not used title
not used title
Receiving a life-altering diagnosis for a child is overwhelming, prompting a deep search for understanding and the reasons behind it. This can be especially true when the condition is as significant and complex as autism spectrum disorder.
With autism, there is a lot we know, there are places we need to study more and there are answers we already have: vaccines and their ingredients are not the cause.
Decades of scientific research and peer-reviewed studies have found no connection exists between vaccines or their ingredients and autism. While researchers continue to study its underlying causes, increases in autism diagnoses are better explained by expanded diagnostic criteria, improved screening and greater public awareness – not vaccines.
Here are three key things to know:
- The evidence is clear. Decades of data show that vaccines and their ingredients do not cause autism.
- Vaccines save lives. The benefits of childhood vaccination far outweigh any potential risks. Vaccines protect children from dangerous diseases that can cause severe illness, long-term complications, cancer and even death.
- False claims have real costs. Revisiting questions that have been asked and answered many times over diverts resources from promising research and progress.
Go deeper: Vaccines are one of the most effective tools we have to keep children and families protected from serious diseases. More than 50 years of clinical studies and real-world use show that the benefits of routine childhood vaccines far outweigh any potential risks. Further, vaccines are closely monitored for safety after approval by government agencies, manufacturers, universities and health systems across the country.
It is critical that conversations are grounded in scientific evidence: vaccines protect against disease, and there is no credible scientific evidence connecting them to autism.
A closer look at the facts:
Thimerosal and aluminum ingredients
Thimerosal is a preservative that has been used in some vaccines to prevent bacterial or fungal contamination. Numerous large-scale studies and reviews spanning more than 20 years have repeatedly confirmed there is no link between vaccines containing thimerosal and autism or other long-term health issues. Since 2001, all vaccines routinely recommended for children six years of age and younger are available in thimerosal-free formulations.
Aluminum is used in vaccines in miniscule amounts – far less than what people encounter through their diet or the environment – to help boost the body’s immune response, making vaccines more effective at a smaller dose. Moreover, a publicly funded, peer-reviewed study in 2025 found no connection between cumulative aluminum exposure from vaccines in early childhood and 50 chronic conditions, including autoimmune diseases, allergies and neurodevelopmental disorders like autism and ADHD.
The MMR (Measles, mumps, rubella) vaccine
Measles was declared eliminated in the United States in 2000, thanks to widespread vaccination with the MMR vaccine. Rigorous testing and decades of real-world data and research – including a 2019 study of over 650,000 Danish children – found no evidence of a connection between autism and MMR vaccines.
Childhood vaccine schedule
Extensive evidence from multiple large-scale studies, including a meta-analysis of millions of children, found no link between the recommended childhood vaccine schedule and autism.
Hepatitis B vaccines
Hepatitis B is called a “silent epidemic” because most people do not have symptoms when they are newly infected or chronically infected. Thus, they can unknowingly spread the virus to others and continue the silent spread of hepatitis B. When infants become infected with hepatitis B, they have about a 90% chance of developing a lifelong, chronic infection. Complications from the infection are much more likely if they get infected in the early days of their lives.
The bottom line: Claims attempting to link vaccines to autism have been thoroughly and consistently debunked by a vast body of scientific research. Vaccines are critical tools that protect our country from dangerous disease and strengthen our nation’s public health – and we must ensure we have a robust vaccine infrastructure that reinforces their value to people and society as a whole.
Read PhRMA’s statement on autism from September 22, 2025.
Mike Ybarra
Michael Ybarra, M.D., is an emergency physician and Chief Medical Officer at PhRMA. He also serves as Senior Vice President in Advocacy and Strategic Alliances. In these roles, he leads PhRMA’s stakeholder engagement and strategic partnerships on federal and international health policy issues. He is PhRMA’s liaison representative to the Advisory Committee on Immunization Practices and is the co-convener of PhRMA’s R&D Leadership Forum. Dr. Ybarra continues to see patients clinically in the emergency department at MedStar Georgetown University Hospital.
