA/RNA can result in adverse interaction of a patient’s antibodies that activate thrombocytes with elements of the vaccine itself and/or free DNA/RNA, which can form a complex with the PF4 factor.
Link to the study:
The Gamaleya Center is ready to share its purification technology with other vaccine producers in order to help them minimize the risk of adverse effects during vaccination.
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