Vaccine Safety: Fear vs. Fact

 

In a recent poll by KFF they found that “1 in 6 parents say they have skipped or delayed a vaccine for their child” (5), but why? Most parents said their reasoning was “concern about side effects, lack of trust in vaccine safety, and that vaccines aren’t necessary” (5). This is a time-tested method of prevention, and we’ve been able to eradicate so many diseases due to vaccines. So why turn away now? The hard reality is there is so much misinformation being spread everyday by individuals on social media or people in our own government who aren’t experienced health professionals.

Vaccine Development and Success Story

The process of creating a vaccine can take up to 10-15 years. The process can be divided into 4 phases: discovery, clinical studies/trials, FDA review, ACIP review, and post approval monitoring and research. This process consists of thousands of participants during the clinical phase to study safety and effectiveness. Even after a vaccine is approved there is still continuous monitoring to track rare reactions. (2)

 

  A diagram from the CDC showing the vaccine development process (2)

An important vaccine is the vaccine that prevents measles. It has eradicated the cases of illness, but in recent years we’ve seen a resurgence due to the lack of parents vaccinating their children against it (3). Measles is an extremely infectious virus that lingers in the air much longer than other respiratory viruses. If left untreated it can lead to major complications such pneumonia, encephalitis, and even death (3). The measles vaccine was created in 1963 by Dr. John Enders, and by the year 2000 measles was considered eradicated in the United States. In the past few years with vaccination rates dropping this has changed. As of September 17, 2025, there have been 1,491 confirmed cases in the United States (3). As seen in the graph below, measles cases are hitting a new high in 2025. (9)

A graph from Johns Hopkins Bloomberg School of Public Health. Depicting raising cases of measles in 2025 as compared to previous years. (9)

Fact vs. Fiction

One of the most popular myths being perpetuated today is “vaccines cause autism”, which is false. Although the exact cause of autism is still unknown, this theory has been disproven time and time again and many articles that stated this have since been retracted. The original 1998 paper by Andrew Wakefield that stated that the MMR vaccine causes autism was retracted due to false data (6). Autism Spectrum Disorder is defined as “challenges with social communication skills and repetitive or restricted behavior/thinking” (1). There are varying severities to autism from needing some support to requiring substantial support. In a study done by Taylor et al. where they observed the relationship between vaccine administration and development of autism, they found no link between the vaccine and autism. (7)

Another misconception also often heard is “natural immunity is better.”. Our bodies have two types of immunity: innate and adaptive. Innate immunity is present at birth. Adaptive immunity on the other hand is built over time with exposure. A vaccine safely exposes an individual to weakened or inactive parts of a virus (2). Since the immune system has already been exposed to the virus it will be able to recognize and fight off the real disease in the future with lower risks of complication, hospitalization, and death that may come with certain illnesses. 

Of course, with any vaccine or medication comes risks. Although, side effects vary from vaccine to vaccine some common ones are soreness, swelling at the site of injection, fever, and headache. In rare cases some vaccines like the MMR (Measles, Mumps, and Rubella) can cause seizures due to fever (4). Serious side effects like seizures are extremely rare and affect 1 in 3,000 to 4,000 children. On the other hand, 1 out 5 unvaccinated individuals that get infected with Measles will be hospitalized. The numbers really do speak for themselves.

Conclusion

Parents, I understand the hesitation, whether it’s concern about side effects, distrust in pharmaceutical companies or government agencies. Your fears are understandable, but we have to put that aside and look at the overwhelming evidence. Vaccines are safe and effect. Vaccine do have mild side effects like any other medication and serious reactions are extremely rare. On the other hand, when unvaccinated the risk of serious complication from certain illnesses is far greater. Vaccines not only protect your children, but the elderly, infants and those who may be immunocompromised.

Misinformation spreads quickly, create an open conversation and seek out all the important information you’d like, but please choose trusted sources. Listen to people who have dedicated years of their lives to medicine, preventing, and health illnesses.

By Muznah Khalid, Master of Medical Sciences Student at the University of Kentucky

References

1.   Autism Spectrum Disorder (ASD). autismspeaks.org. (n.d.).https://www.autismspeaks.org/what-autism

2. Centers for Disease Control and Prevention. (2024, August 10). How Vaccines are Developed and Approved for Use. Centers for Disease Control and Prevention. https://www.cdc.gov/vaccines/basics/how-developed-approved.html

3. Centers for Disease Control and Prevention. (2025, September 17). Measles Cases and Outbreaks. Centers for Disease Control and Prevention. https://www.cdc.gov/measles/data-research/index.html

4. Centers for Disease Control and Prevention. (n.d.). Possible Side effects from Vaccines. Centers for Disease Control and Prevention. https://www.cdc.gov/vaccines/basics/possible-side-effects.html

5. Kffrainl. (2025, September 15). New KFF-Washington Post Survey explores parents’ trust in, and confusion about, childhood vaccines as the Trump administration revamps federal policies. KFF. https://www.kff.org/public-opinion/new-kff-washington-post-survey-explores-parents-trust-in-and-confusion-about-childhood-vaccines-as-the-trump-administration-revamps-federal-policies/

6. Rao TS, Andrade C. The MMR vaccine and autism: Sensation, refutation, retraction, and fraud. Indian J Psychiatry. 2011 Apr;53(2):95-6. doi: 10.4103/0019-5545.82529. PMID: 21772639; PMCID: PMC3136032.

7. Taylor LE, Swerdfeger AL, Eslick GD. Vaccines are not associated with autism: an evidence-based meta-analysis of case-control and cohort studies. Vaccine. 2014 Jun 17;32(29):3623-9. doi: 10.1016/j.vaccine.2014.04.085. Epub 2014 May 9. PMID: 24814559.

8. Patja A, Davidkin I, Kurki T, Kallio MJ, Valle M, Peltola H. Serious adverse events after measles-mumps-rubella vaccination during a fourteen-year prospective follow-up. Pediatr Infect Dis J. 2000 Dec;19(12):1127-34. Doi: 10.1097/00006454-200012000-00002. PMID: 11144371.

9. U.S. Measles Cases Hit Highest Level Since Declared Eliminated in 2000. International Vaccine Access Center. (2025, July 7). https://publichealth.jhu.edu/ivac/2025/us-measles-cases-hit-highest-level-since-declared-eliminated-in-2000