No, vaccines don't cause shaken baby syndrome

Context

Claims that routine vaccinations cause shaken baby syndrome have been circulating on both X (formerly known as Twitter) and Facebook (archived here and here). The viral posts published on June 12, 2024, include a screenshot claiming, "Shaken baby syndrome, also known as abusive head trauma, in reality was encephalitis brought on by vaccines." It specifically points to Diphtheria, Tetanus, and Pertussis (DTaP) vaccines as the "likely" cause. 

The screenshot has been shared with the caption, "Imagine following your pediatrician's advice, only to wind up in jail because of what the pediatrician did to your baby. The level of evil practiced by pediatricians is not quantifiable."

DTaP vaccines offer protection against bacterial infections that can cause diphtheria, tetanus, and pertussis (more commonly known as whooping cough.) The vaccines are given to children under the age of seven. Children are given five doses in total, with the first given at two months and the last between four and six years. 

Vaccines containing pertussis have been linked to encephalitis. However, this side effect is extremely rare, and encephalitis is just one of three symptoms linked to shaken baby syndrome. While the application of the shaken baby syndrome diagnosis has been criticized in recent years, there is no evidence that vaccines cause it. 

What we found

Shaken baby syndrome, or abusive head trauma, is the name given to a cluster of symptoms that can occur after a baby is violently shaken. These symptoms include closed-head bleeding, retinal bleeding, concussion, and encephalitis (swelling of the brain). Shaken baby syndrome can lead to the baby developing chronic conditions like epilepsy, paralysis, or, in extreme cases, death. 

For a caregiver to be criminally charged in shaken baby syndrome cases, a "triad" of symptoms, including encephalitis, retinal bleeding, and bleeding in the subdural area of the brain, must typically be present. There is growing criticism of prosecuting caregivers with child abuse after their children were diagnosed with shaken baby syndrome, including by the man who discovered it, as more evidence has emerged indicating that the triad of symptoms is not definitive proof that child abuse has happened. 

We have not found any evidence linking shaken baby syndrome to vaccines. Encephalitis has been recorded as a very rare side effect of vaccines containing pertussis. A Canadian study that looked at encephalitis cases recorded after vaccines between 1991 and 2021 found that there had been 61 cases reported within the 20-year period. Of these cases, 70.2 percent were more likely attributable to other causes as the patients had symptoms of non-vaccine related infection or had confirmed diagnosis. Three deaths were recorded, but none were confirmed to have been caused by the vaccine.

Cases of encephalitis have also been reported among adults and children who were not vaccinated.

Immunization expert Professor Helen Bedford from the Royal College of Paediatrics and Child Health told Logically Facts that vaccinations against whooping cough are a safe and effective means of immunizing children against the infection. 

"Recent increases in whooping cough cases and the deaths of eight young babies in the first four months of 2024 are the tragic reminders of how serious this disease can be," she said. 

"Whooping cough vaccine is offered in pregnancy between 16-32 weeks, but can still be given after 32 weeks. If you are pregnant and have not been vaccinated yet, or if you're not sure if your child is up-to-date with whooping cough or other routine vaccinations, please contact your GP or midwife as soon as possible."

The verdict 

While shaken baby syndrome has become a more controversial diagnosis in recent years, there is no evidence that it is caused by vaccines. One symptom associated with shaken baby syndrome — encephalitis — has been recorded after pertussis-containing vaccines. However, these cases have been rare, with further evidence indicating they were likely not caused by the vaccine. We have, therefore, rated this claim as false.