Bacterial pneumonia vaccines and childhood pneumonia: are we winning, refining, or redefining?

Pulmonary Diseases in Older Patients: Understanding and Addressing the Challenges

As the global population ages, pulmonary diseases among older people have emerged as a significant and growing public health concern. The increasing incidence of these conditions has led to higher rates of morbidity and mortality among older adults. This perspective study offers a thorough overview of the prevalent pulmonary diseases affecting the elderly demographic. It delves into the challenges encountered during the diagnosis and management of these conditions in older individuals, considering factors such as comorbidities, functional limitations, and medication complexities. Furthermore, innovative strategies and personalized interventions such as precision medicine, advanced therapies, telemedicine solutions, and patient-centered support systems aimed at enhancing the care provided to older individuals grappling with pulmonary disorders are thoroughly explored. By addressing the unique needs and complexities of this vulnerable population, healthcare systems can strive towards improving outcomes and enhancing the quality of life for elderly individuals affected by pulmonary diseases.

Mechanisms of Lung and Intestinal Microbiota and Innate Immune Changes Caused by Pathogenic Enterococcus Faecalis Promoting the Development of Pediatric Pneumonia

Bacterial pneumonia is the main cause of illness and death in children under 5 years old. We isolated and cultured pathogenic bacteria LE from the intestines of children with pneumonia and replicated the pediatric pneumonia model using an oral gavage bacterial animal model. Interestingly, based on 16srRNA sequencing, we found that the gut and lung microbiota showed the same imbalance trend, which weakened the natural resistance of this area. Further exploration of its mechanism revealed that the disruption of the intestinal mechanical barrier led to the activation of inflammatory factors IL-6 and IL-17, which promoted the recruitment of ILC-3 and the release of IL-17 and IL-22, leading to lung inflammation. The focus of this study is on the premise that the gut and lung microbiota exhibit similar destructive changes, mediating the innate immune response to promote the occurrence of pneumonia and providing a basis for the development and treatment of new drugs for pediatric pneumonia.

HUS and TTP: traversing the disease and the age spectrum

Hemolytic uremic syndrome (HUS) and thrombotic thrombocytopenia purpura (TTP) are rare diseases sharing a common pathological feature, thrombotic microangiopathy (TMA). TMA is characterized by microvascular thrombosis with consequent thrombocytopenia, microangiopathic hemolytic anemia and/or multiorgan dysfunction. In the past, the distinction between HUS and TTP was predominantly based on clinical grounds. However, clinical presentation of the two syndromes often overlaps and, the differential diagnosis is broad. Identification of underlying pathogenic mechanisms has enabled the classification of these syndromes on a molecular basis: typical HUS caused by Shiga toxin-producing Escherichia coli (STEC-HUS); atypical HUS or complement-mediated TMA (aHUS/CM-TMA) associated with genetic or acquired defects leading to dysregulation of the alternative pathway (AP) of complement; and TTP that results from a severe deficiency of the von Willebrand Factor (VWF)-cleaving protease, ADAMTS13. The etiology of TMA differs between pediatric and adult patients. Childhood TMA is chiefly caused by STEC-HUS, followed by CM-TMA and pneumococcal HUS (Sp-HUS). Rare conditions such as congenital TTP (cTTP), vitamin B12 metabolism defects, and coagulation disorders (diacylglycerol epsilon mutation) present as TMA chiefly in children under 2 years of age. In contrast secondary causes and acquired ADAMT13 deficiency are more common in adults. In adults, compared to children, diagnostic delays are more frequent due to the wide range of differential diagnoses. In this review we focus on the three major forms of TMA, STEC-HUS, aHUS and TTP, outlining the clinical presentation, diagnosis and management of the affected patients, to help highlight the salient features and the differences between adult and pediatric patients which are relevant for management.

Probiotic-based nanoparticles for targeted microbiota modulation and immune restoration in bacterial pneumonia

While conventional bacterial pneumonia mainly centralizes avoidance of bacterial colonization, it remains unclear how to restore the host immunity for hyperactive immunocompetent primary and immunocompromised secondary bacterial pneumonia. Here, probiotic-based nanoparticles of OASCLR were formed by coating chitosan, hyaluronic acid and ononin on living Lactobacillus rhamnosus. OASCLR nanoparticles could effectively kill various clinic common pathogens and antibacterial efficiency was >99.97%. Importantly, OASCLR could modulate lung microbiota, increasing the overall richness and diversity of microbiota by decreasing pathogens and increasing probiotic and commensal bacteria. Additionally, OASCLR could target inflammatory macrophages by the interaction of OASCLR with the macrophage binding site of CD44 and alleviate overactive immune responses for hyperactive immunocompetent pneumonia. Surprisingly, OASCLR could break the state of the macrophage's poor phagocytic ability by upregulating the expression of the extracellular matrix assembly, immune activation and fibroblast activation in immunocompromised pneumonia. The macrophage's phagocytic ability was increased from 2.61% to 12.3%. Our work provides a potential strategy for hyperactive immunocompetent primary and immunocompromised secondary bacterial pneumonia.

Chest X-ray Classification for the Detection of COVID-19 Using Deep Learning Techniques

Recent technological developments pave the path for deep learning-based techniques to be used in almost every domain of life. The precision of deep learning techniques make it possible for these to be used in the medical field for the classification and detection of various diseases. Recently, the coronavirus (COVID-19) pandemic has put a lot of pressure on the health system all around the world. The diagnosis of COVID-19 is possible by PCR testing and medical imagining. Since COVID-19 is highly contagious, diagnosis using chest X-ray is considered safe in various situations. In this study, a deep learning-based technique is proposed to classify COVID-19 infection from other non-COVID-19 infections. To classify COVID-19, three different pre-trained models named EfficientNetB1, NasNetMobile and MobileNetV2 are used. The augmented dataset is used for training deep learning models while two different training strategies have been used for classification. In this study, not only are the deep learning model fine-tuned but also the hyperparameters are fine-tuned, which significantly improves the performance of the fine-tuned deep learning models. Moreover, the classification head is regularized to improve the performance. For the evaluation of the proposed techniques, several performance parameters are used to gauge the performance. EfficientNetB1 with regularized classification head outperforms the other models. The proposed technique successfully classifies four classes that include COVID-19, viral pneumonia, lung opacity, and normal, with an accuracy of 96.13%. The proposed technique shows superiority in terms of accuracy when compared with recent techniques present in the literature.

Role of lung ultrasound for the etiological diagnosis of acute lower respiratory tract infection (ALRTI) in children: a prospective study

Objective and design

Our prospective study assesses the role of detailed lung ultrasound (LUS) features to discriminate the etiological diagnosis of acute lower respiratory tract infection (ALRTI) in children.

Methodology

We analyzed patients aged from 1 month to 17 years admitted between March 2018 and April 2020 who were hospitalized for ALRTI. For all patients, history, clinical parameters, microbiological data, and lung ultrasound data were collected. Patients were stratified into three main groups (“bacterial”, “viral”, “atypical”) according to the presumed microbial etiology and LUS findings evaluated according to the etiological group. Nasopharyngeal swabs were obtained from all patients. A qualitative diagnostic test developed by Nurex S.r.l. was used for identification of bacterial and fungal DNA in respiratory samples. The Seegene Allplex™ Respiratory assays were used for the molecular diagnosis of viral respiratory pathogens. In addition, bacterial culture of blood and respiratory samples were performed, when indicated.

Results

A total of 186 children with suspected ALRTI (44% female) with an average age of 6 were enrolled in the study. We found that some ultrasound findings as size, number and distribution of consolidations, the position and motion of air bronchograms, pleural effusions and distribution of vertical artifacts significantly differ (p < 0.05) in children with bacterial, viral and atypical ALRTI.

Conclusion

Our study provides a detailed analysis of LUS features able to predict the ALRTI ethology in children. These findings may help the physicians to better manage a child with ALRTI and to offer personalized approach, from diagnosis to treatment and follow-up.

