Pertussis vaccine contain reduced amounts of pertussis antigens compared to DTaP vaccines. Pearl Kendrick and Grace Eldering studied pertussis in the 1930s. They developed and ran the first large scale study of a successful vaccine for the disease. During the 1970s and 1980s, a controversy erupted related to the question of whether the whole-cell pertussis component caused permanent brain injury in rare cases, called pertussis vaccine encephalopathy. Despite this allegation, doctors recommended the vaccine due to the overwhelming public health benefit, because the claimed rate was very low (one case per 310,000 immunizations, or about 50 cases out of the 15 million
Unverricht–Lundborg disease ULD, MRIs taken once the disease has progressed show characteristic damage, which may help to correct a misdiagnosis. While ULD is a rare disease, the lack of well defined cases to study and the difficulty in confirming diagnosis provide strong evidence that this disease is likely under diagnosed. Unverricht–Lundborg disease is also known as EPM1, as it is a form of progressive myoclonic epilepsy (PME). Other progressive myoclonic epilepsies include myoclonus epilepsy and ragged red fibers (MERRF syndrome), Lafora disease (EPM2a or EMP2b), Neuronal ceroid lipofuscinosis (NCL) and sialidosis. Progressive myoclonic epilepsies generally constitute only a small percentage of epilepsy