Serological Epidemiology in Measles **

One usually thinks of measles as a minor childhood illness through which we all must pass and as a nuisance more than a danger. But this was not always the case. In colonial America, two hundred years ago, measles was dreaded like the plague, and today in remote parts of the world, on isolated islands and in the Arctic, it can be a devastating disease. Even here and now in the United States it causes several hundred deaths each year. In 1957, the last year for which complete data is available, 410 deaths were attributed to measles, a greater number than that caused by poliomyelitis. It is for this reason that we have seized upon the serological tests developed by Enders and Peebles' in order to study the epidemiology of measles more fully. Both complement fixation and neutralization tests are available. The two tests give almost identical results and have been used interchangeably. The first part of this paper deals with studies on the development and persistence of measles antibodies. One of the purposes of these studies was to determine the degree to which measles cases are actually reported in the city of New Haven. It was assumed from the start that the reporting would be far from complete as it has been shown in a study carried out in Hagerstown, Maryland' that, even when conditions were unusually favorable, reporting might only account for 40 per cent of the cases actually occurring. A second purpose was to determine whether the pattern of universal susceptibility to a first attack of measles and durable immunity thereafter, which has been observed in epidemics in isolated areas, would also apply in areas where the disease is endemic. A first step was to determine the normal pattern of antibody development during the disease. The curve in Figure 1 is based on data obtained by Dr. Viggo Bech in a study, carried out at Yale, of 212 serum specimens which he had collected from 71 cases of all ages during the severe measles epidemic in Greenland in 1955.1 In both this study and an earlier one carried out by Ruckle and Rogers' antibodies to the measles virus were always