Recurrence of cardiorespiratory events following repeat DTaP-based combined immunization in very low birth weight premature infants

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.

A Improving Birth-dose Hepatitis-B Vaccination in a Tertiary Level IV Neonatal Intensive Care Unit

Background

Perinatal hepatitis B is a global public health concern. To reduce perinatal hepatitis B and its complications, the Hepatitis B vaccine (HBV) is recommended by the New York State Department of Health and Advisory Committee on Immunization Practices within 24 hours of life for infants born with a birth weight ≥2000 g. Infants admitted to the neonatal intensive care unit (NICU) weighing over 2000 g missed their birth dose HBV frequently, which prompted the implementation of a quality improvement initiative to increase birth dose HBV immunization in a level IV NICU in New York.

Methods

May 2019 to April 2021 baseline data showed the birth dose HBV rate of infants born ≥2000 g at 24% and 31% within 12 and 24 hours, respectively. The multidisciplinary QI team identified barriers using an Ishikawa cause-and-effect diagram. Our interventions included multidisciplinary collaboration, electronic medical record reminders, education, posters, and improved communication between staff and parents. We aimed to achieve a 25% improvement from the baseline.

Results

After 19 months of QI interventions (four Plan-Do-Study-Act cycles), the rate of administering birth dose HBV within 12 hours of life increased from 24% to 56% and within 24 hours from 31% to 64%. Process measure compliance improved, exceeding the 25% target, and showed sustained improvement.

Conclusion

This QI initiative improved the rate of eligible infants receiving HBV within the first 24 hours of life in the NICU. This work can serve as a model for other healthcare institutions to improve HBV immunization rates in NICUs.

Cardiorespiratory Events Following the Second Routine Immunization in Preterm Infants: Risk Assessment and Monitoring Recommendations

Due to frequent cardiorespiratory events (CREs) in response to the first routine immunization (rIM), current guidelines recommend readmitting and monitoring extremely preterm infants after the second rIM, though evidence on CREs in response to the second rIM is weak. In a prospective observational study, preterm infants with an increase in CREs after the first rIM were monitored for CREs before and after the second rIM. Seventy-one infants with a median gestational age of 26.4 weeks and a median weight of 820 g at birth were investigated at a median postnatal age of 94 days. All but seven infants showed an increase in CREs after the second rIM. The frequency of hypoxemias (p < 0.0001), apneas (p = 0.0003) and cardiorespiratory events requiring tactile stimulation (CRE-ts) (p = 0.0034) increased significantly. The 25 infants (35%) presenting with CRE-ts were significantly more likely to have been continuously hospitalized since birth (p = 0.001) and to receive analeptic therapy at the first rIM (p = 0.002) or some kind of respiratory support at the first (p = 0.005) and second rIM (p < 0.0001). At a postmenstruational age of 43.5 weeks, CRE-ts ceased. Our data support the recommendation to monitor infants who fulfil the above-mentioned criteria during the second rIM up to a postmenstruational age of 44 weeks.

Hexavalent vaccines in preterm infants: an update by Italian Society of Pediatric Allergy and Immunology jointly with the Italian Society of Neonatology

Hexavalent vaccines, protecting against six diseases (diphtheria, tetanus, pertussis [DTaP], poliovirus, hepatitis B virus [HBV], and Haemophilus influenzae type b [Hib], are routinely the standard of care in Europe. The use of combined vaccines allows the reduction of number of injections and side effects, the reduction of costs, and the increase in adherence of the family to the vaccination schedule both in terms of the number of doses and timing. The safety profile, efficacy and effectiveness of hexavalent vaccines have been extensively documented in infants and children born at term, and data are accumulating in preterm infants. Hexavalent vaccines are particularly important for preterm infants, who are at increased risk for severe forms of vaccine preventable diseases. However, immunization delay has been commonly reported in this age group. All the three hexavalent vaccines currently marketed in Italy can be used in preterm infants, and recent data confirm that hexavalent vaccines have a similar or lower incidence of adverse events in preterm compared to full-term infants; this is likely due to a weaker immune system response and reduced ability to induce an inflammatory response in preterm infants. Apnoea episodes are the adverse events that can occur in the most severe preterm infants and / or with history of respiratory distress. The risk of apnoea after vaccination seems to be related to a lower gestational age and a lower birth weight, supporting the hypothesis that it represents an unspecific response of the preterm infant to different procedures. High seroprotection rates have been reported in preterm infants vaccinated with hexavalent vaccine. However, a lower gestational age seems to be associated with lower antibody titres against some vaccine antigens (e.g. HBV, Hib, poliovirus serotype 1, and pertussis), regardless of the type of hexavalent vaccine used. Waiting for large effectiveness studies, hexavalent vaccines should be administered in preterm infants according to the same schedule recommended for infants born at term, considering their chronological age and providing an adequate monitoring for cardio-respiratory events in the 48–72 h after vaccination, especially for infants at risk of recurrence of apnoea.

