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 October 17, 2025.
Timely Topics
DNA Contamination
Q: Are Moderna’s mRNA COVID-19 vaccines contaminated with DNA?
A: No, Moderna’s mRNA COVID-19 vaccines are not contaminated with DNA.¹ Moderna’s mRNA COVID-19 vaccines simply use DNA as a template to produce large batches of product-specific mRNA. Moderna’s manufacturing processes consistently meet the guidelines set by organizations like the World Health Organization (WHO)² and the U.S. Food and Drug Administration (FDA)³ to control the level of DNA in its products. In adherence to these guidelines, after mRNA synthesis, the DNA template is degraded into small fragments, which are then removed from the mRNA during the purification process.⁴
To measure the amount of DNA remaining in the product after mRNA synthesis, Moderna uses a validated, industry standard, quantitative polymerase chain reaction (qPCR) method.⁵ Validation ensures that the techniques used to measure DNA are accurate, precise, and measure only DNA, and not other components, such as mRNA.⁶
Q: There have been publications that claim mRNA COVID-19 vaccines exceed limits for DNA. Does Moderna refute these claims?
A: A single group of authors shared results from studies using non-validated methodologies that inaccurately measured DNA in mRNA COVID-19 vaccines.⁷ The non-validated methodologies used in the referenced study lacked specificity to accurately quantify trace amounts of DNA due to the high concentration of mRNA and lipids present in the vaccine, resulting in a dramatic overestimation of residual DNA levels.⁸ When using a method capable of accurately differentiating between DNA and mRNA, the levels of DNA present in vials of Moderna’s COVID-19 vaccine were confirmed to be lower than the thresholds established in FDA and WHO guidelines.⁹
These claims have been refuted by researchers and regulators globally.
“A large share of the data and studies on suspected contamination of COVID19 mRNA vaccines circulating in the public are based on methodological deficiencies.” - Paul-Ehrlich-Institut, German Vaccines and Biomedicines Regulator¹⁰
“The Therapeutic Goods Administration (TGA) is aware of misinformation in recent media and online reports that claim the COVID-19 mRNA vaccines are contaminated with excessive levels of DNA. This is not the case. These reports are based on studies conducted by a small number of laboratories that have attempted to investigate the amount of DNA in COVID-19 vaccines… these recent studies fail to apply the required scientific rigor expected in pharmaceutical testing. As such, the results are not robust or reliable, and are creating confusion and concern regarding the safety of vaccines.” – Australia Therapeutic Goods Administration¹¹
“With over a billion doses of the mRNA vaccines administered, no safety concerns related to residual DNA have been identified. The agency has taken into account the totality of the mRNA COVID-19 vaccine product, including the lipid nanoparticles, as it reviewed the manufacturers’ specifications for residual DNA fragments present. Any contamination with residual DNA fragments is monitored routinely as a product specification.” – U.S. FDA¹²
Biodistribution Studies
Q: How long does mRNA stay in the body after injection? Does it accumulate with repeated administration?
A: mRNA is transient and does not accumulate. mRNA is quickly broken down and cleared by the cell's natural processes after it has delivered its instructions for producing a protein.¹³
Claims that the spike protein persists for months following vaccination are not aligned with the broader body of scientific evidence, and in some cases draw conclusions that are not supported by cited studies. A referenced study, Bhattacharjee S., et al [2025], relied on small, uncontrolled samples, and most importantly, could not distinguish whether spike protein was derived from the vaccine or from prior or ongoing COVID-19 infection.¹⁴ Of note, the authors themselves acknowledged the limitations of their findings stating: “this study is early-stage and requires replication and validation. We emphasize the critical task of discerning between meaningful results and random fluctuations in the data.”¹⁵
Q: Did Moderna study biodistribution with their COVID-19 vaccine?
A: Yes. In a well-controlled animal study conducted by Moderna and reviewed by the FDA and other regulatory agencies, spike protein levels, mRNA, and LNP components were found to be transient and there is no evidence of persistence beyond one-two weeks following each dose. Additionally, there is no accumulation of any of these with repeated administration. Following vaccination, spike protein, mRNA, and LNP components were mostly detected at the injection site and in nearby lymph nodes and the spleen, with lower amounts briefly detected in blood and other tissues.¹⁶ The distribution of mRNA-LNP vaccines is therefore consistent with how other types of intramuscularly administered vaccines distribute in the body through the lymphatic system.¹⁷
Moderna plans to present these data at an upcoming scientific conference and submit for peer-reviewed publication.
Cancer Risk
Q: Is there any tie between Moderna’s mRNA COVID-19 vaccine and the risk of cancer?
