Pediatric Vaccine Research Articles

Influence of the Olfatín Project on the reduction of pain related to intranasal influenza vaccination, as part of a school influenza vaccination program

PurposeTo evaluate the influence of viewing the Olfatín Project video on the assessment of school LAIV-associated pain in three and four-year-old children through the Wong Baker Faces® pain classification scale. Design and methodsA three-arm randomized multicenter clinical trial with a placebo control group was carried out. The main variable measured was pain, assessed through the score on the Wong Baker Faces® Pain Rating Scale. There were a total population of 4591 children three and four-year-olds (born in 2019 and 2020) and who attended the 1st and 2nd year of early childhood education. Before the school vaccination, researchers randomly assigned participant schools corresponding to each of the basic health areas to each of the three study groups: Olfatín's video viewing, a control video viewing not related to influenza and no video viewing. ResultsNo significant differences according to sex, age or the minor's grade according to the assigned intervention were detected. 72.3% of those vaccinated assigned a 0 from the Wong Baker Faces® scale: 75.4% of those who watched Olfatín's video, 68.3% for those in Drilo's group and 72.8% for those who didn't watch any video, but without significant differences (p = 0.08). There were no significant differences either stratifying by sex. ConclusionLAIV is a painless vaccine for children, which has to be taken into account by the health authorities when planning the pediatric influenza vaccination campaign. Practice implicationsOlfatín's cartoon video can be used by professionals to create a greater experience for children and therefore a better acceptance.

Estimating Influenza Illnesses Averted by Year-Round and Seasonal Campaign Vaccination for Young Children, Kenya.

In Kenya, influenza virus circulates year-round, raising questions about optimum strategies for vaccination. Given national interest in introducing influenza vaccination for young children 6-23 months of age, we modeled total influenza-associated illnesses (inclusive of hospitalizations, outpatient illnesses, and non‒medically attended illnesses) averted by multiple potential vaccination strategies: year-round versus seasonal-campaign vaccination, and vaccination starting in April (Southern Hemisphere influenza vaccine availability) versus October (Northern Hemisphere availability). We modeled average vaccine effectiveness of 50% and annual vaccination coverage of 60%. In the introduction year, year-round vaccination averted 6,410 total illnesses when introduced in October and 7,202 illnesses when introduced in April, whereas seasonal-campaign vaccination averted 10,236 (October) to 11,612 (April) illnesses. In the year after introduction, both strategies averted comparable numbers of illnesses (10,831-10,868 for year-round, 10,175-11,282 for campaign). Campaign-style vaccination would likely have a greater effect during initial pediatric influenza vaccine introduction in Kenya; however, either strategy could achieve similar longer-term effects.

A whole-cell pertussis vaccine engineered to elicit reduced reactogenicity protects baboons against pertussis challenge.

Whole-cell pertussis (wP) vaccines introduced in the 1940s led to a dramatic reduction of pertussis incidence and are still widely used in low- and middle-income countries (LMICs) worldwide. The reactogenicity of wP vaccines resulted in reduced public acceptance, which drove the development and introduction of acellular pertussis (aP) vaccines in high-income countries in the 1990s. Increased incidence of pertussis disease has been observed in high-income countries following the introduction of aP vaccines despite near universal rates of pediatric vaccination. These increases are attributed to the reduced protection against colonization, carriage, and transmission as well as reduced duration of immunity conferred by aP vaccines relative to the wP vaccines they replaced. A reduced reactogenicity whole-cell pertussis (RRwP) vaccine was recently developed with the goal of achieving the same protection as conferred by wP vaccination but with an improved safety profile, which may benefit countries in which wP vaccines are still in routine use. In this study, we tested the RRwP vaccine in a baboon model of pertussis infection. We found that the RRwP vaccine induced comparable cellular and humoral immune responses and comparable protection following challenge relative to the wP vaccine, while significantly reducing injection-site reactogenicity.IMPORTANCEThe World Health Organization (WHO) recommended in 2015 that countries administering wP vaccines in their national vaccine programs should continue to do so, and that switching to aP vaccines for primary infant immunization should only be considered if periodic booster vaccinations and/or maternal immunization could be assured and sustained in their national immunization schedules (WHO, Vaccine 34:1423-1425, 2016, https://doi.org/10.1016/j.vaccine.2015.10.136). Due to the considerably higher cost of aP vaccines and the larger number of doses required, most LMICs continue to use wP vaccines. The development and introduction of a wP vaccine that induces fewer adverse events without sacrificing protection would significantly benefit countries in which wP vaccines are still in routine use. The results of this study indicate this desirable goal may be achievable.