Streptococcus Pneumoniae-Associated Hemolytic Uremic Syndrome in the Era of Pneumococcal Vaccine

Streptococcus pneumoniae-associated hemolytic uremic syndrome (Sp-HUS) is a serious complication of invasive pneumococcal disease that is associated with increased mortality in the acute phase and morbidity in the long term. Recently, Sp-HUS definition has undergone revision and cases are categorized as definite, probable, and possible, based on less invasive serological investigations that evaluate Thomsen-Friedenreich crypt antigen (T-antigen) activation. In comparison to the pre-vaccine era, Sp-HUS incidence seems to be decreasing after the introduction of 7-serotype valence and 13-serotype valence pneumococcal vaccines in 2000 and 2010, respectively. However, Sp-HUS cases continue to occur secondary to vaccine failure and emergence of non-vaccine/replacement serotypes. No single hypothesis elucidates the molecular basis for Sp-HUS occurrence, although pneumococcal neuraminidase production and formation of T-antigen antibody complexes on susceptible endothelial and red blood cells continues to remain the most acceptable explanation. Management of Sp-HUS patients remains supportive in nature and better outcomes are being reported secondary to earlier recognition, better diagnostic tools and improved medical care. Recently, the addition of eculizumab therapy in the management of Sp-HUS for control of dysregulated complement activity has demonstrated good outcomes, although randomized clinical trials are awaited. A sustained pneumococcal vaccination program and vigilance for replacement serotypes will be the key for persistent reduction in Sp-HUS cases worldwide.

Pneumonia Classification Using Deep Learning from Chest X-ray Images During COVID-19

The outbreak of the novel corona virus disease (COVID-19) in December 2019 has led to global crisis around the world. The disease was declared pandemic by World Health Organization (WHO) on 11th of March 2020. Currently, the outbreak has affected more than 200 countries with more than 37 million confirmed cases and more than 1 million death tolls as of 10 October 2020. Reverse-transcription polymerase chain reaction (RT-PCR) is the standard method for detection of COVID-19 disease, but it has many challenges such as false positives, low sensitivity, expensive, and requires experts to conduct the test. As the number of cases continue to grow, there is a high need for developing a rapid screening method that is accurate, fast, and cheap. Chest X-ray (CXR) scan images can be considered as an alternative or a confirmatory approach as they are fast to obtain and easily accessible. Though the literature reports a number of approaches to classify CXR images and detect the COVID-19 infections, the majority of these approaches can only recognize two classes (e.g., COVID-19 vs. normal). However, there is a need for well-developed models that can classify a wider range of CXR images belonging to the COVID-19 class itself such as the bacterial pneumonia, the non-COVID-19 viral pneumonia, and the normal CXR scans. The current work proposes the use of a deep learning approach based on pretrained AlexNet model for the classification of COVID-19, non-COVID-19 viral pneumonia, bacterial pneumonia, and normal CXR scans obtained from different public databases. The model was trained to perform two-way classification (i.e., COVID-19 vs. normal, bacterial pneumonia vs. normal, non-COVID-19 viral pneumonia vs. normal, and COVID-19 vs. bacterial pneumonia), three-way classification (i.e., COVID-19 vs. bacterial pneumonia vs. normal), and four-way classification (i.e., COVID-19 vs. bacterial pneumonia vs. non-COVID-19 viral pneumonia vs. normal). For non-COVID-19 viral pneumonia and normal (healthy) CXR images, the proposed model achieved 94.43% accuracy, 98.19% sensitivity, and 95.78% specificity. For bacterial pneumonia and normal CXR images, the model achieved 91.43% accuracy, 91.94% sensitivity, and 100% specificity. For COVID-19 pneumonia and normal CXR images, the model achieved 99.16% accuracy, 97.44% sensitivity, and 100% specificity. For classification CXR images of COVID-19 pneumonia and non-COVID-19 viral pneumonia, the model achieved 99.62% accuracy, 90.63% sensitivity, and 99.89% specificity. For the three-way classification, the model achieved 94.00% accuracy, 91.30% sensitivity, and 84.78%. Finally, for the four-way classification, the model achieved an accuracy of 93.42%, sensitivity of 89.18%, and specificity of 98.92%.

New insights into the pathogenesis of Streptococcus pneumoniae-associated hemolytic uremic syndrome

The purpose of this review is to describe Streptococcus pneumoniae-associated hemolytic uremic syndrome (P-HUS) with emphasis on new insights into the pathophysiology and management over the past 10 years. Even though awareness of this clinico-pathological entity has increased, it likely remains under-recognized. Recent observations indicate that although neuraminidase activity and exposure of the T-antigen are necessary for development of P-HUS, they are not sufficient; activation of the alternate pathway of complement may also contribute. It is unclear, however, whether or not eculizumab and/or plasmapheresis are of value.

Prevalence, Risk Factors, and Outcomes of Bacteremic Pneumonia in Children

BACKGROUND

Previous studies examining bacteremia in hospitalized children with pneumonia are limited by incomplete culture data. We sought to determine characteristics of children with bacteremic pneumonia using data from a large prospective study with systematic blood culturing.

METHODS

Children <18 years hospitalized with pneumonia and enrolled in the multicenter Etiology of Pneumonia in the Community study between January 2010 and June 2012 were eligible. Bivariate comparisons were used to identify factors associated with bacteremia. Associations between bacteremia and clinical outcomes were assessed by using Cox proportional hazards regression for length of stay and logistic regression for ICU admission and invasive mechanical ventilation or shock.

RESULTS

Blood cultures were obtained in 2143 (91%) of 2358 children; 46 (2.2%) had bacteremia. The most common pathogens were Streptococcus pneumoniae (n = 23, 50%), Staphylococcus aureus (n = 6, 13%), and Streptococcus pyogenes (n = 4, 9%). Characteristics associated with bacteremia included male sex, parapneumonic effusion, lack of chest indrawing or wheezing, and no previous receipt of antibiotics. Children with bacteremia had longer lengths of stay (median: 5.8 vs 2.8 days; adjusted hazard ratio: 0.79 [0.73-0.86]) and increased odds of ICU admission (43% vs 21%; adjusted odds ratio: 5.21 [3.82-6.84]) and invasive mechanical ventilation or shock (30% vs 8%; adjusted odds ratio: 5.28 [2.41-11.57]).

CONCLUSIONS

Bacteremia was uncommonly detected in this large multicenter cohort of children hospitalized with community-acquired pneumonia but was associated with severe disease. S pneumoniae was detected most often. Blood culture was of low yield in general but may have greater use in those with parapneumonic effusion and ICU admission.

The global burden of respiratory infections in indigenous children and adults: A review

This review article focuses on common lower respiratory infections (LRIs) in indigenous populations in both developed and developing countries, where data is available. Indigenous populations across the world share some commonalities including poorer health and socio-economic disadvantage compared with their non-indigenous counterparts. Generally, acute and chronic respiratory infections are more frequent and more severe in both indigenous children and adults, often resulting in substantial consequences including higher rates of bronchiectasis and poorer outcomes for patients with chronic obstructive pulmonary disease (COPD). Risk factors for the development of respiratory infections require recognition and action. These risk factors include but are not limited to socio-economic factors (e.g. education, household crowding and nutrition), environmental factors (e.g. smoke exposure and poor access to health care) and biological factors. Risk mitigation strategies should be delivered in a culturally appropriate manner and targeted to educate both individuals and communities at risk. Improving the morbidity and mortality of respiratory infections in indigenous people requires provision of best practice care and awareness of the scope of the problem by healthcare practitioners, governing bodies and policy makers.

Pneumococcal vaccination reduces the risk of community-acquired pneumonia in children

BACKGROUND

The seven-valent pneumococcal conjugate vaccine (PCV7) was introduced to Japan in 2009, after which there was a rapid decline in invasive pneumococcal disease. There are few data, however, on the effectiveness of PCV7 against community-acquired pneumonia (CAP). We conducted an ambispective cohort study among children aged 0-6 years old who attended day-care centers.

