Perinatal risk factors for hospitalization for pneumococcal disease in childhood: a population-based cohort study

Risk Factors for Acute Rheumatic Fever: Literature Review and Protocol for a Case-Control Study in New Zealand

Acute rheumatic fever (ARF) and its sequela, rheumatic heart disease (RHD), have largely disappeared from high-income countries. However, in New Zealand (NZ), rates remain unacceptably high in indigenous Māori and Pacific populations. The goal of this study is to identify potentially modifiable risk factors for ARF to support effective disease prevention policies and programmes. A case-control design is used. Cases are those meeting the standard NZ case-definition for ARF, recruited within four weeks of hospitalisation for a first episode of ARF, aged less than 20 years, and residing in the North Island of NZ. This study aims to recruit at least 120 cases and 360 controls matched by age, ethnicity, gender, deprivation, district, and time period. For data collection, a comprehensive pre-tested questionnaire focussed on exposures during the four weeks prior to illness or interview will be used. Linked data include previous hospitalisations, dental records, and school characteristics. Specimen collection includes a throat swab (Group A Streptococcus), a nasal swab (Staphylococcus aureus), blood (vitamin D, ferritin, DNA for genetic testing, immune-profiling), and head hair (nicotine). A major strength of this study is its comprehensive focus covering organism, host and environmental factors. Having closely matched controls enables the examination of a wide range of specific environmental risk factors.

Long-term Vaccine Impact on Invasive Pneumococcal Disease Among Children With Significant Comorbidities in a Large Australian Birth Cohort

BACKGROUND

Little is known about long-term invasive pneumococcal disease (IPD) incidence in children with risk factors (RFs) in populations with high coverage pneumococcal conjugate vaccine (PCV) programs. We measured IPD burden and changes with PCV use in children by RF status.

METHODS

A retrospective cohort of all live births in 2001-2012 in New South Wales, Australia was linked to IPD, hospitalization and death data. RFs were identified from International Classification of Diseases codes in linked hospitalizations. For each RF adjusted hazard ratios (aHRs, using Cox models), population attributable fractions (PAFs) and changes post-PCV relative to baseline for IPD were calculated.

RESULTS

One-thousand two-hundred fifty-one IPD cases occurred in ~1.1 million children in 12-year study cohort. The 75,404 children (6.8% of cohort) with RFs accounted for 255 (20.4%) IPD cases [rate (per 100,000 person-years) of 61 compared with 14 in no RFs]. Asthma was most common RF (n = 41,074; 3.6%) but highest IPD risk was in 2452 children (0.2%) with immunosuppression, splenic dysfunction or breach in cerebrospinal fluid barrier (aHR~20; PAF 0.7-1.8%) versus asthma (aHR 5.3; PAF 14.8%). Compared with 2001-2004 birth cohort (baseline), IPD incidence in PCV-eligible 2009-2012 birth cohort was 78% (95% confidence interval: -72% to -82%) less in children without RFs. IPD declined nonsignificantly (13%; 95% confidence interval: -70% to +138%) in highest IPD risk group, but by 67% (-43% to -82%) in children with other RFs.

CONCLUSIONS

By 8 years of universal PCV, IPD incidence reduced significantly in all children except in the 0.2% at highest risk, for whom antibiotic prophylaxis and additional vaccine doses are recommended but compliance and effectiveness remain uncertain.

Effectiveness of the 10-valent pneumococcal conjugate vaccine among girls, boys, preterm and low-birth-weight infants - Results from a randomized, double-blind vaccine trial

BACKGROUND

Several studies have shown differences in susceptibility to infections and immune response to vaccines by sex. Prematurely born infants are at higher risk for pneumococcal diseases, with lower effectiveness for some vaccines compared to term infants. We have reported the effectiveness of the 10-valent pneumococcal non-typeable Haemophilus influenzae protein D conjugate vaccine (PHiD-CV10) on several endpoints in the Finnish Invasive Pneumococcal disease (FinIP) vaccine trial. Now, we present the results of a post-hoc analysis evaluating PHiD-CV10 effectiveness in subgroups by sex, gestational age, and birth weight.

