DT5aP-Hib-IPV and MCC vaccines: preterm infants' response to accelerated immunisation

Penta- and hexavalent vaccination of extremely and very-to-moderate preterm infants born at less than 34 weeks and/or under 1500 g: A systematic literature review

Debate regarding vaccinating high-risk infants with penta- and hexavalent vaccines persists, despite their good immunogenicity and acceptable safety profile in healthy full-term infants. We report the findings of a systematic literature search that aimed to present data on the immunogenicity, efficacy, effectiveness, safety, impact, compliance and completion of penta- and hexavalent vaccination in high-risk infants, including premature newborns. Data from the 14 studies included in the review showed that the immunogenicity and the safety profile of penta- and hexavalent vaccines in preterm infants was generally similar to those seen in full-term infants, with the exception of an increase in cardiorespiratory adverse events such as apnea, bradycardia and desaturation following vaccination in preterm infants. Despite recommendations of vaccinating preterm infants according to their actual age, and the relatively high completion rate of the primary immunization schedule, vaccination was often delayed, increasing the vulnerability of this high-risk population to vaccine-preventable diseases.

Vaccination in preterm and low birth weight infants in India

In India, the high neonatal and infant mortality rate is due in part to an increasing number of preterm and low birth weight (LBW) infants. Given the immaturity of immune system, these infants are at an increased risk of hospitalization and mortality from vaccine-preventable diseases (VPDs). In this narrative review, we screened the scientific literature for data on the risk of VPDs, vaccination delay and factors related to it in Indian preterm and LBW infants. Although routine childhood vaccinations are recommended regardless of gestational age or birth weight, vaccination is often delayed. It exposes these infants to a higher risk of infections, their associated complications, and death. After-birth complications, lack of awareness of recommendations, vaccine efficacy and effectiveness and concerns related to safety are some of the common barriers to vaccination. Awareness campaigns might help substantiate the need for (and value of) vaccination in preterm and LBW infants.

What is the context?

In India, the high neonatal mortality rate is due in part to an increasing number of pretern and low birth weight intants.

Affected infants have a poorly developed inmune system and are more susceptible to contracting vaccine-preventable diseases.

The Indian Academy of Pediatrics recommends vaccination according to the same schedule used for full term infants, following chronological (not gestational) age.

Delays in vaccinations increase the risk of preventable infections.

What is new?

Our review of the scientific literature shows that, in India:

infections have more serious conseuences in preterm and low birth weight infants

delays to vaccinate affected infants are common, mostly due to safety and effectiveness concerns from parents and healthcare pracitionrs.

What is the impact?

Improving mternal nutritional status and immunization, and perinatal care could help reduce the number of preterm and low birth weight infants.

Combining maternal immunization with vaccination of affected infants can confer safe and effective protection.

Awareness campaigns for parents and healthcare practitioners could address the issue of vaccination delay in pretern and low birth weight infants in India.

Vaccination recommendations, immunization status and safety of vaccination for premature infants in Zhejiang, China

OBJECTIVES

More and more premature infants were born worldwide that are suffering from various complications, vaccination for whom is often delayed in China. We aim to describe current vaccination recommendations in practice, immunization status, and vaccination safety for premature infants in Zhejiang.

METHODS

The demographic information, medical records of treatments, and adverse events following immunization (AEFI) history were collected from infants' parents by questionnaire in the Vaccination Consultation Clinic(VCC). Vaccination data were retrieved from Zhejiang Provincial Immunization Information System. The information of AEFI was collected from the Chinese National Adverse Event Following Immunization Information System.

RESULTS

A total of 1515 premature infants visiting the VCC were included in the study. The majority (65.94%) of them were under 7 months. 47.59% of premature infants were advised to receive normal vaccinations, while 45.94% were advised to defer a specific vaccination and 6.47% were advised to defer all vaccinations. A total of 807 infants received 7187 vaccine doses were administered and only seven cases experienced mild and self-limiting adverse reactions (9.74/10,000). No uncommon or serious side effects were reported.

CONCLUSION

Most premature infants visiting the VCC did not receive vaccines on time. The majority of them can be safely vaccinated according to the national-recommended schedule.

