ACIP presentation focuses on potential vaccine harm while ignoring benefits, physician expert says

A recent presentation to the Advisory Committee on Immunization Practices (ACIP) focused on vaccine potential harms without considering their benefits, said one of the nation’s leading experts on vaccine medicine.

Walter A. Orenstein, MD, responded to questions about a Dec. 5 presentation during ACIP’s two-day meeting this month. In that presentation, Aaron Siri, JD, an author and trial attorney who has served as legal counsel to Health and Human Services Secretary Robert F. Kennedy, Jr., discussed the U.S. childhood vaccine schedule and potential harmful side effects that the shots have in babies and youths.

“My biggest concern is that the presentation focused almost solely on potential adverse effects of vaccines and little related to the benefits of vaccines,” Orenstein wrote to Medical Economics. “It was almost as if there was no benefit and lots of problems with safety.”

Vaccine debate

Siri cited the perspective article, “Funding Postauthorization Vaccine-Safety Science,” co-authored by Orenstein with Daniel A. Salmon, PhD, MPH; Stanley A. Plotkin, MD; and Robert T. Chen, MD. It was published in July 2024 in The New England Journal of Medicine.

Siri used two quotations from the article: “[W]idespread vaccine hesitancy observed during the Covid-19 pandemic suggests that the public is no longer satisfied with the traditional safety goal of simply detecting and quantifying the associated risks after a vaccine has been authorized for use.”

The authors also wrote, and Siri cited: “Postauthorization studies are needed to fully characterize the safety profile of a new vaccine, since prelicensure clinical trials have limited sample sizes, follow-up durations, and population heterogeneity.”

ACIP member H. Cody Meissner, MD, said it was a distortion of the facts for Siri to imply Orenstein and the co-authors were vaccine skeptics.

Medical Economics emailed questions to Orenstein, who spent 26 years working in the immunization program of the U.S. Centers for Disease Control and Prevention. He was director of the United States Immunization Program from 1988 to 2004, and from 2008 to 2011, he was deputy director of immunization programs for the Bill and Melinda Gates Foundation. Orenstein, an author and consultant to the World Health Organization, is now a professor emeritus in the Department of Medicine, Division of Infectious Diseases, at the Emory University School of Medicine.

The following transcript has been edited lightly for style.

Medical Economics: Do you believe Attorney Siri fairly presented the statements of the article?

Walter A. Orenstein, MD: My biggest concern is that the presentation focused almost solely on potential adverse effects of vaccines and little related to the benefits of vaccines. It was almost as if there was no benefit and lots of problems with safety. We do have a comprehensive vaccine safety monitoring system in place. It detected intussusception associated with the initial rotavirus vaccine, detected vaccine-associated polio caused by oral polio vaccines, myocarditis with COVID-19 vaccines, and other conditions. But as noted in the article attached, I think it would be important to enhance the system and assure that funding is adequate and sustained. Using part of the excise tax now used to fund the Vaccine Injury Compensation Program would enhance the system and provide a constant source of funding. There are some statements that are not accurate. For example, inactivated polio vaccine (IPV) does not induce good intestinal immunity. So, to the extent that spread of the poliovirus is from fecal shedding to oral ingestion, IPV is inferior to the oral polio vaccine (OPV). In countries like the US and Scandinavia, with good sanitation systems, the predominant mode of poliovirus spread is probably oral shedding rather that intestinal shedding. Hence, despite switching to an all IPV schedule in 2000, we have not had any major outbreaks of polio.

Medical Economics: ACIP member Dr. Cody Meissner said you have done more to support vaccines and the health of children in the United States than almost anyone else, and for Attorney Siri to include your name and that of Dr. Stanley Plotkin as vaccine skeptics was a gross distortion of the facts. Do you agree with that?

Walter A. Orenstein, MD: I have spent my career trying to reduce the burden of vaccine-preventable diseases. My first experience was working in India on smallpox eradication and saw this terrible disease with a 30% fatality rate disappear before my eyes because of a vaccine. In fact, because of the success of the program, we no longer need to vaccinate against smallpox. I trained in pediatrics and pediatric infectious diseases during the 1970’s. At that time there were thousands of cases of invasive Hemophilus influenzae type b (Hib) disease including meningitis. We had no vaccine at that time to protect against Hib. Because of a highly effective vaccine, it is amazing to me that many pediatricians today have never seen a case of Hib meningitis. Many people don’t understand what a vaccine is and how it works and the system in place to maximize the benefits and minimize the risks of vaccine- preventable diseases. When I speak with lay audiences, I like the describe the immune system we have functions like an army. Its job is to detect the invader and destroy it before the invader can do damage. One would never send an army into battle without training and practice. What a vaccine does is give the immune system practice so when it sees an invader it destroys it. An example of the system in a vaccine against AIDS, the cause being the human immunodeficiency virus (HIV). The virus was discovered more than 40 years ago. We thought we would have a vaccine in a couple of years. We still have no AIDS vaccine. We’ve had promising candidates but none have met the criteria for safety and effectiveness to get approved and recommended.

Medical Economics: Have Attorney Siri or any members of ACIP reached out to you to consult about expanding postauthorization safety studies for vaccines?

Walter A. Orenstein, MD: I have not been consulted.

Medical Economics: Do you agree with the CDC’s update to its website stating: “This webpage has been updated because the statement ‘Vaccines do not cause autism’ is not an evidence-based claim. Scientific studies have not ruled out the possibility that infant vaccines contributed to the development of autism. However, this statement has historically been disseminated by the CDC and other federal health agencies within HHS to prevent vaccine hesitancy.”

Walter A. Orenstein, MD: I agree with what was on the website prior to the alteration.

Editor’s note: Previously, the CDC website stated: “Studies have shown that there is no link between receiving vaccines and developing autism spectrum disorder (ASD). No links have been found between any vaccine ingredients and ASD.”

The November 2025 language change has been criticized by organizations including the American Medical Association, the American Public Health Association, the American Academy of Pediatrics, the National Academies of Science, Engineering and Medicine, the Infectious Diseases Society of America, the Autism Science Foundation, and Autism Speaks.

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The CDC video of the ACIP meeting with Siri’s presentation is here, and the presentation slides are here.