METHODS

A total of 624 children at 10 day-care centers in Sapporo, Japan participated in the study. The parents reported whether their child had received PCV7 one or more times, as well as the exact dates of vaccination from records in maternal and child health handbooks marked by pediatricians. Each CAP event was reported by parents according to doctor diagnosis. A Cox proportional hazards regression model was used to calculate the hazard ratio (HR) and 95%CI of CAP incidence reduced by PCV7 inoculation.

RESULTS

During the observational period, 94 subjects contracted CAP. After adjusting for potentially confounding variables, inoculation with PCV7 was significantly associated with a reduced risk of CAP (HR, 0.22; 95%CI: 0.13-0.34). On stratified analysis by age, PCV7 was significantly associated with a reduced risk of CAP in both children aged <3 years (HR, 0.31; 95%CI: 0.14-0.71), and those ≥3 years (HR, 0.20; 95%CI: 0.09-0.43).

CONCLUSION

PCV7 is highly effective in reducing the risk of CAP in children attending day-care centers.

Pneumonia hospitalisations in Scotland following the introduction of pneumococcal conjugate vaccination in young children

Background

Scotland introduced PCV7 and PCV13 immunisation in young children in 2006 and 2010 respectively. One recent study from the United States reported a decrease in hospitalisation rates for all-cause pneumonia most notably in adults older than 75 years of age following PCV7 introduction in the US child population. We aimed to examine the effect of PCV7 and PCV13 on hospitalisation rates for all-cause pneumonia across all age groups in Scotland.

Methods

We linked hospital records and death certification datasets for the entire Scottish population for the period 2000 to 2012. We included all cases where the primary / secondary diagnosis was pneumonia. Differences in hospital admission rates for pneumonia by age group were calculated using the difference in average annual rates for each period.

Results

We estimated that all-cause pneumonia hospitalisation rates in children <2 years decreased by about 30 % in the post-PCV-13 period compared with the pre-PCV period. However, in adults aged 75–84 years and ≥85 years, all-cause pneumonia hospitalisation rates increased by 63 and 46 % respectively in the post-PCV 13 period compared to the pre-PCV period. This resulted in an additional 7000 hospitalisations across all age groups in Scotland in 2012 about half of which were in adults >75 years. At the same time, the median length of hospital stay decreased by a third in children <2 years and by about 20 % in adults >75 years in the post-PCV13 period compared to the pre-PCV period. Additionally, there was an 11 % reduction in deaths due to all-cause pneumonia, and 30 % reduction in pneumococcal hospitalisations across all age groups in the post-PCV13 period compared with pre-PCV period.

Discussion

The modest and sustained decline in the rates of hospitalisation for all-cause pneumonia in children and the reduction in proportion of pneumonia hospitalisations in children coded as pneumococcal disease in the post-PCV period should alleviate concerns that pneumococcal serotype replacement may have resulted in an increased pneumonia burden in this age group. The indirect impact of child PCV immunisation in those not vaccinated (in terms of reduction in all-cause pneumonia hospitalisations in the elderly) has not been seen in Scotland. Our results are likely to be confounded by changes in clinical coding and healthcare practices over the same period.

Conclusions

Our results illustrate that health care planners cannot, with confidence, predict indirect PCV vaccine impacts on hospitalisations. IPD surveillance across all age groups is needed to assess the indirect effects of PCV in the community.

Electronic supplementary material

The online version of this article (doi:10.1186/s12879-016-1693-x) contains supplementary material, which is available to authorized users.

Impact of the pneumococcal 10-valent vaccine on reducing hospitalization for community-acquired pneumonia in children

OBJECTIVE

To describe and analyze the occurrence of hospitalizations for community-acquired pneumonia in children before and after the pneumococcal 10-valent conjugate vaccine implementation into the National Immunization Program.

METHODS

This is an ecological study that includes records of children younger than one year old, vaccinated and not vaccinated with the pneumococcal 10-valent conjugate vaccine in the periods pre- and post-inclusion of the vaccine in the National Immunization Program in the area covered by the Regional Health Superintendence of Alfenas, state of Minas Gerais, Brazil. Vaccination was considered as the exposure factor and hospitalization for community-acquired pneumonia as the endpoint, using secondary annual data by municipality. The prevalence ratio and its 95% confidence interval (95%CI) were used to verify the association between variables. The Z test was used to calculate the difference between proportions.

RESULTS

Considering the 26 municipalities of the Regional Health Superintendence of Alfenas, there was a significant reduction in hospitalizations for community-acquired pneumonia in children younger than one year of age, with prevalence ratio (PR)=0.81 (95%CI: 0.74 to 0.89; p<0.05), indicating a 19% lower prevalence of hospitalization for community-acquired pneumonia in the post-vaccination period.

CONCLUSIONS

The results suggest the effectiveness of the pneumococcal 10-valent conjugate vaccine in preventing severe cases of community-acquired pneumonia in children younger than one year of age.

Impact of the pneumococcal 10-valent vaccine on reducing hospitalization for community-acquired pneumonia in children

OBJECTIVE

To describe and analyze the occurrence of hospitalizations for community-acquired pneumonia in children before and after the pneumococcal 10-valent conjugate vaccine implementation into the National Immunization Program.

METHODS

This is an ecological study that includes records of children younger than one year old, vaccinated and not vaccinated with the pneumococcal 10-valent conjugate vaccine in the periods pre- and post-inclusion of the vaccine in the National Immunization Program in the area covered by the Regional Health Superintendence of Alfenas, state of Minas Gerais, Brazil. Vaccination was considered as the exposure factor and hospitalization for community-acquired pneumonia as the endpoint, using secondary annual data by municipality. The prevalence ratio and its 95% confidence interval (95%CI) were used to verify the association between variables. The Z test was used to calculate the difference between proportions.

RESULTS

Considering the 26 municipalities of the Regional Health Superintendence of Alfenas, there was a significant reduction in hospitalizations for community-acquired pneumonia in children younger than one year of age, with prevalence ratio (PR)=0.81 (95%CI: 0.74 to 0.89; p<0.05), indicating a 19% lower prevalence of hospitalization for community-acquired pneumonia in the post-vaccination period.

CONCLUSIONS

The results suggest the effectiveness of the pneumococcal 10-valent conjugate vaccine in preventing severe cases of community-acquired pneumonia in children younger than one year of age.

Intranasal vaccination with γ-irradiated Streptococcus pneumoniae whole-cell vaccine provides serotype-independent protection mediated by B-cells and innate IL-17 responses

Generating a pneumococcal vaccine that is serotype independent and cost effective remains a global challenge. γ-Irradiation has been used widely to sterilize biological products. It can also be utilized as an inactivation technique to generate whole-cell bacterial and viral vaccines with minimal impact on pathogen structure and antigenic determinants. In the present study, we utilized γ-irradiation to inactivate an un-encapsulated Streptococcus pneumoniae strain Rx1 with an unmarked deletion of the autolysin gene lytA and with the pneumolysin gene ply replaced with an allele encoding a non-toxic pneumolysoid (PdT) (designated γ-PN vaccine). Intranasal vaccination of C57BL/6 mice with γ-PN was shown to elicit serotype-independent protection in lethal challenge models of pneumococcal pneumonia and sepsis. Vaccine efficacy was shown to be reliant on B-cells and interleukin (IL)-17A responses. Interestingly, immunization promoted IL-17 production by innate cells not T helper 17 (Th17) cells. These data are the first to report the development of a non-adjuvanted intranasal γ-irradiated pneumococcal vaccine that generates effective serotype-independent protection, which is mediated by both humoral and innate IL-17 responses.

