Evaluation of the immunogenicity and reactogenicity of a DTPa-HBV-IPV combination vaccine Co-administered with a hib conjugate vaccine either as a single injection of a hexavalent combination or as two separate injections at 3, 5 and 11 months of age

Immunogenicity and Safety of Childhood Combination Vaccines: A Systematic Review and Meta-Analysis

Background: Vaccination is considered the most effective and economical measure for controlling infectious diseases. Although combination vaccines are widely used worldwide, whether any of the combination vaccines is superior to each separate vaccine has yet to be established. This systematic review and meta-analysis aimed to summarize the available evidence on the effectiveness and safety of combination vaccines in children. Methods: A systematic search was conducted from database inception to August 20, 2021, in MEDLINE, Embase, Cochrane, and Scopus. Published randomized clinical trials (RCTs) and open-label trials of immunogenicity and safety of combined vaccines were selected. The results of the studies were quantitatively synthesized. Results: Overall, 25 articles met the inclusion criteria and were included in the meta-analysis. The results indicated that the combined diptheria−tetanus−acellular pertussis (DTaP)−hepatitis B virus (HBV)−Haemophilus influenzae type B (Hib) vaccine group had lower levels of anti-tetanus antibodies than the combined DTaP−HBV and separate Hib vaccinations group (SMD = −0.23; 95% CI: −0.42, −0.05; p = 0.013). Meanwhile, the combined DTaP−HBV−inactivated polio virus (IPV)−Hib vaccine group had higher levels of anti-pertussis (PT) and anti-filamentous hemagglutinin (FHA) antibodies than the combined DTaP−IPV−Hib and separate HBV vaccinations group (anti-PT: SMD = 0.60; 95% CI: 0.45, 0.75; p < 0.0001; anti-FHA: SMD = 0.40; 95% CI: 0.01, 0.78; p = 0.042). The levels of anti-pertactin (PRN) antibodies were lower in the combined DTaP−IPV−Hib vaccine group than in the combined DTaP−IPV and separate Hib vaccinations group (SMD = −0.13; 95% CI: −0.27, −0.00; p = 0.047). The individuals injected with the DTaP−HBV−IPV−Hib vaccine had a lower risk of pain and swelling than those injected with the combined DTaP−HBV−IPV and separate Hib vaccines (pain: RR = 0.79; 95% CI: 0.69, 0.91; p = 0.001; swelling: RR = 0.87; 95% CI: 0.78, 0.98; p = 0.020). However, the group that received the DTaP−HBV−IPV−Hib vaccine had a higher risk of fever than the group that received DTaP−HBV−IPV and separate Hib vaccinations (RR = 1.13; 95% CI: 1.02, 1.26; p = 0.021). Conclusions: This meta-analysis suggests that the combined vaccines (DTaP−IPV−Hib, DTaP−HBV−Hib, DTaP−HBV−IPV−Hib) are safe, well-tolerated, and provide immunogenic alternatives to separate vaccines in children. The combined DTaP−HBV−IPV−Hib vaccine showed a higher incidence of fever, which was lower than the cumulative incidence of fever induced by all vaccines. Future studies should evaluate the cost-effectiveness of using combined vaccines and compare the potency of different formulations to improve routine local or national childhood immunization programs.

Integration of hexavalent diphtheria, tetanus, acellular pertussis, hepatitis B virus, inactivated poliomyelitis and Haemophilus influenzae type b conjugate vaccine within existing national recommendations following a birth dose of monovalent hepatitis B virus vaccine: results of a systematic review in the Asia Pacific region

Introduction: In Asia Pacific, most countries recommend a monovalent hepatitis B virus (HBV) vaccine dose at birth followed by primary vaccination series including three or four doses of combination vaccines against diphtheria, tetanus, and pertussis, with or without Haemophilus influenzae type b (Hib), HBV or poliomyelitis antigens. If hexavalent conjugate vaccines against diphtheria-tetanus-acellular pertussis-HBV-inactivated poliovirus-Hib (DTPa-HBV-IPV/Hib) replace the vaccines included in the primary vaccination series, co-administration of lower-valent vaccines would be avoided but infants would receive ≥4 doses of HBV-containing vaccines before the age of 2 years. Areas covered: We searched for clinical trials conducted in the South-East Asia and Western Pacific Regions (World Health Organization geographic definition), investigating vaccination regimens with >3 doses of HBV-containing vaccines in infants, including a monovalent HBV vaccine birth dose and ≥1 dose of GSK's hexavalent DTPa-HBV-IPV/Hib vaccine. Expert opinion: The six clinical trials included in this review showed that infants who received the monovalent HBV vaccine at birth and three or four doses of DTPa-HBV-IPV/Hib vaccine achieved protective immunogenic titers with a clinically acceptable safety profile. Our results support the integration of hexavalent DTPa-HBV-IPV/Hib vaccine within existing national recommendations in the Asia Pacific region to reduce the number of injections during infancy.

