Persistence of pneumococcal antibodies after primary immunisation with a polysaccharide-protein conjugate vaccine

Incidence of pneumococcal disease in children ≤48 months old in the United States: 1998-2019

BACKGROUND

Pneumococcal disease (PD) is a major cause of morbidity and mortality among children, particularly in the youngest age groups. This study aimed to assess the incidence of PD over time by age group in young children with commercial or Medicaid coverage in the US.

METHODS

Episodes of invasive pneumococcal disease (IPD), all-cause pneumonia (ACP), and acute otitis media (AOM) were identified in the MarketScan® Commercial and Medicaid claims databases using diagnosis codes among children aged ≤ 48 months with confirmed date of birth (DoB), at any time during the study period (1998-2019). DoB was assigned using diagnosis codes for birth or delivery using the child's or mother's medical claims to ensure accurate age determination. Annual incidence rates (IRs) were calculated as number of disease episodes/100,000 person-years (PY) for IPD and ACP and episodes/1,000 PY for AOM, for children aged 0-6, 7-12, 12-24, and 25-48 months.

RESULTS

Annual IPD IRs declined from 53 to 7 episodes/100,000 PY between 1998 and 2019 in commercially-insured and 58 to 9 episodes/100,000 PY between 2001 and 2019 in Medicaid-insured children. Annual ACP IRs declined from 5,600 to 3,952 episodes/100,000 PY, and from 6,706 to 4,521 episodes/100,000 PY, respectively, over these periods. In both populations, children aged 0-6 months had the highest incidence of IPD and inpatient ACP. Annual AOM IRs declined from 1,177 to 738 episodes/1,000 PY (commercially-insured) and 633 to 624 episodes/1,000 PY (Medicaid-insured), over these periods. IRs were higher in rural vs. urban areas for all disease manifestations.

CONCLUSIONS

Incidence rates of IPD, ACP, and AOM decreased in children with commercial insurance and Medicaid coverage from 1998 to 2019. However, burden of disease remained substantial, with higher annual IRs for IPD and ACP for Medicaid-insured vs. commercially-insured children. IPD and inpatient ACP were most common in the youngest children 0-6 months old, followed by the 7-12-month age group.

Pneumococcal Vaccine Breakthrough and Failure in Infants and Children: A Narrative Review

Globally, Streptococcus pneumoniae is a leading cause of vaccine-preventable morbidity and mortality in infants and children. In recent decades, large-scale pediatric immunization programs have substantially reduced the incidence of invasive pneumococcal disease. Despite this, residual vaccine-type pneumococcal disease remains in the form of vaccine breakthrough and vaccine failure. This targeted literature review aims to discuss aspects of vaccine breakthrough and failure in infants and children, including disease epidemiology, clinical presentation, risk factors, vaccination schedules, vaccine serotypes, correlates of protection, comorbidities, disease surveillance, and potential implications for future vaccine development.

Persistence of Immunity Following 2-Dose Priming with a 10-Valent Pneumococcal Conjugate Vaccine at 6 and 10 Weeks or 6 and 14 Weeks of Age in Nepalese Toddlers

BACKGROUND

The pneumococcal conjugate vaccine has had a substantial impact on invasive pneumococcal disease. Previously, we compared immunity following vaccination with the 10-valent pneumococcal conjugate vaccine (PCV10) administered at 2 slightly different schedules: at 6 and 10 weeks of age, and at 6 and 14 weeks of age, both followed by a 9-month booster. In this study, we followed up those participants to evaluate the medium-term persistence of serotype-specific pneumococcal immunity at 2-3 years of age.

METHOD

Children from the previous studies were contacted and after taking informed consent from their parents, blood samples and nasopharyngeal swabs were collected. Serotype-specific IgG antibody concentrations were determined by enzyme-linked immunosorbent assay, for the 10 vaccine serotypes, at a WHO pneumococcal serology reference laboratory.