Vaccination against RSV infections - update and perspective

Almost 60 years after a disastrous clinical vaccine trial in children, which resulted in enhanced disease and even deaths, the world of RSV vaccination is currently undergoing a dramatic positive change and development, closely linked to advances in new vaccine technologies. Three licensed safe and highly efficacious vaccines, Abrysvo, Arexvy and mRESVIA, reduce the incidence of RSV lower respiratory disease by 80% in people older than 60 years of age. Questions regarding long-term protection and effectiveness in specific risk groups with chronic medical conditions remain, and furthermore, innovative and safe concepts to actively vaccinate pregnant women and infants to prevent severe RSV infections - also in these high-risk populations - are eagerly awaited.Passive vaccination with the long-acting monoclonal antibody Nirsevimab for prevention of severe disease in the first RSV season of infants is a major innovation in global health and the importance and benefits of reducing the number of intramuscular injections for high-risk children is immense. In the coming years, results of numerous pediatric candidate RSV vaccine studies are expected, although particular caution seems advisable for historical reasons. In summary, the field of RSV vaccination has been revolutionized in the last 2 years and we will see further significant progress soon.

Descriptive analysis of safety and immunogenicity profiles of a 15-valent pneumococcal conjugate vaccine between subcutaneous and intramuscular administration in a phase 1 study of healthy Japanese infants (V114-028)

IntroductionSubcutaneous (SC) administration is typically used for pediatric inactivated vaccines in Japan, whereas intramuscular (IM) administration is used outside Japan. We previously reported the safety and immunogenicity of V114, a 15-valent pneumococcal conjugate vaccine (PCV), administered subcutaneously and intramuscularly in a Japanese phase 1 study (V114-028). Here, we report secondary descriptive analyses on V114 groups of the study to further assess the safety and immunogenicity profiles of V114 between the administration routes. MethodsA total of 133 healthy Japanese infants were randomized to receive V114-SC (n = 44), V114-IM (n = 45), or PCV13-SC (n = 44) at approximately 3, 4, 5, and 12–15 months of age. Adverse events (AEs) from Days 1–14 post-vaccination and vaccine-related serious AEs from Day 1 to 1-month post-dose 4 were reported. Serotype-specific immunoglobulin G (IgG) responses were measured across the vaccination series. ResultsProportions of participants with solicited systemic AEs (irritability, somnolence, decreased appetite, and urticaria) and pyrexia were generally comparable between the groups. Compared with V114-SC, patients receiving V114-IM had a lower incidence of irritability and somnolence, and higher incidence of decreased appetite. Proportion of participants with solicited injection-site erythema was lower with V114-IM (82.2%) than V114-SC (100.0%). Those with other solicited injection-site AEs (induration, swelling, and pain) were generally comparable between the groups, with lower observed proportions with V114-IM. Serotype-specific IgG responses were also generally comparable between the groups, including at pre-toddler dose. ConclusionsThese results suggest the utility of IM administration as an option for V114 vaccination in Japanese infants.

Antibody-mediated protection against respiratory syncytial virus in children.

