Duration of hepatitis B immunity in low risk children receiving hepatitis B vaccinations from birth

BACKGROUND: The duration of protection after hepatitis B vaccination of infants is unknown. METHODS: We determined antibody to hepatitis B surface antigen (anti-HBs) at 4-13 years of age in 363 low risk children who had been vaccinated starting at birth with hepatitis B vaccine. Those with nonprotective titers (<10 mIU/mL) received a booster dose. We similarly followed 16 children of hepatitis B surface antigen (HBsAg)-positive mothers. RESULTS: Of low risk infants receiving a plasma-derived vaccine, 41% (42 of 102) of those whose primary response was unknown and 24% (4 of 17) who had initially responded retained protective titers (> or = 10 mIU/mL) of anti-HBs at 9 and 13 years, respectively. Of those who did not have protective antibody titers, 61% (33 of 54) and 67% (8 of 12), respectively, responded to a booster dose. In children of HBsAg-positive mothers, 31% retained protective anti-HBs at 12 years, and 90% (9 of 10) with nonprotective titers responded to a booster. In low risk children initially receiving a recombinant vaccine, 12.5% (26 of 208) and none (0 of 36) retained protective anti-HBs titers at 5 and 7 years of age, respectively. Of those who did not have protective titers, 90% (120 of 134) and 91% (32 of 35), respectively, responded to a booster. CONCLUSIONS: Anti-HBs disappeared by 5 years of age in most children who were vaccinated with hepatitis B vaccine from birth. Although most children showed immunologic memory, one-third failed to demonstrate an anamnestic response to a booster dose. Additional long term studies of low risk infants are needed to determine duration of protection and the necessity for or timing of booster doses.     

Hepatitis A vaccination of infants: effect of maternal antibody status on antibody persistence and response to a booster dose

BACKGROUND: Infants with passively transferred maternal antibody (PMA) to hepatitis A virus (HAV) have lower concentrations of antibody to HAV (anti-HAV) after vaccination. We examined the effect of PMA on persistence of anti-HAV and on immune memory. METHODS: We measured anti-HAV concentrations of 6-year-old children who had responded to a three dose hepatitis A vaccine series at ages 2, 4 and 6 months. Group 1 children were born to anti-HAV-negative women; Group 2 children had anti-HAV-positive mothers and PMA at 2 months of age. Children without detectable antibody at 6-year follow-up were offered a booster dose [360 enzyme-linked immunosorbent units (ELU)]. An anamnestic response was defined as a postbooster anti-HAV concentration of > or =400 mIU/ml. RESULTS: At follow-up, before the booster dose, Group 1 subjects had a higher geometric mean concentration (50 mIU/ml vs.18 mIU/ml, P = 0.007), and a larger proportion retained seroprotective concentrations of anti-HAV [21 of 31 (68%) vs.4 of 17 (24%)] compared with Group 2 subjects. The two stage antibody decline curves for the two groups from 8 months old to follow-up testing were parallel. An anamnestic response occurred in all (5 of 5) Group 1 and 67% (4 of 6) of Group 2 children. The geometric mean antibody concentrations after the booster were 1102 and 406 mIU/ml for Groups 1 and 2, respectively (P = 0.10). CONCLUSIONS: Infants with PMA who receive hepatitis A vaccine have significantly lower concentrations of anti-HAV 6 years later than infants with no PMA who receive hepatitis A vaccine. Immune memory may remain functional despite these lower anti-HAV concentrations.     

Persistence of antibody and immunologic memory in children immunized with hepatitis B vaccine at birth

Forty-two healthy children immunized with a course of hepatitis B vaccine beginning at birth were tested at 6 years of age for persistence of anti-hepatitis B antibody (anti-HBs) and then given a booster dose of vaccine. Although nearly one-half had become seronegative, all retained robust immunologic memory and rapidly regained a protective anti-HBs titer of at least 10 mIU/ml after booster vaccination.     

