Efficacy of nine-valent pneumococcal conjugate vaccine against pneumonia and invasive pneumococcal disease in The Gambia: randomised, double-blind, placebo-controlled trial

Ghana randomized air pollution and health study (GRAPHS): study protocol for a randomized controlled trial

BACKGROUND

Household air pollution exposure is a major health risk, but validated interventions remain elusive.

METHODS/DESIGN

The Ghana Randomized Air Pollution and Health Study (GRAPHS) is a cluster-randomized trial that evaluates the efficacy of clean fuels (liquefied petroleum gas, or LPG) and efficient biomass cookstoves in the Brong-Ahafo region of central Ghana. We recruit pregnant women into LPG, efficient cookstove, and control arms and track birth weight and physician-assessed severe pneumonia incidence in the first year of life. A woman is eligible to participate if she is in the first or second trimester of pregnancy and carrying a live singleton fetus, if she is the primary cook, and if she does not smoke. We hypothesize that babies born to intervention mothers will weigh more and will have fewer cases of physician-assessed severe pneumonia in the first year of life. Additionally, an extensive personal air pollution exposure monitoring effort opens the way for exposure-response analyses, which we will present alongside intention-to-treat analyses. Major funding was provided by the National Institute of Environmental Health Sciences, The Thrasher Research Fund, and the Global Alliance for Clean Cookstoves.

DISCUSSION

Household air pollution exposure is a major health risk that requires well-tested interventions. GRAPHS will provide important new evidence on the efficacy of both efficient biomass cookstoves and LPG, and will thus help inform health and energy policies in developing countries.

TRIAL REGISTRATION

The trial was registered with clinicaltrials.gov on 13 April 2011 with the identifier NCT01335490 .

Acute respiratory infection case definitions for young children: a systematic review of community-based epidemiologic studies in South Asia

OBJECTIVE

To explore the variability in childhood acute respiratory infection case definitions for research in low-income settings where there is limited access to laboratory or radiologic investigations.

METHODS

We conducted a systematic review of community-based, longitudinal studies in South Asia published from January 1990 to August 2013, in which childhood acute respiratory infection outcomes were reported. Case definitions were classified by their label (e.g. pneumonia, acute lower respiratory infection) and clinical content 'signatures' (array of clinical features that would be always present, conditionally present or always absent among cases). Case definition heterogeneity was primarily assessed by the number of unique case definitions overall and by label. We also compared case definition-specific acute respiratory infection incidence rates for studies reporting incidence rates for multiple case definitions.

RESULTS

In 56 eligible studies, we found 124 acute respiratory infection case definitions. Of 90 case definitions for which clinical content was explicitly defined, 66 (73%) were unique. There was a high degree of content heterogeneity among case definitions with the same label, and some content signatures were assigned multiple labels. Within studies for which incidence rates were reported for multiple case definitions, variation in content was always associated with a change in incidence rate, even when the content differed by a single clinical feature.

CONCLUSION

There has been a wide variability in case definition label and content combinations to define acute upper and lower respiratory infections in children in community-based studies in South Asia over the past two decades. These inconsistencies have important implications for the synthesis and translation of knowledge regarding the prevention and treatment of childhood acute respiratory infection.

Biomarkers of Host Response Predict Primary End-Point Radiological Pneumonia in Tanzanian Children with Clinical Pneumonia: A Prospective Cohort Study

Background

Diagnosing pediatric pneumonia is challenging in low-resource settings. The World Health Organization (WHO) has defined primary end-point radiological pneumonia for use in epidemiological and vaccine studies. However, radiography requires expertise and is often inaccessible. We hypothesized that plasma biomarkers of inflammation and endothelial activation may be useful surrogates for end-point pneumonia, and may provide insight into its biological significance.

Methods

We studied children with WHO-defined clinical pneumonia (n = 155) within a prospective cohort of 1,005 consecutive febrile children presenting to Tanzanian outpatient clinics. Based on x-ray findings, participants were categorized as primary end-point pneumonia (n = 30), other infiltrates (n = 31), or normal chest x-ray (n = 94). Plasma levels of 7 host response biomarkers at presentation were measured by ELISA. Associations between biomarker levels and radiological findings were assessed by Kruskal-Wallis test and multivariable logistic regression. Biomarker ability to predict radiological findings was evaluated using receiver operating characteristic curve analysis and Classification and Regression Tree analysis.

Results

Compared to children with normal x-ray, children with end-point pneumonia had significantly higher C-reactive protein, procalcitonin and Chitinase 3-like-1, while those with other infiltrates had elevated procalcitonin and von Willebrand Factor and decreased soluble Tie-2 and endoglin. Clinical variables were not predictive of radiological findings. Classification and Regression Tree analysis generated multi-marker models with improved performance over single markers for discriminating between groups. A model based on C-reactive protein and Chitinase 3-like-1 discriminated between end-point pneumonia and non-end-point pneumonia with 93.3% sensitivity (95% confidence interval 76.5–98.8), 80.8% specificity (72.6–87.1), positive likelihood ratio 4.9 (3.4–7.1), negative likelihood ratio 0.083 (0.022–0.32), and misclassification rate 0.20 (standard error 0.038).

Conclusions

In Tanzanian children with WHO-defined clinical pneumonia, combinations of host biomarkers distinguished between end-point pneumonia, other infiltrates, and normal chest x-ray, whereas clinical variables did not. These findings generate pathophysiological hypotheses and may have potential research and clinical utility.

Risk factors for delay in age-appropriate vaccinations among Gambian children

BACKGROUND

Vaccination has been shown to reduce mortality and morbidity due to vaccine-preventable diseases. However, these diseases are still responsible for majority of childhood deaths worldwide especially in the developing countries. This may be due to low vaccine coverage or delay in receipt of age-appropriate vaccines. We studied the timeliness of routine vaccinations among children aged 12-59 months attending infant welfare clinics in semi-urban areas of The Gambia, a country with high vaccine coverage.

