The possibility of a second attack of measles is a subject which has intrigued medical observers for years. Some clinicians admit the possibility, albeit grudgingly, while others, equally competent, believe that such attacks do occur. A second attack must be distinguished from a relapse, which is in reality a second attack that occurs while the patient is still under treatment for the primary attack. Rolleston and Ronaldson1 noted only 9 cases of relapse in 11,749 cases of measles and claimed that in several cases of so-called relapse the prodromal rash has been mistaken for the primary attack.
Salzmann2 reported from the literature 36 cases of repeated attacks of measles, in which the patient was seen by the same observer during each attack; there were 21 examples of a third attack and 2 of a fourth attack. She commented on the frequency with which repeated attacks occurred in the