Vaccination resources

Vaccine safety is the top priority in the medical community. Before any vaccine is approved, it goes through many years of careful testing by scientists and doctors and once approved, its safety is continuously monitored. The safety threshold for vaccines is higher than that of traditional drugs because, by definition, they're administered to those without a disease.

Serious side effects from vaccines are very rare but minor side effects, like a sore arm or a low-grade fever, are common and show that your child's immune system is building protection. The medical community takes vaccine side effects very seriously, with the Vaccine Adverse Event Reporting System available to healthcare providers to catalogue any side effects outside of normal, minor irritation. Learn more about what to expect.

Hundreds of millions of doses of vaccines have been administered in the United States, and the safety record is excellent.

It's true — children do receive more vaccines now than in the past. That’s because medical science has developed safe and effective vaccines to prevent illnesses that once caused serious complications, hospitalizations, and even death. Diseases like meningitis, pneumonia, and sepsis are now far less common thanks to newer vaccines such as pneumococcal, meningococcal, and Haemophilus influenzae type b (Hib), which were introduced after many of us were children. The current schedule is built on decades of research to ensure children are protected at the ages when they are most at risk.

Vaccine ingredients are present in very small, safe amounts, often less than what your body naturally produces or encounters in daily life. Misinformation about ingredients, like mercury for example, can be scary. The scientific consensus is clear: the trace amounts of these ingredients in vaccines are safe and necessary to make the vaccines work effectively. The potential harm from these trace ingredients is infinitely smaller than the proven dangers of the diseases they prevent, but we understand that this complicates the decision for parents.

The tiny amounts of antigens (the parts of the germ that trigger an immune response) in vaccines are far less than what a child encounters naturally.

Giving many vaccines at once helps protect kids from sickness when they are most likely to get sick, and when it's safe to give the shots. Getting them together or separately doesn't change how often kids have side effects. Also, vaccines that combine several protections are tested together to make sure they still work well and don't cause more side effects.

It's an understandable thought, but it's a bit like saying, "We don't need seatbelts anymore because car accidents are less common." The safety comes from the protective measure. The reason these diseases are rare is because of vaccines. If we stop vaccinating, these diseases can quickly return. We've seen this happen with measles outbreaks in communities with low vaccination rates.

For example, in 2025, the United States experienced its largest measles outbreak in more than 30 years, with over 760 cases in Texas alone. Nearly 96% of those affected were under-immunized, leading to more than 170 hospitalizations — including one in five children under the age of five.

While a healthy lifestyle is important, it cannot fully protect against highly contagious and dangerous diseases like measles or polio. Vaccines train your immune system to recognize and fight off specific viruses and bacteria that can cause severe illness, something natural remedies cannot replicate. The historical data on childhood deaths before vaccines clearly shows that a strong immune system alone was not enough to prevent widespread illness and death from these diseases.

This is one of the most common questions parents ask. The short answer is no — vaccines do not cause autism. The idea started in 1998 with a small study involving only 12 children that suggested a link between the MMR (measles, mumps, rubella) vaccine and autism. That study was later proven to be fraudulent, retracted by the medical journal, and the author lost his medical license. Since then, researchers all over the world have looked closely at this question. Large studies following hundreds of thousands and even millions of children show the same result: that there is no connection between vaccines and autism.

• In Denmark, a study of over 650,000 children found no difference in autism rates between vaccinated and unvaccinated kids (Hviid et al., Ann Intern Med, 2019).

• A review of studies involving more than 1.2 million children also found no link (Taylor et al., Vaccine, 2014).

• Most recently, in 2025, a new Danish study of 1.2 million children looked at 50 different health outcomes—including autism—and again found no increased risk from vaccines or vaccine ingredients (Statens Serum Institut, Ann Intern Med, 2025).

We now know that autism begins very early in brain development, often before a baby is even born. Genetics play the biggest role. Autism is often diagnosed around the same time that children get certain vaccines. That timing, combined with misinformation, fuels the myth. Vaccines are safe, effective, and one of the best ways we have to protect children.