Hepatitis B immunization in low birthweight infants: do they need an additional dose?
OBJECTIVE
To determine the influence of gestation and weight on the development of protective anti-HB levels and geometric mean titres after three doses of HBV vaccine and to ascertain the need for a fourth dose in low birthweight infants.


METHODS
Hepatitis B vaccine (Enivac HB, Panacea Biotec Ltd., India) was given to 82 preterm (PT) and 60 term intrauterine growth-retarded (T-IUGR) infants at birth and at 6, 10 and 14wk of life.


RESULTS
Protective anti-HB levels (>10 mIU/ml) were reached in 86.6% (71/82) of PT infants and 96.7% (58/60) of T-IUGR infants after three doses of HBV vaccine (p = 0.044). The odds of having a protective response after the third dose of HBV vaccine was 1.25 (95% CI 1.02-1.53) with every one-week increase in gestation (p = 0.032). Birthweight was not associated with the development of a protective immune response. After the third dose, only 66.7% (8/12) of the PT infants whose mothers had anti-HB antibodies, developed protective anti-HB levels compared with 90% (63/70) of those with no maternal antibodies (p = 0.028). In PT infants after the fourth dose, there was a significant increase in the proportion of infants with protective antibody levels (8.6%, 95% CI 0.6-16.6%) among those with no maternal antibodies and 12.2% overall (95% CI 6.0-21.3) (p = 0.031 to 0.002) over that reached with the third dose. Administration of the fourth dose to T-IUGR infants did not confer such a benefit.


CONCLUSIONS
In HBV-endemic areas, PT infants, irrespective of their birthweights, may benefit from an additional dose of hepatitis B vaccine in a schedule starting at birth. This approach will prevent vertical transmission and bring their immune response up to par with term infants. Term intrauterine growth-retarded infants should be vaccinated as per the schedule recommended for normal term infants. However, studies in other settings with different vaccine formulations and a longer follow-up period will be required before this strategy can be practised more widely.
Arora
N K
NK
Department of Pediatrics, All India Institute of Medical Sciences, New Delhi. nkmanan@hotmail.com
Ganguly
S
S
Agadi
S N
SN
Irshad
M
M
Kohli
R
R
Deo
M
M
Paul
V K
VK
Deorari
A K
AK
Chellani
H
H
Prasad
M S
MS
Sharma
D
D
D000704:Analysis of Variance; D015331:Cohort Studies; D004305:Dose-Response Relationship, Drug; D005260:Female; D005317:Fetal Growth Retardation / Q000276:immunology*; D005500:Follow-Up Studies; D005865:Gestational Age; D006509:Hepatitis B / Q000151:congenital / Q000517:prevention & control*; D006514:Hepatitis B Surface Antigens / Q000032:analysis*; D017325:Hepatitis B Vaccines / Q000008:administration & dosage*; D006801:Humans; D007109:Immunity / Q000502:physiology; D007115:Immunization Schedule; D007230:Infant, Low Birth Weight / Q000276:immunology*; D007231:Infant, Newborn; D007273:Injections, Intramuscular; D008297:Male; D011336:Probability; D011446:Prospective Studies; D014611:Vaccination / Q000379:methods*
D006514:Hepatitis B Surface Antigens; D017325:Hepatitis B Vaccines