January 1977

The J o u r n a l o f P E D I A T R I C S

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A measles outbreak among adolescents In a May, 1975, outbreak, 147 adolescents, ages 12 to 19years, were identified as having measles by a physician or school nurse. One junior high school, with an enrollment o f 1,122, contributed 131 of the cases. O f the 147 students, 54 were seen by physicians who also supplied their immunization records; 19 of 54 (35%) had received live measles virus vaccine without measles immune globulin, after age one year The remaining 35 received. killed virus vaccine only (1), K + L (4), L + MIG (4), L at < I year o f age (4), L + ? MIG (4), immune serum globulin only, for exposure (6), no vaccine but history o f measles previously (9)," history uncertain (3). Hemagglutination-inhibition antibody titers were consistent with the diagnosis o f acute measles in 11 children. No index case was identified and no secondary cases occurred within the families o f the 54 cases. This measles outbreak among seemingly immunized adolescents raises a serious question as to the duration o f such protection.

Leonard B. Weiner, M.D.,* Robert M. Corwin, M.D., Phillip I. Nieburg, M.D., and Harry A. Feldman, M.D., Syracuse, N. Y.

DE s P t TE the marked decline in the reported incidence of measles in the United States since the introduction of the live virus vaccine in 1963,' outbreaks continue to occur among both its recipients and nonrecipients." -' Measles occurring among previously vaccinated subjects usually has been attributed to immunization failure,-' :~ improperly stored vaccine? the use of vaccine in conjunction with measles immune globulin,:' the administration of vaccine to infants less than one year of age," " and to the exclusive use of killed virus vaccine.:' In addition, there are those children who received only passive immunization with immune serum globulin and are erroneously considered by their parents to be protected against measles. This report describes a measles outbreak that occurred in May, 1975, among a large number of adolescents who presumably had been protected against the disease by one of a variety of immunologic measures, including live attenuated virus vaccine without MIG.

From the Departments o f Pediatrics and Preventive Medicine, State University o f New York, Upstate Medical Center. *Reprint address: Department of Pediatrics, State University Hospital, 750 E. Adams St., Syracuse, NY 13210.

METHODS Subjects. There were 147 students, ages 12 to 19 years (mean 13.7 years), who were identified as having measles. Among them, 131 attended grades 7 thru 9 in a junior high school in Camillus, New York (suburb of Syracuse), in which the total enrollment was 1,122 (11.7%). See related articles, pp. 1, 13, and 156.

Abbreviations used HI: hemagglutination-inhibition ISG: immune serum globulin K: killed measles virus L: live measles virus MIG: measlesimmune globulin ND: not done

Measles. Measles was diagnosed if a rash, fever (_> 102 ~ F) and cough, or other upper respiratory symptoms were recorded during the period of the outbreak. The 131 patients at thejunior high school were all seen by the school nurse sometime during their acute illnesses. She maintained precise records of absenteeism and its cause (fever, rash, cough, etc.). Fifty-four cases, including

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Weiner et al.

The Journal of Pediatrics January 1977

Table I. Age distribution of 147 students with clinically verified* measles

Students Age No. 12 13 14 15 16 17 19

19 46 48 27 5 1 1

Totals

147

%

[

13 31 33 19 3 0.5 0.5 100

*By physicianor nurse.

Table 1I. Immunization procedure and age administered for 54 students with measles clinically diagnosed by physicians

Age administered Procedure* K only KKL L + MIG L only L + ? MIG ISG (for exposure only) Uncertain History of previous measles, no vaccine

< 1 yr [ >- I yr l 0 0 4 1 4

0 4 4 19 3 2 3 9

*K = Killed measles virus vaccine; L = live measles virus vaccine; MIG = measlesimmuneglobulin;ISG = immuneserum globulin.

