Skip to main content
Timely Topics

COVID-19 Resources

The following information addresses common public health questions about mRNA COVID-19 vaccines. It reflects currently available data from global health authorities and scientific literature. This information does not replace recommendations from health authorities or healthcare providers.

Topics are updated on an ongoing basis. Last updated December 8, 2025.

People discussing a print out around a table

Timely Topics

DNA Contamination

Biodistribution Studies

Cancer Risk

Pediatric Safety

IgG4 Class Switching

Myocarditis

References

  1. Therapeutic Goods Administration (TGA). Summary report of residual DNA and endotoxin on COVID-19 mRNA vaccines conducted by TGA Laboratories. 2024. https://www.tga.gov.au/resources/publication/tga-laboratory-testing-reports/summary-report-residual-dna-and-endotoxin-covid-19-mrna-vaccines-conducted-tga-laboratories
  2. World Health Organization (WHO). Guidelines on the quality, safety and efficacy of biotherapeutic protein products prepared by recombinant DNA technology. WHO Technical Report Series No. 987, Annex 4. Geneva: WHO, 2014. https://cdn.who.int/media/docs/default-source/biologicals/biotherapeutics/trs_987_annex4.pdf?sfvrsn=d4ba378a_5
  3. FDA (2010). Guidance for Industry: Characterization and Qualification of Cell Substrates and Other Biological Materials Used in the Production of Viral Vaccines. Washington, DC. https://www.fda.gov/media/78428/download
  4. Ibid.
  5. International Council for Harmonisation (ICH). Q2(R2): Validation of Analytical Procedures. Step 4 adopted 1 Nov 2023. https://database.ich.org/sites/default/files/ICH_Q2%28R2%29_Guideline_2023_1130.pdf
  6. Ibid.
  7. König B, Kirchner J. Methodological considerations regarding the quantification of DNA impurities in the COVID-19 mRNA vaccine Comirnaty®. Methods and Protocols. 2024;7(3):41. https://www.mdpi.com/2409-9279/7/3/41
  8. Kaiser S, Kaiser S, Reis J, Marschalek R. Quantification of objective concentrations of DNA impurities in mRNA vaccines. Vaccine. 2025;55:127022. doi: 10.1016/j.vaccine.2025.127022.
  9. Ibid.
  10. Paul-Ehrlich-Institut (PEI). Testing of mRNA vaccines for residual DNA contamination. Updated 2025. https://www.pei.de/SharedDocs/Downloads/EN/newsroom-en/notification/231222-testing-mrna-vaccinas-dna-contamination.pdf?__blob=publicationFile&v=3
  11. Therapeutic Goods Administration (TGA). Summary report of residual DNA and endotoxin on COVID-19 mRNA vaccines conducted by TGA Laboratories. 2024. https://www.tga.gov.au/news/media-releases/addressing-misinformation-about-excessive-dna-mrna-vaccines
  12. U.S. Food and Drug Administration (FDA). Letter to Florida Surgeon General regarding mRNA vaccines and DNA concerns. December 14, 2023. https://www.fda.gov/files/emergency preparedness and response/published/final_fl_sg_response_12142023.pdf
  13. European Medicines Agency (EMA). Spikevax (previously COVID-19 Vaccine Moderna). Updated September 2025. https://www.ema.europa.eu/en/medicines/human/EPAR/spikevax
  14. Bhattacharjee S, et al. Immunological and Antigenic Signatures Associated with Chronic Post-Vaccination Syndrome (PVS) in COVID-19 Vaccinees. medRxiv [Preprint]. February 2025. https://www.medrxiv.org/content/10.1101/2025.02.18.25322379v1
  15. Ibid.
  16. ModernaTX. Data on File (as of 10/2025)
  17. Gómez-Mantilla JD, et al. ADME process in vaccines and PK/PD approaches for vaccination optimization. In: Zhou H, Theil P, eds. ADME Translational PK/PD of Therapeutic Proteins. John Wiley & Sons; 2016:1–22
  18. NIH: National Cancer Institute. What is Cancer? https://www.cancer.gov/about-cancer/understanding/what-is-cancer
  19. Centers for Disease Control and Prevention (CDC). COVID-19 Vaccine Basics. Updated September 2024. https://www.cdc.gov/covid/vaccines/how-they-work.html