Respiratory syncytial virus (RSV) is a major global pathogen, causing lower respiratory tract disease in at-risk populations including young children. Antibodies form a crucial layer of protection from RSV disease, particularly in immunologically naïve infants. Such antibodies are derived from the mother via transplacental transfer and breast milk, but may be particularly low in high-risk infants such as those born preterm. Maternally derived antibodies can now be supplemented by the administration of anti-RSV monoclonal antibodies, while a rising wave of maternal and paediatric vaccine strategies are approaching. The implementation of these prophylactics may profoundly decrease the healthcare burden of RSV. In this article, we review the role of antibody-mediated immunity in protecting children from RSV. We focus on maternally derived antibodies as the main source of protection against RSV and study factors that influence the scale of this transfer. The role of passive and active prophylactic approaches in protecting infants against RSV are discussed and knowledge gaps in our understanding of antibody-mediated protection against RSV are identified.

Evaluating the Compatibility of Three Aluminum Salt-Adjuvanted Recombinant Protein Antigens (Trivalent NRRV) Combined with a Mock Trivalent Sabin-IPV Vaccine: Analytical and Formulation Challenges.

In this work, we describe compatibility assessments of a recombinant, trivalent non-replicating rotavirus vaccine (t-NRRV) candidate with a mock trivalent Sabin inactivated polio vaccine (t-sIPV). Both t-sIPV and t-NRRV are incompatible with thimerosal (TH), a preservative commonly used in pediatric pentavalent combination vaccines (DTwP-Hib-HepB) distributed in low- and middle-income countries (LMICs), preventing the development of a heptavalent combination. The compatibility of t-NRRV with a mock DTwP-Hib-HepB formulation is described in a companion paper. This case study highlights the analytical and formulation challenges encountered when combining a mock t-sIPV vaccine (unadjuvanted) with Alhydrogel® (AH) adjuvanted t-NRRV. Selective and stability-indicating competition ELISAs were implemented to monitor antibody binding to each of the six antigens (±AH). Simple mixing caused the undesired desorption of t-NRRV from AH with the concomitant binding of t-sIPV to AH. Although the former effect was mitigated by dialyzing sIPV bulks, decreased sIPV storage stability was observed at accelerated temperatures in the bivalent combination with a rank-ordering of P[8] > P[6] > P[4] and sIPV3 > sIPV2 > sIPV1. The compatibility of AH-adsorbed t-sIPV with alternative preservatives was evaluated, and parabens (methyl, propyl) were identified for potential use in this multi-dose bivalent formulation. Along with a companion paper, the lessons learned are discussed to facilitate the future formulation development of pediatric combination vaccines with new antigens.

Immunostimulatory/Immunodynamic model of mRNA-1273 to guide pediatric vaccine dose selection.

COVID-19 vaccines, including mRNA-1273, have been rapidly developed and deployed. Establishing the optimal dose is crucial for developing a safe and effective vaccine. Modeling and simulation have the potential to play a key role in guiding the selection and development of the vaccine dose. In this context, we have developed an immunostimulatory/immunodynamic (IS/ID) model to quantitatively characterize the neutralizing antibody titers elicited by mRNA-1273 obtained from three clinical studies. The developed model was used to predict the optimal vaccine dose for future pediatric trials. A 25-μg primary vaccine series was predicted to meet non-inferiority criteria in young children (aged 2-5 years) and infants (aged 6-23 months). The geometric mean titers and geometric mean ratios for this dose level predicted using the IS/ID model a priori matched those observed in the pediatric clinical study. These findings demonstrate that IS/ID models represent a novel approach to guide data-driven clinical dose selection of vaccines.

Pediatric Respiratory Hospitalizations in the Pre-COVID-19 Era: The Contribution of Viral Pathogens and Comorbidities to Clinical Outcomes, Valencia, Spain.