A review of the role of Haemophilus influenzae in community-acquired pneumonia

In an era when Haemophilus influenzae type b (Hib) conjugate vaccine is widely used, the incidence of Hib as a cause of community-acquired pneumonia (CAP) has dramatcally declined. Non-typeable H. influenzae (NTHi) strains and, occasionally, other encapsulated serotypes of H. influenzae are now the cause of the majority of invasive H. influenzae infectons, including bacteraemic CAP. NTHi have long been recognised as an important cause of lower respiratory tract infecton, including pneumonia, in adults, especially those with underlying diseases. The role of NTHi as a cause of non-bacteraemic CAP in children is less clear. In this review the evidence for the role of NTHi and capsulated strains of H. influenzae will be examined.

Using Standardized Interpretation of Chest Radiographs to Identify Adults with Bacterial Pneumonia--Guatemala, 2007-2012

Background

Bacterial pneumonia is a leading cause of illness and death worldwide, but quantifying its burden is difficult due to insensitive diagnostics. Although World Health Organization (WHO) protocol standardizes pediatric chest radiograph (CXR) interpretation for epidemiologic studies of bacterial pneumonia, its validity in adults is unknown.

Methods

Patients (age ≥15 years) admitted with respiratory infections to two Guatemalan hospitals between November 2007 and March 2012 had urine and nasopharyngeal/oropharyngeal (NP/OP) swabs collected; blood cultures and CXR were also performed at physician clinical discretion. ‘Any bacterial infection’ was defined as a positive urine pneumococcal antigen test, isolation of a bacterial pneumonia pathogen from blood culture, or detection of an atypical bacterial pathogen by polymerase chain reaction (PCR) of nasopharyngeal/oropharyngeal (NP/OP) specimens. ‘Viral infection’ was defined as detection of viral pathogens by PCR of NP/OP specimens. CXRs were interpreted according to the WHO protocol as having ‘endpoint consolidation’, ‘other infiltrate’, or ‘normal’ findings. We examined associations between bacterial and viral infections and endpoint consolidation.

Findings

Urine antigen and/or blood culture results were available for 721 patients with CXR interpretations; of these, 385 (53%) had endpoint consolidation and 253 (35%) had other infiltrate. Any bacterial infection was detected in 119 (17%) patients, including 106 (89%) pneumococcal infections. Any bacterial infection (Diagnostic Odds Ratio [DOR] = 2.9; 95% confidence Interval (CI): 1.3–7.9) and pneumococcal infection (DOR = 3.4; 95% CI: 1.5–10.0) were associated with ‘endpoint consolidation’, but not ‘other infiltrate’ (DOR = 1.7; 95% CI: 0.7–4.9, and 1.7; 95% CI: 0.7–4.9 respectively). Viral infection was not significantly associated with ‘endpoint consolidation’, ‘other infiltrate,’ or ‘normal’ findings.

Interpretation

‘Endpoint consolidation’ was associated with ‘any bacterial infection,’ specifically pneumococcal infection. Therefore, endpoint consolidation may be a useful surrogate for studies measuring the impact of interventions, such as conjugate vaccines, against bacterial pneumonia.

Risk factors for a poor outcome among children admitted with clinically severe pneumonia to a university hospital in Rabat, Morocco

•

Pneumonia remains one of the major killers of children in a middle-income country such as Morocco.

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A history of prematurity, a history of fever, leaving in a house with smokers, impaired consciousness, cyanosis, pallor, having ronchi on auscultation and human metapneumovirus infection are all independent risk factors for an adverse outcome.

•

A history of asthma is independently associated with a positive outcome.

•

Early identification of risk factors for an adverse outcome could improve overall prognosis.

Objectives

Data on prognostic factors among children with severe pneumonia are scarce in middle-income countries. We investigated prognostic factors for an adverse outcome among children admitted to the Hôpital d’Enfants de Rabat, Morocco with World Health Organization-defined clinically severe pneumonia (CSP).

Methods

Children aged 2–59 months admitted to the hospital and fulfilling the CSP definition were recruited into this 13-month prospective study. A poor prognosis was defined as death, a need for intensive care, or a Respiratory Index of Severity in Children (RISC) score ≥3. Multivariate logistic regression was performed to ascertain independent predictive factors for a poor prognosis.

Results

Of the 689 children included in this analysis, 55 (8.0%) required intensive care and 28 died (4.0%). Five hundred and two (72.8%) children were classified as having a good prognosis and 187 (27.2%) as having a poor prognosis. A history of prematurity (odds ratio (OR) 2.50, 95% confidence interval (CI) 1.24–5.04), of fever (OR 2.25, 95% CI 1.32–3.83), living in a house with smokers (OR 1.79, 95% CI 1.18–2.72), impaired consciousness (OR 10.96, 95% CI 2.88–41.73), cyanosis (OR 2.09, 95% CI 1.05–4.15), pallor (OR 2.27, 95% CI 1.34–3.84), having rhonchi on auscultation (OR 2.45, 95% CI 1.58–3.79), and human metapneumovirus infection (OR 2.13, 95% CI 1.13–4.02) were all independent risk factors for an adverse outcome, whereas a history of asthma (OR 0.46, 95% CI 0.25–0.84) was the only independent risk factor for a positive outcome.

Conclusions

The early identification of factors associated with a poor prognosis could improve management strategies and the likelihood of survival of Moroccan children with severe pneumonia.

The epidemiology and aetiology of infections in children admitted with clinical severe pneumonia to a university hospital in Rabat, Morocco

OBJECTIVES

Scarce and limited epidemiological, clinical and microbiological data are available regarding paediatric respiratory tract infections in the Kingdom of Morocco, a middle-income country in northwestern Africa. The results of hospital-based surveillance aiming at describing the aetiology and epidemiology of respiratory distress among children <5 years of age are presented.

METHODS

Children admitted to the Hôpital d'Enfants de Rabat, Morocco, and meeting the World Health Organization clinical criteria for severe pneumonia were recruited over a period of 14 months and were thoroughly investigated to ascertain a definitive diagnosis.

RESULTS

In total, 700 children were recruited for the study. Most frequent clinical diagnoses included wheezing-related conditions (bronchitis/asthma, 46%; bronchiolitis, 15%), while typical bacterial pneumonia was infrequent (only 19% of the cases). Invasive bacterial disease detected by classical microbiology or molecular methods was also uncommon, affecting only 3.5% of the patients, and with an overall low detection of pneumococcal or Haemophilus influenzae type b disease. Conversely, coverage of respiratory viral detection in the nasopharynx was almost universal among cases (92%), with the three most frequent viruses detected being rhinovirus (53%), respiratory syncytial virus (18%) and adenovirus (17%). The overall case fatality rate (CFR) among recruited patients with a known outcome was 4.1% (28/690).

CONCLUSIONS

In Morocco, the epidemiological profile of paediatric acute respiratory infections is markedly shifted towards wheezing-related diseases and thus resembles that of high-income countries. However, the high associated CFRs found in this study call for an improvement in preventive and clinical management strategies.

Management of streptococcal pneumoniae-induced hemolytic uremic syndrome: a case report

Hemolytic uremic syndrome (HUS) secondary to Streptococcus pneumoniae infections (pHUS) has been well reported in the literature and accounts for roughly 5% of all the cases of HUS. However, this condition is likely under-diagnosed and the incidence is believed to be increasing. Given this increase in incidence of pHUS, it is important to have an understanding of the optimal means to manage the disease. We report a case of a 2-year-old male with pneumonia, acute kidney injury (AKI), microangiopathic hemolytic anemia (MAHA), and thrombocytopenia, diagnosed with pHUS and successfully treated with antibiotics, washed red blood cell (RBC) transfusions, plasma exchange (PE) with 5% albumin replacement, steroids, and hemodialysis. The response seen in our patient adds to the current literature and further supports the use of PE with albumin in patients with pHUS.

Assessment of health benefits and cost-effectiveness of 10-valent and 13-valent pneumococcal conjugate vaccination in Kenyan children

BACKGROUND

The GAVI Alliance supported 10-valent pneumococcal conjugate vaccine (PCV10) introduction in Kenya. We estimated the cost-effectiveness of introducing either PCV10 or the 13-valent vaccine (PCV13) from a societal perspective and explored the incremental impact of including indirect vaccine effects.

