Vaccinations in Infants Born Preterm: An Update

An update on vaccination in preterm infants

OBJECTIVE

The objective of this article is to review the most current literature on vaccines, focusing on their safety, immunogenicity, and efficacy in preterm newborns, aiming to improve vaccine coverage in this population.

DATA SOURCE

Most recent scientific publications addressing the immunization of preterm newborns.

DATA SYNTHESIS

Despite its immunological immaturity, vaccination is well tolerated by preterm infants, and protective immune responses are observed, but some studies have shown that preterm infants undergo unjustified delays in their vaccination schedule.

CONCLUSIONS

Despite being widely recommended, the routine immunization of preterm infants is often delayed, putting this vulnerable population at risk for several diseases, many of which are preventable by immunization. Every effort should be made to develop universal guidelines that define the immunization of preterm infants.

Timing of the First Dose of the Hepatitis B Vaccine in Preterm Infants

Introduction: The World Health Organization (WHO) recommends all newborn infants receive the first dose of the hepatitis B vaccine within 24 h of birth irrespective of maternal hepatitis B carrier status. However, the physiological immaturity of the immune system in preterm infants may influence the immune responses to the vaccine particularly in the first few days and weeks of life, and adverse events may occur following vaccination that are not observed in infants born at term. Objectives: To review existing published guidelines surrounding timing of the first dose of the hepatitis B vaccine in preterm infants born to hepatitis B surface antigen negative (HBsAg-negative) mothers. Methods: A search was performed for relevant papers and guidelines published between January 2002 and July 2022 on the Ovid MEDLINE and Embase databases and through targeted searches. Two authors independently reviewed the search results to identify relevant sources, which were then analysed and described through narrative synthesis. Results: Twenty-seven relevant papers and guidelines regarding 15 countries and regions were included. Of these, 13.3% of guidelines, which represented 16.8% of the overall population of 4.1 billion people covered by the identified guidelines, recommended a nationwide birth dose of the hepatitis B vaccine to all preterm infants. In 40.0% of guidelines (77.9% of the overall population), the birth dose was only recommended for infants with a birth weight of more than 2000–2200 g. Another 33.3% of countries and regions (covering 4.4% of the population) recommended no universal birth dose for all infants, including preterm infants, whilst 13.3% (1.0% of the population) had guidelines that varied between jurisdictions and hospitals within their country/region. Conclusions: Existing guidelines surrounding the timing of the first dose of the hepatitis B vaccine in preterm infants vary substantially between countries and regions. Further research comparing the immunogenicity and safety of different hepatitis B vaccine schedules is needed to provide concrete evidence to provide guidance regarding the timing of vaccination against hepatitis B in preterm infants.

Do Pediatricians and Nurses Recommend Vaccines for Preterm Infants? A Survey in Italy

OBJECTIVE

To assess the level of knowledge, attitudes, and behaviors regarding vaccination in preterm infants among primary care pediatricians (PCPs) and health care workers (HCWs) in neonatal intensive care units (NICUs).

STUDY DESIGN

Data were collected from PCPs through a confidential questionnaire distributed by email, whereas the research team distributed a self-administered anonymous questionnaire to all HCWs working in the selected NICUs.

RESULTS

Overall, 64.1% of HCWs consider vaccines in preterm infants to be very safe. The majority of HCWs (69.8%) stated that they always recommend that preterm infants' parents vaccinate their children following the same schedule as for term infants. This behavior was significantly more likely among those who know that the vaccination schedule for preterm infants is the same as for term infants, who consider vaccines in preterm infants very effective, and who strongly agree that preterm infants should be vaccinated on the same schedule as term infants. Moreover, PCPs were more likely than NICU pediatricians to always recommend that preterm infants' parents vaccinate their children following the immunization schedule of term infants, whereas this behavior was significantly less frequent among NICU nurses.

CONCLUSIONS

There is a need for physicians and nurses in the NICU and in the community to counteract missed or delayed immunizations. Engagement of HCWs in healthcare quality improvement initiatives focused on the promotion of timely vaccinations in preterm infants should be encouraged.

In-hospital and web-based intervention to counteract vaccine hesitancy in very preterm infants' families: a NICU experience

BACKGROUND

Vaccine hesitancy is a global problem, carrying significant health risks for extremely vulnerable population as that of preterm infants. Social media are emerging as significant tools for public health promotion. Our aim was to evaluate both the coverage and the timeliness of routine immunizations in a cohort of preterm infants (< 33 weeks of gestational age) at 24 months of age whose families have been subjected to in-hospital and web-based interventions to counteract vaccine hesitancy.