Immunogenicity and safety following primary and booster vaccination with a hexavalent diphtheria, tetanus, acellular pertussis, hepatitis B, inactivated poliovirus and Haemophilus influenzae type b vaccine: a randomized trial in the United States

Combined hexavalent diphtheria-tetanus-acellular pertussis-hepatitis B-inactivated poliomyelitis and Haemophilus influenzae type b vaccine (DTaP-HBV-IPV/Hib) can further reduce the number of injections in pediatric immunization schedules of countries currently using pentavalent DTaP combination vaccines. This open-label, randomized, multicenter study (NCT02096263) conducted in the United States evaluated the immunogenicity and safety of DTaP-HBV-IPV/Hib vaccine compared with concomitant administration of DTaP-HBV-IPV and HibA or DTaP-IPV/Hib and HBV vaccines. We randomized (1:1:1) infants to receive 3-dose priming with DTaP-HBV-IPV/Hib boosted with DTaP+ HibB, DTaP-HBV-IPV+ HibA boosted with DTaP+ HibA, or DTaP-IPV/Hib+ HBV boosted with DTaP-IPV/Hib, at 2, 4, 6, and 15-18 months of age. We enrolled and vaccinated 585 participants, 486 received a booster, and 476 completed the study. Of these, 466 participants were included in the primary and 408 in the booster according-to-protocol cohorts for immunogenicity. We demonstrated non-inferiority of DTaP-HBV-IPV/Hib vaccine to DTaP-HBV-IPV+ HibA co-administered vaccines in terms of geometric mean concentrations for pertussis antibodies post-primary vaccination. Post-primary vaccination, seroprotection/seropositivity rates for all vaccine antigens were similarly high between DTaP-HBV-IPV/Hib (≥ 94.8%), DTaP-HBV-IPV+ HibA (≥ 98.1%) or DTaP-IPV/Hib+ HBV (≥ 97.8%) groups. We observed robust immune responses post-booster, indicating effective priming by the 3 regimens. Reactogenicity was similar in the 3 groups. Twenty-eight serious adverse events were reported during the study; 3 were considered related to vaccination and resolved by the end of the study. These results confirm that DTaP-HBV-IPV/Hib could be a valuable additional source of pediatric DTaP, IPV, HBV, and Hib-containing vaccine in countries that currently use multivalent vaccines.

New perspectives for hexavalent vaccines

With the increase in the number of routine vaccinations the development of pentavalent and hexavalent combination vaccines fitting the routine vaccination schedules became a necessity. In this respect, Europe has taken the lead in comparison with other world regions, and routine vaccination with pentavalent and hexavalent combinations including DTPa, Hib, HepB and IPV has been on European vaccination programs for >15years. Since the marketing authorization of Hexavac® and Infanrix Hexa® in 2000, immunization schedules in most European countries have included hexavalent vaccines. In the last years, two new hexavalent vaccines have been licensed and commercialized worldwide. This paper presents a review of the pharmaceutical profiles of the three hexavalent vaccines currently available. In addition, we aim to review safety, co-administration, tolerability and other practical concerns of their use.

A Randomized, Controlled Study of DTaP-IPV-HB-PRP-T, a Fully Liquid Hexavalent Vaccine, Administered in a 3-, 5- and 11- to 12-month Schedule

BACKGROUND

To assess the immunogenicity and safety of a fully liquid, ready-to-use hexavalent DTaP-IPV-HB-PRP-T vaccine when administered in a 2 + 1 schedule at 3, 5 and 11-12 months of age.

