An investigational tetravalent meningococcal serogroups A, C, W-135 and Y-tetanus toxoid conjugate vaccine co-administered with Infanrix™ hexa is immunogenic, with an acceptable safety profile in 12-23-month-old children

Effectiveness and duration of protection of primary and booster immunisation against meningococcal serogroup C disease with meningococcal conjugate C and ACWY vaccines: Systematic review

OBJECTIVES

To estimate vaccine effectiveness (VE) and duration of protection of single primary and booster immunisation with meningococcal C (MenC) and ACWY (MenACWY) conjugate vaccines in preventing MenC invasive meningococcal disease (IMD).

METHODS

We performed a systematic review on studies of VE and immunogenicity (rSBA/hSBA titers) of participants aged 12-23 months for primary and 6-18 years for booster immunisation (last search: 18 August 2023). Risk of bias and certainty of evidence were evaluated (PROSPERO: CRD42020178773).

RESULTS

We identified 10 studies. Two studies reported VE of primary immunisation with MenC vaccines ranging between 90% (74.9 - 96.1) and 84.1% (41.5 - 95.7) for periods of 2 and 7 years, respectively. Eight studies reported immunogenicity of primary immunisation with MenC and/or MenACWY vaccines, of which two reported -in addition- on booster immunisation. The percentage of participants with protective rSBA titers was high after primary immunisation but waned over the following 6 years. A single booster at the age of 7 years or older seems to prolong protection for several years.

CONCLUSIONS

A single dose of MenC or MenACWY vaccine at 12-23 months of age provides robust protection against MenC IMD. Data on booster immunisation are sparse, but indicate prolonged protection for three years at least.

Antibody persistence and revaccination recommendations of MenACWY-TT: a review of clinical studies assessing antibody persistence up to 10 years after vaccination

INTRODUCTION

Invasive meningococcal disease (IMD) is potentially fatal and associated with severe sequelae among survivors. It is preventable by several vaccines, including meningococcal vaccines targeting the most common disease-causing serogroups (A, B, C, W, Y). The meningococcal ACWY tetanus toxoid conjugate vaccine (MenACWY-TT [Nimenrix]) is indicated from 6 weeks of age in the European Union and >50 additional countries.

AREAS COVERED

Using PubMed, Google Scholar, ClinicalTrials.gov and ad hoc searches for publications to June 2023, we review evidence of antibody persistence for up to 10 years after primary vaccination and up to 6 years after MenACWY-TT revaccination. We also review global MenACWY revaccination recommendations and real-world impact of vaccination policies, focusing on how these data can be considered alongside antibody persistence data to inform future IMD prevention strategies.

EXPERT OPINION

Based on clear evidence that immunogenicity data (demonstrated antibody titers above established correlates of protection) are correlated with real-world effectiveness, long-term persistence of antibodies after MenACWY-TT vaccination suggests continuing protection against IMD. Optimal timing of primary and subsequent vaccinations is critical to maximize direct and indirect protection. Recommending bodies should carefully consider factors such as age at vaccination and long-term immune responses associated with the specific vaccine being used.

Efficacy and Safety of Quadrivalent Conjugate Meningococcal Vaccines: A Systematic Review and Meta-Analysis

Over the last decades, different quadrivalent antimeningococcal vaccine formulations (diphteria toxoid conjugate, MenACWY-D; tetanus toxoid conjugate, MenACWY-TT; CRM₁₉₇ protein conjugate, MenACWY-CRM) have been developed. However, their availability varies, both in terms of authorized formulations and of inclusion in vaccination schedules. Furthermore, several countries include only the monovalent meningococcal C (MenC) vaccine in their immunization programmes. Finally, there is currently no updated systematic review that directly compares the MenACWY formulations. Thus, we summarized the evidence on efficacy and safety through four parallel, independent systematic literature reviews with meta-analysis which included randomized controlled trials comparing the abovementioned vaccines. A total of 16 studies have been included. In terms of efficacy, MenACWY-TT outperformed MenACWY-D and MenACWY-CRM for A, W-135, and Y serogroups, while no significant difference was found for serogroup C. Furthermore, we did not find significant differences in efficacy between MenC and MenACWY-TT. Regarding the safety, we were able to perform a quantitative analysis only between MenACWY-TT and MenC, finding no significant differences. Similarly, among the different MenACWY formulations no relevant differences were identified. These findings suggest that MenACWY-TT could be preferable to other formulations to improve current vaccination programs and to better develop future immunization policies.

Review of clinical studies comparing meningococcal serogroup C immune responses induced by MenACWY-TT and monovalent serogroup C vaccines

Many countries are replacing meningococcal serogroup C (MenC) conjugate vaccines (MCCV) with quadrivalent conjugate (MenACWY) vaccines, such as MenACWY-TT (Nimenrix®). This review examined eight studies comparing MenC immune responses induced by MenACWY-TT and MCCV to determine if these data support these changes. MenC serum bactericidal antibody levels using human (hSBA) or rabbit complement (rSBA) were evaluated at ~1 month postvaccination. Overall, ≥98.4% of infants administered 2 + 1 MenACWY-TT or MCCV schedules had rSBA titers ≥1:8 postprimary and postbooster vaccination; hSBA titers ≥1:8 were similar. In toddlers administered single MenACWY-TT or MCCV doses, ≥97.3% had rSBA titers ≥1:8 postvaccination; percentages with hSBA titers ≥1:8 were higher post-MenACWY-TT. Of children and adolescents receiving primary and booster MenACWY-TT and MCCV, ≥98.6% had rSBA titers ≥1:8; all children receiving MenACWY-TT or MCCV booster had hSBA titers ≥1:8 postdosing. MenC immune responses induced by MenACWY-TT are robust and generally comparable/superior to MCCV, supporting changes to recommendations.

Persistence of bactericidal antibodies following primary and booster MenACWY-TT vaccination of toddlers: A review of clinical studies

The long-term persistence of antibody responses following primary vaccination with quadrivalent conjugate vaccines targeting meningococcal serogroups A, C, W, and Y (MenACWY) and the duration of protection following a booster dose have not been fully elucidated, particularly in children who received primary dosing as toddlers. This review summarizes the findings of one phase 3 and three phase 2 open-label, randomized clinical studies that assessed the long-term antibody persistence of MenACWY conjugated to tetanus toxoid as a carrier protein (MenACWY-TT) in toddlers. Following primary vaccination, antibody responses persisted for approximately 2-3 years and then decreased up to 5 years after vaccination. Geometric mean titers remained elevated for all serogroups up to 5 years after primary vaccination. In children who received a booster dose of MenACWY-TT at 4-5 years after primary dosing as toddlers, antibody responses were documented in >99% of subjects across all serogroups, with minimal decreases in antibody persistence from 2-6 years after booster vaccination. The persistence of meningococcal serogroup C (MenC) antibody responses was similar between MenACWY-TT and MenC vaccine recipients after primary and booster dosing. Together, these findings indicate that antibody responses to primary MenACWY-TT vaccination persist for 2-3 years. Additionally, these findings indicate that in subjects who receive primary MenACWY-TT vaccination as toddlers, the antibody response to booster MenACWY-TT vaccination lasts for up to 6 years and suggest that immune memory is afforded at least into early adolescence, which is an age group at increased risk of invasive meningococcal disease.

Infant vaccine co-administration: review of 18 years of experience with GSK's hexavalent vaccine co-administered with routine childhood vaccines

INTRODUCTION

The benefits of vaccine co-administration include improved vaccine acceptance and uptake resulting in an increased coverage and protection against multiple childhood diseases, with minimal medical visits. The diphtheria-tetanus-acellular pertussis-hepatitis B-poliomyelitis-Haemophilus influenzae type b vaccine (DTaP-HBV-IPV/Hib) has been available for more than 19 years and is recommended for co-administration with several other infant vaccines.

AREAS COVERED

This is a comprehensive review (34 studies, 21,000 participants) describing the immunogenicity and safety of DTaP-HBV-IPV/Hib when co-administered with 12 different vaccines in infants including pneumococcal, meningococcal, rotavirus or measles-mumps-rubella-varicella.

