Correcting this week’s misinformation: week of July 24 2026

More and more parents are choosing not to give their newborn babies the Vitamin K shot. One reason is that anti-vaccine activists, including Karl Jablonski, claim that the shot can cause cancer, infertility (making it harder to have children later), and genetic problems.

Babies are born with very low levels of vitamin K. Vitamin K helps the blood clot, which means it helps stop bleeding. Without enough vitamin K, newborns can develop a rare but serious condition called vitamin K deficiency bleeding. This can cause dangerous bleeding inside the body, including in the brain. The vitamin K shot has greatly reduced these cases.

In 1992, a small study suggested that the vitamin K shot might be linked to childhood leukemia, a type of blood cancer. This raised concerns, so researchers did larger and better studies. Those studies found no link between the vitamin K shot and childhood cancer.

There is also no evidence that the vitamin K shot causes genetic problems or changes a baby’s DNA. After many years of use in millions of newborns, doctors have not found these problems.

The vitamin K shot has been recommended for newborns in the United States since 1961. Millions of babies who received the shot have grown up and had children of their own. There is no evidence that the shot causes infertility. Because of this evidence, the American Academy of Pediatrics and the World Health Organization continue to recommend the vitamin K shot for all newborns.

In some situations, Vitamin K can cause a severe allergic reaction or problems with blood pressure and the heart. However, these serious reactions happen much more often when vitamin K is given through an IV, which delivers medicine directly into a vein, and at much larger doses than newborns receive.

Newborn babies do not get vitamin K this way. They receive a small shot in the muscle. Only one life-threatening reaction to a newborn vitamin K shot has been reported in the medical literature, and it occurred in Turkey.

Brian Hooker, testifying at a Senate committee hearing led by Senator Ron Johnson, said that the only autistic children in Amish communities are the ones who were adopted from outside the community and had been vaccinated before adoption.

Some people claim that Amish families do not vaccinate. However, Amish communities are diverse, and families make different choices about medical care.

Vaccination rates are often lower in Amish communities than in the general population, but they are not zero. In one study, 68% of parents said all of their children were vaccinated. Only 14% said none of their children were vaccinated.

Autism also occurs in people who have never received vaccines. Studies that compare vaccinated and unvaccinated children have not found a meaningful difference in autism rates.

Researchers have also studied autism in Amish communities. In one study, children were screened for autism, and some met the guidelines for an autism spectrum disorder diagnosis. Autism may be less visible in these communities because families value privacy, screening may be harder to access, and fewer support services may be available.

Read more to explore the question: Can living with less modern medical care make people healthier?

In a video online, Naomi Wolf claims that COVID vaccines damaged the part of the brain called the prefrontal cortex. She says this caused changes in people’s personalities and made it harder for them to think clearly.

Naomi Wolf has a PhD in English literature, not medicine. She does not provide studies or other evidence to support this claim. She also does not give clear examples of people losing the ability to think or having major personality changes because of a COVID vaccine.

Billions of COVID vaccine doses have been given around the world. If the vaccines commonly caused serious changes in thinking or personality, doctors, brain specialists, mental health experts, and vaccine safety systems would likely have found a clear pattern.

Brain scans have not found physical changes in the brain after mRNA COVID vaccination. In contrast, studies have found that COVID infection itself can harm the brain. Some people have had problems with memory and thinking after an infection, and some studies have found drops in IQ scores.