Turkish Neonatal Society guideline for the follow-up of high-risk newborn infants

Developments in perinatal and neonatal care have increased the survival rate of high-risk newborns but led to a rise in chronic diseases seen in these infants. A significant number of them attend primary and secondary health care centers after discharge; however, there are very few standard protocols for the long-term follow-up of these babies. Therefore, we aimed to establish a follow-up guideline that emphasizes on universal screening schemes and takes into consideration national data. The guide presented here provides brief recommendations for physicians in light of evidence-based data for the follow-up of high-risk newborn infants. The steps taken to monitor and solve the problems of all high-risk infants may vary. We hope the use of such a standard approach in evaluating each infant in daily routine will improve the life quality of these high-risk infants.

Update on vaccination of preterm infants: a systematic review about safety and efficacy/effectiveness. Proposal for a position statement by Italian Society of Pediatric Allergology and Immunology jointly with the Italian Society of Neonatology

INTRODUCTION

Preterm infants (PIs) are at increased risk of vaccine-preventable diseases (VPDs). However, delayed vaccination start and low vaccine coverage are still reported. Areas covered: This systematic review includes 37 articles on preterm vaccination published in 2008-2018 in PubMed. Both live attenuated and inactivated vaccines are safe and well tolerated in PIs. Local reactions, apnea, and reactivity changes are the most frequently reported adverse events. Lower gestational age and birth weight, preimmunization apnea, longer use of continuous positive airway pressure (CPAP) are risk factors for apnea. The proportion of PIs who develop protective humoral and cellular immunity is generally similar to full terms although later gestational age is associated with increased antibody IgG concentrations (i.e. against certain pneumococcal serotypes, influenza, hepatitis B virus and poliovirus 1) and increased mononuclear cells proliferation (i.e. after inactivated poliovirus). Expert opinion: PIs can be safely and adequately protected by available vaccines with the same schedule used for full terms. Data at this regard have been retrieved by studies using a 3-dose primary series for pneumococcal and hexavalent vaccines. Further studies are needed regarding the 2 + 1 schedule. Apnea represents a nonspecific stress response in PIs, thus those hospitalized at 2 months should have cardio-respiratory monitoring after their first vaccination.

Randomized Controlled Trial on the Effects of Morning versus Evening Primary Vaccination on Episodes of Hypoxemia and Bradycardia in Very Preterm Infants

BACKGROUND

Hypoxemia and bradycardia occur frequently in preterm infants, but are incompletely understood. They are more prevalent during infections and following immunization. Data on adults suggested an increased immune response if subjects slept following vaccination, suggesting an interaction between circadian rhythm and the immune system. Whether this holds true for preterm infants with their less well-established circadian rhythm is unclear.

OBJECTIVE

Do infants born at 26-30 weeks' gestation and having received their first routine hexavalent vaccination in the morning have a lower cardiorespiratory event rate (CER) after vaccination than those receiving it in the evening?

METHODS

Twenty-six infants were randomized to an evening versus morning vaccination group in a pilot and main study with 10 and 16 participants, respectively. Pulse oximeter saturation, actigraphy, and rectal temperature were obtained for 24 h before and after vaccination. Blood samples for vaccination titers were taken before vaccination and during a follow-up examination in our outpatient clinic; another blood sample was taken 24 h after vaccination to determine inflammatory markers.

RESULTS

Vaccination led to an increase in CER in both groups, but there was no difference in CER between the morning and evening groups. Vaccination titers for Bordetella pertussis were increased in both groups, with no difference in inflammatory markers 24 h after vaccination. Body temperature increased in both groups after vaccination. Participants in the evening group slept longer after vaccination.

CONCLUSIONS

We did not identify a difference in CER between morning and evening vaccination but could confirm increased body temperatures and vaccination titers following vaccination.

