Evaluation of vaccine coverage for low birth weight infants during the first year of life in a large managed care population.
OBJECTIVE
There are few recent population-based assessments of vaccine coverage in premature infants available. This study assesses and compares age- and dose-specific immunization coverage in children of different birth weight categories during the first year of life.


METHODS
We performed a retrospective cohort analysis of computerized vaccination data from a large managed care organization in southern California. The participants were children born between January 1, 1997, and December 31, 2002, and continuously enrolled from birth to at least 12 months of age in the Southern California Kaiser Permanente health plan. We measured age-specific up-to-date and age-appropriate immunization rates according to birth weight (extremely low birth weight: <1000 g; very low birth weight: 1000-1499 g; low birth weight: 1500-2499 g; normal birth weight: >/=2500 g) for 4 vaccines (hepatitis B, diphtheria and tetanus toxoids with pertussis, Haemophilus influenzae type b, and poliovirus) through the first year of life.


RESULTS
We identified 127 833 infants born during the study period and continuously enrolled through the first year of life; 120 048 were normal birth weight infants; 6491 were low birth weight infants; 788 were very low birth weight infants; and 506 were extremely low birth weight infants. Vaccine-specific age-appropriate immunization rates were 3% to 15% lower for low birth weight infants and 17% to 33% lower for extremely low birth weight infants compared with the rates for normal birth weight infants in the first 6 months of life. Extremely low birth weight infants had the lowest age-specific up-to-date immunization levels (5%-31% lower) compared with normal birth weight infants at each age assessed. By 12 months, extremely low birth weight infants still had significantly lower up-to-date levels (87%) compared with very low birth weight, low birth weight, and normal birth weight infants (91%-92%).


CONCLUSIONS
Despite recommendations that lower birth weight infants be vaccinated as the same chronological age as normal birth weight infants, extremely low birth weight and very low birth weight infants are immunized at significantly lower rates relative to low birth weight and normal birth weight infants at 2, 4, and 6 months of age. However, by 12 months of age this finding persists only in extremely low birth weight infants.
Batra
Jagmohan S
JS
Harbor-UCLA Medical Center, Liu Research Building, 1124 W Carson St, Torrance, CA 90502, USA. jbatra@memorialcare.org
Eriksen
Eileen M
EM
Zangwill
Kenneth M
KM
Lee
Martin
M
Marcy
S Michael
SM
Ward
Joel I
JI
D000367:Age Factors; D001425:Bacterial Outer Membrane Proteins / Q000008:administration & dosage / Q000009:adverse effects; D002140:California; D015721:Diphtheria-Tetanus-Pertussis Vaccine / Q000008:administration & dosage / Q000009:adverse effects; D022681:Diphtheria-Tetanus-acellular Pertussis Vaccines / Q000008:administration & dosage / Q000009:adverse effects; D005260:Female; D018073:Haemophilus Vaccines / Q000008:administration & dosage / Q000009:adverse effects; D006801:Humans; D007115:Immunization Schedule; D007223:Infant; D052577:Infant, Extremely Low Birth Weight; D007230:Infant, Low Birth Weight; D007231:Infant, Newborn; D007235:Infant, Premature, Diseases / Q000453:epidemiology*; D019102:Infant, Very Low Birth Weight; D008297:Male; D008329:Managed Care Programs / Q000706:statistics & numerical data*; D011054:Poliovirus Vaccine, Inactivated / Q000008:administration & dosage / Q000009:adverse effects; D011135:Polysaccharides, Bacterial / Q000008:administration & dosage / Q000009:adverse effects; D012189:Retrospective Studies; D014611:Vaccination / Q000706:statistics & numerical data*
D001425:Bacterial Outer Membrane Proteins; D015721:Diphtheria-Tetanus-Pertussis Vaccine; D022681:Diphtheria-Tetanus-acellular Pertussis Vaccines; D018073:Haemophilus Vaccines; C061964:Haemophilus influenzae-type b polysaccharide-Neisseria meningitidis outer membrane protein conjugate vaccine; D011054:Poliovirus Vaccine, Inactivated; D011135:Polysaccharides, Bacterial