Long term immune response of universal hepatitis B vaccination in infancy: a community-based study in Taiwan.

OBJECTIVES: To evaluate the long term immunity provided by a universal hepatitis B vaccination program in infancy and the booster effect on school age children who had no protective antibody titers to hepatitis B surface antigen. METHODS: We conducted a community-based seroepidemiologic study of 1337 healthy 7-year-old children in Taiwan one decade after the implementation of a mass hepatitis B vaccination program. A booster vaccination was suggested for noncarrier children who did not have protective titers of surface antibody. Serologic responses and infection rates were compared with those of the nonboostered children. In a nonselected group of 39 volunteer noncarrier vaccinees, quantitative serologic response was determined before, 1 month after a booster vaccination and 1 year later. RESULTS: A total of 572 children (42.8%) had low concentrations of surface antibody, and 9 were hepatitis B surface antigen carriers (0.7%). Eighty-two percent of "nonprotected" vaccinees showed immunologic memory to a booster dose and developed protective antibody titers 1 month later; 60.6% maintained protective titers 1 year later. The frequency of new hepatitis B virus infection was similar for those who received a booster and those who did not as investigated by the core antibody seroconversion during 1-year follow-up. However, the risk was low, with annual incidences of <1% in both groups, and none became chronic carriers. CONCLUSION: According to these data a universal vaccination program in infancy provides adequate protection against hepatitis B virus infection for school age children and a booster vaccination is not recommended.     

Immunogenicity and reactogenicity of DTPa-HBV-IPV/Hib vaccine as primary and booster vaccination in low-birth-weight premature infants

AIM: To assess suitability of a combined DTPa-HBV-IPV/Hib vaccine (Infanrix hexa) for immunization of low-birth-weight (<2.0 kg) preterm infants, with particular focus on the hepatitis B response. METHODS: Open-label study in 170 preterm infants receiving primary vaccination at 2, 4 and 6 months of age and booster vaccination at 18-24 months. Enrollment and analysis were stratified in two groups: infants with birth weight between 1.5 kg and 2.0 kg (low birth weight: LBW), infants with BW <1.5 kg (very low birth weight: VLBW). RESULTS: One month after the three dose primary vaccination, 93.7% and 94.9% of infants in VLBW and LBW groups, respectively, had anti-HBs antibody concentrations > or = 10 mIU/mL. High seroprotection and response rates (92.4-100%) to all vaccine antigens were observed. Those were reinforced (>98%) by booster vaccination for all antigens except for HBs in VLBW children: only 88.7% of those had anti-HBs antibody concentrations > or = 10 mIU/mL, compared with 96.5% of LBW children (difference statistically not significant). The vaccine was well tolerated in both groups of infants. CONCLUSION: Preterm infants will benefit by the administration of a primary and booster vaccination with DTPa-HBV-IPV/Hib vaccine.     

Long-term antibody response and immunologic memory in children immunized with hepatitis B vaccine at birth

Four hundred and fifty three healthy children immunized with a course of hepatitis B vaccine beginning at birth were tested at 10-11 years of age for persistence of anti-hepatitis B-S antigen antibody (anti-HBs); and responses of children without protective antibody to different doses of hepatitis B vaccine booster were evaluated. Although nearly 42% of them were not seroprotected, but most of boosted subjects (87.3%) retained robust immunologic memory and rapidly retained a protective anti-HBs antibody titer of at least 10 IU/L after booster vaccination.     