METHODS

A cross-sectional survey was conducted in four health centres in the Western Region of the Gambia. Vaccination dates were obtained from health cards and timeliness assessed based on the recommended age ranges for BCG (birth-8 weeks), Diphtheria-Pertussis-Tetanus (6 weeks-4 months; 10 weeks-5 months; 14 weeks-6 months) and measles vaccines (38 weeks-12 months). Risk factors for delay in age-appropriate vaccinations were determined using logistic regression. Analysis was limited to BCG, third dose of Diphtheria-Pertussis -Tetanus (DPT3) and measles vaccines.

RESULTS

Vaccination records of 1154 children were studied. Overall, 63.3% (95 % CI 60.6-66.1%) of the children had a delay in the recommended time to receiving at least one of the studied vaccines. The proportion of children with delayed vaccinations increased from BCG [5.8% (95 % CI 4.5-7.0%)] to DPT3 [60.4% (95 % CI 57.9%-63.0%)] but was comparatively low for the measles vaccine [10.8% (95 % CI 9.1%-12.5%)]. Mothers of affected children gave reasons for the delay, and their profile correlated with type of occupation, place of birth and mode of transportation to the health facilities.

CONCLUSION

Despite high vaccination coverage reported in The Gambia, a significant proportion of the children's vaccines were delayed for reasons related to health services as well as profile of mothers. These findings are likely to obtain in several countries and should be addressed by programme managers in order to improve and optimize the impact of the immunization coverage rates.

Region-specific diversification of the highly virulent serotype 1 Streptococcus pneumoniae

Serotype 1 Streptococcus pneumoniae is a leading cause of invasive pneumococcal disease (IPD) worldwide, with the highest burden in developing countries. We report the whole-genome sequencing analysis of 448 serotype 1 isolates from 27 countries worldwide (including 11 in Africa). The global serotype 1 population shows a strong phylogeographic structure at the continental level, and within Africa there is further region-specific structure. Our results demonstrate that region-specific diversification within Africa has been driven by limited cross-region transfer events, genetic recombination and antimicrobial selective pressure. Clonal replacement of the dominant serotype 1 clones circulating within regions is uncommon; however, here we report on the accessory gene content that has contributed to a rare clonal replacement event of ST3081 with ST618 as the dominant cause of IPD in the Gambia.

[Urine antigen testing: Indication and contribution to the treatment of community-acquired pneumonia]

Urinary antigen tests are quick and simple tests helping to provide an etiological diagnosis in community-acquired pneumonia. However, their prescription is sometimes excessive and performed in unjustified situations. The therapeutic benefit is limited. Indeed, studies show that appropriate antibiotic therapy based on the result of urinary antigen tests does not improve the cost and the patient survival compared to empirical antibiotic therapy. One must be careful before antibiotic therapy reduction based on the sole negative result of urinary antigen test. Legionella urinary antigen test is the most commonly method used for the diagnosis of legionellosis but must be prescribed in a specific clinical context. Streptococcus pneumoniae urinary antigen test is especially interesting in the epidemiological surveillance of pneumococcal community-acquired pneumonia.

A Bivalent Vaccine Based on a PB2-Knockout Influenza Virus Protects Mice From Secondary Pneumococcal Pneumonia

BACKGROUND

Secondary bacterial infections after influenza can be a serious problem, especially in young children and the elderly, yet the efficacy of current vaccines is limited. Earlier work demonstrated that a replication-incompetent PB2-knockout (PB2-KO) influenza virus possessing a foreign gene in the coding region of its PB2 segment can serve as a platform for a bivalent vaccine.

METHODS

In the current study, we generated the PB2-KO virus expressing pneumococcal surface protein A (PspA), PB2-KO-PspA virus, the replication of which is restricted to PB2-expressing cells. We then examined the protective efficacy of intranasal immunization with this virus as a bivalent vaccine in a mouse model.

RESULTS

High levels of influenza virus-specific and PspA-specific antibodies were induced in the serum and airways of immunized mice. The intranasally immunized mice were protected from lethal doses of influenza virus or Streptococcus pneumoniae. These mice were also completely protected from secondary pneumococcal pneumonia after influenza virus infection.

CONCLUSIONS

These findings indicate that our recombinant influenza virus serves as a novel and powerful bivalent vaccine against primary and secondary pneumococcal pneumonia as well as influenza.

Impact of PCV7/PCV13 introduction on community-acquired alveolar pneumonia in children <5 years

BACKGROUND

Alveolar community-acquired pneumonia (A-CAP) is mostly considered a bacterial disease, mainly pneumococcal. This study was conducted to document the impact of sequential 7-valent and the 13-valent pneumococcal conjugate vaccines (PCV7; PCV13) on emergency room and hospitalization for A-CAP among children <5 years of age.

METHODS

This is an ongoing prospective population-based study in southern Israel. The current analysis spans over the period July 2002 through June 2013. A-CAP was defined using the World Health Organization (WHO)'s criteria for radiologically-confirmed pneumonia. PCV7 was introduced in Israel in July 2009 and gradually replaced by PCV13 in November 2010. Pneumococcal conjugate vaccine (PCV) impact was calculated by comparing incidences during 3 pre-defined periods: pre-PCV (2002-2008), PCV7 (2010-2011) and PCV13 (2012-2013).