FINDINGS

Two hundred twenty of the 287 children who completed the primary study returned at 2-3 years of age to provide a blood sample and nasopharyngeal swab. The nasopharyngeal carriage rate of PCV10 serotypes in the 6 + 14 group was higher than the 6 + 10 group (13.4% vs. 1.9%). Nevertheless, the proportion of toddlers with serum pneumococcal serotype-specific IgG greater than or equal to 0.35 µg/mL was comparable for all PCV10 serotypes between the 6 + 10 week and 6 + 14 week groups. Similarly, the geometric mean concentrations of serum pneumococcal serotype-specific IgG levels were similar in the 2 groups for all serotypes, except for serotype 19F which was 32% lower in the 6 + 10 group than the 6 + 14 group.

CONCLUSION

Immunization with PCV10 at 6 + 10 weeks or 6 + 14 weeks, with a booster at 9 months in each case, results in similar persistence of serotype-specific antibody at 2-3 years of age. Thus, protection from pneumococcal disease is expected to be similar when either schedule is used.

Pediatric Vaccine Hesitancy and the Utilization of Antibody Measurements: A Novel Strategy with Implications for COVID 19

Vaccine hesitancy is a well researched area with implications for both public health and the health of children and their families The factors leading to vaccine hesitancy are often complex and involve fear of the healthcare system and the process of vaccine development, cultural viewpoints and experiences. Pediatric patients often rely on parental guidance and decision making, and this may result in a lack of immunization for some children. The availability of the COVID 19 vaccine has been widely anticipated, yet not all individuals will seek the vaccine. Once vaccines are available for children under the age of 16 years, this long-standing pediatric management issue may again emerge and impact public health. The clinical trial efficacy and safety data for children and adolescents less than 16 years of age are not yet available. A traditional approach is to discuss the concerns of the parent in relationship to presentation and review of American Association of Pediatrics (AAP) and CDC guidelines in the framework of medical and scientific explanations. This includes the presentation of efficacy and safety data. Therefore, the use of lab-based antibody testing adds scientific evidence and emphasizes the need for vaccination against SARS CoV-2 and other pathogens. The purpose of this commentary is to propose lab-based testing as a potential adjunctive strategy in addressing this public health concern. Further study of a pediatric population is required to assess the impact of the selective use of lab-based testing in improving vaccination rates among a pediatric population.

Assessing the impact of the 13 valent pneumococcal vaccine on childhood empyema in Australia

BACKGROUND

Empyema is a serious complication of pneumonia frequently caused by Streptococcus pneumoniae (SP). We assessed the impact of the 13-valent pneumococcal conjugate vaccine (13vPCV) on childhood pneumonia and empyema after inclusion in the Australian National Immunisation Program.

METHODS

For bacterial pneumonia and empyema hospitalisations, we ascertained incidence rates (IRs) using the National Hospital Morbidity Database International Statistical Classification of Disease discharge codes and relevant population denominators, and calculated incidence rate ratios (IRR) comparing the 13vPCV period (June 2012-May 2017) with the 7vPCV period (June 2007-May 2011). Blood and pleural fluid (PF) cultures and PF PCR of 401 children with empyema from 11 Australian hospitals during the 13vPCV period were compared with our previous study in the 7vPCV period.

FINDINGS

Across 7vPCV and 13vPCV periods, IRs per million children (95% CIs) were 1605 (1588 to 1621) and 1272 (1259 to 1285) for bacterial pneumonia, and 14.23 (12.67 to 15.79) and 17.89 (16.37 to 19.42) for empyema hospitalisations. IRRs were 0.79 (0.78 to 0.80) for bacterial pneumonia and 1.25 (1.09 to 1.44) for empyema. Of 161 empyema cases with SP serotypes, 147 (91.3%) were vaccine types. ST3 accounted for 76.4% of identified serotypes in the 13vPCV period, more than double than the 7vPCV period (p<0.001); ST19A decreased from 36.4% to 12.4%. No cases of ST1 empyema were identified in the 13vPCV period versus 14.5% in the 7vPCV period.

INTERPRETATION

13vPCV resulted in a significant reduction in all-cause hospitalisations for bacterial pneumonia but empyema hospitalisations significantly increased, with emergence of pneumococcal ST3 as the dominant serotype in empyema.

TRIAL REGISTRATION NUMBER

Australian and New Zealand Clinical Trial Registry ACTRN 12614000354684.