Debunking 3 mRNA Myths and Rebuilding Trust in Vaccine Science

Since their initial emergency authorization in 2020, mRNA COVID-19 vaccines have saved millions of lives by preventing severe outcomes of COVID-19.[1] Yet despite their success, mRNA technology remains clouded by misinformation and political polarization. A recent KFF Tracking Poll revealed just how widespread public uncertainty still is: only 32% of U.S. adults say mRNA vaccines are generally safe, while over half (52%) admit they don’t know enough to say. Even more concerning, nearly one-third of Americans believe or lean toward believing the myth that mRNA vaccines can alter a person’s DNA.[2]

This deep-seated skepticism isn’t rooted in science – it stems from misunderstandings of what mRNA is and how it works. To combat these myths, it’s critical to separate fact from fiction and ground the discussion in clear, accessible science.

Myth #1: mRNA Vaccines Alter Your DNA

Fact: mRNA vaccines do not change your DNA. The “m” in mRNA stands for messenger, and that’s exactly the role it plays – carrying instructions to make proteins, which your cells then use to build an immune response. mRNA never enters the nucleus, where DNA lives, and cannot integrate with your genetic material.[3] Once its job is done, the mRNA is broken down by the body, just like any other natural mRNA molecule.[4]

Despite this well-established mechanism, nearly half of Americans (45%) have heard the false claim that mRNA vaccines alter DNA, and 29% say it is probably or definitely true.[2] These beliefs are strongly tied to a lack of trust in vaccine safety overall. Among those who believe the DNA myth, 77% say they lack confidence in COVID-19 vaccine safety.[2]

Myth #2: mRNA Technology Is Too New to Be Trusted

Fact: While mRNA COVID-19 vaccines were authorized for emergency use in 2020, the platform itself is far from new. Scientists have been studying mRNA since the 1960s and developing mRNA-based vaccines since the 1990s.[5] The COVID-19 pandemic accelerated deployment, but the foundational science is decades old. In fact, more than 13 billion doses of COVID-19 vaccines have been safely administered worldwide, making them one of the most studied vaccines in history.[1]

Myth #3: Long-Term Effects of mRNA Vaccines Are Unknown

Fact: With over four years of global use and extensive follow-up, studies continue to show no increase in infertility, miscarriage, or cancer among those vaccinated with mRNA COVID-19 vaccines[6,7] – and no increase in death from non-COVID causes compared to unvaccinated people.[8] Most vaccine side effects occur within six weeks of administration.[9] Rare side effects such as myocarditis following vaccination has been reported, most often among 12-24 year old males, but these cases are typically short-lived and less severe than myocarditis cases associated with COVID-19 infection.[10,11] Health authorities continue to monitor the safety of mRNA COVID-19 vaccines and recommend vaccination as a safer, more reliable way to build immunity than getting sick with COVID-19.[8,12]

Myth #4: mRNA Vaccines Harm Fertility and Reproductive Health

Fact: There is no evidence that mRNA vaccines affect fertility in women or men.[6,13] For both men and women, there is no difference in conception rates between vaccinated and unvaccinated individuals,[13,14] including among IVF patients.[15] mRNA COVID-19 vaccines do not have a negative long-term impact reproductive organs and are safe for pregnant people – with no increased risk of miscarriage, preterm delivery, stillbirth, or birth defects.[6,13,16]

Temporary menstrual changes, such as a heavier or earlier period, have been observed in some cases, likely due to a short-term immune response to vaccination.[13,17] However, these changes typically normalize within one or two cycles.[18,19]

Why So Much Confusion?

According to KFF, the skepticism stems in part from eroding trust in public health agencies. Only 56% of Americans express confidence in the safety of COVID-19 vaccines – far lower than for routine vaccines like measles (83%) or flu (74%). Trust is highly polarized: while 87% of Democrats are at least somewhat confident in COVID-19 vaccine safety, only 30% of Republicans say the same.[2]

This divide is exacerbated by political figures undermining public health guidance. Nearly three-quarters of Republicans now say they trust President Trump and Secretary Robert F. Kennedy Jr. for vaccine information – more so than federal agencies like the CDC or FDA, which approximately half of Republicans surveyed reported as trusted source of vaccine information.[2]

A Path Forward: Science + Trust

Rebuilding public trust starts with transparent, accessible education. The survey also shows that healthcare providers continue to be well trusted by the vast majority of Americans[2], suggesting that HCPs can have a large impact in dispelling myths about mRNA and vaccines in general.  To address misinformation effectively, trusted messengers must be empowered to communicate the science clearly.  

The data shows that mRNA vaccines are safe, effective, and critical tools in the fight against infectious disease. The challenge now is not scientific, but societal. Facts alone won’t win trust, but pairing facts with compassion and clarity might.  Learn more here.

