Received for publication April 12, 1985; accepted July 9, 1985. Reprint requests to (B.R.V.) 50 Maude St, Providence, RI 02908. PEDIATRICS (ISSN 0031 4005). Copyright © 1986 by the American Academy of Pediatrics.
PEDIATRICS
Vol. 77 No. 4 April 1 986
569Age of Diphtheria,
Tetanus,
and Pertussis
Immunization
of Special
Care
Nursery
Graduates
Betty
R. Vohr,
MD, and William
Oh, MD
From the Department of Pediatrics, Brown University Program in Medicine, and Women and Infants Hospital of Rhode Island, Providence
ABSTRACT. Diphtheria, tetanus, and pertussis (DTP) immunization data were collected on 103 special care nursery graduates in our neonatal follow-up clinic to determine whether DTP immunization schedules were significantly delayed relative to recommendations of the American Academy of Pediatrics (2, 4, and 6 months for DTP 1, 2, and 3, respectively). An inverse correlation was found between birth weight and immunization for first, second, and third DTP (r = 0.319, P < .01; r = .205, P < .05; and r = .236, P < .05, respectively). We subsequently conducted a mail survey to determine the DTP immuni-zation policy present in effect in 25 neonatal intensive care units in the United States and Canada. The survey indicates that procedural approaches remain markedly heterogeneous, and 10 of 25 (40%) units have no existing policy for implementation of DTP immunization. These data suggest that special cane nursery populations are at potential risk for pertussis, which requires a conscious implementation of DTP immunization by the special care nursery, the follow-up clinic personnel, and the primary care physician. Pediatrics 1986;77:569-571; diphtheria, tetanus, pertussis, immunization, low birth weight infant, special care nursery.
Diphtheria, tetanus, and pertussis (DTP) im-munization of high-risk, low birth weight infants
has been controversial in the past because of
phy-sicians’ impressions and uncertainty regarding
safety of immunization and effectiveness of
immu-nologic responses. Although the American
Acad-emy of Pediatrics’ Committee on Infectious Disease (The Red Book)’ has developed specific guidelines for DTP immunization ofterm and preterm infants, experience in our follow-up program led us to be-lieve that there was a significant delay in the initi-ation of recommended DTP immunization for
Spe-cial Care Nursery (SCN) graduates. We
hypothe-sized that graduates of the SCN, especially low
birth weight infants, have delayed DTP immuni-zation schedules during the first year of life relative to the recommendations of the American Academy of Pediatrics.
MATERIALS AND METHODS
At the time of the study, our SCN did not have
a firm policy on DTP immunization while infants
were still hospitalized. Following SCN discharge, immunization schedules were left to the discretion
of the primary physician caring for the child
be-cause the follow-up clinic functions primarily as a
neurodevelopmental assessment unit and does not provide primary care. Parents were requested to bring their immunization records when coming to a scheduled follow-up clinic visit. Immunization data, including dosage of DTP and chronologic age
at the time of immunization, were recorded on 103
SCN graduates who visited the neontal follow-up
clinic consecutively between March 1 and
Septem-ben 30, 1983. These infants were between 1 and 5
years of age, and their complete immunization data
were available.
A DTP questionnaire was also sent to 30
ran-domly selected US and Canadian neonatal
inten-sive care units (NICUs) in an attempt to determine the prevalence and type of established immuniza-tion policy in tertiary care centers. The questions asked included the following: (1) number of infants cared for in the NICU per year, (2) existence of an immunization policy, (3) age DTP immunization was initiated, (4) degree to which the immunization policy was enforced (all the time, most of the time,
sometimes).
For statistical analysis, the children in our study were categorized into four groups by birth weight
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DIP
M±SEM (= 031
DIP
#2
AGE OF IMMUNIZATION
0
I
<1000 1001-1500 1501-2500 22501
‘3
DIP3
TABLE 1. Clinical Characteristics
570 DTP IMMUNIZATION
Characteristics Group
I II III IV
n
Wt category (g)
Birth wt (g) (mean ± SD) Gestation (wk) (mean ± SD) Hospitalization (d) (mean ± SD)
11 <1,000 852 ± 70
30 ± 4 86 ± 28
49 1,001-1,500 1,274 ± 152
31 ± 2.6 62 ± 52
20 1,501-2,500 1,930 ± 303
33 ± 2.4 31 ± 15
23 >2,501 3,342 ± 646
38 ± 2.5 9 ± 5
M ±SEM (n 02)
<1000 1001-1500 I5OI-25O025OI (grams)
BIRTH WEIGHT CATEGORIES
Figure. Mean age of infants receiving three immuniza-tions for diphtheria, tetanus, and pertussis (DTP #1, DTP #2, and DTP #3) for the fourth birth weight groups. AAP, American Academy of Pediatrics.
(grams) as shown in Table 1. The clinical charac-tenistics of the study infants are also shown in this table. Statistical analyses consisted of linear
regres-sion analysis between birth weight and age of
im-TABLE 2. Diphtheria, Infants Tetanus, Not Fully Pertussis
Immunized With Three Vaccinations
Age (mo) Group
I II III IV
6 12 10/11 (91%) 3/11 (27%) 40/49 (82%) 7/49 (14%) 11/20 (55%) 1/20 (5%) 14.23* (61%) 1/23* (4.3%) * Three children received diphtheria and tetanus vacci-nations only.
munization for DTP 1, DTP 2, and DTP 3. The mean ages of immunization for DTP 1, 2, and 3 for the study infants are shown in the Figure. Linear regression analysis showed a significant in-verse correlation between birth weight and age of immunization for DTP 1 (r = .319, P < .01); DTP 2 (r = .205, P < .05); and DTP 3 (r = .236, P < .05). The percentages of infants who had not ne-ceived their third DTP and were, therefore, not adequately immunized at 6 and 12 months are shown in Table 2. At 6 months of age, greater than 50% of infants in each weight category were not fully immunized. In the <1,000- and 1,001- to 1,500-g groups, 91% and 82% of infants, respectively, were not fully immunized. At 12 months of age, there was substantial improvement, although in the lowest weight groups (groups I and II) 27% and 14% of infants, respectively, still had not received a complete series.