Viral respiratory diseases place a heavy burden on the healthcare system, with children making up a significant portion of related hospitalizations. While comorbidities increase the risk of complications and poor outcomes, many hospitalized children lack clear risk factors. As new vaccines for respiratory viral diseases emerge, this study examined pediatric respiratory hospitalizations, focusing on viral etiology, complication rates, and the impact of comorbidities to guide future policy. Data were analyzed from eight pre-COVID influenza seasons (2011/2012-2018/2019) involving patients under 18 years hospitalized with respiratory complaints across 4-10 hospitals in Valencia, Spain. Respiratory specimens were tested for eight viral targets using multiplex real-time reverse-transcription polymerase chain reaction. Demographics, clinical outcomes, discharge diagnoses, and laboratory results were examined. Among the hospitalized children, 26% had at least one comorbidity. These children had higher rates of pneumonia, asthma exacerbation, and pneumothorax, and were twice as likely to require ICU admission, though mechanical ventilation and length of stay were similar to those without comorbidities. Respiratory syncytial virus (RSV) was the most common virus detected (23.1%), followed by rhinovirus/enterovirus (9.5%) and influenza (7.2%). Viral codetection decreased with age, occurring in 4.6% of cases. Comorbidities increase the risk of complications in pediatric respiratory illnesses, however, healthcare utilization is driven largely by otherwise healthy children. Pediatric viral vaccines could reduce this burden and should be further evaluated.

SMS-Based Active Surveillance of Adverse Events following Immunization in Children: The VigiVax Study.

Underreporting is the main limitation of spontaneous reporting systems. This cohort-event monitoring study aims to examine the potential of short message service (SMS)-based surveillance compared to traditional surveillance systems. Using VigiVax software, parents of vaccinated children aged two years or younger, in the period March 2021-May 2022, received a single SMS inquiry about adverse events following immunization (AEFI). Responses were collected, validated by health operators and integrated with the information on electronic immunization registries. AEFI reports were automatically submitted to the Italian Pharmacovigilance system. Among 254,160 SMS messages sent, corresponding to 451,656 administered doses (AD), 71,643 responses were collected (28.2% response rate), and 21,231 of them (8.3%) reported AEFI. After a seriousness assessment based on clinical criteria, 50 reports (0.24%) were classified as serious. Among these, a causality assessment identified 31 reports at least potentially related to the vaccination (RR: 6.86/100,000 AD). Febrile seizures following MMRV (measles, mumps, rubella, varicella) vaccination accounted for 11 of these 31 cases, with an incidence of 32 per 100,000 AD. No fatal outcomes were reported. Our findings support the highly favorable risk profile of pediatric vaccinations and the possibility to improve spontaneous reporting through the integration of digital technologies.

Vaccine Completion and Timeliness Among Children in the Military Health System: 2010-2019.

Few studies have evaluated pediatric vaccination coverage in the Military Health System, although some evidence suggests lower than ideal coverage. This study assessed vaccine completion and timeliness among military dependents through age 24 months. Children born at military hospitals from 2010 through 2019 were identified using Department of Defense Birth and Infant Health Research program data. Vaccine completion and timeliness were assessed for diphtheria, tetanus, and pertussis; polio; measles, mumps, and rubella; hepatitis B; Haemophilus influenzae type b; varicella; and pneumococcal conjugate individually and as a combined 7-vaccine series; rotavirus was assessed separately. Modified Poisson regression models were used to calculate risk ratios (RRs) and 95% confidence intervals (CIs) for noncompletion and delays, adjusting for demographic characteristics. Of 275 967 children, 74.4% completed the combined 7-vaccine series, and 36.2% of those who completed the series had delays. Completion peaked at 78.7% among children born in 2016 and 2017. Among all vaccines, completion was lowest for rotavirus (77.5%), diphtheria, tetanus, and pertussis (83.1%), Haemophilus influenzae type b (86.6%), and pneumococcal conjugate (88.4%). Risk for noncompletion was higher among children born to younger pregnant parents (adjusted RR = 1.33; 95% CI = 1.27-1.40) and with a well-child care location change (adjusted RR = 1.10; 95% CI = 1.09-1.12). Risk for delays paralleled that for noncompletion. Vaccine completion and timeliness generally improved among military children, but greater noncompletion of vaccine series with more versus fewer doses and disparities for younger and mobile service members suggest system barriers remain.