METHODS

Phase III, randomized, active-controlled, observer-blind, multicenter study. Infants were randomized to receive DTaP-IPV-HB-PRP-T (N = 275) or a licensed control hexavalent vaccine (DTaP-IPV-HB//PRP~T: N = 275), both given in coadministration with Prevenar 13. Serum was analyzed for immune responses to all vaccine antigens. Noninferiority of DTaP-IPV-HB-PRP-T to the control vaccine was tested at completion of the primary series using predefined seroprotection (SP) rate and vaccine response (VR) rates. Safety was assessed using parental reports.

RESULTS

Noninferiority of DTaP-IPV-HB-PRP-T to the control vaccine was demonstrated postdose 3 for each antigen, and the SP (for D, T, poliovirus 1, 2 and 3, hepatitis B and polyribosylribitol phosphate) and VR rates (for pertussis toxin and filamentous hemagglutinin) were high in each group. SP rates for D, T, polio 1, 2, 3 and VR rates for pertussis toxin and filamentous hemagglutinin were similar in each group. For hepatitis B, SP rate was slightly higher for DTaP-IPV-HB//PRP~T (99.6%) than DTaP-IPV-HB-PRP-T (96.4%), and for PRP, SP rate was higher for DTaP-IPV-HB-PRP-T (93.5%) than DTaP-IPV-HB//PRP~T (85.2%). For Prevenar 13, the SP rate was high for each serotype and similar for both groups. All vaccines were well tolerated.

CONCLUSIONS

These study findings confirm the safety and immunogenicity and thus the suitability of this fully liquid hexavalent vaccine for administration in a 2 + 1 schedule.

Immunogenicity and safety of 3-dose primary vaccination with combined DTPa-HBV-IPV/Hib vaccine in Canadian Aboriginal and non-Aboriginal infants

This study compared immune responses of healthy Aboriginal and non-Aboriginal infants to Haemophilus influenzae type b (Hib) and hepatitis B virus (HBV) components of a DTaP-HBV-IPV/Hib combination vaccine, 1 month after completing dosing at 2, 4 and 6 months of age. Of 112 infants enrolled in each group, 94 Aboriginal and 107 non-Aboriginal infants qualified for the immunogenicity analysis. Anti-PRP concentrations exceeded the protective minimum (≥0.15 μg/ml) in ≥97% of infants in both groups but geometric mean concentrations (GMCs) were higher in Aboriginal infants (6.12 μg/ml versus 3.51 μg/ml). All subjects were seroprotected (anti-HBs ≥10 mIU/mL) against HBV, with groups having similar GMCs (1797.9 versus 1544.4 mIU/mL, Aboriginal versus non-Aboriginal, respectively). No safety concerns were identified. We conclude that 3-dose primary vaccination with DTaP-HBV-IPV/Hib combination vaccine elicited immune responses to Hib and HBV components that were at least as high in Aboriginal as in non-Aboriginal Canadian infants. Clinical Trial Registration NCT00753649.

Combined hexavalent diphtheria-tetanus-acellular pertussis-hepatitis B-inactivated poliovirus-Haemophilus influenzae type B vaccine; Infanrix™ hexa: twelve years of experience in Italy

Infant vaccination using 2-dose priming at 3 and 5 mo of age with a booster at 11–12 mo of age was pioneered in Italy. The 3-5-11 schedule is now used in a growing number of European countries. Infanrix™ hexa (DTPa-HBV-IPV/Hib, GlaxoSmithKline Vaccines) was first licensed for use in 2000 and has been the only pediatric hexavalent vaccine available since 2005. We reviewed available clinical trial data describing the immunogenicity of DTPa-HBV-IPV/Hib when administered at 3, 5, and 11 mo of age, and conducted an analysis of safety using global and Italian post-marketing surveillance data. In Italy, DTPa-HBV-IPV/Hib has a demonstrated safety record extending over a decade of use, it has been associated with record levels of vaccine coverage, and with sustained disease control in vaccinated cohorts. Hexavalent vaccines will continue to contribute to high vaccine coverage in Italy and across Europe.