EXPERT OPINION

Interactions among co-administered vaccines are complex. Therefore, co-administration data are critical before a vaccination regimen can be recommended. Co-administration of DTaP-HBV-IPV/Hib with other routinely administered vaccines was associated with high percentages of children achieving seroprotection/vaccine response against DTaP-HBV-IPV/Hib antigens. In addition, co-administration was not associated with clinically significant interference in immune responses to co-administered vaccines and was well tolerated. Increased systemic reactions observed with some combinations (DTaP-HBV-IPV/Hib + pneumococcal conjugate or meningococcal serogroup B vaccines) were mitigated by prophylactic paracetamol administration. The data reported here, which represent the most frequently used co-administrations of DTaP-HBV-IPV/Hib worldwide, support the concomitant administration of DTaP-HBV-IPV/Hib with other routinely recommended infant vaccines.

Safety of Co-Administration Versus Separate Administration of the Same Vaccines in Children: A Systematic Literature Review

The growing number of available vaccines that can be potentially co-administered makes the assessment of the safety of vaccine co-administration increasingly relevant but complex. We aimed to synthesize the available scientific evidence on the safety of vaccine co-administrations in children by performing a systematic literature review of studies assessing the safety of vaccine co-administrations in children between 1999 and 2019, in line with Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Fifty studies compared co-administered vaccines versus the same vaccines administered separately. The most frequently studied vaccines included quadrivalent meningococcal conjugate (MenACWY) vaccine, diphtheria and tetanus toxoids and acellular pertussis (DTaP) or tetanus toxoid, reduced diphtheria toxoid and acellular pertussis (Tdap) vaccines, diphtheria and tetanus toxoids and acellular pertussis adsorbed, hepatitis B, inactivated poliovirus and Haemophilus influenzae type b conjugate (DTaP-HepB-IPV/Hib) vaccine, measles, mumps, and rubella (MMR) vaccine, and pneumococcal conjugate 7-valent (PCV7) or 13-valent (PCV13) vaccines. Of this, 16% (n = 8) of the studies reported significantly more adverse events following immunization (AEFI) while in 10% (n = 5) significantly fewer adverse events were found in the co-administration groups. Statistically significant differences between co-administration and separate administration were found for 16 adverse events, for 11 different vaccine co-administrations. In general, studies briefly described safety and one-third of studies lacked any statistical assessment of AEFI. Overall, the evidence on the safety of vaccine co-administrations compared to separate vaccine administrations is inconclusive and there is a paucity of large post-licensure studies addressing this issue.

Immunogenicity and safety of a meningococcal serogroups A and C tetanus toxoid conjugate vaccine (MenAC-TT): two immune schedules in toddles aged 12-23 months in China

Background: This exploratory study aimed to assess the immunogenicity and safety of 1 and 2 doses of meningococcal serogroups A and C tetanus toxoid-conjugate vaccine (MenAC-TT) in toddles.Methods: Healthy participants aged 12-23 months were randomized into two groups to receive 1 or 2 doses of the tested vaccine. The interval was 28 days between two doses. Blood samples were collected at day 0 before the immunization and day 28 post-each dose. Safety observation was conducted during 28 days after each vaccination. Serious adverse event (SAE) was conducted throughout 6 month observation period.Results: Overall 301 toddles were vaccinated. Twenty-eight days post full-course vaccination, ≥97.20% toddles had titers ≥1:8 and ≥81.48% had titers ≥1:128 for MenA and MenC in the two schedules groups. There were no significant differences between the two schedule groups for each titer thresholds and serogroups. Up to month 12 post the first dose, titers ≥1:8 and 1:128 were declined to 71.32-80.83% and 26.67-57.85% for each meningococcal serogroups. Most adverse reactions (ARs) were mild or moderate, and the incidence of grade 3 ARs was below 3.33%. The incidence of redness was significantly higher in the two doses group than that in the one dose group, in terms of grade 1 and grade 2 were higher. No SAEs were considered causally related to vaccination.Conclusion: The MenAC-TT showed similarly safety and immunogenicity profile in toddles with two schedules. It will be more important to provide the data for formulating appropriate immunization strategies in different age groups in China.

Immunogenicity and safety of meningococcal group A, C, W and Y tetanus toxoid conjugate vaccine: review of clinical and real-world evidence

Protection by meningococcal group A, C, W and Y (MenACWY) vaccines against four meningococcal disease-causing serogroups is increasingly important because of changing epidemiologic patterns of meningococcal disease, including recent meningococcal serogroup W outbreaks/disease clusters. The MenACWY vaccine conjugated to tetanus toxoid (MenACWY-TT) has been extensively evaluated across the age spectrum (age ≥6 weeks) in randomized Phase II and III and in postmarketing studies. Results support the robust immunogenicity of MenACWY-TT across ages and coadministration with other vaccines. The safety profile is similar regardless of age, primary versus booster vaccination, or concomitant administration; local (swelling, pain, redness) and systemic (fever, fatigue, headache, drowsiness, loss of appetite, irritability) reactogenicity events are most common. These data support use of MenACWY-TT to protect against MenACWY disease.

A review of complement sources used in serum bactericidal assays for evaluating immune responses to meningococcal ACWY conjugate vaccines

Invasive meningococcal disease is rare and potentially devastating but often vaccine-preventable. Evaluation of meningococcal vaccine effectiveness is impractical owing to relatively low disease incidence; protection is therefore estimated using serum bactericidal antibody (SBA) assays. Original experiments on natural immunity established a titer of ≥4 as the correlate of protection for SBA assays using human complement (hSBA), but human complement is relatively difficult to obtain and standardize. Use of baby rabbit complement (rSBA assays), per standard guidelines for serogroups A and C, generally results in comparatively higher titers. Postlicensure effectiveness data for serogroup C conjugate vaccines support acceptance of rSBA titers ≥8 as the correlate of protection for this serogroup, but no thresholds have been formally established for serogroups A, W, and Y. Studies evaluating MenACWY-TT (Nimenrix®; Pfizer Inc, Sandwich, UK) immunogenicity have used both hSBA and rSBA assays, and ultimately suggest that rSBA may be more appropriate for these measurements.

Meningococcal Quadrivalent Tetanus Toxoid Conjugate Vaccine (MenACWY-TT; Nimenrix®): A Review

MenACWY-TT (Nimenrix^®) is a quadrivalent meningococcal tetanus toxoid conjugate vaccine licensed in Europe for active immunisation of individuals aged ≥ 6 weeks against invasive disease caused by Neisseria meningitidis capsular groups A, C, W and Y. MenACWY-TT is the first quadrivalent conjugate vaccine to be approved in Europe for use in infants as young as 6 weeks of age. Numerous phase II-IIIb clinical studies showed that intramuscular MenACWY-TT administered as primary or booster vaccination was highly immunogenic for all four vaccine capsular groups and had an acceptable reactogenicity profile in individuals aged 6 weeks to ≥ 56 years. MenACWY-TT is as immunogenic and safe as other previously licensed monovalent capsular group C or quadrivalent capsular groups A, C, W and Y meningococcal vaccines and can be coadministered with other routine vaccines without adversely affecting the immunogenicity or safety profiles of either vaccine. Current data indicate that primary and booster vaccination with MenACWY-TT is a valuable and safe option for broadening meningococcal protection against four capsular groups across a broad age range, starting as early as 6 weeks of age.

Immunogenicity and Reactogenicity of DTPa-HBV-IPV/Hib and PHiD-CV When Coadministered With MenACWY-TT in Infants: Results of an Open, Randomized Trial

BACKGROUND

This study evaluated the immunogenicity and reactogenicity of a combined diphtheria-tetanus-acellular pertussis-hepatitis B-inactivated poliovirus virus-Haemophilus influenzae type b vaccine (DTPa-HBV-IPV/Hib) and a 10-valent pneumococcal conjugate vaccine (PHiD-CV) coadministered with a quadrivalent meningococcal conjugate vaccine (MenACWY-TT) in infants/toddlers.