RESULTS

Overall, 10,142 A-CAP episodes occurred. The annual incidences (per 1,000 inhabitants) in children <5 years old declined from a mean (±standard deviation) of 13.8 ± 0.9 in the pre-PCV period to 11.2 ± 2.7 in the PCV7 period and 7.4 in the PCV13 period, representing a reduction of 13% and 47%, respectively. The overall decrease was significantly faster among outpatients than among hospitalized children (42% and -8%, respectively in the PCV7 period; 68% vs. 32% in hospitalized children in the PCV13 period). While in children 12-23 months a significant decline was observed during the PCV7 and PCV13 periods, significant declines in A-CAP rates were observed only during the PCV13 period in the <12 months and 24-59 months age groups (44% and 46%, respectively).

CONCLUSIONS

A moderate decline in hospital A-CAP visits in children <5 years old was observed after PCV7 introduction. In contrast, after PCV13 introduction a substantial reduction in all visits was evident.

The case for a typhoid vaccine probe study and overview of design elements

Recent advances in typhoid vaccine, and consideration of support from Gavi, the Vaccine Alliance, raise the possibility that some endemic countries will introduce typhoid vaccine into public immunization programs. This decision, however, is limited by lack of definitive information on disease burden. We propose use of a vaccine probe study approach. This approach would more clearly assess the total burden of typhoid across different syndromic groups and account for lack of access to care, poor diagnostics, incomplete laboratory testing, lack of mortality and intestinal perforation surveillance, and increasing antibiotic resistance. We propose a cluster randomized trial design using a mass immunization campaign among all age groups, with monitoring over a 4-year period of a variety of outcomes. The primary outcome would be the vaccine preventable disease incidence of prolonged fever hospitalization. Sample size calculations suggest that such a study would be feasible over a reasonable set of assumptions.

Pneumonia Prevention during a Humanitarian Emergency: Cost-effectiveness of Haemophilus Influenzae Type B Conjugate Vaccine and Pneumococcal Conjugate Vaccine in Somalia

BACKGROUND

Pneumonia is a leading cause of death among children less than five years old during humanitarian emergencies. Haemophilus influenzae type b (Hib) and Streptococcus pneumoniae are the leading causes of bacterial pneumonia. Vaccines for both of these pathogens are available to prevent pneumonia. Problem This study describes an economic analysis from a publicly funded health care system perspective performed on a birth cohort in Somalia, a country that has experienced a protracted humanitarian emergency.

METHODS

An impact and cost-effectiveness analysis was performed comparing: no vaccine, Hib vaccine only, pneumococcal conjugate vaccine 10 (PCV10) only, and both together administered through supplemental immunization activities (SIAs). The main summary measure was the incremental cost per disability-adjusted life-years (DALYs) averted. One-way sensitivity analysis was conducted for uncertainty in parameter values.

RESULTS

Each SIA would avert a substantial number of cases and deaths. Compared with no vaccine, the DALYs averted by two SIAs for two doses of Hib vaccine was US $202.93 (lower and upper limits: $121.80-$623.52), two doses of PCV10 was US $161.51 ($107.24-$227.21), and two doses of both vaccines was US $152.42 ($101.20-$214.42). Variables that influenced the cost-effectiveness for each strategy most substantially were vaccine effectiveness, case fatality rates (CFRs), and disease burden.

CONCLUSIONS

The World Health Organization (WHO) defines a cost-effective intervention as costing one to three times the per capita gross domestic product (GDP; in 2011, for Somalia=US $112). Based on the presented model, Hib vaccine alone, PCV10 alone, or Hib vaccine and PCV10 given together in SIAs are cost-effective interventions in Somalia. The WHO/Strategic Advisory Group of Experts decision-making factors for vaccine deployment appear to have all been met: the disease burden is large, the vaccine-related risk is low, prevention in this setting is more feasible than treatment, the vaccine duration probably is sufficient for the vulnerable period of the child's life, cost is reasonable, and herd immunity is possible.

Acute respiratory infection and bacteraemia as causes of non-malarial febrile illness in African children: a narrative review

The replacement of "presumptive treatment for malaria" by "test before treat" strategies for the management of febrile illness is raising awareness of the importance of knowing more about the causes of illness in children who are suspected to have malaria but return a negative parasitological test. The most common cause of non-malarial febrile illness (NMFI) in African children is respiratory tract infection. Whilst the bacterial causes of NMFI are well known, the increasing use of sensitive techniques such as polymerase chain reaction (PCR) tests is revealing large numbers of viruses that are potential respiratory pathogens. However, many of these organisms are commonly present in the respiratory tract of healthy children so causality and risk factors for pneumonia remain poorly understood. Infection with a combination of viral and bacterial pathogens is increasingly recognised as important in the pathogenesis of pneumonia. Similarly, blood stream infections with organisms typically grown by aerobic culture are well known but a growing number of organisms that can be identified only by PCR, viral culture, or serology are now recognised to be common pathogens in African children. The high mortality of hospitalised children on the first or second day of admission suggests that, unless results are rapidly available, diagnostic tests to identify specific causes of illness will still be of limited use in guiding the potentially life saving decisions relating to initial treatment of children admitted to district hospitals in Africa with severe febrile illness and a negative test for malaria. Malaria control and the introduction of vaccines against Haemophilus influenzae type b and pneumococcal disease are contributing to improved child survival in Africa. However, increased parasitological testing for malaria is associated with increased use of antibiotics to which resistance is already high.

Methods and challenges in measuring the impact of national pneumococcal and rotavirus vaccine introduction on morbidity and mortality in Malawi

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Evaluation of vaccine impact and effectiveness is critically important but methodologically challenging.

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Challenges include achieving unbiased ascertainment of vaccine status, and non-vaccine-attributable decline in morbidity and mortality.

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Use of multiple sites together with diverse evaluation methods provides more robust evaluation.