Intranasal parainfluenza virus-vectored vaccine expressing SARS-CoV-2 spike protein of Delta or Omicron B.1.1.529 induces mucosal and systemic immunity and protects hamsters against homologous and heterologous challenge.

The continuous emergence of new SARS-CoV-2 variants requires that COVID vaccines be updated to match circulating strains. We generated B/HPIV3-vectored vaccines expressing 6P-stabilized S protein of the ancestral, B.1.617.2/Delta, or B.1.1.529/Omicron variants as pediatric vaccines for intranasal immunization against HPIV3 and SARS-CoV-2 and characterized these in hamsters. Following intranasal immunization, these B/HPIV3 vectors replicated in the upper and lower respiratory tract and induced mucosal and serum anti-S IgA and IgG. B/HPIV3 expressing ancestral or B.1.617.2/Delta-derived S-6P induced serum antibodies that effectively neutralized SARS-CoV-2 of the ancestral and B.1.617.2/Delta lineages, while the cross-neutralizing potency of B.1.1.529/Omicron S-induced antibodies was lower. Despite the lower cross-neutralizing titers induced by B/HPIV3 expressing S-6P from B.1.1.529/Omicron, a single intranasal dose of all three versions of B/HPIV3 vectors was protective against matched or heterologous WA1/2020, B.1.617.2/Delta or BA.1 (B.1.1.529.1)/Omicron challenge; hamsters were protected from challenge virus replication in the lungs, while low levels of challenge virus were detectable in the upper respiratory tract of a small number of animals. Immunization also protected against lung inflammatory response after challenge, with mild inflammatory cytokine induction associated with the slightly lower level of cross-protection of WA1/2020 and B.1.617.2/Delta variants against the BA.1/Omicron variant. Serum antibodies elicited by all vaccine candidates were broadly reactive against 20 antigenic variants, but the antigenic breadth of antibodies elicited by B/HPIV3-expressed S-6P from the ancestral or B.1.617.2/Delta variant exceeded that of the S-6P B.1.1.529/Omicron expressing vector. These results will guide development of intranasal B/HPIV3 vectors with S antigens matching circulating SARS-CoV-2 variants.

Myopericarditis following COVID-19 vaccination in children: a systematic review and meta-analysis.

Myopericarditis is a rare but serious coronavirus disease 2019 (COVID-19) vaccine-related adverse event primarily affecting adolescents. Given recent approvals for childhood vaccination, we performed a meta-analysis investigating myopericarditis following messenger ribonucleic acid COVID-19 vaccination in children aged <19 years, focusing on its overall risk and high-risk subgroups. We searched MEDLINE via PubMed, Embase and Scopus from inception to 1 August 2022 for observational studies reporting myopericarditis in temporal relation to paediatric COVID-19 vaccination. We conducted random-effects meta-analyses (DerSimonian and Laird) on myopericarditis (primary outcome), myocarditis and pericarditis (secondary outcomes). Of 2115 studies, 12 (59,229,160 doses) studies were included in our analysis. There were 19.8 (95% confidence interval [CI]: 10.4-37.6) myopericarditis cases reported per million doses in children, compared to 23.7 (95% CI: 12.2-46.1) cases in adults (eight studies, 376,899,888 doses; P = 0.70). Compared to the second dose (34.4, 95% CI: 15.2-77.8), the number of cases post-first dose was significantly lower (9.1, 95% CI: 4.4-18.8; P = 0.017), while the number of cases post-third dose was not higher than that of post-second dose (28.4, 95% CI: 10.4-61.8; P = 0.57, global P = 0.031). Males were at higher risk of myopericarditis (67.4, 95% CI: 36.5-124.5) than females (6.9, 95% CI: 3.1-15.3; P < 0.0001). Finally, the number of cases was higher (overall P < 0.0001) among children aged ≥12 years (39.9, 95% CI: 24.1-66.0) than among children aged <12 years (3.0, 95% CI: 2.3-3.9). Our meta-analysis showed 19.8 cases of myopericarditis per million doses among children, not significantly different from that of adults. Higher risk subgroups included adolescents, males, and those receiving their second dose of vaccination.