METHODS

The costs and effects of pneumococcal vaccination among infants born in Kenya in 2010 were assessed using a decision analytic model comparing PCV10 or PCV13, in turn, with no vaccination. Direct vaccine effects were estimated as a reduction in the incidence of pneumococcal meningitis, sepsis, bacteraemic pneumonia and non-bacteraemic pneumonia. Pneumococcal disease incidence was extrapolated from a population-based hospital surveillance system in Kilifi and adjustments were made for variable access to care across Kenya. We used vaccine efficacy estimates from a trial in The Gambia and accounted for serotype distribution in Kilifi. We estimated indirect vaccine protection and serotype replacement by extrapolating from the USA. Multivariable sensitivity analysis was conducted using Monte Carlo simulation. We assumed a vaccine price of US$ 3.50 per dose.

FINDINGS

The annual cost of delivering PCV10 was approximately US$14 million. We projected a 42.7% reduction in pneumococcal disease episodes leading to a US$1.97 million reduction in treatment costs and a 6.1% reduction in childhood mortality annually. In the base case analysis, costs per discounted DALY and per death averted by PCV10, amounted to US$ 59 (95% CI 26-103) and US$ 1,958 (95% CI 866-3,425), respectively. PCV13 introduction improved the cost-effectiveness ratios by approximately 20% and inclusion of indirect effects improved cost-effectiveness ratios by 43-56%. The break-even prices for introduction of PCV10 and PCV13 are US$ 0.41 and 0.51, respectively.

CONCLUSIONS

Introducing either PCV10 or PCV13 in Kenya is highly cost-effective from a societal perspective. Indirect effects, if they occur, would significantly improve the cost-effectiveness.

Epidemiology of invasive pneumococcal disease in the pre-conjugate vaccine era: South Africa, 2003-2008

INTRODUCTION

Dynamics of pneumococcal disease incidence and serotype distribution prior to introduction of pneumococcal conjugate vaccines (PCV) will assist in understanding effects of the vaccine over time and will be important in choosing the optimal PCV formulation.

METHODS

We conducted active, laboratory-based, national surveillance for invasive pneumococcal disease (IPD) through the Group for Enteric, Respiratory and Meningeal Disease Surveillance in South Africa (GERMS-SA) from 2003 through 2008. Over 130 laboratories report to this system. Pneumococci were serotyped using Quellung and isolates screened for resistance by disk diffusion; minimum inhibitory concentrations were determined on potentially resistant isolates. We used univariate and multivariable multinomial regression models to assess differences between serotypes.

RESULTS

GERMS-SA identified 8674 cases among children <5 years. Overall, 58% (3849/6668), 65% (4314/6668), and 85% (5669/6668) of cases and 61% (455/751), 64% (482/751), 82% (616/751) of deaths were due to serotypes included in 7-valent PCV, 10-valent PCV and 13-valent PCV, respectively. Serotypes 6A and 19A accounted for 16% (527/3252) of penicillin non-susceptible disease. In 2008, reported incidence of IPD was 6-fold higher in children <1 compared to children 1-4 years of age: 87 per 100,000 population and 14/100,000, respectively. The relative risk of IPD was 21-fold (95% CI, 19-24) and 34-fold (29-41) greater in HIV-infected compared to HIV-uninfected children in the <1 year and 1-4-year-old age groups respectively. On multivariable analysis serotypes 6B (relative risk ratio (RRR) 0.7; confidence interval (CI) 0.5-0.9), 18C (RRR 0.3; CI 0.1-0.5), 1 (RRR 0.2; CI 0.1-0.4) and 8 (RRR 0.2; CI 0.1-0.4) were significantly less common in HIV-infected individuals than serotype 14.

CONCLUSIONS

All vaccine formulations have the potential to prevent most cases and deaths from IPD in children in South Africa. Vaccines with protection against 19A would be advantageous in South Africa.

Prevention of pneumococcal diseases in the post-seven valent vaccine era: a European perspective

BACKGROUND

The burden of invasive pneumococcal disease in young children decreased dramatically following introduction of the 7-valent pneumococcal conjugate vaccine (PCV7). The epidemiology of S. pneumoniae now reflects infections caused by serotypes not included in PCV7. Recently introduced higher valency pneumococcal vaccines target the residual burden of invasive and non-invasive infections, including those caused by serotypes not included in PCV7. This review is based on presentations made at the European Society of Pediatric Infectious Diseases in June 2011.

DISCUSSION

Surveillance data show increased circulation of the non-PCV7 vaccine serotypes 1, 3, 6A, 6C, 7 F and 19A in countries with routine vaccination. Preliminary evidence suggests that broadened serotype coverage offered by higher valency vaccines may be having an effect on invasive disease caused by some of those serotypes, including 19A, 7 F and 6C. Aetiology of community acquired pneumonia remains a difficult clinical diagnosis. However, recent reports indicate that pneumococcal vaccination has reduced hospitalisations of children for vaccine serotype pneumonia. Variations in serotype circulation and occurrence of complicated and non-complicated pneumonia caused by non-PCV7 serotypes highlight the potential of higher valency vaccines to decrease the remaining burden. PCVs reduce nasopharyngeal carriage and acute otitis media (AOM) caused by vaccine serotypes. Recent investigations of the interaction between S. pneumoniae and non-typeable H. influenzae suggest that considerable reduction in severe, complicated AOM infections may be achieved by prevention of early pneumococcal carriage and AOM infections. Extension of the vaccine serotype spectrum beyond PCV7 may provide additional benefit in preventing the evolution of AOM. The direct and indirect costs associated with pneumococcal disease are high, thus herd protection and infections caused by non-vaccine serotypes both have strong effects on the cost effectiveness of pneumococcal vaccination. Recent evaluations highlight the public health significance of indirect benefits, prevention of pneumonia and AOM and coverage of non-PCV7 serotypes by higher valency vaccines.

SUMMARY

Routine vaccination has greatly reduced the burden of pneumococcal diseases in children. The pneumococcal serotypes present in the 7-valent vaccine have greatly diminished among disease isolates. The prevalence of some non-vaccine serotypes (e.g. 1, 7 F and 19A) has increased. Pneumococcal vaccines with broadened serotype coverage are likely to continue decreasing the burden of invasive disease, and community acquired pneumonia in children. Further reductions in pneumococcal carriage and increased prevention of early AOM infections may prevent the evolution of severe, complicated AOM. Evaluation of the public health benefits of pneumococcal conjugate vaccines should include consideration of non-invasive pneumococcal infections, indirect effects of vaccination and broadened serotype coverage.

Potential use of serum based quantitative real-time PCR for the detection of pneumonia pathogens in a densely colonised population

Molecular methods offer improvement in the detection of causative pneumonia pathogens, but there are concerns of false positive results. Here we validate quantitative real-time PCR (qPCR) assays for the detection of Streptococcus pneumoniae and Haemophilus influenzae in: (a) spiked serum samples and (b) in matched serum and nasopharyngeal swabs from a population of Indigenous Australian children without pneumonia, but with a high nasopharyngeal carriage prevalence of S. pneumoniae and H. influenzae. Matched sera and nasopharyngeal swabs were selected from Indigenous children less than 5 years of age without a diagnosis of pneumonia. Specimens were assayed by qPCR targeting the lytA and glpQ genes from S. pneumoniae and H. influenzae, respectively. Using qPCR, neither S. pneumoniae nor H. influenzae DNA was detected in serum samples, even after concentration of serum DNA. In matched nasopharyngeal swabs, bacterial load was high with up to 106 cells/ml detected by qPCR. In this cohort of children with a high nasopharyngeal carriage, prevalence and bacterial load of pneumonia pathogens, qPCR on sera would not have produced a false pneumonia diagnosis. Thus, qPCR analysis of sera appears to be an appropriate method to aid aetiological diagnosis of pneumonia in this population.