Follow Mike on LinkedIn and X.
Mike Ybarra
Why smart vaccine policy matters
August 3, 2026
New study: HPV vaccination helps prevent cervical cancer deaths
July 21, 2026
New research reinforces the importance of hepatitis B vaccination at birth
May 21, 2026
World Immunization Week: Putting preventable diseases in the past
April 24, 2026
ICYMI: Measles resurgence could cost U.S. nearly $8 billion over five years
April 15, 2026
Why shifting childhood vaccines to “shared clinical decision-making” puts kids at risk
February 23, 2026
Changes to America’s childhood vaccine schedule fail to protect our nation's kids
January 13, 2026
New study: Measles setbacks harm health and America’s economy
October 28, 2025
Why the hepatitis B vaccine matters
October 21, 2025
Why the vaccine injury program matters
August 18, 2025
Recognizing the importance of vaccination for American health and security
August 4, 2025
Answering common questions on mRNA technology
July 17, 2025
What to know about vaccine ingredients: Aluminum and thimerosal
June 24, 2025
World Immunization Week: Highlighting the importance of vaccines for public health
April 28, 2025
What you need to know: Measles and the MMR vaccine
March 10, 2025
Improved treatments continue to lead to declining cancer mortality rates in the U.S.
February 25, 2025
Preventing and fighting disease: A look at the biopharmaceutical progress made for patients in 2024
February 3, 2025
Recognizing the value of disease prevention with Dr. Len Friedland from GSK
December 12, 2024
Leveraging the power of vaccines to prevent antimicrobial resistance
October 31, 2024
From the emergency department to the CDC Advisory Committee: Key takeaways from ACIP’s recent meeting
October 30, 2024
The Patient Perspective: Vaccines
October 23, 2024
How to protect your children’s health this school year
August 22, 2024
New Report: Vaccines continue to drive improved health outcomes
July 16, 2024
Showcasing the promise of biopharma at ASCO 2024
June 28, 2024
World Vaccine Congress: Building on vaccine success
April 1, 2024
WHO Pandemic Agreement offers opportunities and risks for American innovators
November 20, 2023
New Report: 1,600 cancer treatments and vaccines in clinical development
November 9, 2023
What you should know about protecting your health this fall
October 16, 2023
A conversation with Dr. Mike Ybarra on the current state of COVID-19
June 27, 2023
What they are saying: Experts reinforce that TRIPS waiver expansion is harmful and unnecessary
April 13, 2023
PhRMA provides comments and testimony to USITC investigation on COVID-19 medicines and the TRIPS Agreement
March 30, 2023
Celebrating the success of the COVID-19 vaccines, and looking to the future
March 27, 2023
What we’ve learned from three years of fighting COVID-19
March 20, 2023
Word of the Month: What is TRIPS?