Background

Pneumonia and gastroenteritis are leading causes of vaccine-preventable childhood morbidity and mortality. Malawi introduced pneumococcal conjugate and rotavirus vaccines to the immunisation programme in 2011 and 2012, respectively. Evaluating their effectiveness is vital to ensure optimal implementation and justify sustained investment.

Methods/Design

A national evaluation platform was established to determine vaccine effectiveness and impact in Malawi. Impact and effectiveness against vaccine-type invasive pneumococcal disease, radiological pneumonia and rotavirus gastroenteritis are investigated using before-after incidence comparisons and case-control designs, respectively. Mortality is assessed using a prospective population cohort. Cost-effectiveness evaluation is nested within the case-control studies. We describe platform characteristics including strengths and weaknesses for conducting vaccine evaluations.

Discussion

Integrating data from individual level and ecological methods across multiple sites provides comprehensive information for policymakers on programme impact and vaccine effectiveness including changes in serotype/genotype distribution over time. Challenges to robust vaccine evaluation in real-world conditions include: vaccination ascertainment; pre-existing rapid decline in mortality and pneumococcal disease in the context of non-vaccine interventions; and the maintenance of completeness and quality of reporting at scale and over time. In observational non-randomised designs ascertainment of vaccine status may be biased particularly in infants with fatal outcomes. In the context of multiple population level interventions targeting study endpoints attribution of reduced incidence to vaccine impact may be flawed. Providing evidence from several independent but complementary studies will provide the greatest confidence in assigning impact. Welcome declines in disease incidence and in child mortality make accrual of required sample sizes difficult, necessitating large studies to detect the relatively small but potentially significant contribution of vaccines to mortality prevention. Careful evaluation of vaccine effectiveness and impact in such settings is critical to sustaining support for vaccine programmes. Our evaluation platform covers a large population with a high prevalence of HIV and malnutrition and its findings will be relevant to other settings in sub-Saharan Africa.

Pneumococcal carriage in rural Gambia prior to the introduction of pneumococcal conjugate vaccine: a population-based survey

OBJECTIVE

To evaluate pneumococcal colonisation before and after the introduction of pneumococcal conjugate vaccine (PCV) in eastern Gambia.

METHODS

Population-based cross-sectional survey of pneumococcal carriage between May and August 2009 before the introduction of PCV into the Expanded Program on Immunization. Nasopharyngeal swabs were collected from all household members, but in selected households, only children aged 6-10 years were swabbed. This age group participated in an earlier trial of a nine-valent PCV between 2000 and 2004.

RESULTS

The prevalence of nasopharyngeal pneumococcal carriage in 2933 individuals was 72.0% in underfives (N = 515), 41.6% in children aged 5-17 (N = 1508) and 13.0% in adults ≥18 (N = 910) years. The age-specific prevalence of serotypes included in PCV7, PCV10 and PCV13 was 24.7%, 26.6% and 46.8% among children <5 years of age; 8.5%, 9.2% and 17.7% among children 5-17 years; and 2.5%, 3.3% and 5.5% among adults ≥18 years. The most common serotypes were 6A (13.1%), 23F (7.6%), 3 (7.3%), 19F (7.1%) and 34 (4.6%). There was no difference in the overall carriage of pneumococci between vaccinated and unvaccinated children 8 years after the primary vaccination with three doses of PCV (48.3% vs. 41.1%).

CONCLUSION

Before the introduction of PCV, serotypes included in PCV13 accounted for about half the pneumococcal serotypes in nasopharyngeal carriage. Thus, the potential impact of PCV13 on pneumococcal disease in the Gambia is substantial.

Differences in Homing Potentials of Streptococcus pneumoniae-Specific Plasmablasts in Pneumococcal Pneumonia and After Pneumococcal Polysaccharide and Pneumococcal Conjugate Vaccinations

Background. Mucosal immune mechanisms in the upper and lower respiratory tracts may serve a critical role in preventing pneumonia due to Streptococcus pneumoniae. Streptococcus pneumoniae–specific plasmablasts presumably originating in the lower respiratory tract have recently been found in the circulation in patients with pneumonia. The localization of an immune response can be evaluated by exploring homing receptors on such plasmablasts, yet no data have thus far described homing receptors in pneumonia.

Methods. The expression of α₄β₇, L-selectin, and cutaneous lymphocyte antigen (CLA) on S. pneumoniae–specific plasmablasts was examined in patients with pneumonia (n = 16) and healthy volunteers given pneumococcal polysaccharide vaccine (PPV; n = 14) or pneumococcal conjugate vaccine (PCV; n = 11).

Results. In patients with pneumonia, the proportion of S. pneumoniae–specific plasmablasts expressing L-selectin was high, the proportion expressing α₄β₇ was moderate, and the proportion expressing CLA was low. The homing receptor α₄β₇ was expressed more frequently in the pneumonia group than in the PPV (P = .000) and PCV (P = .029) groups, L-selectin was expressed more frequently in the PPV group than in the PCV group (P = .014); and CLA was expressed more frequently in the pneumonia group than in the PPV group (P = .001).

Conclusions. The homing receptor profile in patients with pneumonia was unique yet it was closer to that in PCV recipients than in PPV recipients. These data suggest greater mucosal localization for immune response in natural infection, which is clinically interesting, especially considering the shortcomings of vaccines in protecting against noninvasive pneumonia.

Polysaccharide conjugate vaccine against pneumococcal pneumonia in adults

BACKGROUND

Pneumococcal polysaccharide conjugate vaccines prevent pneumococcal disease in infants, but their efficacy against pneumococcal community-acquired pneumonia in adults 65 years of age or older is unknown.

