Measles

MMR vaccination prevents the measles immune amnesia cascade. Canada and the United Kingdom have lost measles elimination status. Koplik spots — white lesions on red mucosa inside the cheeks — are the pathognomonic finding unique to measles among common pediatric illnesses. Measles has a reproductive number of approximately 12, making it one of the most infectious pathogens known. Vaccine distrust and politicised public health messaging are said to explain measles elimination erosion in high-income countries with available vaccines. 1 in 1,000 measles-infected children develops encephalitis; 1 in 10,000 develops fatal SSPE that can emerge years after apparent recovery. Measles causes immune amnesia by erasing antibody memory to other infections, with up to three-quarters of patients losing previously acquired humoral immunity. The United States is described as close to losing measles elimination status.