Clinical and experimental aspects of breathing modulation by inflammation

Neuroinflammation is produced by local or systemic alterations and mediated mainly by glia, affecting the activity of various neural circuits including those involved in breathing rhythm generation and control. Several pathological conditions, such as sudden infant death syndrome, obstructive sleep apnea and asthma exert an inflammatory influence on breathing-related circuits. Consequently breathing (both resting and ventilatory responses to physiological challenges), is affected; e.g., responses to hypoxia and hypercapnia are compromised. Moreover, inflammation can induce long-lasting changes in breathing and affect adaptive plasticity; e.g., hypoxic acclimatization or long-term facilitation. Mediators of the influences of inflammation on breathing are most likely proinflammatory molecules such as cytokines and prostaglandins. The focus of this review is to summarize the available information concerning the modulation of the breathing function by inflammation and the cellular and molecular aspects of this process. I will consider: 1) some clinical and experimental conditions in which inflammation influences breathing; 2) the variety of experimental approaches used to understand this inflammatory modulation; 3) the likely cellular and molecular mechanisms.

Immunization of preterm infants with GSK's hexavalent combined diphtheria-tetanus-acellular pertussis-hepatitis B-inactivated poliovirus-Haemophilus influenzae type b conjugate vaccine: A review of safety and immunogenicity

BACKGROUND

Infants with history of prematurity (<37 weeks gestation) and low birth weight (LBW, <2500 g) are at high risk of infection due to functional immaturity of normal physical and immunological defense mechanisms. Despite current recommendations that infants with history of prematurity/LBW should receive routine immunization according to the same schedule and chronological age as full-term infants, immunization is often delayed.

METHODS

Here we summarize 10 clinical studies and 15 years of post-marketing safety surveillance of GSK's hexavalent vaccine (DTPa-HBV-IPV/Hib), a combined diphtheria-tetanus-acellular-pertussis-hepatitis-B-inactivated-poliovirus-Haemophilus influenzae-type-b (Hib) conjugate vaccine, when administered alone, or co-administered with pneumococcal conjugate, rotavirus, and meningococcal vaccines and respiratory syncytial virus IgG to infants with history of prematurity/LBW in clinical trials.

RESULTS

At least 92.5% of infants with history of prematurity/LBW as young as 24 weeks gestation in clinical studies were seropositive to all vaccine antigens after 3-dose primary vaccination with GSK's hexavalent DTPa-HBV-IPV/Hib vaccine, with robust immune responses to booster vaccination. Seropositivity rates and antibody concentrations to hepatitis B and Hib appeared lower in infants with history of prematurity/LBW than term infants. Between 13-30% of medically stable infants with history of prematurity developed apnea after vaccination with GSK's hexavalent DTPa-HBV-IPV/Hib vaccine; usually after dose 1. The occurrence of post-immunization cardiorespiratory events appears to be influenced by the severity of any underlying neonatal condition. Most cardiorespiratory events resolve spontaneously or require minimal intervention. GSK's hexavalent DTPa-HBV-IPV/Hib vaccine was well tolerated in co-administration regimens.

CONCLUSION

GSK's hexavalent DTPa-HBV-IPV/Hib vaccine alone or co-administered with other pediatric vaccines has a clinically acceptable safety and immunogenicity profile when used in infants with history of prematurity/LBW for primary and booster vaccination. Additional studies are needed in very premature and very LBW infants. However, currently available data support using GSK's hexavalent DTPa-HBV-IPV/Hib vaccine to immunize infants with history of prematurity/LBW according to chronological age.

Respiratory Decompensation and Immunization of Preterm Infants

BACKGROUND

Concern for respiratory decompensation after immunization in premature infants, particularly those with bronchopulmonary dysplasia (BPD), may lead to delayed and altered immunization schedules.

METHODS

A retrospective cohort of premature infants at <32 weeks' gestational age cared for in a tertiary level 4 NICU and immunized during their hospital stay were evaluated for respiratory decompensation within 72 hours of immunization. Respiratory measurements including change in respiratory support, mean fraction of inspired oxygen, and apnea, bradycardia, and desaturation events were compared between those infants with BPD and those without. The primary outcome was the difference in respiratory decompensation defined as a composite of increased respiratory support or increased fraction of inspired oxygen ≥10% within 72 hours of immunization.