  20. Rosa, Sara et al. mRNA Vaccines Manufacturing: Challenges and Bottlenecks. Vaccine. 2021 Mar 24;39(16):2190–2200. doi: 10.1016/j.vaccine.2021.03.038
  21. U.S. Food and Drug Administration (FDA), Center for Biologics Evaluation and Research (CBER). Letter to Florida Surgeon General Joseph A. Ladapo regarding mRNA COVID-19 vaccines and residual DNA/SV40 concerns. December 14, 2023. https://www.fda.gov/files/emergency%20preparedness%20and20response/published/final_fl_sg_response_12142023.pdf
  22. Vaccines and Related Biological Products Advisory Committee. May 22, 2025. Meeting Presentation – Moderna- COVID-19 Vaccines Update. https://www.fda.gov/advisory-committees/advisory-committee-calendar/vaccines-and-related-biological-products-advisory-committee-may-22-2025-meeting-announcement
  23. U.S. Food and Drug Administration (FDA), Center for Biologics Evaluation and Research (CBER). Letter to Florida Surgeon General Joseph A. Ladapo regarding mRNA COVID-19 vaccines and residual DNA/SV40 concerns. December 14, 2023. https://www.fda.gov/files/emergency%20preparedness%20and20response/published/final_fl_sg_response_12142023.pdf
  24. Australian Government DOH, Disability & Ageing. Is it True? Get the Facts on COVID-19 Vaccines. May 2024. https://www.health.gov.au/our-work/covid-19-vaccines/is-it-true
  25. European Medicines Agency. COVID-19 vaccine: Key facts. https://www.ema.europa.eu/en/human-regulatory-overview/public-health-threats/coronavirus-disease-covid-19/covid-19-medicines/covid-19-vaccines-key-facts
  26. Meyer, S. Centers for Disease Control & Prevention (CDC). Update on CDC’s COVID-19 Vaccine Safety Monitoring. June 2025 Advisory Committee on Immunization Practices (ACIP) Meeting. https://www.cdc.gov/acip/downloads/slides-2025-06-25-26/04-Meyer-COVID-508.pdf
  27. Hause et al. Safety Monitoring of Bivalent COVID-19 mRNA Vaccine Booster Doses Among Children Aged 5–11 Years — United States, October 12–January 1, 2023. MMWR Morb Mortal Wkly Rep. 2023 Jan 13;72(2):39-43. https://doi.org/10.15585/mmwr.mm7202a5
  28. Hu, M et al. Safety of ancestral monovalent BNT162b2, mRNA-1273, and NVX-CoV2373 COVID-19 vaccines in U.S. children aged 6 months–17 years. JAMA Network Open, 7(4), e248192; 2024. https://pmc.ncbi.nlm.nih.gov/articles/PMC11043896/
  29. Goddard et al. Safety of COVID-19 mRNA Vaccination Among Young Children in the Vaccine Pediatrics. 2023 Jul 1;152(1):e2023061894. https://doi.org/10.1542/peds.2023-061894
  30. HHS, 2025. ACIP Recommends COVID-19 Immunization Based on Individual Decision-making. https://www.hhs.gov/press-room/acip-recommends-covid19-vaccination-individual-decision-making.html
  31. CDC. About the Vaccine Adverse Event Reporting System (VAERS). https://www.cdc.gov/vaccine-safety-systems/vaers/index.html
  32. Meyer, S. Centers for Disease Control & Prevention (CDC). Update on CDC’s COVID-19 Vaccine Safety Monitoring. June 2025 Advisory Committee on Immunization Practices (ACIP) Meeting. https://www.cdc.gov/acip/downloads/slides-2025-06-25-26/04-Meyer-COVID-508.pdf
  33. Sørup S, Rasmussen T, Fry C, et al. Monitoring the safety of mRNA-1273 COVID-19 vaccine in the general population: results of a regulator-mandated post-authorisation safety study in Denmark, Norway, Spain, and the United Kingdom (EUPAS44273). International Society for Pharmacoepidemiology Annual Meeting; 2025. [Abstract 5C-01, 2025 ISPE Meeting]. https://2025ispe.eventscribe.net/ajaxcalls/presenterInfo.asp?PresenterId=2169776
  34. Vaccines and Related Biological Products Advisory Committee. May 22, 2025. Meeting Presentation – Moderna- COVID-19 Vaccines Update. https://www.fda.gov/advisory-committees/advisory-committee-calendar/vaccines-and-related-biological-products-advisory-committee-may-22-2025-meeting-announcement