A combined Haemophilus influenzae type B Neisseria meningitidis serogroup C tetanus toxoid conjugate vaccine is immunogenic and well-tolerated when coadministered with diphtheria, tetanus, acellular pertussis hepatitis B-inactivated poliovirus at 3, 5 and 11 months of age: results of an open, randomized, controlled study

BACKGROUND

This study evaluated the immunogenicity, reactogenicity and safety of the combined Haemophilus influenzae type B Neisseria meningitidis serogroup C tetanus toxoid conjugate vaccine (Hib-MenC-TT) coadministered with diphtheria, tetanus, acellular pertussis hepatitis B-inactivated poliovirus (DTPa-HBV-IPV) as 2 primary and 1 booster doses at 3, 5 and 11 months of age.

METHODS

In this phase III open study (NCT00327184), 709 infants were randomized in 2 parallel groups (1:1) to receive either Hib-MenC-TT coadministered with DTPa-HBV-IPV or control vaccines (MenC-TT coadministered with DTPa-HBV-IPV/Hib). Serum bactericidal activity for MenC (rSBA-MenC) and antibody concentrations against polyribosylribitol phosphate from Hib (anti-PRP) and hepatitis B (anti-HBs) were measured at 1 month after dose 2, before booster and 1 month after booster dose. Solicited (local/general) and unsolicited symptoms were assessed up to 4 and 31 days, respectively, after each vaccination. Serious adverse events were recorded throughout the study.

RESULTS

One month after dose 2, high percentages of infants in both groups had rSBA-MenC titers ≥ 8 (≥ 99.1%), anti-PRP concentrations ≥ 0.15 μg/mL (≥ 96.5%) and anti-HBs concentrations ≥ 10 mIU/mL (≥ 95.3%), which persisted up to the booster vaccination (≥ 94.5%, ≥ 86.1%, ≥ 94.2%) and increased again after the booster dose (100%, 100%, ≥ 99%). Exploratory analyses indicated that rSBA-MenC geometric mean titers were lower and anti-PRP geometric mean concentrations were higher in the infants vaccinated with Hib-MenC-TT compared with the control vaccines at all time points. The safety profiles of the coadministered vaccines were similar in both groups.

CONCLUSIONS

The Hib-MenC-TT and DTPa-HBV-IPV vaccines are immunogenic with a clinically acceptable safety profile when coadministered as 2 primary doses during infancy and 1 booster dose at 11 months of age.

DTPa-HBV-IPV/Hib vaccine (Infanrix hexa™): a guide to its use in infants

Infanrix hexa™, a diphtheria, tetanus, acellular pertussis, hepatitis B, inactivated poliomyelitis, and Haemophilus influenzae type b (Hib) conjugate vaccine, is indicated for primary and booster vaccination of infants. Available clinical data from more than a decade of experience with the vaccine indicate that primary and booster vaccination with Infanrix hexa™ is a safe and useful option for providing protection against the common childhood diseases of diphtheria, tetanus, poliomyelitis, pertussis, hepatitis B, and disease caused by Hib.

Combined DTP-HBV-HIB vaccine versus separately administered DTP-HBV and HIB vaccines for primary prevention of diphtheria, tetanus, pertussis, hepatitis B and Haemophilus influenzae B (HIB)

BACKGROUND

Advantages to combining childhood vaccines include reducing the number of visits, injections and patient discomfort, increasing compliance and optimising prevention. The World Health Organization (WHO) recommends that routine infant immunisation programmes include a vaccination against Haemophilus influenzae (H. influenzae) type B (HIB) in the combined diphtheria-tetanus-pertussis (DTP)-hepatitis B virus (HBV) vaccination. The effectiveness and safety of the combined vaccine should be carefully and systematically assessed to ensure its acceptability by the community.

OBJECTIVES

To compare the effectiveness of combined DTP-HBV-HIB vaccines versus combined DTP-HBV and separate HIB vaccinations.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2011, Issue 4), which contains the Cochrane Acute Respiratory Infections Group's Specialised Register, MEDLINE (January 1966 to week 1, November 2011), EMBASE (January 1990 to November 2011) and www.clinicaltrials.gov (up to April 2011).

SELECTION CRITERIA

Randomised controlled trials (RCTs) or quasi-RCTs comparing vaccination with any combined DTP-HBV-HIB vaccine, with or without three types of inactivated polio virus (IPV) or concomitant oral polio vaccine (OPV) in any dose, preparation or time schedule, compared with separate vaccines or placebo, administered to infants up to two years old.

DATA COLLECTION AND ANALYSIS

Two review authors independently inspected references identified by the searches and evaluated them against the inclusion criteria, extracted data and assessed the methodological quality of included trials.