Dose-specific efficacy of Haemophilus influenzae type b conjugate vaccines: a systematic review and meta-analysis of controlled clinical trials

Global coverage of infant Haemophilus influenzae type b (Hib) vaccination has increased considerably during the past decade, partly due to GAVI Alliance donations of the vaccine to low-income countries. In settings where large numbers of children receive only one or two vaccine doses rather than the recommended three doses, dose-specific efficacy estimates are needed to predict impact. The objective of this meta-analysis is to determine Hib vaccine efficacy against different clinical outcomes after receiving one, two or three doses of vaccine. Studies were eligible for inclusion if a prospective, controlled design had been used to evaluate commercially available Hib conjugate vaccines. Eight studies were included. Pooled vaccine efficacies against invasive Hib disease after one, two or three doses of vaccine were 59%, 92% and 93%, respectively. The meta-analysis provides robust estimates for use in decision-analytical models designed to predict the impact of Hib vaccine.

Economic burden of acute lower respiratory tract infection in South African children

BACKGROUND

Acute lower respiratory tract infections (ALRTI) are a leading cause of childhood mortality, but there are few data on disease costs in developing countries.

OBJECTIVES

This study's purpose was to analyse ALRTI's costs-of-illness and economic burden in urban South African children.

METHODS

ALRTI costs-of-illness (expressed in US$ 2010) at a tertiary hospital were measured using a micro-costing approach nested within a clinical trial. Demographic, epidemiological and data on use of health resources were integrated with costs-of-illness to estimate the economic burden of ALRTI in urban South African children aged <5 years.

RESULTS

745 children experiencing 858 ALRTI episodes were studied. 338 (39.4%), 513 (59.8%) and 7 (0.8%) episodes were managed in short-stay, paediatric ward and intensive care settings, respectively. Mean lengths of stay in short-stay, paediatric ward and intensive care (ICU) were 1.4, 8.1 and 14.4 days, respectively. The societal costs-of-illness per ALRTI episode managed in short-stay and paediatric ward settings, respectively, were US$266 (95% CI 245-286) and 1287 (95% CI 1174-1401) in HIV-infected patients, and US$257 (95% CI 247-267) and 1032 (95% CI 931-1133) in HIV-uninfected patients. Family costs were not collected in ICUs. ICU direct medical costs were US$5968 (95% CI 4025-8056) in HIV-uninfected patients and US$7849 in one HIV-infected patient. Under-5 children experienced an estimated 424,220 episodes annually of ALRTI. ALRTI treatment cost the public health system an estimated US$28,975,000 while an additional US$539,000 of costs were borne by families.

CONCLUSION

ALRTIs in children <5 years impose a heavy economic burden on families and the South African public health-care system.

Population-based surveillance for invasive pneumococcal disease and pneumonia in infants and young children in Goiânia, Brazil

BACKGROUND

Streptococcus pneumoniae is the leading cause of vaccine-preventable death in children <5 years of age globally. We determined incidence rates of invasive pneumococcal disease (IPD), clinical and chest X-ray-confirmed pneumonia (CXR+Pn), S. pneumoniae serotype distribution, and antimicrobial susceptibility in children in Goiânia, Brazil.

METHODS

Prospective, population-based surveillance was conducted from May 2007 to May 2009 in children 28 days to <36 months of age presenting to all 33 pediatric healthcare services (outpatient departments, emergency rooms, hospitals) in Goiânia. Eligibility criteria were temperature ≥39.0 °C in the previous 24h and/or clinical suspicion of pneumonia or IPD.

RESULTS

14,509 subjects were enrolled. Median age was 14.0 months. S. pneumoniae was detected in 64 samples from 62 subjects: 58 (90.6%) blood; 4 (6.3%) cerebrospinal fluid; and 2 (3.1%) pleural fluid. Incidence rate of IPD (culture- and polymerase chain reaction-positive) for all children aged 28 days to <36 months was 57.5/100,000; overall incidence for culture-positive only was 54.9/100,000. Age stratification of culture-positive-only subjects found the highest rates were, 114.6/100,000 and 69.8/100,000, respectively, for the 6 months to <12 months and 12 months to <24 months age groups. The overall incidence of invasive pneumonia and pneumococcal meningitis was 37.2/100,000 and 5.3/100,000, respectively. The most common IPD serotypes were 14 (45.0%), 6B (13.3%), 18C (6.7%), and 23F (5.0%). Eight isolates (13.3%) were penicillin nonsusceptible. The cumulative percentages of serotypes included in 7-valent, 10-valent, and 13-valent pneumococcal conjugate vaccines were 78.3%, 80.0%, and 88.3%, respectively. The overall incidence of clinical pneumonia and CXR+Pn was, 9598/100,000 and 3428/100,000, respectively. CXR+Pn rates for hospitalized and non-hospitalized subjects were 1751/100,000 and 1677/100,000, respectively.

CONCLUSIONS

The burden of IPD and pneumonia is considerable in children in a large Brazilian city, and is seen in hospitalized as well as ambulatory subjects. Vaccination with pneumococcal conjugate vaccines has the potential to decrease this burden.

Pneumonia and poverty: a prospective population-based study among children in Brazil

BACKGROUND

Children in developing country suffer the highest burden of pneumonia. However, few studies have evaluated associations between poverty and pneumonia.

METHODS

A prospective population-based study on pneumonia was carried out as part of the Latin America Epidemiological Assessment of Pneumococcus (LEAP study). Chest x-rays were obtained for children one to 35 months old with suspected pneumonia presenting to emergency care centers and hospital emergency rooms in Goiania, Brazil. Chest radiographs were evaluated according to WHO guidelines. Clustering of radiologically-confirmed pneumonia were evaluated using a Poisson-based spatial scan statistic. Associations between census socioeconomic indicators and pneumonia incidence rates were analyzed using generalized linear models.

RESULTS

From May, 2007 to May, 2009, chest radiographs were obtained from 11 521 children with clinical pneumonia; 3955 episodes were classified as radiologically-confirmed. Incidence rates were significantly higher in very low income areas (4825.2 per 105) compared to high income areas (1637.3 per 105). Spatial analysis identified clustering of confirmed pneumonia in Western (RR 1.78; p=0.001) and Southeast (RR 1.46; p=0.001) regions of the city, and clustering of hospitalized pneumonia in the Western region (RR 1.69; p=0.001). Lower income households and illiteracy were associated with pneumonia incidence.

CONCLUSIONS

In infants the risk of developing pneumonia is inversely associated with the head of household income and with the woman educational level. Areas with deprived socioeconomic conditions had higher incidence of pneumonia and should be targeted for high vaccination coverage.

Lower respiratory infections in Australian Indigenous children

Despite Australia being one of the wealthiest countries of the world, Australian Indigenous children have a health status and social circumstance comparable to developing countries. Indigenous infants have 10 times the mortality rate for respiratory conditions. The lower respiratory infection (LRI) rate in Australian Indigenous children is at least as high as that of children in developing countries; the frequency of hospitalisations of Indigenous infants is triple that of non-Indigenous Australian infants (201.7 vs. 62.6/1000, respectively). While Indigenous Australian children have many risk factors for LRIs described in developing countries, there is little specific data, and hence, evidence-based intervention points are yet to be identified. Efficacy of conjugate vaccines for common bacterial causes of pneumonia has been less marked in Indigenous children than that documented overseas. Gaps in the management and prevention of disease are glaring. Given the burden of LRI in Indigenous children and the association with long-term respiratory dysfunction, LRIs should be addressed as a matter of priority.