DTP reactions and serologic response with a reduced dose schedule

In a double-blind study, infants received standard (0.5 ml) or modified (0.25 ml) doses of DTP vaccine for the primary series of three immunizations administered at 2, 4, and 6 months of age and the booster immunization at 18 months. Side effects and antibody responses were determined in 80 children who completed the primary series and 73 who received the booster. The modified regimen was associated with significantly reduced febrile reactions and behavioral changes after the primary series and booster inoculation: 63.2% of those who received the standard dose had febrile reactions, compared to 42.3% who received the modified dose during the primary series; a similar difference was observed with the booster. Only 47.2% of the reduced dosage recipients demonstrated marked behavioral changes, and 62.4% of the standard vaccine recipients had comparable reactions. An even larger difference (33.3% vs 64.7%) was noted at the time of the booster. The modified vaccine produced a local reaction incidence of 58.5%, compared to 72.6% in the control population during the primary immunization series; no differences were noted in local reactions with the booster dose. All patients had serologic evidence of protective titers against diphtheria and tetanus. After the primary immunization series, 97.6% and 97.3% of the infants given the modified and standard doses, respectively, had pertussis agglutinin titers of greater than or equal to 1:16. One patient who received the standard dosage had a titer of less than 1:16 one month after the booster immunization, whereas all those given the modified dose had titers greater than or equal to 1:16. Geometric mean titers of pertussis agglutinins were higher in the standard vaccine recipients after the primary series, but were similar in the two study groups before and after the 18-month immunization.     

Hepatitis A booster vaccine in children after infant immunization

BACKGROUND: Hepatitis A vaccine provides long term protection against hepatitis A infection in adults and children older than 2 years of age. Few data are available regarding children younger than 2 years of age. METHODS: Children who were vaccinated in infancy with hepatitis A vaccine were revaccinated at 4 years of age, and antibody titers were followed. Forty-four subjects who had been vaccinated with hepatitis A vaccine [Havrix, 360 enzyme-linked immunosorbent assay units (EU)] at the age of 2, 4 and 6 months were revaccinated with 720 EU of inactivated hepatitis A vaccine (Havrix) at 4 years of age. RESULTS: Geometric mean titer (GMT) of 44 evaluable cases was 41 mIU/ml and 34 children (77.3%) were seropositive before the booster dose. Postvaccination blood samples were obtained from 37 cases. One month after booster dose GMT increased to 2884 mIU/ml, and all subjects were seropositive. Ten seronegative cases also seroconverted. The GMT of the seropositive cases showed anamnestic response after the booster dose (57 mIU/ml before booster dose, 5623 mIU/ml after the booster). No serious adverse event was seen after the booster dose. CONCLUSION: We conclude that childhood hepatitis A virus revaccination after infant immunization is highly immunogenic and safe.     

Immunization against hepatitis A in the first year of life: priming despite the presence of maternal antibody

BACKGROUND: Maternal antibodies interfere with hepatitis A vaccination in young infants. We examined the response to a high dose hepatitis A vaccine administered concomitantly with a combination of diphtheria-tetanus toxoids-acellular pertussis-inactivated poliovirus vaccine/Haemophilus influenzae type b vaccine to initially seropositive vs. initially seronegative infants. METHODS: Three hundred subjects were originally planned to be enrolled at age 6 to 10 weeks and received hepatitis A vaccine (formalin-inactivated vaccine, SB-Bio, 720 enzyme-linked immunosorbent assay units) at 2, 4 and 6 months concomitantly with a diphtheria-tetanus toxoids-acellular pertussis-inactivated poliovirus vaccine/H. influenzae type b vaccine. Children initially seropositive received a booster dose at 12 months of age. An additional 100 twelve-month-old infants previously not vaccinated with hepatitis A vaccine were given 1 dose, to observe the primary response at that age. Reactogenicity was recorded on diary cards for the 3 subsequent days. Immunogenicity was measured at Months 2, 4, 5, 10 and 11 after administration of the first vaccine dose. For the subjects enrolled at 12 months, blood was drawn before and 1 month after the first vaccination. RESULTS: Of 297 initially enrolled infants 36% were seronegative before vaccination (Group A). The geometric mean concentration (GMC) (milli-International Units/ml) of the seropositive infants (Group B) before immunization was 2587. The GMCs of Group A infants 1 month after each dose and at 12 months of age were 93, 518, 1656 and 786, respectively. For Group B infants, the respective GMCs were 1165, 460, 508 and 167. One hundred subjects of Group B received a booster dose at age 12 months; at Month 13 all were seropositive with a GMC of 1902. For comparison, a third group of 100 not previously immunized 12-month-old infants (Group C) were enrolled and received 1 dose of hepatitis A vaccine with pre- and postimmunization GMCs of 52 and 120, respectively. CONCLUSIONS: Our results suggest that the initially seropositive infants were primed despite maternal antibody interference. The hepatitis A vaccine was well-tolerated in this population of young infants.     