MAIN RESULTS

Data for the primary outcome (prevention of disease) were lacking. We performed a meta-analysis to pool the results of 20 studies with 5874 participants in an immunogenicity analysis and 5232 participants in the reactogenicity analysis. There were no data on clinical outcomes for the primary outcome (prevention of disease) and all studies used immunogenicity and reactogenicity (adverse events). The number of vaccine doses differed significantly between the studies. Heterogeneous interventions, study location, healthcare environment and combining research across disparate geographical locations, may have lead to bias. The risk of bias was unclear across most of the included studies. Comparisons found little heterogeneity. In two immunological responses the combined vaccine achieved lower responses than the separate vaccines for HIB and tetanus. No significant differences in immunogenicity were found for pertussis, diphtheria, polio and hepatitis B. Serious adverse events were comparable with mainly hospitalisation and acute bronchiolitis cases. Minor adverse events such as pain and redness were more common in children given the combined vaccine. Overall, the direction shown by the results is in favour of the DTPw (diptheria-tetanus-whole cell pertussis)-HBV-HIB vaccine rather than the DTPa (diptheria-tetanus-acellular pertussis)-HBV-HIB vaccine when compared to the separate vaccines (size of effect: risk ratio (RR) 1.43; 95% confidence interval (CI) 0.98 to 2.10, for 5269 participants).

AUTHORS' CONCLUSIONS

We could not conclude that the immune responses elicited by the combined vaccine were different from or equivalent to the separate vaccines. There was significantly less immunological response for HIB and tetanus and more local reactions in the combined injections. However, these differences rely mostly on one study each. Studies did not use an intention-to-treat (ITT) analysis and we were uncertain about the risk of bias in many of the studies. These results are therefore inconclusive. Studies addressing clinical end points whenever possible, using correct methodology and a large enough sample size should be conducted.

Immunogenicity of Infanrix™ hexa administered at 3, 5 and 11 months of age

A pooled analysis of data from four vaccination studies conducted in Europe was undertaken to assess the immunogenicity of Infanrix™ hexa (DTPa-HBV-IPV/Hib, GlaxoSmithKline Biologicals) when administered in a total of 702 healthy infants at 3, 5 and 11-12 months of age. One month after dose 2, between 96.3% and 100% of subjects had seroprotective antibodies against diphtheria, tetanus, hepatitis B and poliovirus types 1, 2 and 3; 91.7% against Hib and ≥99.0% were seropositive for each pertussis antigen. One month after the third dose, 98.9-100% of subjects were seroprotected/seropositive for all vaccine antigens. Geometric mean antibody concentrations/titres for each vaccine antigen increased by 6.7-52.9 fold after the third vaccine dose. No serious adverse events in DTPa-HBV-IPV/Hib recipients were vaccine related. Infanrix™ hexa induces an adequate immune response after 2-dose primary plus booster doses when administered according to a 3, 5 and 11 months schedule.

Immunogenicity and reactogenicity of diphtheria-tetanus-acellular pertussis-hepatitis B-inactivated poliovirus and Haemophilus influenzae type B

Immunogenicity and reactogenicity of primary vaccination with combined diphtheria-tetanus-acellular pertussis-hepatitis B-inactivated poliovirus (DTPa-HBV-IPV) vaccine when co-administered with Haemophilus influenzae (Hib) conjugate vaccine were assessed in 60 healthy infants. Infants received HBV vaccine at birth, then DTPa-HBV-IPV and Hib vaccines at age 1.5 months, 3.5 months and 6 months. Blood samples were collected before the first DTPa-HBV-IPV and Hib vaccine doses and 1 month after dose 3. Reactogenicity was assessed using diary cards. One month after primary vaccination, all infants were seroprotected/seropositive against all vaccine antigens evaluated. The poliovirus antigen could not be evaluated. The vaccines were well tolerated. No case of fever > 39.0 °C was reported. No serious adverse events were considered related to vaccination. Primary vaccination with DTPa-HBV-IPV and Hib vaccines was immunogenic and well tolerated. Combined vaccines, such as this pentavalent vaccine, minimize the number of injections and vaccination visits required to complete primary vaccination, and provide choice and flexibility for physicians and vaccine providers.

