Vaccines to prevent pneumonia in children - a developing country perspective

Succession and determinants of the early life nasopharyngeal microbiota in a South African birth cohort

BACKGROUND

Bacteria colonizing the nasopharynx play a key role as gatekeepers of respiratory health. Yet, dynamics of early life nasopharyngeal (NP) bacterial profiles remain understudied in low- and middle-income countries (LMICs), where children have a high prevalence of risk factors for lower respiratory tract infection. We investigated longitudinal changes in NP bacterial profiles, and associated exposures, among healthy infants from low-income households in South Africa.

METHODS

We used short fragment (V4 region) 16S rRNA gene amplicon sequencing to characterize NP bacterial profiles from 103 infants in a South African birth cohort, at monthly intervals from birth through the first 12 months of life and six monthly thereafter until 30 months.

RESULTS

Corynebacterium and Staphylococcus were dominant colonizers at 1 month of life; however, these were rapidly replaced by Moraxella- or Haemophilus-dominated profiles by 4 months. This succession was almost universal and largely independent of a broad range of exposures. Warm weather (summer), lower gestational age, maternal smoking, no day-care attendance, antibiotic exposure, or low height-for-age z score at 12 months were associated with higher alpha and beta diversity. Summer was also associated with higher relative abundances of Staphylococcus, Streptococcus, Neisseria, or anaerobic gram-negative bacteria, whilst spring and winter were associated with higher relative abundances of Haemophilus or Corynebacterium, respectively. Maternal smoking was associated with higher relative abundances of Porphyromonas. Antibiotic therapy (or isoniazid prophylaxis for tuberculosis) was associated with higher relative abundance of anerobic taxa (Porphyromonas, Fusobacterium, and Prevotella) and with lower relative abundances of health associated-taxa Corynebacterium and Dolosigranulum. HIV-exposure was associated with higher relative abundances of Klebsiella or Veillonella and lower relative abundances of an unclassified genus within the family Lachnospiraceae.

CONCLUSIONS

In this intensively sampled cohort, there was rapid and predictable replacement of early profiles dominated by health-associated Corynebacterium and Dolosigranulum with those dominated by Moraxella and Haemophilus, independent of exposures. Season and antibiotic exposure were key determinants of NP bacterial profiles. Understudied but highly prevalent exposures prevalent in LMICs, including maternal smoking and HIV-exposure, were associated with NP bacterial profiles. Video Abstract.

Incomplete immunization and its determinants among children in Africa: Systematic review and meta-analysis

Immunization is one of the most cost-effective measures to prevent morbidity and mortality in children. Therefore, the purpose of this systematic review and meta-analysis was to determine the pooled prevalence of incomplete immunization among children in Africa as well as its determinants. PubMed, Google Scholar, Scopus, Science Direct, and online institutional repository homes were searched. Studies published within English language, with full text available for searching, and studies conducted in Africa were included in this meta-analysis. A pooled prevalence, Sub-group analysis, sensitivity analysis and meta-regression were conducted. Out of 1305 studies assessed, 26 met our criteria and were included in this study. The pooled prevalence of incomplete immunization was 35.5% (95% CI: 24.4, 42.7), I² = 92.1%). Home birth (AOR=2.7; 95% CI: 1.5-4.9), rural residence (AOR = 4.6; 95% CI: 1.1-20.1), lack of antenatal care visit (AOR = 2.6; 95% CI: 1.4-5.1), lack of knowledge of immunizations (AOR=2.4; 95% CI: 1.3-4.6), and maternal illiteracy (AOR = 1.7: 95%CI: 1.3-2.0) were associated with incomplete immunization. In Africa, the prevalence of incomplete immunization is high. It is important to promote urban residency, knowledge of immunization and antenatal follow up care.