RESULTS

Of 403 infants admitted to the NICU and immunized, 240 met the study criteria. Of those infants, 172 had a diagnosis of BPD. There was no difference in the primary outcome of respiratory decompensation after immunization between groups (P = .65). There was also no significant difference in apnea, bradycardia, and desaturation events between groups (P = .51).

CONCLUSIONS

In this cohort, respiratory decompensation requiring clinical intervention after immunization of preterm infants both with and without BPD was uncommon and not significantly different between groups. Consideration for immunization of this vulnerable population should not be delayed out of concern for clinical deterioration.

Adverse Events After Routine Immunization of Extremely Low-Birth-Weight Infants

IMPORTANCE

Immunization of extremely low-birth-weight (ELBW) infants in the neonatal intensive care unit (NICU) is associated with adverse events, including fever and apnea or bradycardia, in the immediate postimmunization period. These adverse events present a diagnostic dilemma for physicians, leading to the potential for immunization delay and sepsis evaluations.

OBJECTIVE

To compare the incidence of sepsis evaluations, need for increased respiratory support, intubation, seizures, and death among immunized ELBW infants in the 3 days before and after immunization.

DESIGN, SETTING, AND PARTICIPANTS

In this multicenter retrospective cohort study, we studied 13,926 ELBW infants born at 28 weeks' gestation or less who were discharged from January 1, 2007, through December 31, 2012, from 348 NICUs managed by the Pediatrix Medical Group.

EXPOSURES

At least one immunization between the ages of 53 and 110 days.

MAIN OUTCOMES AND MEASURES

Incidence of sepsis evaluations, need for increased respiratory support, intubation, seizures, and death.

RESULTS

Most of the 13,926 infants (91.2%) received 3 or more immunizations. The incidence of sepsis evaluations increased from 5.4 per 1000 patient-days in the preimmunization period to 19.3 per 1000 patient-days in the postimmunization period (adjusted rate ratio [ARR], 3.7; 95% CI, 3.2-4.4). The need for increased respiratory support increased from 6.6 per 1000 patient-days in the preimmunization period to 14.0 per 1000 patient-days in the postimmunization period (ARR, 2.1; 95% CI, 1.9-2.5), and intubation increased from 2.0 per 1000 patient-days to 3.6 per 1000 patient-days (ARR, 1.7; 95% CI, 1.3-2.2). The postimmunization incidence of adverse events was similar across immunization types, including combination vaccines when compared with single-dose vaccines. Infants who were born at 23 to 24 weeks' gestation had a higher risk of sepsis evaluation and intubation after immunization. A prior history of sepsis was associated with higher risk of sepsis evaluation after immunization.

CONCLUSIONS AND RELEVANCE

All ELBW infants in the NICU had an increased incidence of sepsis evaluations and increased respiratory support and intubation after routine immunization. Our findings provide no evidence to suggest that physicians should not use combination vaccines in ELBW infants. Further studies are needed to determine whether timing or spacing of immunization administrations confers risk for the developing adverse events and whether a prior history of sepsis confers risk for an altered immune response in ELBW infants.

Timeliness of routine immunization in a population-based Italian cohort of very preterm infants: results of the ACTION follow-up project

BACKGROUND

Although very preterm infants are recommended to receive immunizations, according to their chronological age, immunization start in these infants is often delayed. Aim To measure coverage and timeliness of routine immunizations in Italian very preterm infants and to assess determinants of delay.

METHODS

We followed up infants 22-31 completed weeks of gestational age discharged from intensive care. We measured the proportion of children with one dose of diphtheria-tetanus-pertussis-poliohepatitis, B-Hib vaccine (DTP-Pol-HBV-Hib), measles-mumps-rubella vaccine (MMR), conjugate pneumococcal vaccine (Pnc), conjugate meningococcal C vaccine (MenC), and varicella vaccine (Var) by 24 months. We used the Kaplan Meier method and Cox proportional hazard models to estimate the age, at immunization start and determinants of timeliness for each vaccine.