Vaccinations in Infants Born Preterm: An Update

Infants born prematurely (before completion of 37 weeks of gestation) are at increased risk of morbidity and mortality due to vaccine preventable diseases, mostly because of their immunological immaturity and failure of transfer of maternal protective antibodies. Despite their great need of being vaccinated, concerns on vaccine safety and efficacy, constitute the main reasons for which vaccinations are often delayed in this group. In this review we summarize the latest evidence on vaccine safety, efficacy and immunogenicity in preterm infants which is similar to full-term infants. Therefore there is no reason for delaying vaccination in this population.

Common Queries About Immunizations in Preterm Infants

Preterm infants are at an increased risk of morbidity and mortality from vaccine-preventable diseases. Despite this, delays in routine immunization of preterm infants are common. Available guidelines clearly state that they should be immunized according to chronological age, irrespective of gestational age and birth weight or current weight. In this article, we try to assuage parental and provider doubts by reviewing data about immunogenicity, safety, and responses to routine immunizations in preterm infants with and without comorbidities. We also look at evidence for other strategies to help protect this fragile population. [Pediatr Ann. 2018;47(4):e147-e153.].

Risk of Pertussis in Relation to Degree of Prematurity in Children Less Than 2 Years of Age

BACKGROUND

A few previous studies reported increased risk of pertussis in children with birth weight less than 2500 g. The risk of pertussis by degree of prematurity has not been determined in a cohort study. The vaccine effectiveness (VE) against reported pertussis in preterm infants is unknown.

METHODS

Data were obtained from the Medical Birth Registry of Norway (1998-2010) and linked to other national registries. In total, 713,166 children were included in our study and followed until 2 years of age. Incidence rate ratios (IRRs) and confidence intervals (CIs) were estimated with Poisson regression.

RESULTS

We identified 999 reported cases of pertussis. We observed a higher rate of reported pertussis in preterm than in full-term infants, IRR = 1.65 (95% CI: 1.32-2.07). Compared to full-term infants, the risk of reported pertussis in infants born at gestational age (GA) 35-36, 32-34 and 23-27 weeks were higher [IRRs = 1.49 (95% CI: 1.11-2.01), 1.63 (95% CI: 1.06-2.51) and 4.49 (95% CI: 2.33-8.67), respectively]. Moreover, preterm infants had a higher rate of pertussis-related hospitalization than full-term infants [IRR = 1.99 (95% CI: 1.47-2.71)]. The VE against reported pertussis for the third dose was 88.8% (95% CI: 84.3-92.0) in full-term infants and 93.0% (95% CI: 85.8-96.5) in preterm infants.

CONCLUSIONS

In this cohort study, preterm infants including those born at GA 35 and 36 weeks had increased risk of reported pertussis. The VE was similar in preterm and full-term infants.

Immunization of preterm infants

Vaccinations of premature infants are often delayed despite being at an increased risk of contracting vaccine preventable diseases. This article reviews the current knowledge on the immune response to widely used vaccines, on the protection derived from routine immunization and on vaccine safety and tolerability in a population of preterm infants. Available data evaluating the immune response of preterm infants support early immunization without correction for gestational age. For a number of antigens, the antibody response to initial doses of vaccines may be lower than that of term infants, but protective concentrations are often achieved and memory successfully induced. Vaccines are immunogenic, safe and well tolerated in preterm infants. Preterm infants should be vaccinated using the same schedules as those usually recommended for full-term infants, with the exception of the hepatitis B vaccine, where additional doses should be administered in infants receiving the first dose during the first days of life if they weighed less than 2000 g because of a documented reduced immune response.

Vaccine schedule compliance among very low birth weight infants in Lima, Peru

OBJECTIVE

There is little information about vaccine schedule compliance in very-low-birth-weight infants in developing countries. The aim of the study was to describe the compliance with the vaccine schedule among this population in Lima, Peru.