METHODS

For a period of 2 years parents of preterm infants were instructed during their follow up visits by a member of the NICU team to get correct informations about vaccines from a social network page. Vaccination rates of preterm infants were assessed at 24 months of chronological age with an electronic database and compared to both general population and historical cohort.

RESULTS

Coverage and timeliness of vaccinations at 24 months of age of 170 preterm infants were analyzed in December 2019. Gestational age and birth weight median (IQR) were, respectively, 31.0 (5.0) weeks and 1475.0 (843.8) g. Coverage rates were similar to those of the regional population (p > 0.05), while timeliness of administration was significantly delayed compared to the recommended schedule (p < 0.001). Age of administration was not correlated with either body weight and gestational age at birth (Spearman rank, p > 0.05). DTaP-IPV-HBV-Hib 2nd and 3rd doses, MMR and Varicella vaccines coverage data were higher compared to historical cohort (p < 0.05).

CONCLUSION

Increasing vaccine confidence through web-based interventions could have a positive impact on vaccination acceptance of parents of preterm infants, although timeliness results still delayed. There is a strong need to develop different and effective vaccination strategies to protect this very vulnerable population.

Secondary immunodeficiencies: An overview

OBJECTIVE

To review the different causes of secondary immunodeficiencies and provide clinicians with an updated overview of potential factors that contribute to immunodeficiency.

DATA SOURCES

Recent published literature obtained through PubMed database searches, including research articles, review articles, and case reports.

STUDY SELECTIONS

PubMed database searches were conducted using the following keywords: immunodeficiency, antibody deficiency, immunosuppressive drugs, genetic syndrome, malignancy, HIV infection, viral infection, secondary immunodeficiency, nutrition, prematurity, aging, protein-losing enteropathy, nephropathy, trauma, space travel, high altitude, and ultraviolet light. Studies published in the last decade and relevant to the pathogenesis, epidemiology, and clinical characteristics of secondary immunodeficiencies were selected and reviewed.

RESULTS

Researchers continue to investigate and report abnormal immune parameters in the different entities collectively known as secondary immunodeficiencies. Immunodeficiency might occur as a consequence of malnutrition, metabolic disorders, use of immunosuppressive medications, chronic infections, malignancies, severe injuries, and exposure to adverse environmental conditions. The neonate and the elderly may have decreased immune responses relative to healthy adults. Each of these conditions may present with different immune defects of variable severity. The acquired immunodeficiency syndrome results from infections by the human immunodeficiency virus, which targets CD4 T cells leading to defective immune responses. Rituximab is a monoclonal antibody that targets CD20 B cells, and its use might result in persistent hypogammaglobulinemia.

CONCLUSION

Clinicians should consider secondary immunodeficiencies in the differential diagnosis of a patient with recurrent infections and abnormal immunologic evaluation. The use of biological agents for the treatment of inflammatory conditions and malignancies is an increasingly important cause of secondary immunodeficiency.

The Fifth International Neonatal and Maternal Immunization Symposium (INMIS 2019): Securing Protection for the Next Generation

Despite significant progress in reaching some milestones of the United Nations Sustainable Development Goals, neonatal and early infant morbidity and mortality remain high, and maternal health remains suboptimal in many countries. Novel and improved preventative strategies with the potential to benefit pregnant women and their infants are needed, with maternal and neonatal immunization representing effective approaches. Experts from immunology, vaccinology, infectious diseases, clinicians, industry, public health, and vaccine-related social sciences convened at the 5th International Neonatal and Maternal Immunization Symposium (INMIS) in Vancouver, Canada, from 15 to 17 September 2019. We critically evaluated the lessons learned from recent clinical studies, presented cutting-edge scientific progress in maternal and neonatal immunology and vaccine development, and discussed maternal and neonatal immunization in the broader context of infectious disease epidemiology and public health. Focusing on practical aspects of research and implementation, we also discussed the safety, awareness, and perception of maternal immunization as an existing strategy to address the need to improve maternal and neonatal health worldwide. The symposium provided a comprehensive scientific and practical primer as well as an update for all those with an interest in maternal and neonatal infection, immunity, and vaccination. The summary presented here provides an update of the current status of progress in maternal and neonatal immunization.