METHODS

In a randomized, double-blind, placebo-controlled trial involving 84,496 adults 65 years of age or older, we evaluated the efficacy of 13-valent polysaccharide conjugate vaccine (PCV13) in preventing first episodes of vaccine-type strains of pneumococcal community-acquired pneumonia, nonbacteremic and noninvasive pneumococcal community-acquired pneumonia, and invasive pneumococcal disease. Standard laboratory methods and a serotype-specific urinary antigen detection assay were used to identify community-acquired pneumonia and invasive pneumococcal disease.

RESULTS

In the per-protocol analysis of first episodes of infections due to vaccine-type strains, community-acquired pneumonia occurred in 49 persons in the PCV13 group and 90 persons in the placebo group (vaccine efficacy, 45.6%; 95.2% confidence interval [CI], 21.8 to 62.5), nonbacteremic and noninvasive community-acquired pneumonia occurred in 33 persons in the PCV13 group and 60 persons in the placebo group (vaccine efficacy, 45.0%; 95.2% CI, 14.2 to 65.3), and invasive pneumococcal disease occurred in 7 persons in the PCV13 group and 28 persons in the placebo group (vaccine efficacy, 75.0%; 95% CI, 41.4 to 90.8). Efficacy persisted throughout the trial (mean follow-up, 3.97 years). In the modified intention-to-treat analysis, similar efficacy was observed (vaccine efficacy, 37.7%, 41.1%, and 75.8%, respectively), and community-acquired pneumonia occurred in 747 persons in the PCV13 group and 787 persons in placebo group (vaccine efficacy, 5.1%; 95% CI, -5.1 to 14.2). Numbers of serious adverse events and deaths were similar in the two groups, but there were more local reactions in the PCV13 group.

CONCLUSIONS

Among older adults, PCV13 was effective in preventing vaccine-type pneumococcal, bacteremic, and nonbacteremic community-acquired pneumonia and vaccine-type invasive pneumococcal disease but not in preventing community-acquired pneumonia from any cause. (Funded by Pfizer; CAPITA ClinicalTrials.gov number NCT00744263.).

Severe acute respiratory infection in children in a densely populated urban slum in Kenya, 2007-2011

Background

Reducing acute respiratory infection burden in children in Africa remains a major priority and challenge. We analyzed data from population-based infectious disease surveillance for severe acute respiratory illness (SARI) among children <5 years of age in Kibera, a densely populated urban slum in Nairobi, Kenya.

Methods

Surveillance was conducted among a monthly mean of 5,874 (range = 5,778-6,411) children <5 years old in two contiguous villages in Kibera. Participants had free access to the study clinic and their health events and utilization were noted during biweekly home visits. Patients meeting criteria for SARI (WHO-defined severe or very severe pneumonia, or oxygen saturation <90%) from March 1, 2007-February 28, 2011 had blood cultures processed for bacteria, and naso- and oro- pharyngeal swabs collected for quantitative real-time reverse transcription polymerase chain reaction testing for influenza viruses, parainfluenza viruses (PIV), respiratory syncytial virus (RSV), adenovirus, and human metapneumovirus (hMPV). Swabs collected during January 1, 2009 – February 28, 2010 were also tested for rhinoviruses, enterovirus, parechovirus, Mycoplasma pneumoniae, and Legionella species. Swabs were collected for simultaneous testing from a selected group of control-children visiting the clinic without recent respiratory or diarrheal illnesses.

Results

SARI overall incidence was 12.4 cases/100 person-years of observation (PYO) and 30.4 cases/100 PYO in infants. When comparing detection frequency in swabs from 815 SARI cases and 115 healthy controls, only RSV and influenza A virus were significantly more frequently detected in cases, although similar trends neared statistical significance for PIV, adenovirus and hMPV. The incidence for RSV was 2.8 cases/100 PYO and for influenza A was 1.0 cases/100 PYO. When considering all PIV, the rate was 1.1 case/100 PYO and the rate per 100 PYO for SARI-associated disease was 1.5 for adenovirus and 0.9 for hMPV. RSV and influenza A and B viruses were estimated to account for 16.2% and 6.7% of SARI cases, respectively; when taken together, PIV, adenovirus, and hMPV may account for >20% additional cases.

Conclusions

Influenza viruses and RSV (and possibly PIV, hMPV and adenoviruses) are important pathogens to consider when developing technologies and formulating strategies to treat and prevent SARI in children.

Deconstructing the differences: a comparison of GBD 2010 and CHERG's approach to estimating the mortality burden of diarrhea, pneumonia, and their etiologies

Background

Pneumonia and diarrhea are leading causes of death for children under five (U5). It is challenging to estimate the total number of deaths and cause-specific mortality fractions. Two major efforts, one led by the Institute for Health Metrics and Evaluation (IHME) and the other led by the World Health Organization (WHO)/Child Health Epidemiology Reference Group (CHERG) created estimates for the burden of disease due to these two syndromes, yet their estimates differed greatly for 2010.

Methods

This paper discusses three main drivers of the differences: data sources, data processing, and covariates used for modelling. The paper discusses differences in the model assumptions for etiology-specific estimates and presents recommendations for improving future models.

Results

IHME’s Global Burden of Disease (GBD) 2010 study estimated 6.8 million U5 deaths compared to 7.6 million U5 deaths from CHERG. The proportional differences between the pneumonia and diarrhea burden estimates from the two groups are much larger; GBD 2010 estimated 0.847 million and CHERG estimated 1.396 million due to pneumonia. Compared to CHERG, GBD 2010 used broader inclusion criteria for verbal autopsy and vital registration data. GBD 2010 and CHERG used different data processing procedures and therefore attributed the causes of neonatal death differently. The major difference in pneumonia etiologies modeling approach was the inclusion of observational study data; GBD 2010 included observational studies. CHERG relied on vaccine efficacy studies.