METHODS

The FinIP trial was a phase III/IV cluster-randomized, double-blind trial. Infants enrolled < 7 months of age received PHiD-CV10 in two thirds of clusters (3 + 1 or 2 + 1 schedule) and hepatitis B vaccine as control in remaining third. Outcome data included invasive pneumococcal disease, pneumonia, tympanostomy tube placements, and antimicrobial purchases collected through national, routinely used health registers. Negative binomial model was used in the incidence and vaccine effectiveness estimation, and differences in incidences between subgroups were tested among control children.

RESULTS

Of the 30,527 infants enrolled 51% were boys. The incidences of hospital-diagnosed pneumonia and otitis-related outcomes were higher among boys in control groups. There were no significant sex differences in the vaccine effectiveness estimates. Altogether, 1519 (5%) infants were born before 37th gestational week. The incidences of pneumonia outcomes were higher among premature infants when compared to term infants. The vaccine effectiveness estimates among preterm infants were not statistically significant except for antimicrobial purchases, but all point estimates were at the same level among preterm infants as among term infants. There was no significant difference between 2 + 1 and 3 + 1 schedules in any of the subgroups analysed.

CONCLUSION

PHiD-CV10 had a similar effectiveness in both sexes, and seemed to be protective in preterm infants.

TRIAL REGISTRATION

ClinicalTrials.gov NCT00861380 and NCT00839254.

Vaccination of special populations: Protecting the vulnerable

One of the strategic objectives of the 2011-2020 Global Vaccine Action Plan is for the benefits of immunisation to be equitably extended to all people. This approach encompasses special groups at increased risk of vaccine-preventable diseases, such as preterm infants and pregnant women, as well as those with chronic and immune-compromising medical conditions or at increased risk of disease due to immunosenescence. Despite demonstrations of effectiveness and safety, vaccine uptake in these special groups is frequently lower than expected, even in developed countries with vaccination strategies in place. For example, uptake of the influenza vaccine in pregnancy rarely exceeds 50% in developed countries and, although data are scarce, it appears that only half of preterm infants are up-to-date with routine paediatric vaccinations. Many people with chronic medical conditions or who are immunocompromised due to disease or aging are also under-vaccinated. In the US, coverage among people aged 65years or older was 67% for the influenza vaccine in the 2014-2015 season and 55-60% for tetanus and pneumococcal vaccines in 2013, while the coverage rate for herpes zoster vaccination among those aged 60years or older was only 24%. In most other countries, rates are far lower. Reasons for under-vaccination of special groups include fear of adverse outcomes or illness caused by the vaccine, the inconvenience (and in some settings, cost) of vaccination and lack of awareness of the need for vaccination or national recommendations. There is also evidence that healthcare providers' attitudes towards vaccination are among the most important influences on the decision to vaccinate. It is clear that physicians' adherence to recommendations needs to be improved, particularly where patients receive care from multiple subspecialists and receive little or no care from primary care providers.

Immunizations against respiratory infections in children in primary health care in poland: coverage and delays

Pneumococcal infections, pertussis, and influenza are vaccine-preventable diseases. The aim of this study was to determine vaccine coverage and compliance with the dosage regimen among children in Poland. We performed a retrospective chart analysis of 1,356 children in a large primary healthcare establishment. The complete primary pertussis vaccination, 3 doses in the first year of life, was administered to 1,310/1,356 patients (96.6 %). The self-paid combined acellular vaccine was given in 55.2 % of children. The first dose of the pertussis vaccine was administered in a timely manner to 67.1 % of children. The self-paid pneumococcal vaccine was administered in 499/1,356 (36.8 %) children. In 46.1 % of them immunization started within the first 6 months of life; in 12.6 % aged 7-11 months, in 12.6 % aged 12-23 months, and in 28.7 % aged over 24 months. The dosage regimen was compliant in 49.2 % of patients. Only 3.5 % of patients were immunized against both pneumococci and influenza. Compliance with the Polish immunization program should be increased by reducing the number of injections and the cost of vaccines. Education is essential to facilitate simultaneous administration of vaccines during one visit and to prepare the parents for judicious decision-making when it comes to vaccinations.