Safety and immunogenicity of a Haemophilus influenzae type b conjugate vaccine in a high risk American Indian population

The safety and immunogenicity of a Haemophilus influenzae type b polysaccharide conjugate vaccine linked to the outer membrane protein complex of Neisseria meningitidis (Hib-OMP) were evaluated among Apache and Navajo infants and children. One dose of the Hib-OMP was given to 42 children who were from 12 and 60 months of age. Ninety-two infants 6 to 8 weeks old were given one dose of Hib-OMP at the time of enrollment. A subsequent dose of the vaccine was given 2 months later and a third dose was offered between 12 and 15 months of age. All of the 12- to 60-month-old children achieved a protective antibody concentration (greater than 1 microgram/ml) 1 month postvaccination. Among the 6- to 8-week-old infants only 11% of the Apaches and 8% of Navajos had a protective anti-PRP antibody concentration prevaccination. One month post vaccination 68% of the Apaches and 69% of the Navajos had protective anti-PRP antibody concentrations. One month after the second immunization 67% of the Apaches and 75% of Navajos had protective anti-PRP concentrations. Among the infants that received the third (booster) immunization (N = 28) 74% had protective anti-PRP antibody titers just before the booster immunization. One month after the booster immunization all of the infants had protective concentrations of anti-PRP antibody. We conclude that the Hib-OMP is safe and highly immunogenic among Apache and Navajo infants and children.     

Persistence of antibody to hepatitis B and protection from disease among Alaska natives immunized at birth

BACKGROUND: Alaska Native (AN) children were at high risk of acquiring hepatitis B virus (HBV) infection before vaccination began in 1983. We evaluated the long-term protection from hepatitis B (HB) vaccination among AN children immunized when infants. METHODS: During 1984-1995, we recruited a convenience sample of AN children who had received a three dose series of HB vaccine starting at birth and had serum antibody to hepatitis B (anti-HBs) concentrations of >/= 10 mIU/mL at 7-26 months of age. We evaluated anti-HBs concentrations and the presence of anti-HBc in participants' sera every other year up to age 16 years. Anti-HB core antigen (anti-HBc)-positive specimens were tested for hepatitis B surface antigen and for HBV DNA. RESULTS: We followed 334 children for 3151 person-years (median, 10 years per child) with 1610 specimens collected. Anti-HBs concentrations dropped rapidly among all participants. Among children 2, 5 and 10 years of age, 37 of 79 (47%), 33 of 176 (19%) and 8 of 95 (8%), respectively, had anti-HBs concentrations of >/= 10 mIU/mL. Receipt of recombinant vaccine was significantly associated with a more rapid antibody decline (P < 0.001). Six (1.8%) children acquired anti-HBc, 3 of whom had definite breakthrough infections (at least 2 consecutive anti-HBc-positive specimens or at least 1 anti-HBc-positive specimen and HBV DNA detection by PCR). None of these children had detectable hepatitis B surface antigen, and none had symptoms of hepatitis. CONCLUSIONS: Anti-HBs concentrations declined over time among AN infants successfully immunized with HB vaccine starting at birth. Transient anti-HBc appeared in a small percentage of children; however, none developed clinical signs of hepatitis or chronic HBV infection.     