Estimating the vaccine-preventable burden of hospitalized pneumonia among young Mozambican children

Polysaccharide-protein conjugate vaccines against Haemophilus influenzae type b (Hib) and Streptococcus pneumoniae have proven efficacy against radiologically confirmed pneumonia. Measurement of pneumonia incidence provides a platform to estimate of the vaccine-preventable burden. Over 24 months, we conducted surveillance for radiologically confirmed severe pneumonia episodes among children <2 years of age admitted to a rural hospital in Manhiça, southern Mozambique. Study children were tested for HIV during the second year of surveillance. Severe pneumonia accounted for 15% of 5132 hospital admissions and 32% of in-hospital mortality among children <2 years of age. Also, 43% of chest radiographs were interpreted as radiologically confirmed pneumonia. HIV-infection was associated with 81% of fatal pneumonia episodes among children tested for HIV. The minimum incidence rate of radiologically confirmed pneumonia requiring hospitalization was 19 episodes/1000 child-years. Incidence rates among HIV-infected children were 9.3-19.0-fold higher than HIV-uninfected. Introduction of Hib and pneumococcal conjugate vaccines would have a substantial impact on pneumonia hospitalizations among African children if vaccine effects are similar to those observed in clinical trials.

Streptococcus pneumoniae--associated hemolytic uremic syndrome: classification and the emergence of serotype 19A

Streptococcus pneumoniae-associated hemolytic uremic syndrome (HUS) is an underrecognized condition that mainly occurs in young children. Early diagnosis is important because of the potential to improve morbidity and mortality rates. The purposes of this report are to review the clinical and laboratory features of 14 patients with pneumococcal HUS and present a modified classification to capture cases that may not have been documented with a diagnosis of pneumococcal HUS. We thereby provide a rationale for including patients with concurrent disseminated intravascular coagulopathy and/or those whose culture results were negative, and we highlight the emergence of serotype 19A subsequent to the introduction of 7-valent pneumococcal protein conjugate vaccine (Prevnar). This is the largest series of such subjects (to our knowledge) from a single center. Sixty-four percent of the patients recovered without any long-term sequelae. Three patients developed chronic kidney disease, 1 developed end-stage renal failure, and 1 died in the acute phase. The greatest risk factor for the development of chronic kidney disease is the need for acute dialysis for >20 days, and death in the acute phase is rare unless meningitis is the primary infection.

Severe pneumonia in Mozambican young children: clinical and radiological characteristics and risk factors

BACKGROUND

Pneumonia is a leading cause of hospitalization and death among children in Africa. We describe the clinical presentation of severe pneumonia among hospitalized children in a malaria endemic area with a high prevalence of HIV infection.

METHODS

As part of a 2-year prospective study of radiologically confirmed pneumonia, chest radiographs, malaria parasite counts and bacterial blood cultures were systematically performed for children 0-23 months admitted with severe pneumonia. Radiographs were interpreted according to WHO guidelines. HIV tests were performed during a 12-month period.

RESULTS

Severe pneumonia accounted for 16% of 4838 hospital admissions among children 0-23 months; 43% of episodes had endpoint consolidation, 15% were associated with bacteremia and 11% were fatal. Fever, cough >3 days, crepitations, hypoxemia and absence of malaria parasitemia were associated with radiologically confirmed pneumonia. Nineteen per cent of children with severe pneumonia and 27% with radiologically confirmed pneumonia had clinical malaria. HIV-prevalence was 26% among children hospitalized with severe pneumonia and HIV-testing results. HIV infection, anaemia, malnutrition, hypoxemia and bacteremia were associated with fatal episodes of severe pneumonia.

CONCLUSION

Treatment of admitted children with severe pneumonia is complicated in settings with prevalent HIV and malaria. Children with severe pneumonia and clinical malaria require antibiotic and antimalarial treatment. In addition to vertical programs, integrated approaches may greatly contribute to reduction of pneumonia-related mortality.

Seven-valent pneumococcal conjugate vaccines for developing countries

Protein conjugate bacterial vaccines for invasive pneumococcal diseases have revolutionized the epidemiology of invasive bacterial disease in young children in most of the developed world, but only a small proportion of children at greatest risk of dying from this disease are vaccinated in less developed countries. Pneumococcal disease kills more children than any other illness - more than AIDS, malaria and measles combined. While the noble effort of international agencies to promote the use of pneumococcal vaccines is commendable, studies from several developing countries have failed to recognize invasive pneumococcal disease as a major problem. Thus, even at considerably subsidized vaccine pricing, this failure to recognize the pneumococcal disease burden will deter the introduction of vaccine programs in areas where it is most needed. This lack of awareness creates an impassé for the acceptance of a 'solution'. Whether this absence of evidence is real or simply misleading deserves further urgent evaluation. Such an evaluation could propose the use of the vaccine as a 'probe' for defining the problem. In settings where disease burden is likely to be highest, disease surveillance is nonexistent, childhood immunization programs are fractured or nonexistent, and there is no system to ensure delivery, even if the vaccine is offered free of charge. Ongoing challenges with global polio eradication programs suggest that, critical to the success of any immunization program, is investment in setting up credible disease surveillance systems for vaccine preventable diseases to generate local or regional disease burden data. This will promote local ownership of any immunization programs and reveal myths about a 'hidden agenda' by foreign vaccine manufacturers.

Haemophilusinfluenzae type b conjugate vaccine for preventing pneumonia in infants hospitalized for bronchiolitis: a case-control study

BACKGROUND

Haemophilus influenzae type b (Hib) conjugate vaccine reduces the risk of pneumonia in infants.

OBJECTIVE

To determine the effect of Hib conjugate vaccine (HibCV) on the prevention of pneumonia as a complication among infants hospitalized for bronchiolitis.

METHODS

This record-based case-control study was conducted at The Children's Hospital "Dr. Ovidio Aliaga U" in La Paz, Bolivia during 2003 and 2004. Cases were infants hospitalized for bronchiolitis under 1 year of age who developed radiological pneumonia during hospitalization. Controls were patients who had good clinical progress without the use of antibiotics. Pneumonia was defined by alveolar consolidation on chest X-ray that justified the use of antibiotics.

RESULTS

Eighty patients were studied (16 cases and 64 controls). Their median age was 4.5 months. Demographic and clinical features were similar in both groups, except for a higher proportion of vomiting (56.3% vs. 28.1%; p<0.05) in the case group. The percentage of unvaccinated infants was significantly higher in cases (68.8% vs. 26.6%; p<0.05) and the length of hospital stay longer (8.5+/-5.4 vs. 3.1+/-2.2 days; p<0.05). There was a strong association between unvaccinated infants and the occurrence of pneumonia as a complication (odds ratio 6.1, 95% confidence interval 1.8-20.1; p<0.01).

CONCLUSIONS

Unvaccinated infants admitted for bronchiolitis have a higher risk of radiologically confirmed pneumonia. Larger studies are needed to validate these results and reconsider the burden of Hib infection among infants in less developed countries.

Recommendations for treatment of childhood non-severe pneumonia

WHO recommendations for early antimicrobial treatment of childhood pneumonia have been effective in reducing childhood mortality, but the last major revision was over 10 years ago. The emergence of antimicrobial resistance, new pneumonia pathogens, and new drugs have prompted WHO to assemble an international panel to review the literature on childhood pneumonia and to develop evidence-based recommendations for the empirical treatment of non-severe pneumonia among children managed by first-level health providers. Treatment should target the bacterial causes most likely to lead to severe disease, including Streptoccocus pneumoniae and Haemophilus influenzae. The best first-line agent is amoxicillin, given twice daily for 3–5 days, although co-trimoxazole may be an alternative in some settings. Treatment failure should be defined in a child who develops signs warranting immediate referral or who does not have a decrease in respiratory rate after 48–72 h of therapy. If failure occurs, and no indication for immediate referral exists, possible explanations for failure should be systematically determined, including non-adherence to therapy and alternative diagnoses. If failure of the first-line agent remains a possible explanation, suitable second-line agents include high-dose amoxicillin–clavulanic acid with or without an affordable macrolide for children over 3 years of age.