Complex Involvement of Interleukin-26 in Bacterial Lung Infection

Pneumonia is a global cause of mortality, and this provides a strong incentive to improve the mechanistic understanding of innate immune responses in the lungs. Here, we characterized the involvement of the cytokine interleukin (IL)-26 in bacterial lung infection. We observed markedly increased concentrations of IL-26 in lower airway samples from patients with bacterial pneumonia and these correlated with blood neutrophil concentrations. Moreover, pathogen-associated molecular patterns (PAMPs) from both Gram-negative and -positive bacteria increased extracellular IL-26 concentrations in conditioned media from human models of alveolar epithelial cells, macrophages, and neutrophils in vitro. Stimulation with IL-26 inhibited the inherent release of neutrophil elastase and myeloperoxidase in unexposed neutrophils. This stimulation also inhibited the expression of activity makers in neutrophils exposed to Klebsiella pneumoniae. In addition, priming of human lung tissue ex vivo with exogenous IL-26 potentiated the endotoxin-induced increase in mRNA for other cytokines involved in the innate immune response, including the master Th17-regulator IL-23 and the archetype inhibitory cytokine IL-10. Finally, neutralization of endogenous IL-26 clearly increased the growth of Klebsiella pneumoniae in the macrophage culture. These findings suggest that IL-26 is involved in bacterial lung infection in a complex manner, by modulating critical aspects of innate immune responses locally and systemically in a seemingly purposeful manner and by contributing to the killing of bacteria in a way that resembles an antimicrobial peptide. Thus, IL-26 displays both diagnostic and therapeutic potential in pneumonia and deserves to be further evaluated in these respects.

Complete basic childhood vaccination and associated factors among children aged 12-23 months in East Africa: a multilevel analysis of recent demographic and health surveys

Background

Complete childhood vaccination remains poor in Sub-Saharan Africa, despite major improvement in childhood vaccination coverage worldwide. Globally, an estimated 2.5 million children die annually from vaccine-preventable diseases. While studies are being conducted in different East African countries, there is limited evidence of complete basic childhood vaccinations and associated factors in East Africa among children aged 12–23 months. Therefore, this study aimed to investigate complete basic childhood vaccinations and associated factors among children aged 12–23 months in East Africa.

Methods

Based on the Demographic and Health Surveys (DHSs) of 12 East African countries (Burundi, Ethiopia, Comoros, Uganda, Rwanda, Tanzania, Mozambique, Madagascar, Zimbabwe, Kenya, Zambia, and Malawi), secondary data analysis was performed. The study included a total weighted sample of 18,811 children aged 12–23 months. The basic childhood vaccination coverage was presented using a bar graph. Multilevel binary logistic regression analysis was fitted for identifying significantly associated factors because the DHS has a hierarchical nature. The Intra-class Correlation Coefficient (ICC), Median Odds Ratio (MOR), Proportional Change in Variance (PCV), and deviance (−2LLR) were used for checking model fitness, and for model comparison. Variable with p-value ≤0.2 in the bi-variable multilevel analysis were considered for the multivariable analysis. In the multivariable multilevel analysis, the Adjusted Odds Ratio (AOR) with 95% Confidence Interval (CI) were reported to declare the significance and strength of association with full vaccination.

Results

Complete basic childhood vaccination in East Africa was 69.21% (95% CI, 69.20, 69.21%). In the multivariable multilevel analysis; Mothers aged 25–34 years (AOR = 1.21, 95% CI: 1.10, 1.32), mothers aged 35 years and above (AOR = 1.50, 95% CI: 1.31, 1.71), maternal primary education (AOR = 1.26, 95% CI: 1.15, 1.38), maternal secondary education and above (AOR = 1.54, 95% CI: 1.36, 1.75), husband primary education (AOR = 1.25, 95% CI: 1.13, 1.39), husband secondary education and above (AOR = 1.24, 95% CI: 1.11, 1.40), media exposure (AOR = 1.23, 95% CI: 1.13, 1.33), birth interval of 24–48 months (AOR = 1.28, 95% CI: 1.15, 1.42), birth interval greater than 48 months (AOR = 1.35, 95% CI: 1.21, 1.50), having 1–3 ANC visit (AOR = 3.24, 95% CI: 2.78, 3.77), four and above ANC visit (AOR = 3.68, 95% CI: 3.17, 4.28), PNC visit (AOR = 1.34, 95% CI: 1.23, 1.47), health facility delivery (AOR = 1.48, 95% CI: 1.35, 1.62), large size at birth 1.09 (AOR = 1.09, 95% CI: 1.01, 1.19), being 4–6 births (AOR = 0.83, 95% CI: 0.75, 0.91), being above the sixth birth (AOR = 0.60, 95% CI: 0.52, 0.70), middle wealth index (AOR = 1.16, 95% CI: 1.06, 1.28), rich wealth index (AOR = 1.20, 95% CI: 1.09, 1.33), community poverty (AOR = 1.21, 95% CI: 1.11, 1.32) and country were significantly associated with complete childhood vaccination.