Safety and immunogenicity of heptavalent pneumococcal CRM197 conjugate vaccine in infants and toddlers.

OBJECTIVES: The objectives of this study were (1) to determine the safety and immunogenicity of heptavalent pneumococcal CRM197 conjugate (PNCRM7) vaccine in infants and (2) to determine the effect of concurrent hepatitis B immunization during the primary series and the effect of concurrent diphtheria and tetanus toxoid and acellular pertussis [DTaP (ACEL-IMUNE)] and conjugate CRM197 Haemophilus influenzae type b [HbOC (HibTITER) immunization at time of the booster dose on the safety and immunogenicity of PNCRM7and these other concurrently administered vaccines. METHODS: This was a randomized double-blinded study in 302 healthy infants in the Northern California Kaiser Permanente (NCKP) Health Plan. Infants received either PNCRM7 vaccine or meningococcal group C conjugate vaccine as a control at 2, 4 and 6 months of age and a booster at 12 to 15 months of age. Study design permitted the evaluation of immunology and safety of concurrent administration of routine vaccines. Antibody titers were determined on blood samples drawn before and 1 month after the primary series and the booster dose. RESULTS: After the third dose of PNCRM7 geometric mean concentrations (GMCs) ranged from 1.01 for serotype 9V to 3.72 microg/ml for serotype 14. More than 90% of all subjects had a post-third dose titer of > or =0.15 microg/ml for all serotypes, and the percentage of infants with a post-third dose titer of > or =1.0 microg/ml ranged from 51% for type 9V to 89% for type 14. After the PNCRM7 booster dose, the GMCs of all seven serotypes increased significantly over both post-Dose 3 and pre-Dose 4 antibody levels. In the primary series there were no significant differences in GMCs of pneumococcal antibodies between the subjects given PN-CRM7 alone or concurrently with hepatitis B vaccine. At the toddler dose concurrent administration of PNCRM7 and DTaP and HbOC resulted in a near conventional threshold for statistical significance of a post-Dose 4 GMC for serotype 23F [alone 6.75 mirog/ml vs. concurrent 4.11 microg/ml (P = 0.057)] as well as significantly lower antibody GMCs for H. influenza polyribosylribitol phosphate, diphtheria toxoid, pertussis toxin and filamentous hemagglutinin. For all antigens there were no differences between study groups in defined antibody titers that are considered protective. CONCLUSION: We conclude that PNCRM7 vaccine was safe and immunogenic. When this vaccine was administered concurrently at the booster dose with DTaP and HbOC vaccines, lower antibody titers were noted for some of the antigens when compared with the antibody response when PNCRM7 was given separately. Because the GMCs of the booster responses were all generally high and all subjects achieved similar percentages above predefined antibody titers, these differences are probably not clinically significant.     

Antibodies against Haemophilus influenzae type b capsular polysaccharide and tetanus toxoid before and after a booster dose of the carrier protein nine years after primary vaccination with a protein conjugate vaccine

IgG antibodies against Haemophilus influenzae type b (Hib) capsular polysaccharide (CPS) and tetanus toxoid (TT) were measured for 53 children, 10 years of age, before and 1 month after a booster dose of diphtheria-tetanus vaccine (DT). All children had been vaccinated at 3, 5 and 12 months of age with DT and a Hib-TT conjugate. Geometric mean concentrations of Hib CPS serum IgG antibody were 4.16 and 4.30 microg/mL before and after the DT booster, respectively. The geometric mean concentration of TT IgG antibody increased from 0.09 IU/mL to 4.58 IU/mL (P < 0.001). Hib CPS IgG levels remained well above protective titers for 9 years after 3 doses of Hib-TT appropriately spaced in infancy. A booster dose of TT did not affect Hib CPS antibody concentrations but induced a pronounced IgG response against TT.     