16 who did not attend this school but did go to other schools in the area, were seen in either of two physicians' offices. Paired sera were obtained from the three patients who required hospitalization and from 11 others whose immunization status was unknown at the time of bleeding. Acute and convalescent hemagglutination-inhibition antibody titers to measles virus were measured (New York State Department of Health Laboratory) and considered significant if they revealed a fourfold or greater rise. RESULTS Among the 147 study subjects (Table I), all had rash; 94%, fever; 82%, headache; 79%, cough. Koplik spots were observed in some of them. The duration of signs and symptoms in the 131 attending the junior high school were as follows: < 9 days, 27%; 10 to 12 days, 49%: 13 to 15 days, 16%; ___ 16 days, 8%. When the absentee rates for May, 1974, and May, 1975, in this school were compared, there was a significant increase during the May, 1975,

measles outbreak. Whereas, 1,132 pupil absentee days were recorded for May, 1974, there were 1~743 in May, 1975, an increase of 53.1%. The dates of onset of illness in the 131 students with measles ranged from May 9 to May 22 with the peak on May 15. A review of the school health records of the 131 students did not reveal any immunization data which could be substantiated. Fortunately, such information was obtainable from the records in the two physicians' offices which cared for the 54 patients; 19 (35%) of them had received live measles virus vaccine without MIG after the age of one year. In 14 of the 19, such vaccine had been administered more than eight years previously, but the other five were immunized in 1968 (1), 1969 (2), and 1971 (2), respectively. The remaining 35 children had received: killed measles virus vaccine (1), a sequence of two doses of killed measles virus vaccine followed by live virus vaccine (4), live measles virus vaccine plus MIG (4), live measles virus vaccine at less than one year of age (4), live measles virus vaccine possibly with MIG (4), only ISG for possible measles exposure (6), no vaccine but history of measles previously (9), and uncertain about measles immunization of any kind (3) (Table II). Measles HI titers were obtained from 14 patients. Of the paired sera: nine showed significant increases; one decreased from 256 to 32; one had a stable acute and convalescent titer of 32; and one increased from 16 to 32. In the remaining two patients only convalescent titers were obtained (Table III). DISCUSSION Of the 54 patients with measles whose immunization histories were available from physician records, 35% should have been adequately immunized by recommendations current at that time.: Since immunization was administered at various ages, by different physicians, and in a variety of geographic locations, it is highly unlikely that failures can be uniformly ascribed to improperly stored 4 or otherwise defective lots of vaccine. The failure to identify secondary cases within the households of the 54 patients seen by physicians despite specific searches was somewhat surprising. Three sibling pairs, similar in age and attending the same junior high school, had measles concurrently. Although an index case for this outbreak was not identified, sporadic measles was reported throughout central New York state in 1975. It also is probable that additional students were infected, but were not detected, because they failed to develop rashes or other signs and symptoms. The identification of such cases would have required extensive, repeated serologic determinations which were beyond the scope of this investigation. Nonetheless, it is probable that the actual

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Measles outbreak among adolescents

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Table III. Immunization data for 14 students whose measles HI titers were measured

HI titerst Student 1 2 3 4 5 6 7 8 9 10 11 12 13 14

~ 12 19 14 13 12 13 14 13 13 14 15 15 13 14

Previousvaccine*

Year

Age > 1 yr

KKL KK L KKL L L L + ? MIG ISG ISG Unknown Unknown None None Unknown Unknown

1964 1963 1965 1965 1967 1964 1961 1962 1963 Unknown Unknown

Yes Yes Yes Yes Yes Yes No No Yes '~ ? ? Unknown Unknown

Acute < 4 ND:~ < 4 < 4 < 4 ND < 16 < 4 256 32 < 4 < 4 8 16

Convalescence 512 512 256 16 16 ~> 16 32 32 32 32 32 32 32 32

*K = Killed measles virus; L = live measles virus; MIG = measles immune globulin; ISG = immune serum globulin. ~N.Y. State Health Department Laboratory. ~ND = Not done.