One infant in group II with a birth weight of 1,070 g and multiple peninatal complications, in-cluding bronchopulmonary dysplasia, who had not received any immunization, contracted pertussis at 5 months of age. The diagnosis was confirmed by nasopharyngeal culture of Bordetella pertussis and fluorescent antibody techniques. The infant be-came moderately ill with respiratory distress in-cluding spasmodic coughing and wheezing requiring hospitalization for 3 weeks.
In our survey, 25 of 30 (83%) NICUs with a mean
census of 750 ± 360 infants responded to the
im-munization questionnaire. Sixty percent of the
NI-CUs had an established policy for immunization
(Table 3). Two months chronologic (postnatal) age, the currently recommended age for onset of DTP immunization, was used in only four of 15 (27%) of
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TABLE 3. Neonatal Intensive Care Data*
Annual Neonatal Census (mean ±
SD [range])
DTP Policy
Yes No
Age of Immunization Policy Enforced
2 Mo Chron-ologic 2 Mo Cor-rected
Other Always Most
Times
Sometimes
750 ± 360 [350-1,611] 15/25 10/25 60% 40% 4/15 27% 5/15 33% 6/15 40% 3/15 20% 8/15 53% 4/15 26% ACKNOWLEDGMENTS
The authors thank the directors of the 25 intensive
care units in the United States and Canada who
re-sponded to our survey, Dr Georges Peter for advice and interest in this study, and Janice Brusini for technical assistance in preparation of this manuscript.
REFERENCES
1. Report of the Committee on Infectious Diseases: The 1982 Redbook, ed 19. Evanston, IL, American Academy of Pedi-atrics, pp 200-222
2. Bernbaum JC, Daft A, Anolik R, et al: Response of preterm infants to diphtheria-tetanus-pertussis immunizations. J Pediatr 1985;107:184-188
3. Bernbaum J, Anolik R, Polin RA, et a): Development of premature infant’s host defense system and its relationship to routine immunization. Clin Perinatol 1984;11:73-84
4. Committee on Infectious Diseases, American Academy of Pediatrics: Pertussis vaccine. Pediatrics 1984;74;303-305 5. Immunization Practices Advisory Committee: Supplementary
Statement of Contraindications to Receipt of Pertussis Vac-cine. MMWR 1984;33:169-171
ARTICLES
571* Data taken from questionnaires returned
care units.
the NICUs with an immunization policy. The re-maining NICUs used either 2 months corrected age (gestational age at birth + postnatal age) (33%) or a variety of age and weight criteria (40%). The
survey also showed that only three of 15 NICUs
that had an immunization policy enforced their guidelines; the majority of the units carried out their policy either “most of the time” on “some-times” only.
DISCUSSION
Our data confirmed our previous impression that graduates of a SCN are a neglected population with respect to appropriate timing of DTP immuniza-tion. The inverse relationship between birth weight and age of immunization also suggests that the lack
of an established policy in our SCN for DTP
im-munization of very low birth weight infants who often are hospitalized for 2 to 3 months was partly responsible for the delayed immunization. Further-more, the concern of primary care physicians that very low birth weight infants may have an increased
risk of complications from immunization may
ac-count for the delay in scheduling and the adminis-tration of partial doses.
The responses to our NICU DTP immunization questionnaire indicate that the situation as it
ex-isted in our NICU is not unique. Although there is
evidence that some NICUs have on are developing immunization policies for their at-risk populations, there is still a need for standardization of procedure. Since the completion of this study, we have initi-ated a DTP immunization program for very low birth weight SCN infants prior to discharge if the infant is 2 months of age (chronologic).
Recent studies have shown that preterm infants have few side effects and an adequate response to pertussis.2 In addition, susceptibility to pertussis in unimmunized low birth weight infants may be in-creased because this population is relatively im-munocompromised;3 second, severity of pertussis may be worsened because of underlying chronic
by 25 US and Canadian neonatal intensive
lung disease and poor nutritional status which are often present in SCN graduates, particularly the very low birth weight infant. The documentation of one index case of pertussis in our study group, although anecdotal, illustrates the potential occur-nence of the disease in the at-risk population.
In summary, these data identify a high-risk seg-ment of the population (the low birth weight SCN graduate) that has been inadequately immunized in the first year of life. There is a discrepancy, there-fore, between recommended policy and actual im-plementation of immunization procedures. The present literature, however, should reassure physi-cians that DTP immunization can be safely admin-istered as recommended by the American Academy of Pediatrics unless there are specific contraindi-cations such as a progressive neurologic disorder on a history of seizures.4’5 If we are to protect this high-risk population, a specific policy for initiating im-munization of SCN infants prior to hospital dis-charge should be implemented.
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1986;77;569
Pediatrics
Betty R. Vohr and William Oh
Graduates
Age of Diphtheria, Tetanus, and Pertussis Immunization of Special Care Nursery
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1986;77;569
Pediatrics
Betty R. Vohr and William Oh
Graduates
Age of Diphtheria, Tetanus, and Pertussis Immunization of Special Care Nursery
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