5 Things Every Parent Should Know About Childhood Vaccines

A plethora of factors influence a parent’s or a caregiver's decision to vaccinate. Although numerous data and publications indicate the safety and efficacy of vaccines, hesitancy to vaccinate remains among the top threats to global health, even more so in the wake of the COVID-19 pandemic.¹ Skepticism and uncertainty about vaccine composition, whether vaccination is truly necessary, concerns about a link to autism, and cultural and religious beliefs carry a lot of weight in this discussion.² In the midst of growing controversy, here are 5 things parents should know about childhood vaccinations.

The best way to stay protected against preventable disease is to get vaccinated. | Image credit: didesign - stock.adobe.com

1. School Requirements

Vaccination laws generally apply to public schools, but also often pertain to private schools and even homeschooling in many states. Certain exceptions can be granted on religious or medical bases, among others, to allow students to attend.³

Two of the more common requirements are polio, varicella, diphtheria, tetanus, and pertussis (DTaP, whooping cough) and measles, mumps, and rubella (MMR). Additionally, several states include the meningitis vaccine prior to seventh grade, while others require vaccination against hepatitis A and hepatitis B at earlier ages. Rhode Island also requires the 3-series human papillomavirus vaccine (HPV) be completed before entering ninth grade, with the first and second vaccine being administered before seventh and eighth grade.

2. Safety, Efficacy, Adverse Effects

Every year, millions of children, adolescents, and infants are vaccinated against preventable infectious diseases. One of the FDA’s primary responsibilities is making sure these vaccinations are safe and effective for public use. Each available vaccine undergoes extremely careful and extensive evaluation from the FDA.⁴

Additionally, recommended vaccines are under continuous study and remain closely monitored. These vaccines teach the immune system how to recognize and counteract numerous pathogens and have nearly eradicated devastating illnesses, such as polio.⁵

Notably, the series of DTaP vaccinations has demonstrated 100% efficacy against tetanus, 97% efficacy against developing diphtheria, 95% against Haemophilus influenzae type b (when infants are given 2-3 doses), 94% against hepatitis A, 90% for hepatitis B, 100% for HPV, 96% for measles, 86% for mumps, 89% for rubella, and 69% to 88% effectiveness against meningitis.

Severe reactions to a vaccine are rare, occurring in 0.01% to 0.1% of cases. Although more serious reactions are possible, these risks for vaccine-related harm are substantially less likely than the risk of contracting a serious illness after foregoing a vaccine. Allergic reactions occur anymore between 1 case per 100,000 doses to 1 in 1 million. Less severe adverse events may occur, including injection-site soreness, minimal swelling, and mild fever.^4,5

For more data on vaccine efficacy, safety, and adverse effects, visit The Journalist’s Resource webpage.

3. Common Myths

There are a lot of misconceptions that circulate about vaccines, including the beliefs that vaccines contain harmful ingredients, that contracting a disease or herd immunity is better than vaccine-granted immunity, and that vaccines cause diseases, will alter DNA, or are not sufficiently tested. Chief among these concerns is that vaccines can lead to autism.⁵

Some substances in vaccines are harmful or toxic in large doses; however, vaccine composition includes these ingredients in safe, small doses far lower than what people are naturally exposed to. Examples include formaldehyde, mercury, and aluminum. Their concentration in vaccines falls well below the levels found in common household items or everyday foods, and even bolster individual immunity and better preserve vaccines without added safety risks. Although these ingredients can sound alarming, milk, tuna, cosmetics, health products, medicines, and other products often contain trace amounts of these substances, too.

Vaccines often administer an inactivated disease strain. There are some that use living, or activated, organisms; however, this is not the same as giving someone a disease. While some mild reactions can occur, and actually indicate the vaccine is working, these are not harmful.

Although natural immunity can occur for preventable diseases, the risk for additional complications can be avoided when someone is vaccinated. Furthermore, if someone foregoes a vaccination for themselves or their children due to belief in herd immunity, it is important to realize that herd immunity only occurs when a large portion of a community already has immunity against a disease. When herd immunity becomes ineffective, infants, immunocompromised individuals, and pregnant women all stand at increased risks.