A: Current scientific evidence shows no biological mechanism by which mRNA vaccines could alter one’s DNA or increase cancer risk. Cancer arises from changes to the DNA, such as mutations, insertions or deletions, or chromosomal rearrangements, which lead to uncontrolled cell growth.¹⁸ While mRNA serves as a messenger between DNA and the cell’s machinery responsible for making proteins, mRNA vaccines have no capacity to change or influence our DNA.¹⁹ The RNA delivered by mRNA vaccines enters the cytoplasm of cells, not the nucleus, which is where our DNA (genetic material) is. mRNA molecules remain in the cytoplasm until eliminated by the body’s natural mRNA decay processes.²⁰
The safety of Moderna’s mRNA COVID-19 vaccine is closely and continuously monitored by Moderna, the U.S. Food and Drug Administration, and regulators in more than 90 countries worldwide. Regulators across the world have reviewed data from more than one billion administered doses globally, and have not found evidence suggesting an increased cancer risk.²¹ ²²
“It is quite implausible that the residual small DNA fragments located in the cytosol could find their way into the nucleus through the nuclear membrane present in intact cells and then be incorporated into chromosomal DNA….Pharmacovigilance data in hundreds of millions of individuals also indicate no evidence indicative of genotoxicity.” – U.S. FDA 2023²³
“COVID-19 vaccines do not alter your DNA……The mRNA is broken down quickly by the body. It never enters the nucleus and cannot affect or combine with our DNA in any way to change our genetic code.” – Australian Government, Department of Health, Disability & Ageing²⁴
“The mRNA used in COVID-19 vaccines does not interfere with our genetic code…. mRNA does not enter the cell’s nucleus where our DNA is kept…No side effects linked to gene mutations, such as cancer, have been observed after vaccination with mRNA vaccines.” – European Medicines Agency²⁵
Pediatric Safety
Q: How are mRNA COVID-19 vaccines, including those developed by Moderna, monitored for safety in children?
A: Multiple, complementary safety monitoring systems across the globe are in place to detect and evaluate any new or evolving safety considerations, including Vaccine Adverse Event Reporting System (VAERs), Vaccine Safety Datalink (VSD), V-Safe, FDA’s Biologics Effectiveness and Safety System (BEST), and post-licensure studies. At the June 2025 ACIP meeting, the Centers for Disease Control and Prevention (CDC) reaffirmed that COVID-19 vaccines have been evaluated under the most extensive safety monitoring program in U.S. history.²⁶ Peer-reviewed, high-quality research throughout the world continues to demonstrate a favorable risk–benefit profile for Moderna’s mRNA COVID-19 vaccine,²⁷ ²⁸ ²⁹ and most recently, the U.S. FDA approved the 2025-2026 formula of Moderna’ mRNA COVID-19 vaccine for use in children as young as six months with at least one underlying condition that puts them at high risk for severe outcomes from COVID-19.³⁰
Q: There are VAERs reports linking the COVID-19 vaccine to pediatric deaths. Is this true? How does VAERs work?
A: Reports to the Vaccine Adverse Event Reporting System (VAERS) alone cannot be used to determine whether a vaccine caused a specific health outcome.
VAERS is the US early warning system used to detect possible vaccine safety-related problems and is jointly run by the FDA and CDC. Anyone can submit a report (patients, caregivers, friends, etc.). Healthcare providers and manufacturers are required to file reports. As with all approved vaccines, Moderna regularly submits reports to VAERS and monitors findings alongside regulatory agencies. Importantly, individual reports received by VAERS are most appropriately considered as “tips,” meaning that they are unverified and are not used as proof that a vaccine caused the adverse event. Public health experts regularly review VAERS reports, and flag unusual cases and trends for further evaluation, typically through studies that compare outcomes in vaccinated versus unvaccinated groups.³¹ Claims of increased pediatric deaths based solely on VAERS reports are misleading, as they do not establish risk or causation.
Both FDA and CDC routinely analyze VAERS alongside other safety monitoring systems, with findings shared publicly through the established Advisory Committee on Immunization Practices (ACIP) process.³¹ The CDC concluded that reporting rates to VAERS remain below expected background rates in the U.S., and analyses from the Vaccine Safety Datalink found no increase in all-cause or non-COVID deaths.³² Similarly, a large multinational European post-marketing safety study did not find an elevated risk of sudden death or death from any cause.³³
With more than one billion doses distributed globally, these systems – in the U.S., Australia, Canada and across European national health systems – continue to confirm the well-established safety profile including in children.³⁴
“Since the beginning of the vaccine rollout to 29 October 2023, almost 69 million doses of COVID-19 vaccines have been given in Australia…There have been no deaths in children or adolescents determined to be linked to COVID-19 vaccination.” – Australian Therapeutic Goods Administration³⁵
“EMA carefully reviews all safety data and can confirm that there is no evidence of an increase in deaths related to COVID-19 vaccination in any age group, including in children.” – European Medicines Agency³⁶