METHODS

In this open, controlled, phase III study (NCT01144663), 2095 healthy infants were randomized (1:1:1:1) into 4 groups to receive MenACWY-TT at 2, 3, 4 and 12 months of age or MenACWY-TT, MenC-CRM197, or MenC-TT at 2, 4 and 12 months of age. All participants received PHiD-CV and DTPa-HBV-IPV/Hib at 2, 3, 4 and 12 months of age. Immunogenicity of DTPa-HBV-IPV/Hib was evaluated in exclusive randomized subsets of 25% of participants from each group postprimary, prebooster and postbooster vaccination, whereas immunogenicity of PHiD-CV was evaluated at all time points. Reactogenicity was evaluated on the total vaccinated cohorts during 8 days after each vaccination.

RESULTS

For each DTPa-HBV-IPV/Hib antigen, ≥97.2%, ≥76.5% and ≥97.9% of participants had seropositive/seroprotective levels 1 month postprimary vaccination, before the booster dose and 1 month postbooster, respectively. For each vaccine pneumococcal serotype, ≥74.0% of infants had antibody concentrations ≥0.35 μg/mL at 1 month postprimary vaccination, and robust increases in antibody geometric mean concentrations were observed from prebooster to postbooster. Redness was the most frequent solicited local symptom at the DTPa-HBV-IPV/Hib and PHiD-CV injection sites, reported after up to 47.7% and 57.0% of doses postprimary and postbooster vaccination, respectively.

CONCLUSIONS

Primary and booster vaccinations of infants/toddlers with DTPa-HBV-IPV/Hib and PHiD-CV coadministered with MenACWY-TT were immunogenic with clinically acceptable reactogenicity profiles. These results support the coadministration of MenACWY-TT with routine childhood vaccines.

Effect of Tdap upon antibody response to meningococcal polysaccharide when administered before, with or after the quadrivalent meningococcal TT-conjugate vaccine (coadministered with the 13-valent pneumococcal CRM197-conjugate vaccine) in adult Hajj pilgrims: A randomised controlled trial

Hajj pilgrims are susceptible to several serious infections and are required to receive multiple vaccinations. Polysaccharide-protein conjugate vaccines contain carrier proteins such as tetanus toxoid (TT), diphtheria toxoid or a mutant of diphtheria toxoid (CRM197). These carrier proteins may interact with other conjugate or combination vaccines containing tetanus or diphtheria on concurrent or sequential administration. We examined the immune interaction of separate and concomitant administration of a tetanus/diphtheria/acellular pertussis (Tdap) vaccine with a TT-conjugated quadrivalent meningococcal vaccine (MCV4) (coadministered with 13-valent pneumococcal CRM197-conjugate vaccine [PCV13]) in adult Australian pilgrims before attending Hajj in 2015. We randomly assigned each participant to one of three vaccination schedules. Group 1 received Tdap 3-4 weeks before receiving MCV4 coadministered with PCV13. Group 2 received all three vaccines concomitantly. Group 3 received MCV4 and PCV13 3-4 weeks before Tdap. Blood samples were collected at baseline, at each vaccination visit and 3-4 weeks after vaccination and tested for response to meningococcal serogroups C, W and Y using a serum bactericidal antibody (rSBA) assay with baby rabbit complement, and to diphtheria and tetanus toxoid, measuring IgG antibodies by ELISA. Participants completed symptom diaries after each vaccination. A total of 166 participants aged 18-64 (median 42) years were recruited, of whom 160 completed the study. Compared to the other groups, Group 1 (given Tdap first) had significantly lower proportion of subjects achieving a ≥4-fold rise in rSBA for serogroup W. No difference was detected across the three groups in achieving protection threshold (rSBA ≥8 post vaccination) or SBA geometric mean titre (GMT) post vaccination. Group 3, which was given MCV4/PCV13 first, had high levels of antibody against diphtheria and tetanus than the other groups, when tested prior to receipt of Tdap; Only the anti-tetanus responses remained significantly higher after Tdap administration. No serious adverse events were reported. In conclusion, when multiple vaccination is required for Hajj pilgrims, administering Tdap concurrently with MCV4/PCV13 produces adequate immune responses, and avoids meningococcal immune interference, in the convenience of a single consultation. However, giving Tdap 3-4 weeks after MCV4/PCV13 has the advantage of an enhanced tetanus toxoid response. The trial is Trials Registry (ANZCTR): ACTRN12613000536763.

Immunogenicity and safety of MenACWY-TT, a meningococcal conjugate vaccine, co-administered with routine childhood vaccine in healthy infants: A phase III, randomized study

BACKGROUND

Invasive meningococcal disease has a high burden in young children, particularly during infancy. We investigated the immunogenicity and safety of a quadrivalent meningococcal conjugated vaccine (MenACWY-TT) co-administered with routine vaccines in healthy infants.

METHODS

In this phase IIIb study (NCT01340898) conducted in 2 centers in Lebanon and Mexico, 750 infants were randomized (2:1:1) to receive MenACWY-TT according to 3 schedules: 3+1 (at ages 2, 4, 6 and 15-18 months; group ACWY3+1); 1+1 (at 6 and 15-18 months; group ACWY1+1) or single-dose at 15-18 months (group ACWY1). All infants received PHiD-CV and DTPa-IPV/Hib at ages 2, 4, 6, 15-18 months. Immune responses to MenACWY-TT were assessed by rSBA and hSBA at 7 months (groups ACWY3+1, ACWY1+1) and pre- and post-vaccination at 15-18 months of age (all groups). Immune responses to co-administered vaccines, reactogenicity and safety were also evaluated.

RESULTS

Immunogenicity of MenACWY-TT at 1 month post-primary vaccination was demonstrated in group ACWY3+1: the lower limit of the 95% confidence interval for the percentage of infants with rSBA titers ≥8 was >80% for each serogroup. At 7 months of age, ≥93.9% of MenACWY-TT-primed infants had rSBA titers ≥8. Post-MenACWY-TT vaccination at age 15-18 months, ≥96.3% of participants in all groups had rSBA titers ≥8, regardless of the number of doses received previously. The percentage of infants with hSBA titers ≥4 were ≥87.2% and ≥89.7% at post-primary and booster/single-dose vaccination, respectively. Immune responses to PHiD-CV and DTPa-IPV/Hib did not seem impacted by co-administration with MenACWY-TT in infancy. The incidence of all adverse events was similar among groups. Serious adverse events were reported for 63/750 children in all groups; none were considered vaccine-related by investigators.

CONCLUSION

Primary vaccination with 3 or 1 dose(s) of MenACWY-TT when co-administered with routine pediatric vaccines in infants is immunogenic and well-tolerated.

Immunogenicity and safety of one or two doses of the quadrivalent meningococcal vaccine MenACWY-TT given alone or with the 13-valent pneumococcal conjugate vaccine in toddlers: A phase III, open-label, randomised study

BACKGROUND

We evaluated the immunogenicity and safety of 1 and 2 doses of quadrivalent meningococcal serogroup A, C, W and Y tetanus toxoid-conjugate vaccine (MenACWY-TT) given alone or co-administered with 13-valent pneumococcal conjugate vaccine (PCV13) in toddlers.

METHODS

In this phase III, open-label, controlled, multicentre study (NCT01939158), healthy toddlers aged 12-14 months were randomised into 4 groups to receive 1 dose of MenACWY-TT at month (M) 0 (ACWY_1), 2 doses of MenACWY-TT at M0 and M2 (ACWY_2), MenACWY-TT and PCV13 at M0 (Co-ad), or PCV13 at M0 and MenACWY-TT at M2 (PCV13/ACWY). Immune responses were assessed 1 month post-each vaccination. Solicited and unsolicited symptoms were recorded for 4 and 31 days post-each vaccination, respectively; serious adverse events (SAEs) and new onset of chronic illnesses (NOCIs) up to M9 from first vaccination.

RESULTS

802 toddlers were vaccinated. Post-dose 1 of MenACWY-TT, ≥92.8% of toddlers had rSBA titres ≥1:8, and ≥62.5% had hSBA titres ≥1:4 for each meningococcal serogroup. Post-dose 2 of MenACWY-TT, rSBA titres ≥1:8 were observed in ≥98.0% and hSBA titres ≥1:4 in ≥95.3% of toddlers. Percentages of toddlers with hSBA titres ≥1:4 were higher after 2 doses versus 1 dose of MenACWY-TT for MenW (97.1% versus 62.5-68.9%) and MenY (95.3% versus 64.3-67.6%). Non-inferiority of immune responses to co-administered MenACWY-TT and PCV13 over their separate administration was demonstrated. AEs incidence was comparable among groups. SAEs were reported for 4.9%, 5.1%, 5.5% and 7.5%, and NOCIs for 2.0%, 3.0%, 0.5% and 3.5% of toddlers in the ACWY_1, ACWY_2, Co-ad and PCV13/ACWY groups, respectively; 4 SAEs reported in 3 toddlers were vaccine-related. Two fatal vaccine-unrelated SAEs were reported.