Population-based study of the association between asthma and pneumococcal disease in children

Background

Although asthma has recently been established as a risk factor for pneumococcal disease (PD), few studies have specifically evaluated this association in children.

Methods

We conducted a nation-wide population-based cohort study of the effect of asthma on childhood PD among all singleton live births in Denmark from 1994 to 2007, before the introduction of the 7-valent pneumococcal conjugate vaccine. All data were abstracted from Danish medical registries. Because underlying comorbidity substantially increases the PD risk in children, standard methods were used to assess the evidence of biologic interaction between comorbidity and asthma on the risk of PD.

Results

There were 2,253 cases of childhood PD among 888,655 children born in Denmark from 1994 to 2007. The adjusted incidence rate ratio of the effect of asthma on childhood PD was 2.2 (95% confidence interval [CI]: 2.0, 2.5). Age-stratified incidence rate ratios were 2.1 (95% CI: 1.8, 2.9) in children 6 months to <24 months, 4.1 (95% CI: 3.3, 5.1) in children 24 months to <60 months, and 2.3 (95% CI: 1.6, 3.2) in children ≥60 months. Evaluation of the biologic interaction between asthma and comorbidity in older children revealed that 55% (24 months to <60 months) to 73% (≥60 months) of cases among asthma-exposed children can be accounted for by the interaction between asthma and comorbidity.

Conclusion

These results confirm that asthma is an important risk factor for PD in children and suggest that children with underlying comorbidities are more sensitive to the effect of asthma on PD than children without comorbidities.

10-Valent pneumococcal non-typeable haemophilus influenzae protein D-conjugate vaccine: a review in infants and children

The 10-valent pneumococcal non-typeable Haemophilus influenzae protein D-conjugate vaccine (PHiD-CV) (Synflorix™) includes ten serotype-specific polysaccharides of Streptococcus pneumoniae, eight of which are conjugated individually to a nonlipidated cell-surface lipoprotein (protein D) of non-typeable H. influenzae and two of which are conjugated to nontoxic tetanus or diphtheria toxoid carrier proteins. This article provides an overview of the well-established immunogenicity of PHiD-CV, including functional immune responses and immunologic memory, as well as immune responses in preterm infants and HIV-infected children. It also includes a brief discussion of cross-protection against vaccine-related serotypes (6A and 19A) and focuses on labelling in the EU, where PHiD-CV is approved for active immunization against invasive disease, pneumonia, and acute otitis media (AOM) caused by S. pneumoniae in infants and young children up to 5 years of age. Evidence of the protective efficacy and effectiveness of PHiD-CV against pneumococcal diseases is available from several studies, including the randomized, double-blind trials COMPAS (Clinical Otitis Media and Pneumonia Study) and FinIP (Finnish Invasive Pneumococcal disease), as well as postmarketing studies from various countries. As would be expected, protection against pneumonia or AOM is substantially lower than that against invasive pneumococcal disease, as many micro-organisms other than pneumococcal vaccine serotypes can cause pneumonia and AOM, thereby limiting the overall protection of PHiD-CV against these diseases. PHiD-CV has a safety and reactogenicity profile similar to that of other pneumococcal conjugate vaccines.