November 29, 2022
What you should know about RSV
November 15, 2022
Word of the Month: Long COVID
October 19, 2022
Protecting against influenza: A conversation with David Ross, Vice President, Commercial Operations, North America, CSL Seqirus
October 13, 2022
Partnerships are driving global COVID-19 treatment access
September 22, 2022
ICYMI: PhRMA’s Ubl pens op-ed on IP waiver for COVID-19 technologies
July 15, 2022
New Data: COVID-19 vaccine global production capacity projected to exceed 20 billion doses this year
February 24, 2022
What you need to know about newly authorized COVID-19 antiviral treatments
February 22, 2022
Guest Blog: COVID-19 vaccines are the key to keeping kids healthy
February 16, 2022
Global COVID-19 vaccination matters now and for the future
November 29, 2021
Understanding breakthrough COVID-19 infections
November 11, 2021
The important role of antivirals in the fight against COVID-19
October 6, 2021
A year and a half later: The biopharmaceutical industry remains committed to beating COVID-19
September 8, 2021
Recognizing National Immunization Awareness Month
August 31, 2021
Driving further innovation is critical to global vaccine equity
August 24, 2021
Supporting country readiness to boost global vaccine access
August 12, 2021
Ensuring global vaccine equity requires eliminating trade and regulatory barriers
August 5, 2021
Setting the record straight: Addressing common misconceptions about the COVID-19 vaccine
August 4, 2021
Increasing global access to vaccines by optimizing production
July 29, 2021
Guest post: Retired medics return to the field to take on vaccine delivery and disaster relief
July 23, 2021
Guest Post: A patient’s story of the long-term health impacts of COVID-19
July 21, 2021
Dose sharing as a part of the COVID-19 global vaccine equity strategy
July 20, 2021
Promoting global vaccine equity while protecting innovation
July 15, 2021
Data shows COVID-19 vaccines are creating a pathway to a strong U.S. recovery
July 2, 2021
Americans 12 years of age and older are eligible for COVID-19 vaccines
June 17, 2021
ICYMI: PhRMA president and CEO Stephen J. Ubl joins other industry leaders for a conversation on COVID-19 vaccines with Axios
May 21, 2021
Supporting India during the devastating coronavirus surge
May 20, 2021
PhRMA CAREs Grant request for proposals: Addressing inequities in access to COVID-19 testing, therapeutics and vaccines
May 6, 2021
Ron Busby, Sr., President and CEO of the U.S. Black Chambers, Inc. on improving vaccine confidence in community
May 5, 2021
Patient safety is at the heart of COVID-19 vaccine R&D
April 26, 2021
Data shows that Americans are relying on vaccines to get us through the pandemic
April 22, 2021
Diversifying clinical trials and fighting disease requires equity and trust
April 12, 2021
Building confidence in the COVID-19 vaccine through education
March 22, 2021
ICYMI: WSJ showcases breakthrough science of COVID-19 vaccines and implications for future medicines
March 8, 2021
Intellectual property is the key to vaccine development, manufacturing and technology sharing
March 5, 2021
Coming together to fight COVID-19: A conversation with Paul Perreault, CEO and Managing Director of CSL
February 24, 2021
Fighting variants of COVID-19
February 22, 2021
Growing trend: Increased vaccine confidence
January 28, 2021
Guest post: How COVID-19 underscores the importance of public confidence in vaccines
December 7, 2020
Understanding the emergency use authorization process for COVID-19 vaccines
November 12, 2020
Flu Season 2020: Why it’s time to talk to your doctor today about getting a flu shot
October 8, 2020
Coming together to fight COVID-19: A conversation with Albert Bourla, Chairman & CEO of Pfizer, Inc.
September 17, 2020
Coming together to fight COVID-19: A conversation with Paul Hudson, CEO of Sanofi
September 2, 2020
Supporting access to vaccines for Part D beneficiaries
August 12, 2020
New report shows more than 400 medicines and vaccines in development to tackle infectious diseases, including COVID-19
July 21, 2020
PhRMA’s Lori Reilly joined CSG to discuss the industry’s response to COVID-19 and what it means for states
July 13, 2020
How biopharmaceutical researchers are ensuring COVID-19 vaccines will be safe and effective
June 29, 2020
Guest Post: From lab to jab: Vaccine development to prevent COVID-19
June 11, 2020
What scientific experts are saying about vaccine safety
June 4, 2020
New report shows nearly 260 vaccines in development, including dozens for COVID-19
April 23, 2020
ICYMI: Continued biopharmaceutical action on COVID-19
March 6, 2020
Why vaccines work in the fight against measles and other infectious diseases
February 13, 2019
Medicare Monday: Helping beneficiaries access vaccines
December 18, 2017
New report and event examine the new era of vaccines
November 9, 2017
Medicare Monday: Strengthening access to vaccines for seniors
August 14, 2017
Vaccines
Vaccines and autism: Decades of scientific evidence find no link
September 22, 2025