CONCLUSION

MenACWY-TT was immunogenic when administered as a single dose at 12-14 months of age. A second dose in toddlers increased hSBA responses against MenW and MenY. MenACWY-TT and PCV13 can be co-administered without impairing the immunogenicity or safety profile of either vaccine.

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.

Safety and Immunogenicity of the Quadrivalent Meningococcal Serogroups A, C, W and Y Tetanus Toxoid Conjugate Vaccine Coadministered With Routine Childhood Vaccines in European Infants: An Open, Randomized Trial

BACKGROUND

This was the first study evaluating the immunogenicity and safety of the quadrivalent meningococcal tetanus toxoid conjugate vaccine (MenACWY-TT) coadministered with routine childhood vaccines in young infants.

METHODS

In this open, randomized, controlled, phase III study (NCT01144663), 2095 infants (ages 6-12 weeks) were randomized (1:1:1:1) into 4 groups to receive MenACWY-TT at 2, 3, 4 and 12 months of age, or MenACWY-TT, MenC-cross-reactive material (CRM197) or MenC-TT at 2, 4 and 12 months of age. All participants received PHiD-CV and DTPa-HBV-IPV/Hib at 2, 3, 4 and 12 months of age. Immune responses were measured by serum bactericidal activity assays using rabbit (rSBA) and human (hSBA) complement. Solicited and unsolicited symptoms were recorded during 8 and 31 days post-vaccination, respectively, and serious adverse events throughout the study.

RESULTS

Noninferiority of immune responses to MenC induced by 2 or 3 doses of MenACWY-TT versus 2 doses of MenC-TT or MenC-CRM197 was demonstrated. Predefined criteria for the immunogenicity of MenACWY-TT to MenA, MenW and MenY were met. One month after 2 or 3 primary MenACWY-TT doses, ≥93.1% and ≥88.5% of infants had rSBA and hSBA titers ≥1:8 for all serogroups. The robust increases in rSBA and hSBA titers observed for all vaccine serogroups postbooster vaccination suggested that MenACWY-TT induced immune memory. MenACWY-TT coadministered with childhood vaccines had a clinically acceptable safety profile.

CONCLUSIONS

This study supports the coadministration of MenACWY-TT with routine childhood vaccines as 2 or 3 primary doses during infancy followed by a booster dose in the second year of life.

Five-year Antibody Persistence and Booster Response After 1 or 2 Doses of Meningococcal A, C, W and Y Tetanus Toxoid Conjugate Vaccine in Healthy Children

BACKGROUND

We evaluated antibody persistence up to 5 years postvaccination with a quadrivalent meningococcal serogroups A, C, W and Y tetanus toxoid conjugate vaccine (MenACWY-TT), and subsequent booster responses to MenACWY-TT in healthy US children.

METHODS

In the initial phase II, open, multicenter study (NCT00471081), 349 infants were randomized (1:1) to receive MenACWY-TT (1 or 2 doses). In the follow-up study (NCT00718666), we evaluated antibody persistence at years 1, 3 and 5 by serum bactericidal assay using human complement (hSBA). At year 5, children received a booster dose of MenACWY-TT. We compared their immune responses at 1 month postbooster with those from 100 age-matched, meningococcal naive children, who received a primary MenACWY-TT dose. We recorded solicited adverse events for 4 days and unsolicited adverse events for 31 days, followed by an additional 5-month extended safety follow-up.

RESULTS

At year 5, ≥64.0% of 1-dose and ≥74.6% of 2-dose recipients had hSBA titers ≥8 for MenC, MenW and MenY. For MenA, 31.7% of 1-dose and 38.0% of 2-dose recipients had hSBA titers ≥8. One month postvaccination, all booster dose recipients and ≥78.5% of primary dose recipients exhibited hSBA titers ≥8 for all serogroups. Geometric mean titers were higher in primed than in naive children. MenACWY-TT had a clinically acceptable safety profile.

CONCLUSIONS

With the exception of serogroup W, antibody persistence 5 years after MenACWY-TT vaccination did not differ substantially between children who received 1 or 2 doses in infancy. A booster dose of MenACWY-TT elicited robust anamnestic responses and was well tolerated.

Persistence of the immune response two years after vaccination with quadrivalent meningococcal ACWY-tetanus toxoid conjugate vaccine (MenACWY-TT) in Asian adolescents

Invasive meningococcal disease is a serious infection that is most often vaccine-preventable. Long-term protection relies on antibody persistence. Here we report the persistence of the immune response 2 y post-vaccination with a quadrivalent meningococcal serogroups A, C, W, Y tetanus toxoid conjugate vaccine (MenACWY-TT) compared with a MenACWY polysaccharide vaccine (Men-PS), in Asian adolescents aged 11–17 y. We also report a re-analysis of data from the primary vaccination study. This persistence study (NCT00974363) conducted in India and the Philippines included subjects who previously (study NCT00464815) received a single dose of MenACWY-TT or Men-PS. Persistence of functional antibodies was measured in 407 MenACWY-TT recipients and 132 Men-PS recipients (according-to-protocol cohort) using a rabbit complement serum bactericidal assay (rSBA, cut-off 1:8). Vaccine-related serious adverse events (SAEs) occurring since the end of the initial vaccination study were retrospectively recorded. Two y post-vaccination ≥99.3% of adolescents who received MenACWY-TT had persisting antibody titers ≥1:8 against each vaccine serogroup. Antibody persistence was higher (exploratory analysis) in the MenACWY-TT group than the Men-PS group in terms of rSBA titers ≥1:8 for serogroups W and Y; rSBA titers ≥1:128 for serogroups A, W and Y; and rSBA GMTs for serogroups A, W and Y; and was lower in the MenACWY-TT group for rSBA GMTs for serogroup C. No vaccine-related SAEs were reported. The results of this study indicated that antibodies persisted for at least 2 y in the majority of adolescents after vaccination with a single dose of MenACWY-TT.

Meningococcal quadrivalent tetanus toxoid conjugate vaccine (MenACWY-TT, Nimenrix™): A review of its immunogenicity, safety, co-administration, and antibody persistence

INTRODUCTION

Meningococcal disease is a major cause of morbidity and mortality worldwide with reported epidemics and outbreaks in different parts of the world. Despite the availability of antimicrobial therapy, challenges remain in early recognition and prevention of disease. Several vaccines have been developed to date aiming at preventing disease spread.

DISCUSSION

MenACWY-TT (Nimenrix™) has been extensively studied for use in different age groups. Phase II and III randomized trials have demonstrated its immunogenicity when administered in children aged 1 year and older, adolescents and adults. It has an acceptable safety profile with minor adverse events comparable to other vaccines. Follow up studies have shown persistence of protective antibodies up to three years. MenACWY-TT was safely and effectively co-administered with different recommended vaccines.

CONCLUSION

MenACWY-TT is a safe and immunogenic vaccine that can be used to protect against these four serogroups in individuals older than 1 year of age.

Five-year Antibody Persistence and Booster Response to a Single Dose of Meningococcal A, C, W and Y Tetanus Toxoid Conjugate Vaccine in Adolescents and Young Adults: An Open, Randomized Trial

BACKGROUND

We evaluated antibody persistence after 1 dose of meningococcal serogroups ACWY tetanus toxoid (MenACWY-TT) or diphtheria toxoid (MenACWY-DT) conjugate vaccines and subsequent booster responses to MenACWY-TT.

METHODS

In the initial phase II, open, multicenter study (NCT00454909), 872 participants aged 10-25 years received 1 MenACWY-TT or MenACWY-DT dose. In this study (NCT00715910), antibody persistence was evaluated at years 1, 3 and 5 by serum bactericidal activity assays using human complement (hSBA). At year 5, all participants received a MenACWY-TT booster dose. Immune responses at 1-month postbooster were compared with a control group including 101 participants aged 15-30 years who received a primary MenACWY-TT dose. Solicited and unsolicited adverse events were recorded for 4 and 31 days, respectively, followed by a 6-month extended safety follow-up.