RESULTS

Data on 1102 (92.1%) children out of 1196 included in the cohort were analyzed. Immunization start by 24 months of age occurred in 95.9% of children for DTP-Pol-HBV-Hib; 84.0% for MMR; 49.7% for Pnc; 38.5% for MenC; and 4.1% for Var. Eighty-seven percent of participants received the first dose of DTP-Pol-HBV-Hib by 6 months of age, and 66.7% had their first MMR administered by 18 months. Hospitalization was associated with delay for all vaccines with the exception of MenC and Var. Maternal employment was associated with earlier immunization for MMR, Pnc, and MenC. DTP-Pol-HBV-Hib timeliness improved with increasing birthweight and paternal employment and decreased with a larger number of siblings in the household. MMR was delayed in children with cerebral palsy, and in those with a larger number of children in the household. Immunization for Pnc was delayed in children with larger number of siblings.

CONCLUSIONS

Immunization start for all vaccines was considerably delayed in many very preterm infants. Public health strategies taking into account determinants of delay should be implemented to improve coverage and timeliness of vaccination in this group of infants.

Possible predictors of cardiorespiratory events after immunization in preterm neonates

BACKGROUND

The influence of the first immunization on cardiorespiratory (CR) stability in very preterm infants is still a controversial subject.

OBJECTIVES

To describe the changes induced by immunization on heart and respiratory rate variability (HRV-RRV) and to test a potential association between preimmunization profiles and postimmunization CR events.

METHODS

Continuous 72-hour CR recordings and 2.5-hour polysomnographic recordings were performed on very preterm infants immunized after 7 weeks. The results are expressed as medians (interquartile ranges).

RESULTS

Immunization was performed on 31 very preterm infants [28 weeks' gestation (26.9-29), birth weight: 965 g (795-1,105)], and was associated with an increased incidence (p < 0.01) of events lasting more than 10 s: bradycardia <80 bpm [2.2 (1.1-7) vs. 1.8 (1-4)/12 h], desaturation [17.6 (9.4-36.4) vs. 13.9 (7.7-33.8)/12 h] and associated bradycardia-desaturation [IB+D, 4.1 (1.4-7.3) vs. 2.4 (1-4.6)/12 h], with mild changes in HRV and no change in RRV. The changes in IB+D frequency were correlated with preimmunization IB+D frequency (r = 0.44, p < 0.05), HRV spectral parameter low frequency/high frequency ratio (LF/HF, r = 0.55, p < 0.01) and approximate entropy of HRV (r = -0.39, p < 0.05).

CONCLUSION

The increase in CR events after the first immunization in very preterm infants was associated with: (1) sympathetic predominance in heart rate control (high LF/HF ratio), (2) abnormal oversimplification of HRV (low entropy) and (3) persistent respiratory rhythm control immaturity (high IB+D before vaccine).

Pentapeptide commonality between Corynebacterium diphtheriae toxin and the Homo sapiens proteome

Cross-reactivity may affect diagnostic tests and cause harmful autoimmune reactions following immunotherapy. To predict potential cross-reactivity and search for safe immunotherapeutic approaches, we analyzed sequence identity between microbial antigens and the human proteome. Using diphtheria toxin (DT) as a model, we examined its patterns of identity with human proteins at the pentapeptide level. DT shares 503 pentapeptides with the human proteome, while only 31 pentapeptides are unique to the toxin. DT pentapeptide identity involves multiple/repeated matches in human proteins (a total of 4966 occurrences). Human proteins containing bacterial peptide matches include antigens linked to fundamental cellular functions, such as cell cycle control, proliferation, development and differentiation. The data presented in this article offer a rational basis for designing peptide-based vaccines that specifically target DT and thus eliminate the potential risk of cross-reactivity with human proteins. More generally, this study proposes a methodological approach for avoiding cross-reactivity in immune reactions.

Vaccines and preterm neonates: why, when, and with what

This review analyses what is known concerning the immune response of preterm (PTIs) and low birth weight infants (LBWIs) to widely used vaccines, the protection they receive from routine immunisation, and the safety and tolerability of the vaccines themselves. It shows why PTIs and LBWIs should be vaccinated using the same schedules as those usually recommended for full-term infants (FTIs), except in the case of hepatitis B vaccine, whose schedule should be repeated in infants who received the first dose during the first days of life when they weighed less than 2000 g because of their reduced immune response. Vaccines are immunogenic, safe and well tolerated in PTIs and LBWIs, in whom early active immunisation is particularly important because they are among the most vulnerable subjects for pediatric infectious diseases. It is therefore essential to make every effort to convince pediatricians and parents that compliance with these recommendations will not cause any clinical problems.