Impact of a birth dose of hepatitis B vaccine on the reactogenicity and immunogenicity of diphtheria-tetanus-acellular pertussis-hepatitis B-inactivated poliovirus-Haemophilus influenzae type b combination vaccination

OBJECTIVES: To assess the impact of a birth dose of hepatitis B vaccine (HepB) on the reactogenicity and immunogenicity of a novel diphtheria-tetanus-acellular pertussis (DTaP)- HepB-inactivated poliovirus (IPV)/ type b (Hib) combination vaccine administered subsequently at 2, 4 and 6 months of age. METHODS: Neonates ( = 550) were randomized into two groups with regard to receipt of HepB at birth. All subjects in both groups received DTaP-HepB-IPV/Hib at 2, 4 and 6 months of age. Solicited local and general adverse events were recorded for 8 days after each dose. Antibodies to hepatitis B surface antigen were measured 1 month after the third dose of DTaP-HepB-IPV/Hib in a subset of 170 infants; titers of at least 10 mIU/ml were considered protective. RESULTS: The DTaP-HepB-IPV/Hib combination vaccine was well-tolerated in both groups. Of the infants who received a birth dose of HepB, 22.6% had severe (Grade 3) reactions after any of the three doses of DTaP-HepB-IPV/Hib combination vaccine compared with 23.2% of subjects who did not receive a birth dose of HepB (difference, -0.5%; 90% confidence interval, -7.4 to 6.1). Antibody to hepatitis B surface antigen titers were > or =10 mIU/ml for all tested infants. Geometric mean titers were 2996.2 and 1240.1 mIU/ml with and without a birth dose of HepB, respectively. CONCLUSIONS: A HepB birth dose does not increase the reactogenicity of a combination DTaP-HepB-IPV/Hib vaccine administered at 2, 4 and 6 months of age, and all tested subjects achieved protective anti-HBs titers (> or =10 mIU/ml), although geometric mean titers were higher when a birth dose of HepB was given.     

Prevention of perinatal transmission of the hepatitis B virus. Outcome of infants in a community prevention program.

OBJECTIVE. To assess the outcome of infants born to hepatitis B surface antigen (HBsAg)-positive mothers who received prenatal and infant care in a large, public health care system. DESIGN. Follow-up of a cohort of infants born to HBsAg-positive mothers. SETTING. Large, urban hospital providing prenatal care and obstetric services to county health departments. PARTICIPANTS. Forty-two infants born to HBsAg-positive women. INTERVENTIONS. Prenatal testing of women and immunoprophylaxis of infants with hepatitis B immune globulin at birth and hepatitis B vaccine at birth and ages 1 and 6 months. RESULTS. All 42 infants received hepatitis B immune globulin and the first dose of vaccine. Of forty-one infants (98%) who received the second dose of vaccine, 37 received it by age 4 months. Thirty-two infants (76%) completed the three-dose vaccine series by age 12 months, and 34 infants (81%) completed the series by age 18 months. The rate of completion of the hepatitis B vaccine series was comparable to that of infants receiving the third dose of diphtheria-pertussis-tetanus vaccine. Of 26 infants who completed the hepatitis B vaccine series and had follow-up serologic testing, 24 (92%) had adequate levels of antibody to HBsAg. Only one infant who did not complete the vaccine series had serologic evidence of hepatitis B virus infection. No infant was HBsAg-positive. CONCLUSIONS. Public programs serving urban populations can effectively deliver hepatitis B immunoprophylaxis to infants born to HBsAg-positive mothers.     