RESULTS

At year 5, ≥79.5% of MenACWY-TT-primed (n = 170) and MenACWY-DT-primed (n = 45) participants had hSBA titers ≥1:8 for MenC, MenW and MenY, and ≥37.5% for MenA. For all serogroups, ≥85.7% and ≥67.1% of MenACWY-TT booster and primary dose recipients exhibited vaccine responses 1-month postmvaccination, respectively. Geometric mean titers were potentially higher in primed versus naive participants, with no potential difference between MenACWY-TT-primed and MenACWY-DT-primed participants (exploratory analyses). MenACWY-TT had a clinically acceptable safety profile.

CONCLUSIONS

Before the booster dose administration at year 5, hSBA-MenC, -MenW and -MenY antibody persistence was observed in most participants. However, only ≥37.5% of MenACWY-TT and 44.4% of MenACWY-DT recipients retained hSBA-MenA titers ≥1:8. MenACWY-TT booster doses elicited robust anamnestic responses, irrespective of the priming vaccine, and were well tolerated.

Long-term immunogenicity and safety after a single dose of the quadrivalent meningococcal serogroups A, C, W, and Y tetanus toxoid conjugate vaccine in adolescents and adults: 5-year follow-up of an open, randomized trial

Background

Long-term protection against meningococcal disease is associated with persistence of post-vaccination antibodies at protective levels. We evaluated the bactericidal antibody persistence and safety of the quadrivalent meningococcal serogroups A, C, W and Y tetanus-toxoid conjugate vaccine (MenACWY-TT) and the meningococcal polysaccharide serogroups A, C, W, and Y vaccine (MenACWY-PS) up to 5 years post-vaccination.

Methods

This phase IIb, open, randomized, controlled study conducted in the Philippines and Saudi Arabia consisted of a vaccination phase and a long-term persistence phase. Healthy adolescents and adults aged 11–55 years were randomized (3:1) to receive a single dose of MenACWY-TT (ACWY-TT group) or MenACWY-PS (Men-PS group). Primary and persistence results up to 3 years post-vaccination have been previously reported. Antibody responses against meningococcal serogroups A, C, W, and Y were assessed by a serum bactericidal antibody assay using rabbit complement (rSBA, cut-off titers 1:8 and 1:128) at Year 4 and Year 5 post-vaccination. Vaccine-related serious adverse events (SAEs) and cases of meningococcal disease were assessed up to Year 5.

Results

Of the 500 vaccinated participants, 404 returned for the Year 5 study visit (Total Cohort Year 5). For the Total Cohort Year 5, 71.6–90.0 and 64.9–86.3 % of MenACWY-TT recipients had rSBA titers ≥1:8 and ≥1:128, respectively, compared to 24.8–74.3 and 21.0–68.6 % of MenACWY-PS recipients. The rSBA geometric mean titers (GMTs) remained above the pre-vaccination levels in both treatment groups. Exploratory analyses suggested that both rSBA GMTs as well as the percentages of participants with rSBA titers above the cut-offs were higher in the ACWY-TT than in the Men-PS group for serogroups A, W and Y, with no apparent difference for MenC. No SAEs related to vaccination or cases of meningococcal disease were reported up to Year 5.

Conclusion

These results suggest that a single dose of MenACWY-TT could protect at least 72 % of vaccinated adolescents and adults against meningococcal disease at least 5 years post-vaccination.

Trial registration

ClinicalTrials.gov NCT00356369

Electronic supplementary material

The online version of this article (doi:10.1186/s12879-015-1138-y) contains supplementary material, which is available to authorized users.

Safety and immunogenocity of a novel combined Haemophilus influenzae type b-Neisseria meningitidis serogroups A and C-tetanus-toxoid conjugate vaccine in healthy Chinese children aged 6 months to 5 years old

A novel combined Haemophilus influenzae type b-Neisseria meningitidis serogroups A and C-tetanus-toxoid conjugate vaccine (Hib-MenAC vaccine) has been developed to protect children against diseases caused by Hib, MenA, and MenC. This study investigated the safety and immunogenicity of the Hib-MenAC vaccine administered in 2-dose series to children aged 6-23 months and in a single dose to children aged 2-5 y. A randomized, positive-controlled, non-inferiority clinical trial was conducted for 1200 healthy participants in each age group. Within each age group, participants were randomly allocated to the Hib-MenAC group or the control group at a ratio of 1:1. Adverse reactions were recorded within 28 d after each dose. Blood samples were obtained to assess immunogenicity on day 0 and at 28 d after a complete vaccination course. For the investigational vaccine, the incidence of total adverse reactions in vaccinees aged 6-23 months was 46.8% and that in vaccinees aged 2-5 y was 29.8%. Most adverse reactions were mild or moderate. One non-fatal serious adverse event occurred in the Hib-MenAC group, but was unrelated to vaccination. The seroconversion rate to the 3 components reached 94.0%, and the proportion of vaccinees with rSBA titers ≥ 1:8 and PRP ≥ 0.15 g/mL reached 97.0% in both age groups. The safety and immunogenicity of the Hib-MenAC vaccine were non-inferior when compared to the licensed vaccines. It was concluded that the novel vaccine would be expected to protect children against all of the targeted diseases.

Glycoconjugate vaccines: an update

INTRODUCTION

Globally, the three main pathogens causing serious infections are Haemophilus influenzae type b, Streptococcus pneumoniae and Neisseria meningitidis. Over the last 5 years, new vaccines protecting against these bacteria have been developed and introduced in various countries.

AREAS COVERED

This review describes the recently licensed glycoconjugates being used to protect against these encapsulated bacteria. Immunogenicity and safety data that led to licensure or licensure expansion of these glycoconjugates are discussed in addition to the resultant impact on the disease burden.

EXPERT OPINION

The maintenance of robust immunisation programmes with high uptake rates is important in maintaining low rates of disease. Epidemiological surveillance systems are essential in monitoring any changes in infectious disease trends and in identifying emerging infections such as from non-typeable H. influenzae, pneumococcal serotype replacement disease and changes in the epidemiology of meningococcal serogroups. This is important to guide future vaccine development. Accessibility of these glycoconjugate vaccines in resource poor regions, which bear the highest disease burden from these pathogens, remains challenging largely due to high vaccine pricing. Recent aids from public and private funding, tiered vaccine pricing and the transfer of vaccine technology have helped in introducing these vaccines where they are most needed.

Meningococcal serogroups A, C, W-135, and Y tetanus toxoid conjugate vaccine: a new conjugate vaccine against invasive meningococcal disease

Invasive meningococcal disease is a serious infection that occurs worldwide. It is caused by Neisseria meningitidis, of which six serogroups (A, B, C, W-135, X, and Y) are responsible for most infections. The case fatality rate of meningococcal disease remains high and can lead to significant sequelae. Vaccination remains the best strategy to prevent meningococcal disease. Polysaccharide vaccines were initially introduced in the late 1960s but their limitations (poor immunogenicity in infants and toddlers and hyporesponsiveness after repeated doses) have led to the development and use of meningococcal conjugate vaccines, which overcome these limitations. Two quadrivalent conjugated meningococcal vaccines – MenACWY-DT (Menactra^®) and MenACWY-CRM₁₉₇ (Menveo^®) – using diphtheria toxoid or a mutant protein, respectively, as carrier proteins have already been licensed in the US. Recently, a quadrivalent meningococcal vaccine conjugated to tetanus toxoid (MenACWY-TT; Nimenrix^®) was approved for use in Europe in 2012. The immunogenicity of MenACWY-TT, its reactogenicity and safety profile, as well as its coadministration with other vaccines are discussed in this review. Clinical trials showed that MenACWY-TT was immunogenic in children above the age of 12 months, adolescents, and adults, and has an acceptable reactogenicity and safety profile. Its coadministration with several other vaccines that are commonly used in children, adolescents, and adults did not affect the immunogenicity of MenACWY-TT or the coadministered vaccine, nor did it affect its reactogenicity and safety. Other studies are now ongoing in order to determine the immunogenicity, reactogenicity, and safety of MenACWY-TT in infants from the age of 6 weeks.

