| − | *Adam Achs, Tatiana Sedlackova, Lukas Predajna, Jaroslav Budis, Maria Bartosova, Vladimir Zelnik, Diana Rusnakova, Martina Melichercikova, Marta Miklosova, Veronika Gencurova, Barbora Cernakova, Tomas Szemes, Boris Klempa, Juraj Kopacek & Silvia Pastorekova: ''Systematic analysis of COVID-19 mRNA vaccines using four orthogonal approaches demonstrates no excessive DNA impurities'', npj Vaccines volume 10, Article number: 259 (13. Dezember 2025)<br>''Abstract - Despite substantial evidence for benefits of vaccination in mitigating the COVID-19 pandemic, the use of mRNA vaccines faces skepticism built on coincidental health events occurring after vaccination without proven causality. One of the claims regarding excessive amounts of residual DNA from the vaccine manufacturing process has arisen from misinterpretation of improperly conducted analyses. Here, we assessed the quantity, quality and identity of residual DNA in mRNA vaccines based on thoroughly performed and properly interpreted orthogonal methods, including qPCR, fluorometry, capillary electrophoresis and short-read DNA sequencing. Our results show that the quantity of residual DNA in all 15 analysed batches of Comirnaty and Spikevax vaccines is below approved limits and that it consists of small fragments originating from the template used to transcribe mRNA during vaccine production. We demonstrate that reliable mRNA vaccine analysis for DNA impurities requires rigorous application of well-controlled methods that minimise mutual interference of vaccine components.'' | + | *Adam Achs, Tatiana Sedlackova, Lukas Predajna, Jaroslav Budis, Maria Bartosova, Vladimir Zelnik, Diana Rusnakova, Martina Melichercikova, Marta Miklosova, Veronika Gencurova, Barbora Cernakova, Tomas Szemes, Boris Klempa, Juraj Kopacek & Silvia Pastorekova: ''Systematic analysis of COVID-19 mRNA vaccines using four orthogonal approaches demonstrates no excessive DNA impurities'', npj Vaccines volume 10, Article number: 259 (13. Dezember 2025)<br>''Abstract - Despite substantial evidence for benefits of vaccination in mitigating the COVID-19 pandemic, the use of mRNA vaccines faces skepticism built on coincidental health events occurring after vaccination without proven causality. One of the claims regarding excessive amounts of residual DNA from the vaccine manufacturing process has arisen from misinterpretation of improperly conducted analyses. Here, we assessed the quantity, quality and identity of residual DNA in mRNA vaccines based on thoroughly performed and properly interpreted orthogonal methods, including qPCR, fluorometry, capillary electrophoresis and short-read DNA sequencing. Our results show that the quantity of residual DNA in all 15 analysed batches of Comirnaty and Spikevax vaccines is below approved limits and that it consists of small fragments originating from the template used to transcribe mRNA during vaccine production. We demonstrate that reliable mRNA vaccine analysis for DNA impurities requires rigorous application of well-controlled methods that minimise mutual interference of vaccine components.'' ...''Despite these facts, the public domain contains reports on the evaluation of residual DNA in final COVID-19 mRNA vaccine products. According to the results of analyses published in the form of peer-reviewed scientific publications in reputable scientific journals and the statements by regulatory and control authorities, the amount of residual DNA does not exceed the established limit of 10 ng per vaccine dose2,4,8,9,10....<br>...Overall, we analysed the presence of DNA in the vaccines using 8 different combinations of primers and targets. The outputs from these qPCR tests of all analysed vaccine batches are summarised in Fig. 3 and individually shown in Figs. S3–S5. Results were initially expressed as the number of copies per µl of sample, and subsequently calculated to the number of copies per vaccine dose. Since regulatory standards are established as the total amount of DNA in nanograms per vaccine dose, and not in copy numbers, we then converted this copy number data to nanograms of DNA per dose, based on the molecular weight of the template plasmid DNA. The results obtained by the analysis of all vaccine batches using all qPCR assays demonstrated no presence of excessive residual DNA. ... Results of the fluorometric assessment of residual DNA isolated from all vaccine batches by two alternative methods are summarised in Fig. 5. In accordance with the qPCR analysis, quantity of residual DNA was in all cases below the limits set by the regulatory guidelines. The differences between the data obtained from each extraction method reflect variations in extraction yields between the two methods. Moreover, different vaccine vials were used for each extraction method....Overall, our findings provide independent confirmation of the regulatory compliance of mRNA vaccines with respect to residual DNA content. In addition to supporting ongoing public vaccination programs, this study also demonstrates the value of transparent, science-based investigations in addressing misinformation and strengthening vaccine confidence. Future research may explore the dynamics of DNA degradation over extended storage or evaluate alternative purification technologies, though our findings indicate no current need for concern under existing manufacturing practices.'' |