Combined DTP-HBV-HIB vaccine versus separately administered DTP-HBV and HIB vaccines for primary prevention of diphtheria, tetanus, pertussis, hepatitis B and Haemophilus influenzae B (HIB)

BACKGROUND

Advantages to combining childhood vaccines include reducing the number of visits, injections and patient discomfort, increasing compliance, and optimizing prevention. The World Health Organization recommends that routine infant immunization programs include a vaccination against Haemophilus influenza type B (HIB) in the combined diphtheria, tetanus, pertussis (DTP)-hepatitis B (HBV) vaccination. The effectiveness and safety of the combined vaccine should be carefully and systematically assessed to ensure their acceptability by the community.

OBJECTIVES

To compare the effectiveness of combined DTP-HBV-HIB vaccine with DTP-HBV and HIB vaccinations.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2009, issue 1) which contains the Acute Respiratory Infection Group's Specialized Register; MEDLINE (January 1966 to March 2009) and EMBASE (January 1990 to March 2009).

SELECTION CRITERIA

Randomized or quasi-randomized controlled trials comparing vaccination with any combined DTP-HBV-HIB vaccine, with or without three types of inactivated poliovirus (IPV) or concomitant oral polio vaccine (OPV) in any dose, preparation or time schedule, compared with separate vaccines or placebo, administered to infants aged up to two years.

DATA COLLECTION AND ANALYSIS

Two review authors independently inspected references identified by the searches and evaluated them against the inclusion criteria, extracted data and assessed the methodological quality of included trials.

MAIN RESULTS

Meta-analysis was performed to pool the results of 18 studies. There were no data on clinical outcomes for the primary outcome and all studies used immunogenicity and reactogenicity (adverse events). In two immunological responses the combined vaccine achieved lower responses than the separate vaccines for HIB and HBV. Comparison found little heterogeneity. No significant differences in immunogenicity were found for pertussis, diphtheria, polio and tetanus. Serious adverse events were comparable. Minor adverse events were more common in children given the combined vaccine.

AUTHORS' CONCLUSIONS

We could not conclude that the immune responses elicited by the combined vaccine were different from, or equivalent to, the separate vaccines. Data for the primary outcome (prevention of disease) were lacking. There was significantly less immunological response for HIB and HBV, and more local reactions in the combined injections. However, these differences rely mostly on one study each. Studies did not use an intention-to-treat analysis and we were uncertain about the risk of bias in many of the studies. These results are therefore inconclusive. Studies addressing clinical end-points whenever possible, using correct methodology and a large enough sample size should be conducted.

Review of 8 years of experience with Infanrix hexa (DTPa-HBV-IPV/Hib hexavalent vaccine)

Combination vaccines that include multiple antigens within one formulation are now widely accepted as an effective means of eliciting protection against several diseases at the same time. Owing to improvements in quality and convenient modes of administration, they have become part of routine pediatric practice. Hexavalent vaccines, including diphtheria, tetanus, pertussis, hepatitis B, polio and Haemophilus influenzae type b antigens represent the latest advance in the development of combination vaccines. Over 8 years since its first licensure, this review looks at the immunogenicity, efficacy and safety profile of the only hexavalent pediatric vaccine currently in use--Infanrix hexa (diphtheria, tetanus, acellular pertusis-hepatitis B virus-inactivated poliovirus vaccine/Haemophilus influenzae type b vaccine [DTPa-HBV-IPV/Hib]; GlaxoSmithKline Biologicals, Rixensart, Belgium)--through published clinical trials and postmarketing surveillance data. These data show DTPa-HBV-IPV/Hib to be highly immunogenic and well tolerated across a range of different primary and booster vaccination schedules, as well as when administered concomitantly with other licensed vaccines (e.g., pneumococcal conjugate vaccine). Additional issues surrounding the use of hexavalent vaccines are also reviewed.

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.

Antibody persistence and booster vaccination during the second and fifth years of life in a cohort of children who were born prematurely

BACKGROUND

These studies assessed the immunogenicity and reactogenicity of booster vaccination with diphtheria-tetanus-acellular pertussis-hepatitis B-inactivated poliovirus-adsorbed conjugated Haemophilus influenzae type b (DTaP-HBV-IPV/Hib) at 18-20 months, and with DTaP during the fifth year of life in children who had been born prematurely (<37 weeks gestation).