Conclusions

In East Africa, full basic childhood vaccine coverage remains a major public health concern with substantial differences across countries. Complete basic childhood vaccination was significantly associated with maternal age, maternal education, husband education, media exposure, preceding birth interval, number of ANC visits, PNC visits, place of delivery, child-size at birth, parity, wealth index, country, and community poverty. Public health interventions should therefore target children born to uneducated mothers and fathers, poor families, and those who have not used maternal health services to enhance full childhood vaccination to reduce the incidence of child mortality from vaccine-preventable diseases.

[Guidelines for the Management of Community Acquired Pneumonia in Children and Adolescents (Pediatric Community Acquired Pneumonia, pCAP) - Issued under the Responsibility of the German Society for Pediatric Infectious Diseases (DGPI) and the German Society for Pediatric Pulmonology (GPP)]

The present guideline aims to improve the evidence-based management of children and adolescents with pediatric community-acquired pneumonia (pCAP). Despite a prevalence of approx. 300 cases per 100 000 children per year in Central Europe, mortality is very low. Prevention includes infection control measures and comprehensive immunization. The diagnosis can and should be established clinically by history, physical examination and pulse oximetry, with fever and tachypnea as cardinal features. Additional signs or symptoms such as severely compromised general condition, poor feeding, dehydration, altered consciousness or seizures discriminate subjects with severe pCAP from those with non-severe pCAP. Within an age-dependent spectrum of infectious agents, bacterial etiology cannot be reliably differentiated from viral or mixed infections by currently available biomarkers. Most children and adolescents with non-severe pCAP and oxygen saturation > 92 % can be managed as outpatients without laboratory/microbiology workup or imaging. Anti-infective agents are not generally indicated and can be safely withheld especially in children of young age, with wheeze or other indices suggesting a viral origin. For calculated antibiotic therapy, aminopenicillins are the preferred drug class with comparable efficacy of oral (amoxicillin) and intravenous administration (ampicillin). Follow-up evaluation after 48 - 72 hours is mandatory for the assessment of clinical course, treatment success and potential complications such as parapneumonic pleural effusion or empyema, which may necessitate alternative or add-on therapy.

Anti-Inflammatory Effects of Neochlorogenic Acid Extract from Mulberry Leaf (Morus alba L.) Against LPS-Stimulated Inflammatory Response through Mediating the AMPK/Nrf2 Signaling Pathway in A549 Cells

Neochlorogenic acid (nCGA) is a phenolic compound isolated from mulberry leaf (Morus alba L.), which possesses multiple pharmacological activities containing antioxidant and anti-inflammatory effects. However, the role of nCGA in the treatment of acute pneumonia and the underlying molecular mechanism are still unclear. Hence, the aim of study is to investigate the anti-inflammatory properties of nCGA on LPS-stimulated inflammation in A549 cells. In the present study, results reported that nCGA without cytotoxicity significantly reduced the production of TNF-α, IL-6, and NO, and further suppressed the proteins of iNOS, COX2, TNF-α, IL-6 expression. Furthermore, nCGA also inhibited NF-κB activation and blocked MAPKs signaling pathway phosphorylation. In addition, we found nCGA significantly increased the expression of HO-1 via activating the AMPK/Nrf2 signaling pathway to attenuate the inflammatory response, whereas this protective effect of nCGA was reversed by pre-treatment with compound C (C.C, an AMPK inhibitor). Therefore, all these results indicated that nCGA might act as a natural anti-inflammatory agent for the treatment of acute pneumonia.