PATIENTS AND METHODS

We conducted a prospective cohort study in four hospitals in Lima in infants with a birth-weight of less than 1500 g, followed from birth up to 12 months of age every 2 weeks. The date and age at administration of each vaccine was recorded

RESULTS

222 infants were enrolled. The median birth-weight was 1250 g (range 550-1499 g) and the median gestational age was 30.0 weeks (range 23-37 weeks). The mean age for the first pentavalent (DPT, Hib, HepB) and oral polio vaccine administration was 4.3 ± 1.4 months in infants with a birth-weight of < 1000 g vs. 3.1 ± 1.0 in infants with a birth-weight 1000-1500 g (p < 0.001); 4.1 ± 0.9 vs. 3.3 ± 1.1 for rotavirus (p < 0.05); and 5.1 ± 2.1 vs. 4.3 ± 1.8 for the 7-valent pneumococcal conjugated vaccine. Only 35% had received the three doses of oral polio and pentavalent vaccine by seven months, although by nine months 81% had received these vaccines.

CONCLUSIONS

Vaccination of very-low-birth-weight infants in Peru is significantly delayed, especially in infants with a birth-weight of < 1000 g and lower gestational age. Urgent educational interventions targeting physicians and nurses should be implemented in order to improve vaccination rates and timing in these high risk populations.

Fully liquid DTaP-IPV-Hib pediatric combination vaccine (Pediacel): a review of 18 years of clinical experience

Safe and effective combination pediatric vaccines are necessary to simplify complex immunization schedules and to improve coverage and protection for children worldwide. We provide an overview of the 18 years of clinical and worldwide experience with DTaP-IPV-Hib (Pediacel(®)), a unique fully liquid pentavalent vaccine (diphtheria [D], tetanus [T], acellular pertussis, inactivated poliovirus [IPV], Haemophilus influenzae type b [Hib]). Pediacel has demonstrated good and lasting immunogenicity in many populations, with differing primary series and booster schedules, and with a variety of coadministered vaccines. The acellular pertussis antigens have proven efficacy and real-world effectiveness. Clinical and post-marketing studies confirm the safety of Pediacel. Pediacel can be used for primary series and toddler booster doses, as well as in mixed pediatric vaccine schedules.

Randomized, controlled, multicenter study of the immunogenicity and safety of a fully liquid combination diphtheria-tetanus toxoid-five-component acellular pertussis (DTaP5), inactivated poliovirus (IPV), and haemophilus influenzae type b (Hib) vaccine compared with a DTaP3-IPV/Hib vaccine administered at 3, 5, and 12 months of age

This study compared the levels of immunogenicity and safety of diphtheria-tetanus toxoid-five-component acellular pertussis (DTaP(5)), inactivated poliovirus (IPV), and Haemophilus influenzae type b (Hib) (DTaP(5)-IPV-Hib) and DTaP(3)-IPV/Hib vaccines for study participants 3, 5, and 12 months of age. Post-dose 3 noninferiority criteria comparing DTaP(5)-IPV-Hib to DTaP(3)-IPV/Hib using rates of seroprotection were demonstrated against diphtheria, tetanus, and polio types 1 to 3, but not for polyribosylribitol phosphate (PRP). While PRP did not meet noninferiority criteria, the seroprotection rate and geometric mean concentration (GMC) were high, indicating a clinically robust immune response. GMCs or titers for other antigens (including pertussis) and the safety profiles were generally similar between groups. Fully liquid DTaP(5)-IPV-Hib can be administered using the 3-, 5-, and 12-month vaccination schedule. (This study has been registered at ClinicalTrials.gov under registration no. NCT00287092.).

Persistence at one year of age of antigen-induced cellular immune responses in preterm infants vaccinated against whooping cough: comparison of three different vaccines and effect of a booster dose

Due to their high risk of developing severe Bordetella pertussis (Bp) infections, it is recommended to immunize preterm infants at their chronological age. However, little is known about the persistence of their specific immune responses, especially of the cellular responses recognized to play a role in protection. We compared here the cellular immune responses to two major antigens of Bp between three groups of one year-old children born prematurely, who received for their primary vaccination respectively the whole cell vaccine Tetracoq(®) (TC), the acellular vaccine Tetravac(®) (TV), or the acellular vaccine Infanrix-hexa(®) (IR). Whereas most children had still detectable IFN-γ responses at one year of age, they were lower in the IR-vaccinated children compared to the two other groups. In contrast, both the TV- and the IR-vaccinated children displayed higher Th2-type immune responses, resulting in higher antigen-specific IFN-γ/IL-5 ratios in TC- than in TV- or IR-vaccinated children. The IFN-γ/IL-5 ratio of mitogen-induced cytokines was also lower in IR- compared to TC- or TV-vaccinated children. No major differences in the immune responses were noted after the booster compared to the pre-booster responses for each vaccine. The IR-vaccinated children had a persistently low specific Th1-type immune response associated with high specific Th2-type immune responses, resulting in lower antigen-specific IFN-γ/IL-5 ratios compared to the two other groups. We conclude that antigen-specific cellular immune responses persisted in one year-old children born prematurely and vaccinated during infancy at their chronological age, that a booster dose did not significantly boost the cellular immune responses, and that the Th1/Th2 balance of the immune responses is modulated by the different vaccines.