Comparison of the Safety and Immunogenicity of a Novel Quadrivalent Meningococcal ACWY-Tetanus Toxoid Conjugate Vaccine and a Marketed Quadrivalent Meningococcal ACWY-Diphtheria Toxoid Conjugate Vaccine in Healthy Individuals 10-25 Years of Age

BACKGROUND

Universal immunization of adolescents against meningococcal disease with a quadrivalent meningococcal ACWY (MenACWY) conjugate vaccine is recommended in a number of countries.

METHODS

In a randomized, controlled, observer-blinded, multicenter trial, 1016 participants, 10-25 years of age, were randomly allocated 1:1:1 to receive a single dose of 1 of 2 lots of an investigational tetanus toxoid-conjugated MenACWY vaccine (MenACWY-TT) or a marketed diphtheria toxoid-conjugated MenACWY vaccine (MenACWY-DT). The primary outcome was the noninferiority of the vaccine response after MenACWY-TT (lot A) compared with MenACWY-DT for all 4 serogroups. Vaccine response was defined as a postvaccination human serum bactericidal antibody (hSBA) titer against each of the serogroups of at least 1:8 in persons initially seronegative (<1:4) or as a 4-fold increase in titer pre- to postvaccination in persons initially seropositive (≥1:4). Adverse events (AEs) after immunization were measured 4 and 31 days postvaccination.

RESULTS

The mean age of participants was 16.3 years; 977 (96.6%) completed the study. The noninferiority of MenACWY-TT (lot A) to the control vaccine in terms of the percentage of participants with hSBA vaccine response was demonstrated for each serogroup. Vaccine response rates ranged from 51.0% to 82.5% for the 4 serogroups after MenACWY-TT (both lots) compared with 39.0%-76.3% for the 4 serogroups after MenACWY-DT. Pain was the most common injection-site reaction reported by 50.8%-55.4% across the 3 groups. Fatigue and headache were the most common systemic solicited AEs, reported by 27.3%-29.2% and 25.5%-26.4%, respectively.

CONCLUSIONS

Tetanus toxoid-conjugated MenACWY vaccine was well tolerated and elicited an immune response that was noninferior to that of a marketed MenACWY-DT (www.clinicaltrials.gov NCT01165242).

Comparing Haemophilus influenzae type b conjugate vaccine schedules: a systematic review and meta-analysis of vaccine trials

BACKGROUND

The optimal schedule and the need for a booster dose are unclear for Haemophilus influenzae type b (Hib) conjugate vaccines. We systematically reviewed relative effects of Hib vaccine schedules.

METHODS

We searched 21 databases to May 2010 or June 2012 and selected randomized controlled trials or quasi-randomized controlled trials that compared different Hib schedules (3 primary doses with no booster dose [3p+0], 3p+1 and 2p+1) or different intervals in primary schedules and between primary and booster schedules. Outcomes were clinical efficacy, nasopharyngeal carriage and immunological response. Results were combined in random-effects meta-analysis.

RESULTS

Twenty trials from 15 countries were included; 16 used vaccines conjugated to tetanus toxoid (polyribosylribitol phosphate conjugated to tetanus toxoid). No trials assessed clinical or carriage outcomes. Twenty trials examined immunological outcomes and found few relevant differences. Comparing polyribosylribitol phosphate conjugated to tetanus toxoid 3p+0 with 2p+0, there was no difference in seropositivity at the 1.0 μg/mL threshold by 6 months after the last primary dose (combined risk difference -0.02; 95% confidence interval: -0.10, 0.06). Only small differences were seen between schedules starting at different ages, with different intervals between primary doses, or with different intervals between primary and booster doses. Individuals receiving a booster were more likely to be seropositive than those at the same age who did not.

CONCLUSIONS

There is no clear evidence from trials that any 2p+1, 3p+0 or 3p+1 schedule of Hib conjugate vaccine is likely to provide better protection against Hib disease than other schedules. Until more data become available, scheduling is likely to be determined by epidemiological and programmatic considerations in individual settings.

Immunogenicity and safety of a quadrivalent meningococcal serogroups A, C, W-135 and Y tetanus toxoid conjugate vaccine (MenACWY-TT) administered to adults aged 56 Years and older: results of an open-label, randomized, controlled trial

Background

The burden of invasive meningococcal disease is substantial in older adults in whom the case fatality rate is high. Travelers to regions with high rates of meningococcal disease, such as Hajj pilgrims, are at increased risk of meningococcal infection, and disease transmission from travelers to their close contacts has been documented. In younger individuals, meningococcal conjugate vaccines offer advantages over polysaccharide vaccines in terms of duration of protection and boostability, and induction of herd immune effects through reductions in nasopharyngeal carriage of meningococci. To date, few data are available evaluating meningococcal conjugate vaccine use in adults >55 years of age.

Objective

To evaluate the immunogenicity and safety of quadrivalent meningococcal serogroups A, C, W-135 and Y vaccine with all serogroups conjugated to tetanus toxoid (MenACWY-TT, Nimenrix™, GlaxoSmithKline, Belgium) and a licensed quadrivalent polysaccharide vaccine (MenPS, Mencevax™ GlaxoSmithKline, Belgium) in adults >55 years of age.

Methods

This was a phase IIIb, open-label, randomized (3:1), controlled study conducted at one study center in Lebanon. A total of 400 healthy adults between 56 and 103 years of age without previous MenPS or tetanus toxoid vaccination within the previous 5 years or meningococcal conjugate vaccination at any time previously were included. They received a single-dose vaccination with MenACWY-TT or MenPS with blood sampling before and 1 month after vaccination. The main outcome measures were serum bactericidal activity (rabbit complement source: rSBA) vaccine response (VR) rate [rSBA titer of ≥1:32 in initially seronegative subjects (rSBA titer <1:8); ≥4-fold increase in subjects with pre-vaccination rSBA titers between 1:8 and 1:128, and ≥2-fold increase in subjects with pre-vaccination rSBA titers ≥1:128]. The percentages of subjects with rSBA titers ≥1:8 and ≥1:128 and rSBA geometric mean titers (GMTs) were assessed. Solicited adverse events were recorded for 4 days following vaccination, and all other adverse events, including the incidence of new onset chronic diseases, were recorded for 31 days after vaccination.

Results

One month after a single dose of MenACWY-TT, the rSBA VR rate in the MenACWY-TT group was 76.6 % for serogroup A, 80.3 % for serogroup C, 77.5 % for serogroup W-135 and 81.9 % for serogroup Y. VR rates in the MenPS group were 91.7, 84.8, 87.1 and 89.1 %, respectively. One month after vaccination, ≥93.2 % of subjects in the MenACWY-TT group and ≥93.9 % in the MenPS group had rSBA titers ≥1:128. In each group, GMTs increased by ≥13-fold for each serogroup. rSBA VR and GMTs tended to be lower in subjects who were over 65 years compared to 56–65 years of age. Only 6.3 % of MenACWY-TT recipients had anti-TT ≥0.1 IU/ml prior to vaccination, increasing to 28.1 % post-vaccination. The rSBA GMTs were 1.9- to 4-fold higher in anti-TT responders. Each local and general solicited symptom was reported by no more than 3.0 % of subjects in either group. No serious adverse events were considered vaccine related.

Conclusion

In adults 56 years of age and older, MenACWY-TT was immunogenic, with a vaccine response rate ≥76 % and with ≥93 % of subjects achieving rSBA titers ≥1:128 against all four serogroups after a single dose. MenACWY-TT induced low anti-TT concentrations in this population, which deserves further study.

Electronic supplementary material

The online version of this article (doi:10.1007/s40266-013-0065-0) contains supplementary material, which is available to authorized users.

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.

One or two doses of quadrivalent meningococcal serogroups A, C, W-135 and Y tetanus toxoid conjugate vaccine is immunogenic in 9- to 12-month-old children

BACKGROUND

The incidence of invasive meningococcal disease is highest in infants. A quadrivalent meningococcal serogroups A, C, W-135 and Y tetanus toxoid conjugate vaccine (MenACWY-TT) was evaluated in children 9-12 months of age.