Factors Influencing Vaccine Receipt During a 2018 Pediatric Typhoid Conjugate Vaccine Campaign in Navi Mumbai, India.

In 2018, the Navi Mumbai Municipal Corporation implemented phase 1 of a public sector typhoid conjugate vaccine campaign in Navi Mumbai, India, targeting all children aged 9 months to 14 years within its administrative boundaries. To assess associations with receipt of vaccine in phase 1, we used generalized estimating equations to calculate estimates of vaccination by child-, household-, and community-level demographics (child education and age; household head education, income, and occupation; community informal settlement percent). Campaign vaccine receipt was most associated with children enrolled in school (odds ratio [OR] = 3.84, 95% CI: 2.18-6.77), the lowest household income tertile when divided into three equal parts (OR = 1.64, 95% CI: 1.43-1.84), and lower community-level socioeconomic status (OR = 1.06, 95% CI: 1.04-1.08 per 10% informal settlement proportion). The campaign was successful in reaching the most underserved populations of its target communities.

Pediatric Coronavirus Disease 2019 Vaccine Experiences, Practices, and Attitudes in Rural Primary Care Clinicians

ObjectivePediatric coronavirus disease 2019 (COVID-19) vaccination rates remain low in rural areas. A strong clinician recommendation improves vaccine uptake, but the pediatric COVID-19 vaccine recommendation practices of rural primary care clinicians have not been reported. Our objectives were to describe, among rural Colorado pediatric clinicians: 1) recommendation practices for COVID-19 vaccine compared to influenza and school-entry required vaccines, and 2) personal attitudes. MethodsFrom July to October 2023, surveys were distributed to clinicians in rural Colorado identified as pediatric vaccine providers in counties designated as rural through the Colorado Immunization Information System using mail and email. ResultsOf 89 survey respondents, 37% of clinicians strongly recommended COVID-19 vaccines for children 6 months–5 years old, compared to 79% for influenza (P = 0.05) and 92% for school-entry required vaccines (P = 0.04). For children 6–11 and 12–17 years old, 43% and 44% of clinicians strongly recommended COVID-19 vaccines, respectively, compared to 71% and 70% for influenza (P < 0.01), and 91% for school-entry required vaccines (P < 0.01). Forty four percent of clinicians agreed that COVID-19 vaccines are important for pediatric patients. The most common clinician-perceived challenges to discussing pediatric COVID-19 vaccines included a lack of parent interest in more information (76% “somewhat” or “strongly” agree), lack of ability to change parents’ minds (71%), and concerns that the vaccines are too political (40%). ConclusionsMost rural Colorado clinicians do not strongly recommend pediatric COVID-19 vaccines compared to influenza and school-entry required vaccines. Efforts to improve pediatric COVID-19 vaccine uptake should aim to strengthen clinicians’ recommendations of these vaccines.

Parents' views on pediatric COVID-19 vaccine in Saudi Arabia.

