AMERICAN JOURNAL OF EPIDEMIOLOGY
Vol. 101, No. 6
Copyright © 1975 by The Johns Hopkins University
Printed in U.SA.
MEASLES (RUBEOLA) SUSCEPTIBILITY AMONG ELEMENTARY SCHOOLCHILDREN1 JANAL M. KALIS, PAUL G. QUIE AND HENRY H. BALFOUR, JR. 2 Kalis. J. M.. P. G. Quie and H. H. Balfour. Jr. (Box 437 Mayo. U. of Minnesota Health Sciences Center, Minneapolis, MN 55455). Measles (rubeola) susceptibility among elementary schoolchildren. Am J Epidemiol 101:527-531, 1975.—Measles (rubeola) immunity among 479 elementary schoolchildren from suburban Minneapolis was serologically surveyed in December 1971. Of the 479 children. 25 (5.2% ) had hemagglutination-inhibition (HI) titers < 2 . These children were considered susceptible to measles. For the 233 immunized children with no measles history, 13 (5.6%) had rubeola HI titers < 2 while 5 (5.1%) of the 98 youngsters with a history of clinical measles had rubeola HI titers < 2 . Of the 454 immune children, 73 (16%) had measles HI titers between 2 and 8. These findings confirm durable immunity and a low rate of vaccine failure following live attenuated measles vaccination but demonstrate the importance of testing sera beginning at a dilution of 2 in order to detect children with low antibody levels. This survey also suggests that maternal antibody interferes with the active immune response in youngsters immunized when < 1 year of age because this group of children had significantly lower geometric mean titers and significantly more susceptibles than the children immunized when > 2 years. hemagglutination-inhibition; measles; rubeola; vaccination
Reports of measles outbreaks in highly immunized elementary school populations have posed questions concerning rubeola immunity levels in vaccinated children and the frequency of clinical and subclinical measles infections in all youngsters, The history of vaccination, clinical measles and measles immunity status of elementary schoolchildren in a highly immunized Minnesota suburban community were surReceived for publication August 9, 1974, and in final form December 16,1974. Abbreviations: GMT, geometric mean titer; HI, hemagglutination-inhibition; ISG, immune serum gl
veyed in order to examine these parameters. MATERIALS AND METHODS
Venous blood from 530 Chanhassen elementary schoolchildren was collected in December 1971 using sterile technics. Sera were separated and stored at -70 C until tested. The sera were assayed for rubeola hemagglutination-inhibition (HI) antibodies in a microtiter system using 0.5 per cent African green monkey red blood cells , . , , . . . fr>i_-i J I hemagglutinating units of Philadelphia 26 measles virus antigen obtained from t n e National Center for Disease Con-
a n d 4
° S m the Departments of Laboratory Medicine, t r o 1 (D • Initially, the lowest serum dilution Pathology, Surgery and Pediatrics, University of Mintested was 10. (Titers are expressed as nesota Medical School, and the Division of Medical reciprocals of serum dilutions.) Additional Laboratories, Minnesota Department of Health. . _, . XJT o _ Supported by grants from the Minnesota Arthritis H I tests using Edmonston 84F measles Foundation and the Graduate School of the Univer- antigen (Lot M944028) obtained from Flow sity2 of Minnesota. Laboratories, Rockville, Maryland, were Reprint requests to Dr. Balfour, Box 437 Mayo, . , . „ , , „_„ . , ^ University of Minnesota Health Sciences Center, performed in December 1973 using a StartMinneapolis, Minnesota 55455. ing dilution of 2. Children were considered 527
528
KALIS, QUIE AND BALFOUR
susceptible if their measles HI titers were
Vol. 101, No. 6
Copyright © 1975 by The Johns Hopkins University
Printed in U.SA.
MEASLES (RUBEOLA) SUSCEPTIBILITY AMONG ELEMENTARY SCHOOLCHILDREN1 JANAL M. KALIS, PAUL G. QUIE AND HENRY H. BALFOUR, JR. 2 Kalis. J. M.. P. G. Quie and H. H. Balfour. Jr. (Box 437 Mayo. U. of Minnesota Health Sciences Center, Minneapolis, MN 55455). Measles (rubeola) susceptibility among elementary schoolchildren. Am J Epidemiol 101:527-531, 1975.—Measles (rubeola) immunity among 479 elementary schoolchildren from suburban Minneapolis was serologically surveyed in December 1971. Of the 479 children. 25 (5.2% ) had hemagglutination-inhibition (HI) titers < 2 . These children were considered susceptible to measles. For the 233 immunized children with no measles history, 13 (5.6%) had rubeola HI titers < 2 while 5 (5.1%) of the 98 youngsters with a history of clinical measles had rubeola HI titers < 2 . Of the 454 immune children, 73 (16%) had measles HI titers between 2 and 8. These findings confirm durable immunity and a low rate of vaccine failure following live attenuated measles vaccination but demonstrate the importance of testing sera beginning at a dilution of 2 in order to detect children with low antibody levels. This survey also suggests that maternal antibody interferes with the active immune response in youngsters immunized when < 1 year of age because this group of children had significantly lower geometric mean titers and significantly more susceptibles than the children immunized when > 2 years. hemagglutination-inhibition; measles; rubeola; vaccination
Reports of measles outbreaks in highly immunized elementary school populations have posed questions concerning rubeola immunity levels in vaccinated children and the frequency of clinical and subclinical measles infections in all youngsters, The history of vaccination, clinical measles and measles immunity status of elementary schoolchildren in a highly immunized Minnesota suburban community were surReceived for publication August 9, 1974, and in final form December 16,1974. Abbreviations: GMT, geometric mean titer; HI, hemagglutination-inhibition; ISG, immune serum gl
veyed in order to examine these parameters. MATERIALS AND METHODS
Venous blood from 530 Chanhassen elementary schoolchildren was collected in December 1971 using sterile technics. Sera were separated and stored at -70 C until tested. The sera were assayed for rubeola hemagglutination-inhibition (HI) antibodies in a microtiter system using 0.5 per cent African green monkey red blood cells , . , , . . . fr>i_-i J I hemagglutinating units of Philadelphia 26 measles virus antigen obtained from t n e National Center for Disease Con-
a n d 4
° S m the Departments of Laboratory Medicine, t r o 1 (D • Initially, the lowest serum dilution Pathology, Surgery and Pediatrics, University of Mintested was 10. (Titers are expressed as nesota Medical School, and the Division of Medical reciprocals of serum dilutions.) Additional Laboratories, Minnesota Department of Health. . _, . XJT o _ Supported by grants from the Minnesota Arthritis H I tests using Edmonston 84F measles Foundation and the Graduate School of the Univer- antigen (Lot M944028) obtained from Flow sity2 of Minnesota. Laboratories, Rockville, Maryland, were Reprint requests to Dr. Balfour, Box 437 Mayo, . , . „ , , „_„ . , ^ University of Minnesota Health Sciences Center, performed in December 1973 using a StartMinneapolis, Minnesota 55455. ing dilution of 2. Children were considered 527
528
KALIS, QUIE AND BALFOUR
susceptible if their measles HI titers were