METHODS

We randomized infants (1:1) to receive 1 dose of MenACWY-TT at 12 months of age (ACWY-1 group) or 2 doses at 9 and 12 months (ACWY-2). We measured immunogenicity after each dose and 1 year after completing vaccination using human serum bactericidal antibody (hSBA) assays according to prespecified criteria of ≥ 1:8. Local and general symptoms were solicited for 8 days after vaccination. Adverse events were recorded for 6 months after the last dose.

RESULTS

We enrolled and vaccinated 349 subjects, of whom 248 reenrolled at Year 1 for evaluation of antibody persistence. Percentages of subjects with postvaccination hSBA ≥ 1:8 in the ACWY-1 group were 79.5%, 94.6%, 50.8% and 56.1% and in the 2-dose group (ACWY-2) were 88.4%, 100%, 99.3% and 99.3% postdose 2 for serogroups A, C, W-135 and Y, respectively. At Year 1, 80.0-99.1% in each group had hSBA ≥ 1:8, except for serogroup A, for which 20.6% (ACWY-1) and 25.9% (ACWY-2) retained hSBA ≥1:8. Both schedules were well-tolerated, with no observed increase in reactogenicity after the second dose.

CONCLUSIONS

MenACWY-TT was immunogenic when administered as a single dose at 12 months of age, or as 2 doses at 9 and 12 months, and had a clinically acceptable safety profile. Good antibody persistence was observed through 12 months postvaccination after both treatment schedules for serogroups C, W-135, Y.

Meningococcal serogroup A, C, W₁₃₅ and Y conjugated vaccine: a cost-effectiveness analysis in the Netherlands

Background

In 2002, vaccination with a serogroup C meningococcal conjugate vaccine (MenC) was introduced in the Netherlands for all children aged 14 months. Despite its success, herd immunity may wane over time. Recently, a serogroup A,C,W135,Y meningococcal conjugate vaccine (MenACWY) was licensed for use in subjects of 12 months of age and above.

Objectives

To evaluate the cost-effectiveness of meningococcal vaccination at 14 months and an additional vaccination at the age of 12 years, both with the MenACWY vaccine.

Methods

A decision analysis cohort model, with 185,000 Dutch newborns, was used to evaluate the cost-effectiveness of different immunization strategies. For strategies including a vaccination at 12 years of age, an additional cohort with adolescents aged 12 years was followed. The incremental cost-effectiveness ratio (ICER) was estimated for the current disease incidence and for a scenario when herd immunity is lost.

Results

Vaccination with MenACWY at 14 months is cost-saving. Vaccinating with MenACWY at 14 months and at 12 years would prevent 7 additional cases of meningococcal serogroup A,C,W135,Y disease in the birth cohort and adolescent cohort followed for 99 years compared to the current vaccine schedule of a single vaccination with MenC at 14 months. With the current incidence, this strategy resulted in an ICER of €635,334 per quality adjusted life year. When serogroup C disease incidence returns to pre-vaccination levels due to a loss of vaccine-induced herd-immunity, vaccination with MenACWY at 14 months and at 12 years would be cost-saving.

Conclusions

Routine vaccination with MenACWY is cost-saving. With the current epidemiology, a booster-dose with MenACWY is not likely cost-effective. When herd immunity is lost, a booster-dose has the potential of being cost-effective. A dynamic model should be developed for more precise estimation of the cost-effectiveness of the prevention of disappearance of herd immunity.

Meningococcal quadrivalent (serogroups A, C, W135 and Y) tetanus toxoid conjugate vaccine (Nimenrix™)

Nimenrix™ (MenACWY-TT) is a quadrivalent meningococcal conjugate vaccine, comprising the polysaccharide serogroups A, C, W135 and Y, and tetanus toxoid (TT) as carrier protein. It is the first quadrivalent vaccine (administered as a single dose) to be approved in Europe for active immunization of individuals aged ≥ 12 months against invasive meningococcal disease caused by Neisseria meningitidis serogroups A, C, W135 and Y. Administration of a single dose of Nimenrix™ elicited a strong immune response against all four vaccine serogroups in healthy toddlers aged 12-23 months, children and adolescents aged 2-17 years and adults aged 18-55 years in randomized, multicentre, phase III trials. In toddlers, Nimenrix™ was noninferior to Meningitec® in terms of seroresponse rates against meningococcal serogroup C 42 days post-vaccination. In children, adolescents and adults, Nimenrix™ was noninferior to Mencevax™ in terms of vaccination response rates against all four serogroups 1 month post-vaccination. Furthermore, several phase II studies and a phase III trial showed that the immune response elicited by Nimenrix™ in all age groups persisted for 7-42 months after the primary vaccination (when evaluated by rabbit serum bactericidal activity), with the vaccine also inducing immune memory in toddlers. In addition, several randomized, multicentre, phase III, noninferiority trials showed that when coadministered with other childhood vaccines or a seasonal flu vaccine, the immunogenicity of Nimenrix™ or that of the coadministered vaccine was generally not altered. Nimenrix® was generally well tolerated in all age groups whether administered as a single vaccine or coadministered with other routine vaccines. The incidence of grade 3 local or systemic solicited adverse events during the first 4 days following vaccination and of serious adverse events over an extended follow-up period of up to 6 months was low (<4.5%). Although protective effectiveness and longer-term persistence studies are required, current evidence suggests that Nimenrix™, administered as a single dose, provides a valuable vaccination option for the prevention of meningococcal disease across a broad age group, including children as young as 12 months.

Immunogenicity and safety of a meningococcal serogroup A, C, Y and W glycoconjugate vaccine, ACWY-TT

A quadrivalent meningococcal serogroup A, C, W and Y conjugate vaccine (ACWY), utilising tetanus toxoid (TT) as its carrier protein (ACWY-TT; Nimenrix™, GlaxoSmithKline Vaccines, Rixensart, Belgium) has been demonstrated to be safe and immunogenic when administered to young children from 12 months of age, older children, adolescents, and adults. Administration of a single dose of ACWY-TT induces protective serum bactericidal antibodies against all four serogroups as well as good antibody persistence. Coadministration studies have demonstrated that ACWY-TT can be administered with diphtheria, tetanus, three-component acellular pertussis, hepatitis B, inactivated polio virus and Haemophilus influenzae type b conjugate vaccine (DTaP3-IPV-HBV/Hib, Infanrix™ hexa; GlaxoSmithKline Vaccines, Rixensart, Belgium); measles, mumps, rubella, varicella vaccine (Priorix-Tetra™; GlaxoSmithKline Vaccines, Rixensart, Belgium); 10-valent pneumococcal conjugate vaccine (Synflorix(®); GlaxoSmithKline Vaccines, Rixensart, Belgium); hepatitis A and B vaccine (Twinrix(®); GlaxoSmithKline Vaccines, Rixensart, Belgium); and seasonal influenza vaccine (Fluarix™; GlaxoSmithKline Vaccines, Rixensart, Belgium). Studies in young infants from 2 months of age have now commenced but immunisation with a single dose of ACWY-TT from 12 months of age is a safe and immunogenic option in the prevention of meningococcal disease.

Immune response, antibody persistence, and safety of a single dose of the quadrivalent meningococcal serogroups A, C, W-135, and Y tetanus toxoid conjugate vaccine in adolescents and adults: results of an open, randomised, controlled study

BACKGROUND

The best strategy to protect individuals against meningococcal disease is to immunize against multiple serogroups. Immunogenicity, antibody persistence, and safety of the EU-licensed meningococcal ACWY-tetanus toxoid conjugate vaccine (MenACWY-TT) were evaluated in healthy participants aged 11-55 years from the Philippines and Saudi Arabia.

METHODS

In this phase IIb, open, controlled study, 500 participants were randomised (3:1) to receive one dose of MenACWY-TT or a licensed meningococcal polysaccharide vaccine (Men-PS). Functional antibody responses against meningococcal serogroups A, C, W-135, and Y were assessed by a serum bactericidal antibody assay using rabbit complement (rSBA) at Month 0, Month 1, Year 1, Year 2, and Year 3. Vaccine response was defined as an rSBA titre ≥32 at Month 1 in participants who were seronegative (rSBA titre <8) pre-vaccination and as at least a four-fold increase in titre in participants who were seropositive pre-vaccination. Solicited symptoms were recorded up to Day 4, safety outcomes up to Month 6, and serious adverse events related to vaccination up to Year 3.