To end the COVID-19 pandemic, we need to reach herd immunity. A successful pediatric COVID-19 immunization program is the only way to achieve this goal. The objective of this study was to determine the views of parents in Saudi Arabia on the COVID-19 vaccine in children. This cross-sectional study took place within the Family Medicine Pediatric clinics at the King Faisal Specialist Hospital and Research Center (KFSH and RC). All parents of patients of Family Medicine Pediatric Clinics at KFSH and RC, Riyadh, were invited to participate in this study between January 2022 and June 2022. A culturally sensitive and specially designed questionnaire was administered using an interview-based model. Safety concerns were the primary reason for vaccine hesitancy among parents, with 29.7% of parents expressing concerns about side effects and 25.1% not knowing where to get reliable information about vaccines. Negative information and lack of perceived need were also important factors, with 17.1% and 18.3% of parents citing these reasons, respectively. Poor knowledge about vaccines was a significant predictor of parental vaccine hesitancy. Mothers had more concerns about the efficacy and safety of vaccines than fathers. Our study demonstrated a negative attitude toward the pediatric COVID-19 vaccine among parents in Saudi Arabia. A higher level of awareness about the vaccine was significantly associated with planning on having the vaccine. There is a need for effective awareness programs for better pediatric COVID-19 vaccine-related education to increase the acceptance of the vaccine among parents in Saudi Arabia.

Pediatric Pneumococcal Conjugate Vaccine and Dosing Schedule Perceptions Among Health Care Providers and Caregivers in Germany, France, Spain, and Greece.

Most European infant national immunization programs (NIPs) recommend pneumococcal conjugate vaccines (PCVs), which currently cover 10-15 serotypes administered in a three-dose schedule (two primary plus one booster). Recently, a PCV covering 20 serotypes that is administered in a four-dose schedule (three primary plus one booster) was licensed. An online survey was administered to collect data from health care providers (HCPs) and caregivers of children aged 0-5 (including expectant mothers) in four European countries (Germany, France, Spain, and Greece). All caregiver respondents had a shared or full responsibility to make health decisions for their child. Data on opinions, perceptions, and openness to a change in childhood vaccination dosing schedules were collected, along with demographic information for HCPs as well as caregivers. A total of 601 HCPs and 1954 caregivers were recruited across the four countries. Nearly all HCPs (93%) agreed that broader serotype coverage against pneumococcal disease for children is a significant unmet need, and 92% had a "sense of urgency" to vaccinate children. Both HCPs and caregivers were supportive of an additional PCV dose and doctor visit, assuming it provided at least 20% more serotype coverage than what is currently available. Caregivers strongly agreed on the importance of full vaccination for pneumococcal disease, even if an extra dose and visit to the doctor was required. HCPs and caregivers were virtually unanimous in their support for a PCV with broader serotype coverage and showed a subsequent willingness to include an extra infant dose/visit. These results can help guide broader discussions regarding public health policy and vaccine administration in the context of important efforts to reduce the global disease burden associated with pneumococcal disease.

Regional differences in pediatric pneumococcal vaccine schedules for Indigenous children in Canada: an environmental scan

BackgroundStreptococcus pneumoniae bacteria causes substantial morbidity and mortality worldwide, especially in children under 5 years of age. Prevention of these outcomes by pneumococcal conjugate vaccines (PCV) is an important public health initiative, supported by publicly funded vaccination programs in Canada. While the National Advisory Committee on Immunization (NACI) provides national recommendations for vaccination schedules, decisions on vaccination program delivery are made regionally, creating potential for variability across the country. In addition, defining the groups that are most at risk has become a complex endeavor for provinces and territories in Canada, specifically considering Indigenous children.MethodsIn this environmental scan, we reviewed policy documents, provincial/territorial and international PCV schedules, and scientific literature, and consulted with vaccination program stakeholders and experts from across the country, in order to understand the evolution of PCV vaccination guidelines and policies in Canada and identify whether and how the needs of Indigenous children are addressed.ResultsAs of March 2023, most regions do not specify particular vaccination requirements for Indigenous children; however, three provinces identify Indigenous children as “high risk” and use varying language to recommend a four dose, rather than the routine three dose, schedule. Our results also draw attention to evidence gaps supporting a differing practice for Indigenous populations.ConclusionsFuture PCV program innovation requires inclusive and clear policies as well as definitive evidence-based policies and practices in order to improve equitable population health.