4. Autism

Claims connecting vaccines and the development of autism date back to 2 debunked studies conducted by Andrew Wakefield. Wakefield hypothesized that the MMR vaccine was a catalyst for intestinal inflammation, which allowed dangerous proteins to enter the blood stream, harm the brain, and subsequently cause autism.⁶

Each study is now known to be critically flawed. The first, conducted in 1998, found that 8 children in England developed autism in the month following their MMR vaccine. Yet, Wakefield did not compare incidence rates between unvaccinated and vaccinated children. At the time, approximately 90% of English children were receiving MMR vaccines in the same time frame that autism was typically diagnosed, which could explain why their diagnosis came so close to their vaccination. Furthermore, although Wakefield claimed that intestinal inflammation contributed to autism, these symptoms occurred after the children showed signs of autism, not before.

The second of the Wakefield studies investigated the relationship between the measles vaccine and autism. Intestinal biopsy samples of children with and without autism were evaluated, with investigators looking for the presence of the measles virus. The virus was observed in over 80% (75/91) of children with autism vs just over 7% (5/70) of samples from children without autism. However, these conclusions were challenged because the researchers did not distinctly identify whether this was the vaccine-granted virus or that of natural measles (which was still circulating at the time in England). Children in these groups also were not matched according to their immunization status, nor for the time period between vaccination and sample collections. Extremely sensitive testing techniques also meant there was a higher risk for results that were falsely positive. Additionally, for the best results, those performing the laboratory tests should be blinded as to which group the samples are coming from; this blinding was not stated in the study, nor was there any mention of matched cohorts.

Both studies have since been retracted and Wakefield’s medical license revoked because of his falsified claims. Several studies have since invalidated his findings.⁷

For more information on studies disproving the link between vaccination and autism, please visit the Children’s Hospital of Philadelphia webpage.

5. Current Measles Outbreak

Texas has been experiencing a significant measles outbreak. Since late January, 327 cases have been confirmed, with well over 50% of cases occurring in children 0 to 4 years (n = 105) and 5 to 17 years (n = 140).⁸

Officials tracking vaccination statuses reported that 325 of these cases were in unvaccinated individuals or those with no record of the measles vaccine in the 2 weeks leading up to symptom onset. That 2-week marker is an important measure because, after receiving the vaccine, it typically requires 14 days for immunity to develop. The Texas Department of State Health Services noted the best way to stay protected against measles is to be vaccinated. Vaccinations can be received during pharmacy visits, from a health care provider, or via the Vaccines for Children programs.

Thus far in 2025, 40 measles-related hospitalizations have occurred, as well as a fatal case in 1 school-aged child.

For more on vaccine efficacy, risks, and detailed information behind different types/forms of vaccination, please visit the FDA website.

References

1. Munz K. Vaccine hesitancy: COVID-19 to influenza. AJMC^®. October 22, 2024. Accessed March 21, 2025. https://www.ajmc.com/view/vaccine-hesitancy-covid-19-to-influenza

2. Why are some parents failing to vaccinate their children. Children’s Defense Fund. July 2, 2019. Accessed March 21, 2025. https://www.childrensdefense.org/blog/why-are-some-parents-failing-to-vaccinate-their-children

3. State school vaccination laws. CDC. Accessed March 21, 2025. https://www.cdc.gov/phlp/php/publications/vaccination-laws.html

4. Vaccines for children – a guide for parents and caregivers. FDA. Updated November 4, 2024. Accessed March 21, 2025. https://www.fda.gov/vaccines-blood-biologics/consumers-biologics/vaccines-children-guide-parents-and-caregivers

5. Vaccines: the myths and the facts. AAAAI. Updated January 10, 2024. Accessed March 25, 2025. https://www.aaaai.org/tools-for-the-public/conditions-library/allergies/vaccine-myth-fact

6. Vaccines & Autism: The Wakefield Studies. Children’s Hospital of Philadelphia. Reviewed February 5, 2024. Accessed March 25, 2025. https://www.chop.edu/vaccine-education-center/vaccine-safety/vaccines-and-other-conditions/autism

7. Link between autism and vaccination debunked. Mayo Clinic Health System. March 24, 2024. Accessed March 25, 2025. https://www.mayoclinichealthsystem.org/hometown-health/speaking-of-health/autism-vaccine-link-debunked

8. Measles outbreak – March 25, 2025. Texas Department of State Health Services. Accessed March 25, 2025. https://www.dshs.texas.gov/news-alerts/measles-outbreak-2025