infection rate was higher than the infection rate identified. The highest convalescent antibody titers were noted in three subjects who had received two injections of killed vaccine prior to live virus vaccine some months later (Table III). These three patients were the only ones who were admitted to hospitals during the outbreak. Two of them (Cases 2 and 3) had clinical findings consistent with the syndrome o f atypical measles, including interstitial pneumonia, hilar adenopathy, hemorrhagic rash, and laboratory evidence of disseminated intravascular coagulation. The third hospitalized individual (Case 1) presented with post-infectious Bell's palsy and subsequently developed Guillain-Barr6 syndrome. Several recent pediatric surveys have demonstrated seroimmunity to measles in the range of 65 to 85%,:'although the overall seroconversion rate following live measles virus vaccine in children aged one year or more has been estimated to be 95 to 98%.'-'. :~ Krugman:' and Lepow and Nankervis ~' have reported satisfactory persistence o f measles HI antibody for periods of eight to ten years after live virus immunization. More recently, Bass and associates'" and Yeager" have presented serologic data suggestive of waning immunity to measles eight to ten years following vaccination. Although the vaccine type was not always specified, both live and killed virus preparations had been administered. The outbreak described in this report suggests that measles immunization considered to be appropriate may not result in adequate long-term protection in a significant proportion of adolescents; increasing proportions of

vaccinated adolescents and adults have been reported to have acquired measles in recent outbreaks? .... The continuing systematic surveillance of cohorts of i m m u nized children for lengthy periods to determine their antibody decay rates and concomitant increasing susceptibility to measles (and probably rubella and m u m p s as well) appears to be indicated. The authors are indebted to Ms. W. Micki Wilder, R.N., the school nurse-teacher, for her meticulous and helpful illness records and Dr. Paul Palmer for immunization and other information. REFERENCES

I. 2. 3.

4. 5.

6.

7. 8.

Barkin RM: Measles: regaining control, JAMA 231:737, 1975. Plotkin SA: Failure of protection by measles vaccine, J PEmA~R 82:908, 1973. Krugman S: Present status of measles and rubella immunization in the United States: A medical progress report, J PEDIATR78:1, 1971. Lerman SJ, and Gold E: Measles in children previously vaccinated against measles, JAMA 216:1311, 1971. Arbeter AM, Arthur JH, Blakeman GJ, and Mclntosh K: Measles immunity: Re-immunization of children who previously received live measles vaccine and gamma globulin, J PEDIATR81:737, 1972. Lepow ML, Steele BM, Ross MR, and Randolph MF: Measles immunization status in 1972 among first- and second-grade school children in Danbury, Connecticut, Pediatrics 55:348, 1975. Report of the Committee on Infections Disease, American Academy of Pediatrics, pp 80-81, 1974. SchiffGM, Linnemann CC, Shea L, Rotte T, Grundy B, and

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Ashe HS: Rubella and measles serosurvey among a norturban pediatric population, Am J Dis Child 129:312, 1975. Lepow ML, and Nankervis GA: Eight year serologic evaluation of Edmonston live measles vaccine, J PEOIATR75:407, 1969. 10. Bass JW, Halstead SB, Fischer GW, Podgore JK, Pearl WR~ Schydlower M, Wiebe RA, and Ching FM: Booster vacci-

The Journal of Pediatrics January 1977

nation with further live attenuated measles vaccine, JAMA 235:31, t976. 11. Yeager AS: Measles immunity: California 1975 (abst.) Clin Res 24:186, 1976. 12. Rawls WE, Rawls ML, and Chernesky MA: Analysis of a measles epidemic; possible role of vaccine failures, Can Med Assoc J 113:941, 1975.

A measles outbreak among adolescents.

January 1977 The J o u r n a l o f P E D I A T R I C S 17 A measles outbreak among adolescents In a May, 1975, outbreak, 147 adolescents, ages 12 t...
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