  35. Australian Government DOH, Disability & Ageing. COVID-19 vaccine safety report - 02-11-23. https://www.tga.gov.au/news/covid-19-vaccine-safety-reports/covid-19-vaccine-safety-report-02-11-23
  36. European Medicines Agency. COVID-19 vaccine: Key facts. https://www.ema.europa.eu/en/human-regulatory-overview/public-health-threats/coronavirus-disease-covid-19/covid-19-medicines/covid-19-vaccines-key-facts
  37. Kaplonek et al. IgG4 Neutralization and Sustained Total IgG Fc-Effector Functions Following Repeated SARS-CoV-2 mRNA Vaccination. Preprint MedRxiv https://www.medrxiv.org/content/10.1101/2025.09.30.25336755v1
  38. CDC [Tenforde et al.] Early estimates of bivalent mRNA vaccine effectiveness in preventing COVID-19–associated emergency department or urgent care encounters and hospitalizations among immunocompetent adults — VISION Network, United States, September–November 2022. MMWR Morb Mortal Wkly Rep. 2022. https://pubmed.ncbi.nlm.nih.gov/36921274/
  39. CDC [DeCuir et al.] Interim effectiveness of updated 2023–2024 COVID-19 vaccines against COVID-19–associated emergency department/urgent care visits and hospitalizations among adults — VISION and IVY Networks, United States, September 2023–January 2024. MMWR Morb Mortal Wkly Rep. 2024;73(8):177–184. https://www.cdc.gov/mmwr/volumes/73/wr/mm7308a5.htm
  40. CDC [Link-Gelles, et al.] Interim effectiveness of 2024–2025 COVID-19 vaccines against COVID-19–associated emergency department/urgent care visits and hospitalizations — VISION and IVY Networks, United States, September 2024–January 2025. MMWR Morb Mortal Wkly Rep. 2025b;74(8):197–204. https://www.cdc.gov/mmwr/volumes/74/wr/mm7406a1.htm
  41. CDC. Overview of COVID-19 Vaccines and Vaccination. Nov. 4, 2025. https://www.cdc.gov/covid/hcp/vaccine-considerations/overview.html
  42. CDC. Clinical Considerations: Myocarditis and Pericarditis after Receipt of COVID-19 Vaccines Among Adolescents and Young Adults. https://www.cdc.gov/vaccines/covid-19/clinical-considerations/myocarditis.html
  43. NIH. Heart Inflammation Causes and Risk Factors. https://www.nhlbi.nih.gov/health/heart-inflammation/causes
  44. Oster ME, et al. Myocarditis Cases Reported After mRNA-Based COVID-19 Vaccination in the US From December 2020 to August 2021. JAMA. 2022;327(4):331–340. doi:10.1001/jama.2021.24110
  45. CDC [Block, et al] Cardiac Complications After SARS-CoV-2 Infection and mRNA COVID-19 Vaccination — PCORnet, United States, January 2021–January 2022 Weekly / April 8, 2022 / 71(14);517-523 https://www.cdc.gov/mmwr/volumes/71/wr/mm7114e1.htm
  46. Buoninfante, et al. Myocarditis associated with COVID-19 vaccination. Nature. 2024;122. https://doi.org/10.1038/s41541-024-00893-1
  47. ACIP June 2025. Meyer. Update on COVID-19 Vaccine Safety Monitoring. https://www.cdc.gov/acip/downloads/slides-2025-06-25-26/04-Meyer-COVID-508.pdf
  48. CDC [Wallace] The Advisory Committee on Immunization Practices’ Recommendation for Use of Moderna COVID-19 Vaccine in Adults Aged ≥18 Years and Considerations for Extended Intervals for Administration of Primary Series Doses of mRNA COVID-19 Vaccines — United States, February 2022.https://www.cdc.gov/mmwr/volumes/71/wr/mm7111a4.htm
  49. https://www.fda.gov/media/155675/download?attachment
  50. https://www.fda.gov/media/186738/download?attachment
  51. MHRA. Myocarditis and pericarditis after COVID-19 vaccination: clinical management guidance for healthcare professionals.https://www.gov.uk/government/publications/myocarditis-and-pericarditis-after-covid-19-vaccination/myocarditis-and-pericarditis-after-covid-19-vaccination-guidance-for-healthcare-professionals
  52. Dear HCP letter: COVID-19 mRNA Vaccines Comirnaty and Spikevax: risk of myocarditis and pericarditis https://www.ema.europa.eu/en/documents/dhpc/direct-healthcare-professional-communication-dhpc-covid-19-mrna-vaccines-comirnaty-and-spikevax-risk-myocarditis-and-pericarditis_en.pdf