Design and characterisation of a dissolving microneedle patch for intradermal vaccination with heat-inactivated bacteria: A proof of concept study

This work describes the formulation and evaluation of dissolving microneedle patches (MNs) for intradermal delivery of heat-inactivated bacteria. Pseudomonas aeruginosa, strain PA01, was used as a model bacterium. Utilising a simple, cost effective fabrication process, P. aeruginosa was heat-inactivated and formulated into dissolving MNs, fabricated from aqueous blends of 20% w/w poly(methylvinylether/maleic acid). The resultant MNs were of sufficient mechanical strength to consistently penetrate a validated skin model Parafilm M®, inserting to a depth of between 254 and 381 µm. MNs were successfully inserted into murine skin and partially dissolved. Analysis of MN dissolution kinetics in murine ears via optical coherence tomography showed almost complete MN dissolution 5 min post-insertion. Mice were vaccinated using these optimised MNs by application of one MN to the dorsal surface of each ear (5 min). Mice were subsequently challenged intranasally (24 h) with a live culture of P. aeruginosa (2 × 10⁶ colony forming units). Bacterial load in the lungs of mice vaccinated with P. aeruginosa MNs was significantly (p = 0.0059) lower than those of their unvaccinated counterparts. This proof of concept work demonstrates the potential of dissolving MNs for intradermal vaccination with heat-inactivated bacteria. MNs may be a cost effective, potentially viable delivery system, which could easily be implemented in developing countries, allowing a rapid and simplified approach to vaccinating against a specific pathogen.

Beyond new vaccine introduction: the uptake of pneumococcal conjugate vaccine in the African Region

The number of vaccines available to low-income countries has increased dramatically over the last decade. Overall infant immunization coverage in the WHO African region has stagnated in the past few years while countries’ ability to maintain high immunization coverage rates following introduction of new vaccines has been uneven. This case study examines post-introduction coverage among African countries that introduced PCV between 2008 and 2013 and the factors affecting Pneumococcal Conjugate Vaccine (PCV) introduction. Nearly one-third of countries did not achieve 80% infant PCV3 coverage by two years post-introduction and 58% of countries experienced a decline in coverage between post introduction years two and four. Major factors affecting coverage rates included introduction without adequate preparation, insufficient supply chain capacity and management, poor communication between organizations and with the public, and data collection systems that were insufficient to meet information needs. Deliberately addressing these issues as well as longstanding weaknesses during new vaccine introduction can strengthen the immunization and broader health system. Further study is required to identify and address factors that affect maintenance of high coverage following introduction of new vaccines in the African region. Immunization with PCV is one of the most important interventions protecting against pneumonia, the second leading cause of death for children under five globally.

Encouraging rational antibiotic use in childhood pneumonia: a focus on Vietnam and the Western Pacific Region

Globally, pneumonia is considered to be the biggest killer of infants and young children (aged <5 years) outside the neonatal period, with the greatest disease burden in low- and middle-income countries. Optimal management of childhood pneumonia is challenging in settings where clinicians have limited information regarding the local pathogen and drug resistance profiles. This frequently results in unnecessary and poorly targeted antibiotic use. Restricting antibiotic use is a global priority, particularly in Asia and the Western Pacific Region where excessive use is driving high rates of antimicrobial resistance. The authors conducted a comprehensive literature review to explore the antibiotic resistance profile of bacteria associated with pneumonia in the Western Pacific Region, with a focus on Vietnam. Current management practices were also considered, along with the diagnostic dilemmas faced by doctors and other factors that increase unnecessary antibiotic use. This review offers some suggestions on how these issues may be addressed.