METHODS

Open-label, parallel group studies in which preterm and full-term subjects primed with DTaP-HBV-IPV/Hib received booster vaccination with DTaP-HBV-IPV/Hib (Infanrix hexa) at 18-20 months and DTaP (Infanrix) at 4 years of age. Immunogenicity was assessed before and 1 month after DTaP-HBV-IPV/Hib dose and 1 month after DTaP administration. Local and general symptoms were recorded for 4 days, unsolicited symptoms for 31 days after each dose.

RESULTS

Before the second year booster, Hib, hepatitis-B, and polio type 3 seroprotection rates were higher in the full-term group (antipolyribosyl ribitol phosphate > or =0.15 microg/mL observed in 76.2%/83.6% preterm/full term respectively, anti-HBs > or =10 mIU/mL in 75.0%/80.6% respectively). One month after the DTaP-HBV-IPV/Hib booster, > or =98% in both groups were seroprotected/seropositive for all vaccine antigens, except hepatitis-B in preterms (seroprotection rate 91.6%). By the fifth year hepatitis-B seroprotection rates were 85.3%/70.5% (preterm/full term) in subjects who had previously responded to hepatitis-B vaccination, and seroprotection rates for polio and polyribosyl ribitol phosphate were >95%. No differences between groups were observed after the DTaP booster. Both booster doses were generally well tolerated with minimal differences observed between groups. Local symptoms occurred more frequently after the fifth vaccination at 4 years of age.

CONCLUSIONS

Despite trends for lower immune responses to some vaccine antigens in preterm subjects, these findings support undelayed primary and booster vaccination in infants and children born before term. Booster vaccinations with DTaP-HBV-IPV/Hib and DTaP were well tolerated in this susceptible group.

Should hepatitis B vaccination be introduced into childhood immunisation programmes in northern Europe?

Infection with hepatitis B causes between 500,000 and 1.2 million deaths per year worldwide, and is the leading cause of liver cancer. Over 12 years ago, WHO recommended that universal childhood hepatitis B vaccination be implemented globally. Despite this, Denmark, Finland, Iceland, Ireland, the Netherlands, Norway, Sweden, and the UK have yet to implement such a policy and instead currently adopt an "at-risk" strategy. Although all eight countries are classed as having low endemicity, factors such as increased travel and integration of immigrant communities are increasing the number of at-risk individuals in these countries. Considering the difficulty in identifying all at-risk individuals, and the lack of effectiveness of at-risk vaccination on reducing the overall incidence of hepatitis B, we recommend that these countries reassess their hepatitis B prevention strategies. Universal vaccination against hepatitis B is the only way to eliminate the major public-health impact of this disease.

Combination Vaccines

Infections are still a leading cause of morbidity and mortality in children under five years of age, most of which can be prevented by vaccination. However, there are too many vaccines to be administered, increasing the cost of immunization and visits to the paediatrician. Combination vaccines can be an answer to these problems till the development of a single vaccine containing all the possible antigens. Researchers are aiming at development of an ideal vaccine, which can be given orally at birth, has negligible side effects, is heat stable and is affordable to all the parents.

Immunogenicity and reactogenicity of primary immunization with a hexavalent diphtheria-tetanus-acellular pertussis-hepatitis B-inactivated polio-Haemophilus influenzae type B vaccine coadministered with two doses of a meningococcal C-tetanus toxoid conjugate vaccine

BACKGROUND

This study evaluated the concurrent use of meningococcal C tetanus conjugate (MenC-TT) vaccine (NeisVac-C) with DTaP-based combinations, according to 2 vaccination schedules, one of which included hepatitis B vaccination at birth (Trial DTaP-HBV-IPV/Hib-097).

METHODS

Healthy infants were randomized to receive either DTaP-HBV-IPV/Hib (Infanrix hexa) at 2, 4, and 6 months (N = 115) or HBV at birth followed by DTaP-HBV-IPV/Hib at 2 and 6 months and DTaP-IPV/Hib (Infanrix-IPV Hib) at 4 months (N = 115). In both groups 2 doses of MenC-TT conjugate were coadministered at 2 and 4 months, and compared with 3 doses of MenC-CRM197 conjugate (Meningitec) coadministered at 2, 4, and 6 months with DTaP-HBV-IPV/Hib (N = 120). Antibody concentrations were measured at 2, 6 and 7 months. Solicited local and general symptoms, unsolicited symptoms, and serious adverse events (SAEs) were recorded.