Discussion

Greater transparency in modeling methods and more timely access to data sources are needed. In October 2013, the Bill & Melinda Gates Foundation (BMGF) hosted an expert meeting to examine possible approaches for better estimation. The group recommended examining the impact of data by systematically excluding sources in their models. GBD 2.0 will use a counterfactual approach for estimating mortality from pathogens due to specific etiologies to overcome bias of the methods used in GBD 2010 going forward.

Electronic supplementary material

The online version of this article (doi:10.1186/s12879-014-0728-4) contains supplementary material, which is available to authorized users.

Global, regional, and national age-sex specific all-cause and cause-specific mortality for 240 causes of death, 1990-2013: a systematic analysis for the Global Burden of Disease Study 2013

BACKGROUND

Up-to-date evidence on levels and trends for age-sex-specific all-cause and cause-specific mortality is essential for the formation of global, regional, and national health policies. In the Global Burden of Disease Study 2013 (GBD 2013) we estimated yearly deaths for 188 countries between 1990, and 2013. We used the results to assess whether there is epidemiological convergence across countries.

METHODS

We estimated age-sex-specific all-cause mortality using the GBD 2010 methods with some refinements to improve accuracy applied to an updated database of vital registration, survey, and census data. We generally estimated cause of death as in the GBD 2010. Key improvements included the addition of more recent vital registration data for 72 countries, an updated verbal autopsy literature review, two new and detailed data systems for China, and more detail for Mexico, UK, Turkey, and Russia. We improved statistical models for garbage code redistribution. We used six different modelling strategies across the 240 causes; cause of death ensemble modelling (CODEm) was the dominant strategy for causes with sufficient information. Trends for Alzheimer's disease and other dementias were informed by meta-regression of prevalence studies. For pathogen-specific causes of diarrhoea and lower respiratory infections we used a counterfactual approach. We computed two measures of convergence (inequality) across countries: the average relative difference across all pairs of countries (Gini coefficient) and the average absolute difference across countries. To summarise broad findings, we used multiple decrement life-tables to decompose probabilities of death from birth to exact age 15 years, from exact age 15 years to exact age 50 years, and from exact age 50 years to exact age 75 years, and life expectancy at birth into major causes. For all quantities reported, we computed 95% uncertainty intervals (UIs). We constrained cause-specific fractions within each age-sex-country-year group to sum to all-cause mortality based on draws from the uncertainty distributions.

FINDINGS

Global life expectancy for both sexes increased from 65.3 years (UI 65.0-65.6) in 1990, to 71.5 years (UI 71.0-71.9) in 2013, while the number of deaths increased from 47.5 million (UI 46.8-48.2) to 54.9 million (UI 53.6-56.3) over the same interval. Global progress masked variation by age and sex: for children, average absolute differences between countries decreased but relative differences increased. For women aged 25-39 years and older than 75 years and for men aged 20-49 years and 65 years and older, both absolute and relative differences increased. Decomposition of global and regional life expectancy showed the prominent role of reductions in age-standardised death rates for cardiovascular diseases and cancers in high-income regions, and reductions in child deaths from diarrhoea, lower respiratory infections, and neonatal causes in low-income regions. HIV/AIDS reduced life expectancy in southern sub-Saharan Africa. For most communicable causes of death both numbers of deaths and age-standardised death rates fell whereas for most non-communicable causes, demographic shifts have increased numbers of deaths but decreased age-standardised death rates. Global deaths from injury increased by 10.7%, from 4.3 million deaths in 1990 to 4.8 million in 2013; but age-standardised rates declined over the same period by 21%. For some causes of more than 100,000 deaths per year in 2013, age-standardised death rates increased between 1990 and 2013, including HIV/AIDS, pancreatic cancer, atrial fibrillation and flutter, drug use disorders, diabetes, chronic kidney disease, and sickle-cell anaemias. Diarrhoeal diseases, lower respiratory infections, neonatal causes, and malaria are still in the top five causes of death in children younger than 5 years. The most important pathogens are rotavirus for diarrhoea and pneumococcus for lower respiratory infections. Country-specific probabilities of death over three phases of life were substantially varied between and within regions.

INTERPRETATION

For most countries, the general pattern of reductions in age-sex specific mortality has been associated with a progressive shift towards a larger share of the remaining deaths caused by non-communicable disease and injuries. Assessing epidemiological convergence across countries depends on whether an absolute or relative measure of inequality is used. Nevertheless, age-standardised death rates for seven substantial causes are increasing, suggesting the potential for reversals in some countries. Important gaps exist in the empirical data for cause of death estimates for some countries; for example, no national data for India are available for the past decade.

FUNDING

Bill & Melinda Gates Foundation.

Global, regional, and national age-sex specific all-cause and cause-specific mortality for 240 causes of death, 1990-2013: a systematic analysis for the Global Burden of Disease Study 2013

BACKGROUND

Up-to-date evidence on levels and trends for age-sex-specific all-cause and cause-specific mortality is essential for the formation of global, regional, and national health policies. In the Global Burden of Disease Study 2013 (GBD 2013) we estimated yearly deaths for 188 countries between 1990, and 2013. We used the results to assess whether there is epidemiological convergence across countries.

