IMMUNIZATION

The

of Adolescent Girls to Rubella

Susceptibility Observations

John M. Stoffman, M.D.,

F.R.C.P.(C.),

~N

1973, we became interested in assessing the level of susceptibility to rubella in the population of female adolescents under our care. These girls, sometimes living as transients, and often psychologically immature, not only are at risk of becoming pregnant, but also are usually unaware of knowing about their rubella susceptibility. Observations

hemagglutination inhibition (H-1) titers were measured by means of a standard test on serum samples taken from 297 girls who attended Teen Clinic (a general medical clinic for adolescents) between October, 1973 and June, 1974. The mean age of all who attended the clinic was 16.1 years, and that of the girls in this series was 16.3 years. Any person with a titer less than 1/10 is judged to be susceptible to rubella. Seventyfive girls (25.3%) had rubella H-1 antibody titers less than 1/10 (Table 1). Of these 75 girls, 31 (41.3%) were given live attenuated rubella vaccine (HPV-i’7 Rubella

antibody

.

on

297 Girls in Toronto

Martin G. Wolfish, M.D.,

F.R.C.P.(C.)

strain). Mean age of the immunized girls 15.9 years. Eleven (14.7%) had other arrangements made by a letter or phone

was

advising that they should contact their family doctors. Thirty-three (44%) were awaiting reappointment or could not be

call

contacted. Of the 297 girls, 134 were asked if they had had rubella previously or if they had been immunized. Approximately one out of five of both the susceptibles and the total immune group did not know. Among those who said they &dquo;knew,&dquo; they were approximately as likely to be correct as incorrect as judged by the serologic tests (Table 2). Of the 40 girls who thought TABLE 1. Rubella H-1 Antibody Titer Levels in 297 Adolescent Girls in Toronto

From the Division of Adolescent Medicine, the Hos-

pital for Sick Children, Toronto, Canada. Correspondence to John M. Stoffman, M.D.,

266 Oxford Street East, London, Ontario, Canada, N6A 1V1.

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TABLE 2.

they

were

to Iiubella-A Real and Perceived

Susceptibility

Comparison of

immune, 29 (73%)

were

Of the 36

girls

who

correct.

thought they

were

24 (67%) were incorrect. Because rubella immunization is contraindicated during pregnancy,’ such prophylaxis must be considered individually for each postmenarchal patient. With a girl who positively is not sexually active, immunization is presumably safe. With a girl who is sexually active, before giving the immunization the physician must be satisfied that the patient is not pregnant and is protected against pregnancy for at least two months. Our patients’ susceptibility rate of 25.3 per cent is somewhat higher than the 10 to 15 per cent presently quoted for Ontario adult females.2 One reason for our higher figure may be that adolescents only infrequently seek medical care, reducing the opportunity for comprehensive evaluation by the physician. Also, our patients, being still adolescent, may have had less opportunity to contract natural rubella. Furthermore, school immunization programs miss up to half of the studentS.3 Because history alone is inaccurate in identifying susceptibility to rubella, it would be wise to perform rubella H-I antibody titers in adolescent girls and immunize those susceptible. Rubella epidemics still occur, 4,5 and in reported epidemics most cases have been in unvaccinated teen-agers and young adults. 4,6 Recently, it has been suggested that we preferentially immunize susceptible adolescent girls, in order to increase their protection closer to the time when it may

susceptible,

be needed.6,7 One cannot rely on herd immunity alone to prevent spread of rubella because even a high level of pre-existing herd immunity is ineffectual. 3,6 Immunization is painless and easy. We did not follow up our patients for side effects such as arthralgia, arthritis, or paresthesia,5 but received no reports of side effects. Where feasible, the rubella H-I titer should be measured again six weeks after immunization, in order to confirm the development of immunity.

Recapitulation Since serum rubella H-I antibody titers of 297 adolescent girls showed 25.3 per cent be susceptible, mendation that all to

we

support the

recom-

be imthat after individual evaluation there is no risk of pregnancy at the time of immunization or in the ensuing two months.

susceptible girls

munized, provided of

course

Acknowledgments The authors thank Dr. Diane Sacks, Ms. Shirley R. N., and Ms. Maureen Khan for assistance in carrying out the study, and Dr. Helen Reid for help with the evaluation.

Wheatley,

References A. J., Wilson, M. G., and Lennette, E. H.: Avoidance of Rubella immunization of women during or shortly before pregnancy. JAMA 215: 632, 197 1. 2. Iwakata, S., Rhodes, A. J., and Labzoffsky, N. A.: Laboratory diagnosis of Rubella virus infection. Can. Med. Assoc. J. 108: 894, 1973. 3. Anglin, C. S., and Johnson, S. E.: Proceedings 1.

Chin, J., Ebbin,

the international rubella conference on protection for the postpubertal female. Can. J. Public Health 62: (Monograph supplement) 21, 1971. 4. Rachelefsky, G. S., and Herrmann, K. L.: Congenital rubella surveillance following epidemic rubella in a partially vaccinated community. J. on

Pediatr.

84, 474, 1974. P. J., Stoffels, M. A., Anderson, E., and Witte, J. J.: Epidemic rubella in adolescent boys. JAMA 227: 1283, 1974.

5. Landrigan, 6.

Farquhar, J. D.: Experience with

rubella and rubella immunization in institutionalized children. J. Pediatr. 83: 51, 1973. 7. Katz, M.: Rubella vaccine (Editor’s column). J. Pediatr. 84: 615, 1974.

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