The protective efficacy of recombinant hepatitis B vaccine in newborn infants of hepatitis B e antigen-positive-hepatitis B surface antigen carrier mothers

Recombinant hepatitis B vaccine has been shown to be as safe and effective as plasma-derived vaccines. However, its efficacy in the prevention of perinatal infection has not been fully evaluated in an endemic area. We recruited 110 high risk infants born to hepatitis B e antigen-positive-hepatitis B surface antigen (HBsAg) carrier mothers in a study of recombinant vaccine efficacy. They were randomized into 2 groups, A (54 infants) and B (56 infants), to receive 4 doses of vaccine, containing 20 or 10 micrograms of surface antigen, respectively, at 0, 1, 2 and 12 months of age. An additional 60 high risk infants were recruited later (Group C) and received three 20-micrograms doses of vaccine at 0, 1 and 6 months of age. All infants also received a dose (145 IU) of hepatitis B immunoglobulin soon after birth. Sera were collected at 0, 1, 2, 3, 6, 12 and 14 months of age to assay HBsAg and anti-HBs. At 12 months of age the HBsAg carrier rates were 7.4 and 1.8%, in Groups A and B, respectively. In Group C the HBsAg-positive rate was 3.3%. HBsAg was invariably first observed between 0 and 2 months of age. Virtually all noncarrier infants developed substantial titers of anti-HBs at 12 months of age. No serious adverse effect was observed after vaccination.     

Immunogenicity and reactogenicity of DTPa-IPV-HBV/Hib and DTPa-IPV/Hib vaccines coadministered with 7-valent pneumococcal conjugate vaccine as primary vaccination and booster in healthy infants, according to the French vaccination calendar]

OBJECTIVE: Assessment of immunogenicity and reactogenicity of DTPa-IPV/Hib (Infanrixquinta) and DTPa-IPV-HBV/Hib (Infanrixhexa) combined vaccines coadministered in healthy infants with 7-valent pneumococcal conjugate vaccine (Prevenar), according to the current French vaccine recommendations. METHOD: Multicenter, open label, non-controlled study performed in France. Each subject received 1 dose of DTPa-IPV-HBV/Hib combined vaccine at 2, 4 and 16-18 months of age, coadministered with conjugated pneumococcal vaccine and 1 dose of DTPa-IPV/Hib vaccine at 3 months of age coadministered with conjugated pneumococcal vaccine. RESULTS: Among the 102 enrolled infants, 64 were analysed (10.09 weeks+/-1.22 of age; boys: 58%) in the According-To-Protocol (ATP) immunogenicity cohort. One month after the administration of the booster dose of DTPa-IPV-HBV/Hib vaccine, 93.8% of subjects had protective titres for anti-HBs antibody superior or equal to 10 mIU/ml (primary objective). Seroprotection rate against Haemophilus influenzae type b component (anti-PRP antibody >or=0.15 microg/ml) was 98.4% and the immune response for the 7-valent pneumococcal serotypes (antipneumococcal antibody >or=0,05 microg/ml) was between 98.4 and 100%. Local reactogenicity increased with the number of doses administered, but was comparable between combined vaccines and conjugated pneumococcal vaccine. The incidence of fever increased between the primary vaccination and the booster. CONCLUSION: The immunogenicity and reactogenicity profile of DTPa-IPV-HBV/Hib and DTPa-IPV/Hib combined vaccines coadministered with conjugated pneumococcal vaccine according to the schedule recommended in the French vaccine calendar is acceptable and similar to previous reports.     

Long term efficacy of hepatitis B vaccine in infants born to hepatitis B e antigen-positive mothers.

The long term protective efficacy of recombinant hepatitis B vaccine, administered alone or concomitantly with hepatitis B immunoglobulin, was assessed in 263 healthy neonates of hepatitis B e antigen-positive mothers. Infants received the first dose of vaccine at birth; additional doses were given at either Months 1, 2 and 12 or Months 1 and 6. During the follow-up period, which ranged from 2 to 4 years, protective titers (> or = 10 mIU/ml) of anti-hepatitis B surface antibodies were found in virtually all infants who had responded to the primary course of vaccination. "Natural boosts," without persistent infection, were observed in only a small number of children. All children who were shown to have become chronic carriers were infected within the first year of life. No statistical difference in long term protective efficacy could be shown between the two vaccination schedules used or between the use of vaccine alone or vaccine plus hepatitis B immunoglobulin for either schedule.     

