The Fate of Mumps Antibodies Following Their Passage Through the Placenta

Summary and Conclusions Analysis of 68 sera from infants under 6 months of age showed that although 31 of 34 newborns had detectable mumps complement fixing (CF) antibodies, the serum from only 1 infant over 44 days of age gave a positive CF reaction. The rate of disappearance of mumps complement fixing (CF) and agglutination-inhibiting (A-I) antibodies was followed in 4 infants, and although there was considerable variation, the average time of disappearance for both antibodies was surprisingly similar—53 and 45 days respectively. Since placenta-passing mumps antibodies as determined in this study disappear from the circulation rather early in life, one must look to other factors to account for the rarity of mumps in infancy.