RESULTS

All MenC-TT recipients had seroprotective concentrations of anti-PRP antibodies (> or = 0.15 microg/mL) 1 month after the third vaccine dose and all had SBA-MenC titers > or = 1:8 after the second dose of MenC-TT. These responses were noninferior to those seen after 3 doses of DTaP-HBV-IPV/Hib and MenC-CRM. Anti-PRP antibody GMCs were significantly higher in MenC-TT than MenC-CRM vaccinees (7.9, 7.3, 3.8 microg/mL, respectively). Immune responses to all other coadministered antigens were unimpaired, with seroprotection/seropositivity rates > or = 98.1% in MenC-TT vaccinees. All schedules studied were well tolerated, with no differences in reactogenicity between the study groups.

CONCLUSIONS

Coadministration of DTaP-HBV-IPV/Hib or DTaP-IPV/Hib with 2 doses of MenC-TT conjugate vaccine is safe, well tolerated, and immunogenic, with no impairment of the response to the coadministered antigens.

Prevention of pertussis across the age spectrum through the use of the combination vaccines PENTACEL™ and ADACEL™

Acellular pertussis-containing combination vaccines are widely used in the developed world for the control of pertussis and have been successful in controlling disease in preschool-aged children. Combination vaccines formulated for use in adolescents and adults have been developed more recently and are increasingly being implemented for the control of pertussis in these age groups. One such family of products is PENTACEL (Haemophilus influenzae type b conjugate vaccine reconstituted with component pertussis vaccine and diphtheria and tetanus toxoids adsorbed combined with inactivated poliomyelitis vaccine, DTaP-IPV-Hib), for use in young children, and ADACEL (tetanus and diphtheria toxoids adsorbed combined with component pertussis vaccine, dTap) for use in adolescents and adults. These products have been demonstrated to be safe, immunogenic and effective for the control of pertussis and the other included diseases.

Combination conjugate vaccines

Increasingly, more diseases are becoming vaccine preventable, but maintaining community and provider acceptance demands that the number of injections does not increase. Combination conjugate vaccines represent an inevitable and important advance. This paper reviews the efficacy and safety of combination conjugate vaccines, including immunological mechanisms underlying interactions among vaccine epitopes, the role of immunological memory, and correlates of immunity. Specific attention is given to the experience with combination vaccines against each of Haemophilus influenzae type b, Streptococcus pneumoniae and Neisseria meningitidis. The implications of these findings for different communities are discussed, key areas for further research identified and implications for post-licensure monitoring addressed.

Hepatitis B vaccination in a school age population: a feasibility study

There remains no consensus on whether to adopt a universal hepatitis B vaccination strategy in the United Kingdom, where the endemicity of hepatitis B virus (HBV) is considered to be very low in the general population. To assess the feasibility and acceptance of a school-based adolescent vaccination approach, 11-13 years old pupils in local secondary schools in the London Borough of Camden and Islington were contacted and offered a three-dose hepatitis B vaccination course using a 0, 1, and 12 months schedule. The adult dose of hepatitis B vaccine (Engerix B GlaxoSmithKline) containing 20 mug recombinant hepatitis B surface antigen (HBsAg) in 1 ml suspension was administered. This dosage is normally intended for adults and children older than 15 years of age, but can be administered in 10-15 years old children when compliance may be low, since a higher proportion of those vaccinated develop protective antibody levels following administration of only two doses of vaccine. Overall, a total of 528 pupils were contacted, with 122 (23%) consenting to be vaccinated. Of these, 117 (96%) received the complete three-dose regimen according to the schedule (four did not receive vaccine: three were non-attendees and one was previously vaccinated; one withdrew following a flu-like adverse event). The results of this study show that it is feasible and practical to administer hepatitis B vaccination to adolescents in a school setting, and that it is possible to achieve high rates of uptake for the complete three-dose course among adolescents. However, in order to attain and sustain high coverage rates among pupils, this would require additional general health promotion, including health education and provision of information, targeting of teachers, pupils, and parents in order to increase participation in a school-based hepatitis B vaccination programme. A further requirement includes the availability of good local health support within schools so as to allow for an efficient vaccine delivery system to maximize vaccination in this setting.