Widespread Vaccinations are Essential for a Healthy US

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By Joshua S. Anbar, DrPH, MPH, and Ran D. Anbar, MD

On November 19^th the Centers for Disease Control and Prevention (CDC) updated their guidance on vaccine safety to state that the claim “vaccines do not cause autism” is not an evidence-based observation. The implication of this updated guidance is the idea that vaccines could cause autism.

Much of the updated guidance is based on the observation that there has been an increase in autism prevalence in the US over the last 25 years, from 67 to 322 per 10,000 children at 8 years of age. This has occurred at the same time that the number of recommended childhood vaccine administrations by the age of 1 year increased from 5 to 25 since the 1980s.

Available Evidence about Vaccines and Autism

Unstated in this updated guidance is that there is no widely-accepted study conclusively proving a link between autism and specific vaccines or the number of administered vaccines. The few studies that have found the potential for autism to be associated with vaccines have proven difficult to reproduce or to apply to the general population.

Additionally, the CDC’s updated guidance ignores the robust body of literature that has examined the relationship between autism and vaccines. Using publicly available databases like Google Scholar show that there are over 47,000 scientific articles on the subject. Multiple reviews of this literature have found no causal relationship between autism and vaccines, including recently published reviews in 2022 and 2025.

While it is true that there are gaps in our understanding of how vaccines can affect our health, claiming that there is no evidence to support the idea that vaccines do not cause autism is incorrect. Further, implying that vaccine safety is in question has profound implications for the public’s health.

The Importance of Vaccines

The vaccines discussed in the CDC’s updated guidelines have been critical in defeating various childhood illness that can result in long-term disability or even death.

Since the introduction of the modern measles, mumps, and rubella (MMR) vaccine in the 1980s, the number of measles cases per year had dropped from a high of 27,808 in 1990 to a low of 13 as recently as 2020. Just last year in 2024 there were only 285 cases, a 99% reduction from the 1990 high.

However, in 2025 alone, measles – a vaccine preventable disease – has infected over 1,700 people in the US alone, the majority of which have been children and who are unvaccinated or have an unknown vaccination status. This has resulted in hundreds of hospitalizations and three confirmed deaths.

In the early 1980’s pediatricians working in emergency departments were taught how to treat a drooling young child who insisted on sitting upright, using the arms to support their trunk, and holding their head in a sniffing position maximally that allowed them to breathe. This occurred because their epiglottis (a cartilage in the throat that covers the main airway) had become very swollen because of an infection by the Hemophilus influenzae bacteria.

Such children would need to be kept calm while taken to an operating room because if they cried their throat could close off completely. In the OR they were sedated with anesthesia and had a tube inserted into their throat so that they could breathe while antibiotics were administered intravenously for a few days to treat their infection.

Since the vaccine for Hemophilus was introduced in the mid-1980’s most young pediatricians have never encountered a patient suffering from epiglottitis. Similarly, they have hardly ever encountered children experiencing lockjaw because of tetanus, or paralysis because of polio.

To achieve these important successes, it is important to ensure that as many people as possible are vaccinated. Being vaccinated not only protects you from getting infected or experiencing severe complications from a disease, but it also protects other people by breaking the chain of transmission – when disease spreads from one person to the next.

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In public health this concept is called herd immunity, when enough people are immunized against an infectious disease and an outbreak has difficulty spreading between communities.

Different diseases have different requirements for when herd immunity is achieved. For example, herd immunity for measles requires 95% of the public to be vaccinated but only 80% for polio. But vaccination efforts all work towards to same goal: to prevent the occurrence and spread of otherwise preventable infections.

By incorrectly stating that the claim “vaccines do not cause autism” is not evidence-based, the CDC’s updated guidance calls into question the safety of vaccines and creates confusion.

Many people may erroneously conclude that vaccines are unsafe, which may lead to some of them to delay or withhold vaccinating their children. This may result in the return of various infectious diseases that have largely been confined to medical history textbooks.

Conclusions

It is important to continue doing research and ensuring the effectiveness and safety of our vaccines. However, implying with insufficient evidence that vaccines could cause autism or other problems may be very harmful.

Instead, gold standard science should be funded that allows researchers to comprehensively examine the safety of vaccines as we continue our efforts to improve our health as a society.

Then, with strong evidence in hand, we can affirm or challenge the idea that vaccines do not cause autism. Until then, parents should feel confident that they can best protect their children from serious and life-threatening infectious diseases through the routine use of childhood vaccinations.

Joshua S. Anbar, DrPH, MPH is a clinical assistant professor at Arizona State University. He leads a public health surveillance effort to track the prevalence of autism in Arizona.