Combined Haemophilus Influenzae type B-Neisseria meningitidis serogroup C vaccine is immunogenic and well tolerated in preterm infants when coadministered with other routinely recommended vaccines

BACKGROUND

Preterm infants are at greater risk of morbidity from vaccine-preventable diseases. Therefore, their responses to vaccination are of particular interest.

METHODS

In this open, controlled, Spanish multicenter study, we assessed immunogenicity and safety following primary vaccination of 163 preterm infants (n = 56, <31 weeks' gestation; n = 107, 31-36 weeks' gestation) and 150 full-term infants (>36 weeks' gestation), with Haemophilus Influenzae type B (Hib)-MenC-TT, DTaP(diphtheria-tetanus-acellular pertussis vaccine)-HepB-IPV, and PCV7 at 2 to 4-6 months of age followed by booster vaccination at 16 to 18 months of age. Serum bactericidal activity (rabbit complement) against MenC, and antibodies to Hib and hepatitis b (anti-HBs) were determined. Local/general symptoms were assessed after each vaccination via diary cards. Serious adverse events were recorded throughout the study.

RESULTS

There were no statistically significant differences between preterm and full-term infants in either Hib or MenC seroprotection rates or geometric mean concentrations at 1 month postdose 3, before or 1 month postbooster. Postdose 3, >99% of participants had seroprotective anti-HBs antibody concentrations. Anti-HBs geometric mean concentrations was significantly lower in the <31-week group compared with other groups and this difference persisted until 16 to 18 months of age. Hib-MenC-TT vaccine was well tolerated at all ages. There was one death caused by meningococcal serogroup-B sepsis (full term). No serious adverse events were assessed by the investigator as being vaccine related.

CONCLUSIONS

Hib-MenC-TT vaccine had a similar immunogenicity and safety profile in preterm and full-term infants. These results demonstrate that preterm infants can be safely vaccinated with Hib-MenC-TT at the recommended chronologic age without impacting the responses to the Hib and MenC antigens.

Immunogenicity and safety of fully liquid DTaP₅-IPV-Hib compared with DTaP₃-IPV/Hib when both coadministered with a heptavalent pneumococcal conjugate vaccine (PCV7) at 2, 3, 4, and 12 to 18 months of age: a phase III, single-blind, randomised, controlled, multicentre study

This study compared immunogenicity and safety of DTaP(5)-IPV-Hib to DTaP(3)-IPV/Hib coadministered with PCV7 at 2, 3, and 4 months (primary series) and a fourth-dose booster at 12-18 months of age. Seroprotection rates for DTaP(5)-IPV-Hib were high (noninferior to DTaP(3)-IPV/Hib for the primary series) for antigens common to both vaccines and PCV7 antigens. Geometric mean concentration (GMC) for Hib antibodies were higher in the DTaP(5)-IPV-Hib group than the DTaP(3)-IPV/Hib group after the primary series and booster dose; GMCs or titers for other antigens were generally similar between groups after the primary series and booster dose. Safety profiles were similar between groups.