Hepatitis B vaccination in premature and low birth weight (LBW) babies

OBJECTIVE: To assess the immune response of preterm and low birth weight babies (LBW) to hepatitis B (HB) vaccine. SETTING: Neonatal Intensive Care Unit (NICU), postnatal ward and follow up clinics of KEM Hospital, Pune. DESIGN: Open trial. METHODS: 100 babies were enrolled in four study groups. Group I - preterm, gestational age (GA) < 34 weeks; Group II - GA 34 to 36 weeks; Group III full term <2.5 kg (LBW babies); and Group IV full term >2.5 kg (controls). A recombinant DNA HB vaccine was given at 0, 1, 2 and 12 month schedule. The first injection was administered as soon as the neonate was stabilized. Immune response in terms of anti HBs titres (AUSAB EIA Diagnostic kit) was measured one month after each of the first three injections and at the time of one year booster. Adverse events were monitored. RESULTS: 88 and 62 babies completed the study till the third dose and one year booster dose respectively. Immune response of HB vaccine was uniformly good in all the study groups with 100 % sero-conversion after the second dose itself. By one year (i.e. before the booster dose), very high titres were recorded in all 100%, with 85% demonstrating titres >1000 mIU/ml. Preterm and LBW babies had higher GMT as compared to full term babies till one month after third dose. By one year (before booster), full term babies had higher GMT than preterm and LBW babies. However, these differences were not statistically significant. The vaccine was well tolerated and safe and there were no adverse reactions. CONCLUSION: Immune response of preterm, LBW and full term babies to the new generation recombinant DNA HB vaccine was uniformly good. High and long term seroprotective levels were achieved after the second dose itself.     

Comparative long term immunogenicity of two recombinant hepatitis B vaccines and the effect of a booster dose given after five years in a low endemicity country

BACKGROUND: Few data are available concerning the long term immunogenicity of the pediatric doses of hepatitis B vaccines given to preteenagers. The long term effect of the booster dose in teenagers is unknown. We evaluated the immunogenicity of 2 pediatric hepatitis vaccines after primary vaccination and after a booster dose. METHODS: A prospective 15-year follow-up study of the immunogenicity of 2 hepatitis B vaccines was initiated in 1995 in Quebec City, Canada. One year apart, 1129 children 8-10 years old received Engerix-B 10 microg (EB), and 1126 received Recombivax-HB 2.5 microg (RB) vaccine after a 0-, 1-, 6-month schedule. After 5 years, one-third of the 2 cohorts were randomly selected. A booster dose of EB 10 microg or RB 5 microg was administered according to the vaccine used in the primary immunization. Antibodies were measured before, 1 month after and 1 year after the booster injection. RESULTS: Before the booster dose, anti-HB surface antibody (HBs) was detected in 94.7% of the EB subjects and in 95.2% of the RB subjects (P = 0.85). The geometric mean titer (GMT) was higher in the EB than in the RB group (252 mIU/mL versus 66 mIU/mL, P < 0.0001). One month after the booster, 99.7% of subjects in the EB group and 99.6% in the RB group had a detectable anti-HBs, and 99.0 and 99.3%, respectively, had anti-HBs > or =10 mIU/mL. The anti-HBs GMT was 113,201 mIU/mL in the EB and 16,623 mIU/mL in the RB groups (P < 0.0001). One year after the booster, 99.3% of subjects in the EB group and 100% in the RB group had detectable anti-HBs, and 97.9 and 98.5% respectively, had anti-HBs > or =10 mIU/mL. The anti-HBs GMT was 14,028 mIU/mL in the EB and 3437 mIU/mL in the RB group (P < 0.0001). CONCLUSIONS: The immunity persists for at least 5 years after the primary vaccination with both pediatric vaccines in 99% of children vaccinated at the age of 8-10 years. It confirms that no booster is needed at that point.