METHODS

We estimated age-sex-specific all-cause mortality using the GBD 2010 methods with some refinements to improve accuracy applied to an updated database of vital registration, survey, and census data. We generally estimated cause of death as in the GBD 2010. Key improvements included the addition of more recent vital registration data for 72 countries, an updated verbal autopsy literature review, two new and detailed data systems for China, and more detail for Mexico, UK, Turkey, and Russia. We improved statistical models for garbage code redistribution. We used six different modelling strategies across the 240 causes; cause of death ensemble modelling (CODEm) was the dominant strategy for causes with sufficient information. Trends for Alzheimer's disease and other dementias were informed by meta-regression of prevalence studies. For pathogen-specific causes of diarrhoea and lower respiratory infections we used a counterfactual approach. We computed two measures of convergence (inequality) across countries: the average relative difference across all pairs of countries (Gini coefficient) and the average absolute difference across countries. To summarise broad findings, we used multiple decrement life-tables to decompose probabilities of death from birth to exact age 15 years, from exact age 15 years to exact age 50 years, and from exact age 50 years to exact age 75 years, and life expectancy at birth into major causes. For all quantities reported, we computed 95% uncertainty intervals (UIs). We constrained cause-specific fractions within each age-sex-country-year group to sum to all-cause mortality based on draws from the uncertainty distributions.

FINDINGS

Global life expectancy for both sexes increased from 65.3 years (UI 65.0-65.6) in 1990, to 71.5 years (UI 71.0-71.9) in 2013, while the number of deaths increased from 47.5 million (UI 46.8-48.2) to 54.9 million (UI 53.6-56.3) over the same interval. Global progress masked variation by age and sex: for children, average absolute differences between countries decreased but relative differences increased. For women aged 25-39 years and older than 75 years and for men aged 20-49 years and 65 years and older, both absolute and relative differences increased. Decomposition of global and regional life expectancy showed the prominent role of reductions in age-standardised death rates for cardiovascular diseases and cancers in high-income regions, and reductions in child deaths from diarrhoea, lower respiratory infections, and neonatal causes in low-income regions. HIV/AIDS reduced life expectancy in southern sub-Saharan Africa. For most communicable causes of death both numbers of deaths and age-standardised death rates fell whereas for most non-communicable causes, demographic shifts have increased numbers of deaths but decreased age-standardised death rates. Global deaths from injury increased by 10.7%, from 4.3 million deaths in 1990 to 4.8 million in 2013; but age-standardised rates declined over the same period by 21%. For some causes of more than 100,000 deaths per year in 2013, age-standardised death rates increased between 1990 and 2013, including HIV/AIDS, pancreatic cancer, atrial fibrillation and flutter, drug use disorders, diabetes, chronic kidney disease, and sickle-cell anaemias. Diarrhoeal diseases, lower respiratory infections, neonatal causes, and malaria are still in the top five causes of death in children younger than 5 years. The most important pathogens are rotavirus for diarrhoea and pneumococcus for lower respiratory infections. Country-specific probabilities of death over three phases of life were substantially varied between and within regions.

INTERPRETATION

For most countries, the general pattern of reductions in age-sex specific mortality has been associated with a progressive shift towards a larger share of the remaining deaths caused by non-communicable disease and injuries. Assessing epidemiological convergence across countries depends on whether an absolute or relative measure of inequality is used. Nevertheless, age-standardised death rates for seven substantial causes are increasing, suggesting the potential for reversals in some countries. Important gaps exist in the empirical data for cause of death estimates for some countries; for example, no national data for India are available for the past decade.

FUNDING

Bill & Melinda Gates Foundation.

Sinusitis and pneumonia hospitalization after introduction of pneumococcal conjugate vaccine

BACKGROUND AND OBJECTIVE

Streptococcus pneumoniae is a major cause of pneumonia and sinusitis. Pneumonia kills >1 million children annually, and sinusitis is a potentially serious pediatric disease that increases the risk of orbital and intracranial complications. Although pneumococcal conjugate vaccine (PCV) is effective against invasive pneumococcal disease, its effectiveness against pneumonia is less consistent, and its effect on sinusitis is not known. We compared hospitalization rates due to sinusitis, pneumonia, and empyema before and after sequential introduction of PCV7 and PCV13.

METHOD

All children 0 to <18 years old hospitalized for sinusitis, pneumonia, or empyema in Stockholm County, Sweden, from 2003 to 2012 were included in a population-based study of hospital registry data on hospitalizations due to sinusitis, pneumonia, or empyema. Trend analysis, incidence rates, and rate ratios (RRs) were calculated comparing July 2003 to June 2007 with July 2008 to June 2012, excluding the year of PCV7 introduction.

RESULTS

Hospitalizations for sinusitis decreased significantly in children aged 0 to <2 years, from 70 to 24 cases per 100 000 population (RR = 0.34, P < .001). Hospitalizations for pneumonia decreased significantly in children aged 0 to <2 years, from 450 to 366 per 100 000 population (RR = 0.81, P < .001) and in those aged 2 to <5 years from 250 to 212 per 100 000 population (RR = 0.85, P = .002). Hospitalization for empyema increased nonsignificantly. Trend analyses showed increasing hospitalization for pneumonia in children 0 to <2 years before intervention and confirmed a decrease in hospitalizations for sinusitis and pneumonia in children aged 0 to <5 years after intervention.

CONCLUSIONS

PCV7 and PCV13 vaccination led to a 66% lower risk of hospitalization for sinusitis and 19% lower risk of hospitalization for pneumonia in children aged 0 to <2 years, in a comparison of 4 years before and 4 years after vaccine introduction.

