Safety and immunogenicity of pneumococcal conjugate vaccines in preterm infants

Safety and Immunogenicity of V114 in Preterm Infants: A Pooled Analysis of Four Phase Three Studies

BACKGROUND

Risk of invasive pneumococcal disease is 3-fold higher in preterm versus full-term infants. V114 is a 15-valent pneumococcal conjugate vaccine (PCV) containing the 13 serotypes in PCV13 plus 2 unique serotypes, 22F and 33F. A pooled subgroup analysis was performed in preterm infants (<37 weeks gestational age) enrolled in 4 pediatric phase 3 studies evaluating the safety and immunogenicity of different 4-dose regimens of V114 or PCV13.

METHODS

Healthy preterm infants were randomized 1:1 to receive V114/PCV13 in the 4 studies. Safety was evaluated as the proportion of participants with adverse events (AEs) following receipt of PCV. Serotype-specific antipneumococcal immunoglobulin G (IgG) geometric mean concentrations, IgG response rates and opsonophagocytic activity geometric mean titers were measured at 30 days postdose 3, pretoddler dose and 30 days postdose 4.

RESULTS

V114 and PCV13 were administered to 174 and 180 participants, respectively. Mean gestational age was 35.4 weeks (range: 27 - <37 weeks). Proportions of participants with AEs were comparable between vaccination groups; most AEs experienced were of short duration (≤3 days) and mild-to-moderate intensity. V114-elicited IgG geometric mean concentrations, IgG response rates and opsonophagocytic activity geometric mean titers were generally comparable to PCV13 for the 13 shared serotypes and higher for serotypes 22F and 33F at 30 days postdose 3 and postdose 4.

CONCLUSIONS

In preterm infants, V114 was well tolerated and induced comparable immune responses to PCV13 for the 13 shared serotypes and higher immune responses to serotypes 22F and 33F. Results support the use of V114 in preterm infants.

Safety of Vaccination within First Year of Life-The Experience of One General Medicine Center

Vaccines represent an important preventive strategy in paediatric populations, but the rate of vaccination has been constantly declining in the last decade. Concerns about vaccines' safety represent one of the main causes of vaccine hesitancy among parents. The aim of this study was the analysis of the immediate adverse reactions induced by vaccines included in the national program of immunization for the first year of life. Method: Eighty-one children born between 1st of January 2018 and 31st of March 2019 were included. The vaccination refusal rate, and incidence and severity of adverse effects induced by three mandatory vaccines (Hexavalent, Prevenar 13 and MMR) were analyzed. The level of parents' education and the sources of information that were consulted in order to understand the adverse effects were also analyzed. Results and conclusions: The rate of adverse events was lower than 30% of the total number of doses, and most of them were mild. The incidence and severity of vaccine-induced adverse effects were correlated with prematurity. The vaccine hesitancy rate was lower than the national one, possibly due to a high level of education and good information provided by doctors that might have led to parents' concerns regarding vaccination being answered.

Success of Current COVID-19 Vaccine Strategies vs. the Epitope Topology of SARS-CoV-2 Spike Protein-Receptor Binding Domain (RBD): A Computational Study of RBD Topology to Guide Future Vaccine Design

Coronavirus disease-2019 (COVID-19) is a pandemic with a high morbidity rate occurring over recent years. COVID-19 is caused by the severe acute respiratory syndrome causing coronavirus type-2 (SARS-CoV-2). COVID-19 not only challenged mankind but also gave scope to the evolution of various vaccine design technologies. Although these vaccines protected and saved many lives, with the emerging viral strains, some of the strains may pose a threat to the currently existing vaccine design that is primarily based on the wild type spike protein of SARS-CoV-2. To evaluate the risk involved from such mutant viral strains, we performed a systematic in silico amino acid substitution of critical residues in the receptor binding domain (RBD) of the spike protein. Our molecular modeling analysis revealed significant topological changes in the RBD of spike protein suggesting that they could potentially contribute to the loss of antigen specificity for the currently existing therapeutic antibodies/vaccines, thus posing a challenge to the current vaccine strategies that are based on wild type viral spike protein epitopes. The structural deviations discussed in this article should be considered carefully in the future vaccine design.

Vaccines

The safety of COVID-19 vaccines, as was the case last year, remains a large part of the focus in this volume. COVID-19 placed a large magnifying glass on both vaccines, specifically vaccine safety. This was most readily apparent as the number of records in VAERS ballooned to about 10 times the size from 2020 to 2021 (Vaccine Adverse Event Reporting System (VAERS), 2022) [S]. While we have added and/or improved VAERS during COVID-19, including adding or improving other vaccine safety surveillance tools like v-safe and vaccine safety datalink (Blumenthal, Phadke, et al., 2021) [MC], there is still room for improvement in these pharmacovigilance tools (Rizk et al., 2021) [r]. A major global initiative in this realm is the Global Vaccines Safety Blueprint 2.0 (GVSB2.0) (Organization, 2021, pp. 2021–2023) [S]. We wholeheartedly endorse these initiatives, which could significantly improve vaccine safety.

As noted in past SEDA issues, clinicians should be mindful of the risks of AEs and SAEs associated with each individual vaccine.

Vaccines

In this volume of the Side Effects of Drugs Annual, although other vaccines will be covered, the safety of COVID vaccines is the focus as COVID-19 has led to heightened attention on vaccine safety in general. As such, this chapter will be more relevant than ever before. As noted in past SEDA issues, clinicians should be mindful of the risks of AEs and SAEs associated with each vaccine.

Maternal Immunization: Nature Meets Nurture

Vaccinating women in pregnancy (i.e., maternal immunization) has emerged as a promising tool to tackle infant morbidity and mortality worldwide. This approach nurtures a 'gift of nature,' whereby antibody is transferred from mother to fetus transplacentally during pregnancy, or postnatally in breast milk, thereby providing passive, antigen-specific protection against infections in the first few months of life, a period of increased immune vulnerability for the infant. In this review, we briefly summarize the rationale for maternal immunization programs and the landscape of vaccines currently in use or in the pipeline. We then direct the focus to the underlying biological phenomena, including the main mechanisms by which maternally derived antibody is transferred efficiently to the infant, at the placental interface or in breast milk; important research models and methodological approaches to interrogate these processes, particularly in the context of recent advances in systems vaccinology; the potential biological and clinical impact of high maternal antibody titres on neonatal ontogeny and subsequent infant vaccine responses; and key vaccine- and host-related factors influencing the maternal-infant dyad across different environments. Finally, we outline important gaps in knowledge and suggest future avenues of research on this topic, proposing potential strategies to ensure optimal testing, delivery and implementation of maternal vaccination programs worldwide.