Factors That Negatively Affect the Prognosis of Pediatric Community-Acquired Pneumonia in District Hospital in Tanzania

Community-acquired pneumonia (CAP) is still the most important cause of death in countries with scarce resources. All children (33 months ± 35 DS) discharged from the Pediatric Unit of Itigi Hospital, Tanzania, with a diagnosis of CAP from August 2014 to April 2015 were enrolled. Clinical data were gathered. Dried blood spot (DBS) samples for quantitative real-time polymerase chain reaction (PCR) for bacterial detection were collected in all 100 children included. Twenty-four percent of patients were identified with severe CAP and 11% died. Surprisingly, 54% of patients were admitted with a wrong diagnosis, which increased complications, the need for antibiotics and chest X-rays, and the length of hospitalization. Comorbidity, found in 32% of children, significantly increased severity, complications, deaths, need for chest X-rays, and oxygen therapy. Malnourished children (29%) required more antibiotics. Microbiologically, Streptococcus pneumonia (S. p.), Haemophilus influenza type b (Hib) and Staphylococcus aureus (S. a.) were the bacteria more frequently isolated. Seventy-five percent of patients had mono-infection. Etiology was not correlated with severity, complications, deaths, oxygen demand, or duration of hospitalization. Our study highlights that difficult diagnoses and comorbidities negatively affect clinical evolution. S. p. and Hib still play a large role; thus, implementation of current vaccine strategies is needed. DBS is a simple and efficient diagnostic method for bacterial identification in countries with scarce resources.

Community-acquired pneumonia in children - a changing spectrum of disease

Pneumonia remains the leading cause of death in children outside the neonatal period, despite advances in prevention and management. Over the last 20 years, there has been a substantial decrease in the incidence of childhood pneumonia and pneumonia-associated mortality. New conjugate vaccines against Haemophilus influenzae type b and Streptococcus pneumoniae have contributed to decreases in radiologic, clinical and complicated pneumonia cases and have reduced hospitalization and mortality. The importance of co-infections with multiple pathogens and the predominance of viral-associated disease are emerging. Better access to effective preventative and management strategies is needed in low- and middle-income countries, while new strategies are needed to address the residual burden of disease once these have been implemented.

Pneumococcal Carriage in Children under Five Years in Uganda-Will Present Pneumococcal Conjugate Vaccines Be Appropriate?

BACKGROUND

Pneumonia is the major cause of death in children globally, with more than 900,000 deaths annually in children under five years of age. Streptococcus pneumoniae causes most deaths, most often in the form of community acquired pneumonia. Pneumococcal conjugate vaccines (PCVs) are currently being implemented in many low-income countries. PCVs decrease vaccine-type pneumococcal carriage, a prerequisite for invasive pneumococcal disease, and thereby affects pneumococcal disease and transmission. In Uganda, PCV was launched in 2014, but baseline data is lacking for pneumococcal serotypes in carriage.

OBJECTIVES

To study pneumococcal nasopharyngeal carriage and serotype distribution in children under 5 years of age prior to PCV introduction in Uganda.

METHODS

Three cross-sectional pneumococcal carriage surveys were conducted in 2008, 2009 and 2011, comprising respectively 150, 587 and 1024 randomly selected children aged less than five years from the Iganga/Mayuge Health and Demographic Surveillance Site. The caretakers were interviewed about illness history of the child and 1723 nasopharyngeal specimens were collected. From these, 927 isolates of S. pneumoniae were serotyped.

RESULTS

Overall, the carriage rate of S. pneumoniae was 56% (957/1723). Pneumococcal carriage was associated with illness on the day of the interview (OR = 1.50, p = 0.04). The most common pneumococcal serotypes were in descending order 19F (16%), 23F (9%), 6A (8%), 29 (7%) and 6B (7%). One percent of the strains were non-typeable. The potential serotype coverage rate for PCV10 was 42% and 54% for PCV13.

CONCLUSION

About half of circulating pneumococcal serotypes in carriage in the Ugandan under-five population studied was covered by available PCVs.