evidence: Some people concerned about vaccine safety wonder whether vaccines may enter the brain and cause neurological conditions. In order to affect the brain, vaccine components would need to reach the brain. Importantly, our brains are protected by a barrier, called the blood-brain barrier (BBB), which keeps foreign substances from entering the brain. [...] - Vaccination – Vaccines can protect against several infections that can cause meningitis or encephalitis, including measles, mumps, rubella, chickenpox (varicella), meningococcus, Haemophilus influenzae type b (Hib), pneumococcus, and Japanese encephalitis virus.