Pertussis vaccine effectiveness following country-wide implementation of a hexavalent acellular pertussis immunization schedule in infants and children in Panama

ABSTRACT Despite high pediatric vaccination coverage rates (VCRs), pertussis incidence has increased worldwide, including in several countries in Latin America in the last two decades. Given the few vaccine effectiveness (VE) studies in Latin American countries, this retrospective, observational, cohort study estimated the effectiveness of hexavalent acellular (aP) primary and booster vaccination (wP) against pertussis in infants (6.5–18.5 months) and children (18.5–48.5 and 48.5–72.5 months) in Panama. Age-specific incidence rates (IRs) were calculated for the vaccine’s pre-initiation (2001–2013), initiation (2014), and post-initiation (2015–2019) periods. VCRs and trends were determined, and VE was analyzed using a case coverage or screening method to compare proportions of vaccinated cases and vaccinated individuals in the population. Between 2001–2019, 868 confirmed pertussis cases were reported in Panama; 712 (82.0%; 54.8 cases/year) during the pre-initiation period, 19 (2.2%; 19 cases/year) during the initiation period, and 137 (15.8%; 27.4 cases/year) during the post-initiation period. Panama underwent cyclical increases in IRs, which varied between age groups. VCRs increased for primary and booster doses. Between 2015 and 2019, third-dose yearly vaccine coverage increased, on average, 3.3%. Specifically, during the post-initiation period, 109/137 (79.6%) of cases were unvaccinated. Relative VE was estimated at 96.2% [95% CI: 86.5%, 98.9%] with three doses; 100% with 4 and 5 booster doses. Absolute VE was estimated at 99.3% with three doses only. These results show that vaccination played an important role in maintaining a low number of pertussis cases in Panama, affirming the need for sustained investment and commitment to vaccination programs.

Potential impact of replacing the 13-valent pneumococcal conjugate vaccine with 15-valent or 20-valent pneumococcal conjugate vaccine in the 1 + 1 infant schedule in England: a modelling study

Paediatric pneumococcal conjugate vaccine (PCV) programmes in England using seven-valent PCV (PCV7) in 2006 and 13-valent PCV (PCV13) in 2010 have reduced vaccine-type invasive pneumococcal disease, but the overall effect has been reduced by an increase in invasive pneumococcal disease due to non-vaccine serotypes and serotype 3. We developed pneumococcal transmission models to investigate the potential effect on invasive pneumococcal disease of higher valency PCVs covering an additional two (ie, 15-valent PCV [PCV15]) or seven serotypes (ie, 20-valent PCV [PCV20]) in England. We conducted a modelling study using realistic, age-structured, and compartmental deterministic models fitted to carriage data from before the introduction of PCVs and invasive pneumococcal disease data from before and after the introduction of PCV7 and PCV13 in England from the UK Heath Security Agency invasive pneumococcal disease surveillance system. We estimated key parameters, including PCV7 and PCV13 efficacy against vaccine-type carriage and invasiveness of PCV7 serotypes; the additional serotypes in PCV13, PCV15 and PCV20; and non-vaccine serotypes. We simulated the effect of transitioning from PCV13 to PCV15 or PCV20 in infants under the current 1 + 1 vaccination schedule and investigated the effect of reduced carriage protection against PCV13 serotypes due to attenuation of immunogenicity in higher valency vaccines. Our results suggest that PCV15 might increase overall invasive pneumococcal disease as the reduction in vaccine-type invasive pneumococcal disease would be counterbalanced by an increase in non-PCV15 invasive pneumococcal disease. By contrast, PCV20 is projected to have a substantial impact on overall invasive pneumococcal disease due to higher invasiveness of the additional serotypes covered by PCV20 than the replacing non-vaccine serotypes. Reduced carriage protection against PCV13 serotypes with higher valency vaccines would amplify these effects. Replacing PCV13 with PCV20 is likely to have a substantial public health benefit, but PCV15 could potentially increase the overall burden of disease. UK Health Security Agency and National Institute of Health Research.