Maternal and perinatal factors associated with subsequent meningococcal, Haemophilus or enteroviral meningitis in children: database study

We used a database of 248 659 births, with follow-up to subsequent disease, in the Oxford record linkage archive (1979-1999) to study the influence of family, maternal, and perinatal factors on subsequent hospital admission for meningococcal, Haemophilus, and enteroviral meningitis in the children. In this summary, we report key findings that were significant in multivariate analysis. Meningococcal meningitis was significantly associated with maternal smoking [odds ratio (OR) 2·1, 95% confidence interval (CI) 1·2-3·7]. Haemophilus meningitis was associated with having older siblings (e.g. second child compared to first-born, OR 3·3, 95% CI 2·0-5·6). Enteroviral meningitis was associated with low birth weight (OR 2·2, 95% CI 1·3-3·6) and male sex (OR 1·7, 95% CI 1·2-2·3). The mothers of six of the 312 children with enteroviral meningitis had previously had enteroviral meningitis themselves. We concluded that several maternal characteristics influence the risk of these types of meningitis.

Sleep-disordered breathing is a risk factor for community-acquired alveolar pneumonia in early childhood

BACKGROUND

Data are scarce with regard to risk factors for acute community-acquired alveolar pneumonia (CAAP) in children, but it is known that children with sleep-disordered breathing (SDB) experience more respiratory infections. We aimed to assess whether SDB is a risk factor for CAAP in early childhood.

METHODS

We conducted a prospective, nested, case-control study assessing children < 5 years old who had been given a diagnosis of CAAP based on World Health Organization radiographic criteria. Demographic and clinical data were collected. SDB symptoms were documented using a structured questionnaire. CAAP study and retrospective sleep laboratory databases were compared. SDB presence and severity were determined by questionnaire and polysomnography (PSG).

RESULTS

A total of 14,913 children underwent chest radiography during the study period; 1,546 children with radiographically proven CAAP (58% boys) and 441 control subjects (54% boys) were prospectively enrolled. Frequent snoring was reported in 18.6% vs 2.9% subjects with CAAP and control subjects, respectively (P < .001). The respective figures for subjects with CAAP and control subjects for restless sleep, nocturnal breathing problems, abnormal behavior, and chronic rhinorrhea were 21.6% vs 5.3%, 5% vs 1.4%, 6.4% vs 0.2%, and 12.9% vs 1.8%, (P < .001 for each). Fifty children (3.3%) with CAAP vs three control subjects (0.7%) underwent adenoidectomy (P < .001). PSG diagnosis of obstructive sleep apnea had been established previously in 79 patients (5%) with CAAP vs six (1.3%) of the control subjects (OR, 3.7 [95% CI, 1.6-10.0]; P < .001), with higher severity in patients with CAAP than in control subjects.

CONCLUSIONS

SDB is common in children with CAAP and is possibly a predisposing risk factor for CAAP in children < 5 years old. We recommend considering SDB in young children who are given a diagnosis of CAAP.

Immunization of preterm infants with 10-valent pneumococcal conjugate vaccine

OBJECTIVE

The safety and immunogenicity of the 10-valent pneumococcal nontypeable Haemophilus influenzae protein D conjugate vaccine (PHiD-CV) in preterm infants were assessed in this study.

METHODS

Three parallel groups of infants received 3-dose primary immunization with PHiD-CV at 2, 4, and 6 months of age and a booster dose at 16 to 18 months: preterm I (gestation period ≥ 27 and <31 weeks, N = 50); preterm II (≥31 and <37 weeks, N = 87); and term (≥37 weeks, N = 149). Solicited symptoms and adverse events were recorded. Immune responses to PHiD-CV and coadministered vaccine antigens were measured.

RESULTS

The incidence of solicited general symptoms was similar across groups, and the frequency of grade 3 general symptoms was low. Incidences of redness and swelling were generally lower in preterm infants. PHiD-CV was immunogenic for each of the 10 vaccine pneumococcal serotypes (postprimary, ≥92.7% of infants reached enzyme-linked immunosorbent assay antibody concentrations ≥ 0.2 μg/mL and postbooster, ≥97.6%) and for protein D, with a trend for lower postprimary geometric mean antibody concentrations and opsonophagocytic activity (OPA) titers in preterm infants for some pneumococcal serotypes. Postbooster, ≥91.9% of subjects in each group had an OPA titer ≥ 8 for each of the vaccine serotypes. Pneumococcal antibody concentrations and OPA titers after priming and booster vaccination were comparable between the 2 preterm groups.