Pneumonia and other respiratory infections

Pneumonia is a leading killer of children in developing countries and results in significant morbidity worldwide. This article reviews the management of pneumonia and its complications from the perspective of both developed and resource-poor settings. In addition, evidence-based management of other respiratory infections, including tuberculosis, is discussed. Finally, the management of common complications of pneumonia is reviewed.

Novel approaches to the identification of Streptococcus pneumoniae as the cause of community-acquired pneumonia

Current diagnostic tests lack sensitivity for the identification of the bacterial etiology of pneumonia. Attempts during the past 2 decades to improve sensitivity of detection of bacterial constituents in blood by use of antibody-antigen complexes and polymerase chain reaction have been disappointing. Recent data using pneumococcal conjugate vaccines as probes suggest that increased levels of both C-reactive protein and procalcitonin may be useful adjuncts to chest radiographs in the selection of patients with presumed bacterial pneumonia for inclusion in clinical trials. Among pneumococcal diagnostics currently under investigation, quantitative real-time polymerase chain reaction of respiratory secretions, as well as urinary antigen detection and pneumococcal surface adhesin A serological analysis for adults, are candidates for use in future clinical trials of antibiotics.

Bacterial pneumonia and pandemic influenza planning

Prevention and treatment of secondary bacterial complications are important but neglected areas of planning.

Pandemic influenza planning is well under way across the globe. Antiviral drugs and vaccines have dominated the therapeutic agenda. Far less work has been conducted on stockpiling and planning for deployment of antimicrobial drugs against secondary bacterial pneumonia, a cause of substantial illness and death in previous pandemics and epidemics. In the event of a pandemic, effective antimicrobial drug measures are expected to substantially benefit public health. We address issues regarding use of antimicrobial drugs as stocks of individual agents are diminished and the role of resistance surveillance in informing such policy. Furthermore, vaccination with polysaccharide and conjugate pneumococcal vaccines is considered as part of a pandemic strategy. Most illness and death from influenza are likely to occur in developing countries, where neuraminidase inhibitors and vaccines may be neither affordable nor available; thus, compared with industrialized countries, the benefits of treating bacterial complications in developing countries may be substantially greater.

Immunization in patients with HIV infection: are practical recommendations possible?

The purpose of this article is to review immunization recommendations for HIV-infected individuals in resource-constrained countries, particularly in sub-Saharan Africa. Recent evidence suggests that HIV-infected children are at risk for low immunization coverage in sub-Saharan Africa. Routine immunization is recommended for these children. In comparison with immunocompetent children, recommendations for live-attenuated vaccines differ in HIV-infected children. However, limited laboratory capacity to diagnose HIV infection amongst young children prevents the implementation of these HIV-specific guidelines in resource-constrained countries. Re-immunization has been the focus of recent research in high- and middle-income countries. Findings show that children established on highly active antiretroviral therapy have suboptimal vaccine-specific immunity and may benefit from re-immunization. Before re-immunization guidelines can be formulated for resource-constrained countries, several questions should be addressed, including whether all HIV-infected children will benefit from routine re-immunization and what optimal number of vaccine doses should be administered. Pneumococcal and influenza infections are important causes of morbidity and mortality amongst HIV-infected individuals. There is compelling evidence showing that pneumococcal conjugate vaccines will protect HIV-infected and uninfected children against invasive infection. Pneumococcal conjugate vaccines should be prioritized for introduction in countries with high HIV prevalence. Although, annual influenza immunization is recommended for HIV-infected individuals, the effectiveness in Africa remains unclear. In conclusion, this brief overview has identified several limitations of current immunization policy and practice for HIV-infected individuals living in resource-constrained countries.

A real-time polymerase chain reaction for the detection of Streptococcus pneumoniae in blood using a mouse model: a potential new "gold standard"

Better diagnostics for pneumococcal disease are urgently needed. In a murine model, real-time polymerase chain reaction was superior to conventional culture in detecting pneumococcus in blood, particularly in early disease and after antibiotic administration, and could distinguish between commensalism and infection.

Immunogenicity and serotype-specific efficacy of a 9-valent pneumococcal conjugate vaccine (PCV-9) determined during an efficacy trial in The Gambia

This study aimed to determine the immunogenicity of a 9-valent pneumococcal conjugate vaccine (PCV-9) in a subgroup of Gambian children enrolled in a large vaccine efficacy trial. To place the antibody results in context, in this paper we also report previously unpublished data on serotype-specific clinical vaccine efficacy from the main trial. In the sub-study, a single 2-4 ml venous blood specimen was collected from 212 Gambian children 4-6 weeks after the administration of a third dose of PCV-9 or placebo. IgG antibodies to pneumococcal serotype 1, 4, 5, 6B, 9V, 14, 18C, 19F and 23F polysaccharides were measured by ELISA. The proportions of infants with antibody concentrations above 0.2, 0.35 and 1.0 microg/ml, and the geometric mean concentrations (GMCs) of anti-pneumococcal polysaccharide antibodies were substantially higher for each serotype in children who received three doses of PCV-9 than those in the placebo group. Among PCV-9 recipients, GMCs ranged between 2.61 and 11.09 microg/ml with the highest being against serotype 14 and the lowest against 9V polysaccharide. The estimated overall protective antibody level for all nine serotypes, based on the vaccine efficacy against vaccine-type invasive pneumococcal disease (IPD) of 77% (95% CI: 51, 90) observed in the trial, was 2.3 microg/ml (95% CI: 1.0, 5.0). The PCV-9 studied was immunogenic in a Gambian population where it was also found to be efficacious.

Serotype-specific problems associated with pneumococcal conjugate vaccination

A conjugate vaccine against seven of the 91 known pneumococcal serotypes was licensed in the USA in 2000 and has had profound effects on pneumococcal disease and ecology. Among these is the virtual disappearance of vaccine serotypes from carriage, and their replacement with nonvaccine serotypes, some of which are making an impact upon pneumococcal disease. Here, the impact of this serotype replacement on pneumococcal disease is discussed, and those serotypes that are important players in the post-vaccine era are identified. Furthermore, the impact of replacement in vulnerable patient populations, such as Alaska Natives and persons living with HIV is discussed, as well as its consequences for other disease manifestations such as otitis media. Finally, lessons from the US experience for conjugate vaccination in other settings including sub-Saharan Africa are drawn.

Changes in serotypes and antimicrobial susceptibility of invasive Streptococcus pneumoniae strains in Cleveland: a quarter century of experience

The serotypes and susceptibilities to penicillin, macrolides, and clindamycin of 1,655 invasive isolates of Streptococcus pneumoniae recovered between 1979 and 2004 were determined. A precipitous decrease of 61% in the number of isolates was found following 2000, the year of 7-valent protein-conjugated pneumococcal vaccine (PCV7) introduction (139 versus 55 per 2-year period prior to versus after 2000; P < 0.001). This decrease was 84% in children <5 years old (80 versus 13 per 2-year period; P < 0.001) and 18 to 23% in other age groups (P, not significant). PCV7 serotypes decreased by 76% overall (103 versus 25 per 2-year period; P < 0.001) and by 92% in children <5 years old (65 versus 5 per 2-year period; P < 0.001), with significant decreases in six of the seven PCV serotypes. Other serotypes, except for type 19A, decreased from 32 to 22 per 2-year period, while type 19A increased from 4 to 8 per 2-year period, although none of these changes reached significance. Drug resistance emerged slowly, with the first penicillin-intermediate strain isolated in 1980 and the first macrolide/lincosamide-resistant strain isolated in 1984. The first penicillin-resistant strain was isolated in 1993. Resistance increased steadily thereafter until 2003-2004, when 51.1% of isolates were penicillin nonsusceptible and 53.3% were macrolide resistant. Clindamycin resistance remained low until 2003-2004, when 26.7% of strains were resistant; this was associated with the emergence of multidrug-resistant type 19A strains. This study documents the emergence of resistance over a quarter century among invasive pneumococci in the Cleveland area, as well as the reduction in disease caused by PCV7 serotypes following the introduction of PCV7 in 2000.