Notes on the Effect of Measles and Measles Vaccine in a Virgin-Soil Population of South American Indians1

Noel, J. V. (Dept. Human Genetics, Univ. of Michigan Medical School, Ann Arbor, Mich. 48104), W. R. Centerwall, N. A. Chagnon and H. L Casey. Notes on the effect of measles and measles vaccine in a virgin-soil population of South American Indians. Amer. J. Epid., 1970, 91: 418–429.—Serologic studies conducted on 606 blood specimens obtained during expeditions in 1966 and 1967 to the primitive Yanomama Indians of Southern Venezuela and Northern Brazil revealed these Indians to be essentially a “virgin-soil” population for measles. Accordingly, measles vaccine was obtained for administration during an expedition in 1968. Measles itself was introduced to the Indians coincidental with the arrival of the expedition in the field. Observations are recorded on the effect of Edmonston B vaccine administered both with and without MIG in standard doses, as well as on the response to the disease itself. Although the circumstances surrounding the epidemic were such that the observations were fragmentary, we think the response of these probably previously unexposed Indians to measles virus is only slightly greater than that of the members of long-civilized Caucasian populations. This greater response may well be due to factors other than an increased genetic susceptibility.