CONCLUSIONS

PHiD-CV was well tolerated and immunogenic in preterm infants when given as a 3-dose primary vaccination, with robust enzyme-linked immunosorbent assay antibody and OPA booster responses in the second year of life.

Immunogenicity and safety of heptavalent conjugate vaccine against Streptococcus pneumoniae in pre-term Polish infants

The purpose of the study was to assess post-vaccination immune response and occurrence of adverse events in the group of prematurely born infants. The study included 40 pre-term infants. Each child was vaccined four times (2, 4, 6 and 16 months) with the heptavalent conjugated pneumococcal vaccine (PCV7). Assessing of the level of antibodies was performed before vaccination, 4 weeks after primary series, before and 4 weeks after the booster dose. The research participants were qualified into 2 groups: group I - 19 children born before 30th gestational week, group II - 21 children born between the 30th and 34th gestational week. After the basic vaccination, an increase in the average antibody concentration in the area of all serotypes in most of the children tested was registered, with no significant differences observed between the groups. However, differences between individual serotypes were observed. The lowest values were found for serotype 6B. Before administering the booster dose, a significant drop in antibody titre in all of the children tested was noted. The last vaccination caused another significant increase in antibody concentration in both groups and the results obtained were markedly higher than those obtained after administering three vaccine doses. The majority of the children tested (with the exception of three from group II) achieved the preventive antibody level ≥ 0.35 μg/ml. In all of the children, no serious adverse events were observed. Our research showed, that heptavalent pneumococcal conjugate vaccine is immunogenic in children born before the completion of the 34th week of pregnancy. A booster dose of vaccine must be given at the right time to optimal response to the vaccine for all serotypes. Finally, any serious adverse events were observed.

Apgar score and dental caries risk in the primary dentition of five year olds

BACKGROUND

Conditions in utero and early life underlie risk for several childhood disorders. This study tested the hypothesis that the Apgar score predicted dental caries in the primary dentition.

METHODS

A retrospective cohort study conducted in 2003 examined associations between conditions at birth and early life with dental caries experience at five years. Dental examination data for a random sample of five-year-old South Australian children were obtained from School Dental Service electronic records. A questionnaire mailed to the parents obtained information about neonatal status at delivery (five-minute Apgar score, birthweight, plurality, gestational age) and details about birth order, weaning, and behavioural, familial and sociodemographic characteristics.

RESULTS

Of the 1398 sampled children with a completed questionnaire (response rate=64.6%), 1058 were singleton term deliveries among whom prevalence of dental caries was 40.1%. In weighted log-binomial regression analysis, children with an Apgar score of <=8 relative to a score of 9-10 had greater probability of dental caries in the primary dentition after adjusting for sociodemographic and behavioural covariates and water fluoridation concentration (adjusted PR=1.47, 95% CI=1.11, 1.95).

CONCLUSIONS

Readily accessible markers of early life, such as the Apgar score, may guide clinicians in identifying children at potentially heightened risk for dental caries and aid decision-making in allocating preventive services.

Hospital admissions from birth to early adolescence and early-life risk factors: the 11-year follow-up of the 1993 Pelotas (Brazil) birth cohort study

The aim of this prospective analysis was to describe the cumulative incidence of hospital admissions in the first year of life and between 1 and 11 years of age and to explore associated factors. Hospital admissions were collected through regular monitoring in the first year of life, and through maternal report on admissions between 1 and 11 years. Analyses were stratified by sex and adjusted for confounding factors. 18.1% of children were hospitalized in the first year of life, and 30.7% between ages 1 and 11 years. Among boys, hospital admission in the first year was associated with low family income, paternal smoking during pregnancy, preterm delivery, and low birthweight. Among girls, in addition to the variables described for boys, black/mixed skin color was also a risk factor for hospital admission. For admissions between 1 and 11 years of age, low family income and gestational age > 37 weeks were found to be significant risk factors.