Cellular immune responses of preterm infants after vaccination with whole-cell or acellular pertussis vaccines

Based on studies reporting specific antibody titers, it is recommended to vaccinate preterm infants against Bordetella pertussis according to their chronological age. However, as specific T-cell responses also are involved in the protection against B. pertussis, we have determined whether highly preterm infants (<31 weeks) are able to mount these immune responses during vaccination. Forty-eight premature infants were vaccinated at 2, 3, and 4 months of their chronological age with an acellular (Pa; n = 24) or a whole-cell (Pw; n = 24) tetravalent diphtheria-tetanus-pertussis-polio vaccine, and blood samples were collected at 2, 3, and 6 months of age. Most of the Pa- and Pw-vaccinated infants developed at 3 or 6 months of age a gamma interferon (IFN-gamma) response to the B. pertussis antigens, accompanied by an interleukin-5 (IL-5) and IL-13 secretion for the Pa-vaccinated infants. No association was found between a very low infant birth weight, the occurrence of severe infections, and corticosteroid treatment or the administration of gammaglobulins with a low level of antigen-induced IFN-gamma secretion. We conclude that like full-term infants, most preterm infants are able to mount a specific cellular immune response to the administration of the first doses of an acellular or a whole-cell pertussis vaccine.

Active immunization of premature and low birth-weight infants: a review of immunogenicity, efficacy, and tolerability

Preterm infants are at increased risk of disease and hospitalization from a number of vaccine-preventable diseases. However, these same infants have immunologic immaturities that may impact vaccine responses. Larger premature infants mount immune responses to vaccines similar to those of full-term infants, but very premature infants (<28-32 weeks' gestation at birth) may have specific defects in vaccine responsiveness. Although there are minor differences in immunogenicity, the immune responses to diphtheria, tetanus, pertussis, and polio antigens are similar enough between full-term and premature infants that clinical consequences are unlikely to result. However, the immunogenicity of Haemophilus influenzae type b conjugate vaccines varies widely among studies of premature infants, and may be affected by the choice of conjugate protein, inclusion in a combination vaccine, and by an infant's overall health. Pneumococcal conjugate vaccine is efficacious in larger premature infants, but little information is available about immunogenicity in smaller premature infants. Meningococcal group C conjugate vaccine appears immunogenic in even very premature infants, but the duration of immunity may be limited. Hepatitis B vaccine given at birth appears poorly immunogenic in infants with birth weights <1500-2000 g, with delay in the administration of the first dose yielding improved immunogenicity. Few data on influenza vaccine in premature infants are available, but infants with pulmonary disease may respond less robustly than others. Bacille Calmette Guérin vaccine appears to be most immunogenic if delayed until at least 34-35 weeks' postmenstrual age in very premature infants, although there may be non-specific advantages to its earlier administration. Premature infants may have persistently lower antibody titers than full-term infants, even years after initial immunization. Sick premature infants experience increased episodes of apnea or cardiorespiratory compromise following vaccine administration, necessitating careful monitoring. Specific factors that impair immune response, quality of the immune response, and safety and immunogenicity evaluation of new vaccines in premature infants are topics needing further research. Premature infants are at significant risk for decisions from healthcare providers that delay beginning and completing their vaccine regimens. A major challenge facing those who care for these infants is the provision of timely immunization.

Immunogenicity, safety and tolerability of meningococcal C CRM197 conjugate vaccine administered 3, 5 and 11 months post-natally to pre- and full-term infants

A total of 79 pre-term infants with a gestational age > or =32 weeks and 74 full-term infants were studied in order to evaluate the immunogenicity, safety and tolerability of meningococcal C (MenC)-CRM(197) conjugate vaccine administered 3, 5 and 11 months post-natally. The evoked immune response seemed to be substantially similar in the pre- and full-term infants, and there were only clinically marginal differences in safety and tolerability between the groups. The results support the use of two doses of MenC-CRM(197) vaccine at 3 and 5 months of age for primary immunisation, with a booster dose being given at about 1 year. In addition to reducing costs, this scheme seems to assure global immunogenicity and potential efficacy that is better than that offered by the accelerated scheme of administration with only three doses of vaccine in the first months of life, and similar to that observed with a fourth dose used as booster after the first year.

Immunisation of premature infants

Premature infants are at increased risk of vaccine preventable infections, but audits have shown that their vaccinations are often delayed. Early protection is desirable. While the evidence base for immunisation of preterm infants is limited, the available data support early immunisation without correction for gestational age. For a number of antigens the antibody response to initial doses may be lower than that of term infants, but protective concentrations are often achieved and memory successfully induced. A 2-3-4 month schedule may be preferable for immunisation of preterm infants in order to achieve protection as early as possible, but an additional dose may be required to achieve persistence of protection. This update focuses on the use of routine childhood vaccines in premature infants.