RESULTS

Pre-specified criteria for non-inferiority of MenACWY-TT versus Men-PS were met in terms of rSBA vaccine response and incidence of grade 3 general symptoms. At Month 1, 82.7%-96.3% of MenACWY-TT and 69.7%-91.7% in Men-PS recipients had a vaccine response for each serogroup. At Year 3, ≥99.1% and ≥92.9% of MenACWY-TT recipients retained rSBA titres ≥8 and ≥128, respectively, as compared to ≥86.7% and ≥80.0% in the Men-PS group. Both vaccines had a clinically acceptable safety profile, although injection site redness and swelling were more frequent in MenACWY-TT recipients.

CONCLUSIONS

These results suggest that MenACWY-TT could protect adolescents and adults against meningococcal disease up to three years post-vaccination.

TRIAL REGISTRATION

This study is registered at http://www.clinicaltrials.gov/NCT00356369.

Immunogenicity and safety of a booster dose of the 10-valent pneumococcal Haemophilus influenzae protein D conjugate vaccine coadministered with the tetravalent meningococcal serogroups A, C, W-135 and Y tetanus toxoid conjugate vaccine in toddlers: a randomized trial

BACKGROUND

This open, randomized clinical trial (NCT00758264) evaluated the coadministration of a booster dose of the 10-valent pneumococcal conjugate vaccine (PHiD-CV) and a single dose of the tetravalent meningococcal conjugate vaccine (MenACWY-TT) in Taiwanese and Mexican toddlers.

METHODS

Healthy toddlers aged 12-23 months (N = 363) were randomized (2:1:1) to receive either both vaccines at first visit, MenACWY-TT at first visit and 1 month later PHiD-CV, or PHiD-CV at first visit and 1 month later MenACWY-TT. Immune responses were measured 1 month after MenACWY-TT vaccination by meningococcal serum bactericidal activity (rSBA) assay and 1 month after PHiD-CV vaccination by pneumococcal 22F-inhibition enzyme-linked immunosorbent assay and functional opsonophagocytic activity assay. Solicited and unsolicited symptoms were recorded for days 4 and 31 postvaccination, respectively. Serious adverse events were recorded throughout the study.

RESULTS

The prespecified criteria for noninferiority of coadministration versus individual administrations were met for all meningococcal serogroups (in terms of percentages of toddlers with rSBA titer ≥8) and all vaccine pneumococcal serotypes (in terms of antibody geometric mean concentration ratios), except pneumococcal serotype 18C. For each meningococcal serogroup, ≥97.5% of toddlers across the 3 groups had rSBA titers ≥128 at 1 month after MenACWY-TT vaccination. For each pneumococcal serotype, at 1 month after PHiD-CV vaccination, ≥96.0% and ≥92.9% of toddlers across the 3 groups had antibody concentrations ≥0.2 µg/mL and opsonophagocytic activity titers ≥8, respectively. The safety profiles of both vaccines when coadministered were clinically acceptable.

CONCLUSIONS

This study supports the coadministration of PHiD-CV and MenACWY-TT in toddlers.

MenACWY-TT vaccine for active immunization against invasive meningococcal disease

Meningococcal disease remains a significant global cause of morbidity and mortality despite the availability of polysaccharide and conjugate vaccines. The implementation of monovalent meningococcal serogroup C vaccine in developed countries has significantly decreased the incidence of meningococcal disease, while the recent introduction of monovalent serogroup A conjugate vaccine in the African meningitis belt aims to reduce the incidence of high endemic disease in this area. Three quadrivalent meningococcal vaccines have already been licensed; a polysaccharide (MenACWY-PS) and two conjugated (MenACWY-DT and MenACWY-CRM) vaccines. An investigational MenACWY-TT vaccine is described in this article. Clinical trials in infants older than 9 months of age, toddlers, children, adolescents and adults have indicated that this vaccine is well tolerated and immunogenic. The inclusion of a spacer molecule coupled with the polysaccharide (for serogroups A and C) and tetanus toxoid as the carrier protein aims to elicit robust immune responses. The tolerability of this vaccine is comparable to that of polysaccharide quadrivalent vaccines and monovalent meningococcal serogroup C vaccines. More importantly, the immunogenicity, antibody persistence and induction of immune memory aim to provide protection to a wide range of susceptible subjects.

Randomized trial to assess the immunogenicity, safety and antibody persistence up to three years after a single dose of a tetravalent meningococcal serogroups A, C, W-135 and Y tetanus toxoid conjugate vaccine in toddlers

Effective vaccines offering broad protection to toddlers, who are at high risk for invasive meningococcal disease, are needed. Here, the immunogenicity, safety and antibody persistence of the tetravalent meningococcal ACWY tetanus toxoid conjugate vaccine (MenACWY-TT) were evaluated in toddlers. Healthy participants aged 12 to 23 mo (n = 304) were randomized (3:1) to receive one dose of MenACWY-TT or a monovalent meningococcal serogroup C conjugate vaccine (MenC-CRM₁₉₇). Serum bactericidal activity was evaluated with assays using rabbit (rSBA) and human (hSBA) complement up to three years post-vaccination. MenACWY-TT was demonstrated to be non-inferior to MenC-CRM₁₉₇ in terms of immunogenicity to serogroup C, and the pre-specified immunogenicity criteria for serogroups A, W-135 and Y were met. Exploratory analyses suggested that rSBA geometric mean titers (GMTs), hSBA GMTs and proportions of toddlers with rSBA titers ≥ 1:128 and hSBA titers ≥ 1:4 and ≥ 1:8 were higher for all serogroups at one month post-vaccination with MenACWY-TT compared with MenC-CRM₁₉₇. At three years post-vaccination, at least 90.8% and 73.6% of MenACWY-TT recipients retained rSBA titers ≥ 1:8 for all serogroups and hSBA titers ≥ 1:4 for serogroups C, W-135 and Y, respectively, but the percentages of toddlers with hSBA titers ≥ 1:4 for serogroup A decreased to 21.8%. In both groups, grade 3 adverse events were infrequently reported and no serious adverse events were considered causally related to vaccination. These results suggest that one single dose of MenACWY-TT induces a robust and persistent immune response and has an acceptable safety profile in toddlers. This study has been registered at www.clinicaltrials.gov NCT00427908.

A randomized study to assess the immunogenicity, antibody persistence and safety of a tetravalent meningococcal serogroups A, C, W-135 and Y tetanus toxoid conjugate vaccine in children aged 2-10 years

Incidence of meningococcal diseases is high in children, and effective vaccines are needed for this age group. In this phase II, open, controlled study, 309 children aged 2–10 y from Finland were randomized (3:1) into two parallel groups to receive one dose of meningococcal ACWY-tetanus toxoid conjugate vaccine (ACWY-TT group; n = 231) or a licensed meningococcal ACWY polysaccharide vaccine (Men-PS group; n = 78). Serum bactericidal activity using rabbit complement (rSBA) was evaluated up to three years post-vaccination. Exploratory comparisons suggested that rSBA vaccine response rates and geometric mean titers (GMTs) for each serogroup at one month post-vaccination and rSBA GMTs for serogroups A, W-135 and Y up to three years post-vaccination were higher in the ACWY-TT compared with Men-PS group, but did not detect any difference between groups in terms of rSBA-MenC GMTs at three years post-vaccination; this is explained by the higher proportion of children from the Men-PS group who were excluded because they were re-vaccinated with a monovalent meningococcal serogroup C vaccine due to loss of protective antibody levels against this serogroup. Although there was a higher incidence of local reactogenicity in the ACWY-TT group, general and unsolicited symptoms reporting rates were comparable in both groups. This study showed that MenACWY-TT was immunogenic with a clinically acceptable safety profile in children aged 2–10 y. MenACWY-TT induced higher functional antibody titers for all serogroups, which persisted longer for serogroups A, W-135 and Y, than the MenACWY polysaccharide vaccine. This study has been registered at www.clinicaltrials.gov NCT00427908.

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.