1. COVID-19 advice for the public: Getting vaccinated. World Health Organization. https://www.who.int/emergencies/diseases/novel-coronavirus-2019/covid-19-vaccines/advice. Updated October 8, 2024. Accessed May 28,2025.
2. KFF Tracking Poll on Health Information and Trust: Vaccine Safety and Trust. KFF. https://www.kff.org/health-information-and-trust/poll-finding/kff-tracking-poll-on-health-information-and-trust-vaccine-safety-and-trust/. Published May 6, 2025. Accessed May 28,2025.
3. COVID-19 Vaccine Basics. Centers for Disease Control. https://www.cdc.gov/covid/vaccines/how-they-work.html. Updated September 3, 2024. Accessed May 28, 2025.
4. Pardi N, Hogan MJ, Porter FW, Weissman D. mRNA vaccines – a new era in vaccinology. Nat Rev Drug Discov. 2018;17(4):261-279. doi:10.1038/nrd.2017.243
5. The Long History of mRNA Vaccines. Johns Hopkins University. https://publichealth.jhu.edu/2021/the-long-history-of-mrna-vaccines. Published October 6, 2021. Accessed May 28, 2025.
6. COVID-19 Vaccination for Women Who Are Pregnant or Breastfeeding. Centers for Disease Control. https://www.cdc.gov/covid/vaccines/pregnant-or-breastfeeding.html. Updated September 10, 2024. Accessed May 28, 2025.
7. COVID-19 Vaccines and People with Cancer. National Institutes of Health National Cancer Institute. https://www.cancer.gov/about-cancer/coronavirus/covid-19-vaccines-people-with-cancer. Updated October 10, 2023. Accessed May 28, 2025.
8. Coronavirus Disease 2019 (COVID-19) Vaccine Safety. Centers for Disease Control. https://www.cdc.gov/vaccine-safety/vaccines/covid-19.html. Updated January 31, 2025. Accessed May 28, 2025.
9. Getting Your COVID-19 Vaccine. Centers for Disease Control. https://www.cdc.gov/covid/vaccines/getting-your-covid-19-vaccine.html. Updated September 10, 2024. Accessed May 28, 2025.
10. mNEXSPIKE (COVID-19 Vaccine, mRNA) 2024-2025 Formula Prescribing Information. https://static.modernatx.com/pm/6cef78f8-8dad-4fc9-83d5-d2fbb7cff867/9f00fca4-1dca-4c9e- 9bdd-d21a1c0bf5c6/9f00fca4-1dca-4c9e-9bdd-d21a1c0bf5c6_viewable_rendition__v.pdf
11. Panagiotakopoulos L. Use of 2025–2026 COVID-19 Vaccines: Work Group Considerations. Presented at: Advisory Committee on Immunization Practices meeting; April 15, 2025. https://www.cdc.gov/acip/downloads/slides-2025-04-15-16/05-Panagiotakopoulos-COVID-508.pdf. Accessed May 28, 2025.
12. Staying Up to Date with COVID-19 Vaccines. Centers for Disease Control. https://www.cdc.gov/covid/vaccines/stay-up-to-date.html. Updated January 7, 2025. Accessed May 28, 2025.
13. COVID-19 Vaccination for People Who Would Like to Have a Baby. Centers for Disease Control. https://www.cdc.gov/covid/vaccines/planning-for-pregnancy.html. Updated September 10, 2024. Accessed May 28, 2025.
14. Wesselink AK, Hatch EE, Rothman KJ, et al. A Prospective Cohort Study of COVID-19 Vaccination, SARS-CoV-2 Infection, and Fertility. Am J Epidemiol. 2022;191(8):1383-1395. doi:10.1093/aje/kwac011
15. Chen H, Zhang X, Lin G, Gong F, Hocher B. Safety of COVID-19 vaccination in women undergoing IVF/ICSI treatment – Clinical study and systematic review. Front Immunol. 2023;13:1054273. doi:10.3389/fimmu.2022.1054273
16. Vaccinating Pregnant Individuals: Eight Key Recommendations for COVID-19 Vaccination Sites. The American College of Obstetricians and Gynecologists. Accessed May 28, 2025.
17. Alsaeedi FA, Gharib AF, Hassan AF, et al. Influence of COVID-19 infection/vaccination on menstrual regularity and hormonal function in Saudi females of reproductive age. Heliyon. 2023;9(11):e22291. doi:10.1016/j.heliyon.2023.e22291
18. Edelman A, Boniface ER, Benhar E, et al. Association Between Menstrual Cycle Length and Coronavirus Disease 2019 (COVID-19) Vaccination: A U.S. Cohort. Obstet Gynecol. 2022;139(4):481-489. doi:10.1097/AOG.0000000000004695
19. Alvergne A, Woon EV, Male V. Effect of COVID-19 vaccination on the timing and flow of menstrual periods in two cohorts. Front Reprod Health. 2022;4:952976. doi:10.3389/frph.2022.952976