The radiological diagnosis of pneumonia in children

Despite the importance of paediatric pneumonia as a cause of short and long-term morbidity and mortality worldwide, a reliable gold standard for its diagnosis remains elusive. The utility of clinical, microbiological and radiological diagnostic approaches varies widely within and between populations and is heavily dependent on the expertise and resources available in various settings. Here we review the role of radiology in the diagnosis of paediatric pneumonia. Chest radiographs (CXRs) are the most widely employed test, however, they are not indicated in ambulatory settings, cannot distinguish between viral and bacterial infections and have a limited role in the ongoing management of disease. A standardised definition of alveolar pneumonia on a CXR exists for epidemiological studies targeting bacterial pneumonias but it should not be extrapolated to clinical settings. Radiography, computed tomography and to a lesser extent ultrasonography and magnetic resonance imaging play an important role in complicated pneumonias but there are limitations that preclude their use as routine diagnostic tools. Large population-based studies are needed in different populations to address many of the knowledge gaps in the radiological diagnosis of pneumonia in children, however, the feasibility of such studies is an important barrier.

Effects of vaccination on invasive pneumococcal disease in South Africa

BACKGROUND

In South Africa, a 7-valent pneumococcal conjugate vaccine (PCV7) was introduced in 2009 with a three-dose schedule for infants at 6, 14, and 36 weeks of age; a 13-valent vaccine (PCV13) replaced PCV7 in 2011. In 2012, it was estimated that 81% of 12-month-old children had received three doses of vaccine. We assessed the effect of vaccination on invasive pneumococcal disease.

METHODS

We conducted national, active, laboratory-based surveillance for invasive pneumococcal disease. We calculated the change in the incidence of the disease from a prevaccine (baseline) period (2005 through 2008) to postvaccine years 2011 and 2012, with a focus on high-risk age groups.

RESULTS

Surveillance identified 35,192 cases of invasive pneumococcal disease. The rates among children younger than 2 years of age declined from 54.8 to 17.0 cases per 100,000 person-years from the baseline period to 2012, including a decline from 32.1 to 3.4 cases per 100,000 person-years in disease caused by PCV7 serotypes (-89%; 95% confidence interval [CI], -92 to -86). Among children not infected with the human immunodeficiency virus (HIV), the estimated incidence of invasive pneumococcal disease caused by PCV7 serotypes decreased by 85% (95% CI, -89 to -79), whereas disease caused by nonvaccine serotypes increased by 33% (95% CI, 15 to 48). Among adults 25 to 44 years of age, the rate of PCV7-serotype disease declined by 57% (95% CI, -63 to -50), from 3.7 to 1.6 cases per 100,000 person-years.

CONCLUSIONS

Rates of invasive pneumococcal disease among children in South Africa fell substantially by 2012. Reductions in the rates of disease caused by PCV7 serotypes among both children and adults most likely reflect the direct and indirect effects of vaccination. (Funded by the National Institute for Communicable Diseases of the National Health Laboratory Service and others.).

A randomised trial to evaluate the immunogenicity, reactogenicity, and safety of the 10-valent pneumococcal non-typeable Haemophilus influenzae protein D conjugate vaccine (PHiD-CV) co-administered with routine childhood vaccines in Singapore and Malaysia

Background

The immunogenicity, reactogenicity, and safety of the 10-valent pneumococcal non-typeable Haemophilus influenzae protein D conjugate vaccine (PHiD-CV) co-administered with routine childhood vaccines were evaluated among infants from Singapore and Malaysia, where PHiD-CV has been licensed.

Methods

In the primary vaccination phase, 298 infants from Singapore and 168 infants from Malaysia were randomised to receive the Phase III Clinical (Clin) or the Commercial (Com) lot of PHiD-CV at 2, 3, and 5 months of age. In the booster vaccination phase, 238 toddlers from Singapore received one dose of the PHiD-CV Commercial lot at 18–21 months of age. Immune responses to pneumococcal polysaccharides were measured using 22F-inhibition enzyme-linked immunosorbent assay (ELISA) and functional opsonophagocytic activity (OPA) assay and to protein D, using ELISA.

Results

Immune responses induced by primary vaccination with the PHiD-CV Commercial lot were non-inferior to the Phase III Clinical lot in terms of adjusted antibody geometric mean concentration (GMC) ratios for each vaccine pneumococcal serotype and protein D. For each vaccine pneumococcal serotype, ≥93.6% and ≥88.5% of infants from Malaysia and Singapore had post-primary vaccination antibody concentrations ≥0.2 μg/mL and OPA titres ≥8, in the Clin and Com groups, respectively. For each vaccine pneumococcal serotype, ≥60.8% and ≥98.2% of toddlers from Singapore had pre- and post-booster antibody concentrations ≥0.2 μg/mL, in the Clin and Com groups, respectively. All children, except one, had measurable anti-protein D antibodies and the primary and booster doses of the co-administered vaccines were immunogenic. The incidence of each grade 3 solicited symptom was ≤11.1% in both study phases. No serious adverse events considered causally related to vaccination were reported throughout the study.

Conclusions

PHiD-CV given as three-dose primary vaccination to infants in Singapore and Malaysia and booster vaccination to toddlers in Singapore was shown to be immunogenic with a clinically acceptable-safety profile.

This study has been registered at http://www.clinicaltrials.govNCT00808444 and NCT01119625.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2334-14-530) contains supplementary material, which is available to authorized users.

Predicting the impact of new pneumococcal conjugate vaccines: serotype composition is not enough

Streptococcus pneumoniae is a major cause of childhood morbidity and mortality worldwide. A heptavalent polysaccharide-protein conjugate vaccine (PCV) has proven highly effective in preventing pneumococcal disease in industrialized countries. Two higher-valent pneumococcal conjugate vaccines are now widely available, even in the poorest countries. These differ from each other in the number of serotypes and carrier proteins used for their conjugation. Some have assumed that the only meaningful clinical difference between PCV formulations is a function of the number of serotypes each contains. A careful review of recent clinical data with these and several unlicensed PCV formulations points to important similarities but also that some key properties of each vaccine likely differ from one another.

Respiratory risks from household air pollution in low and middle income countries

A third of the world's population uses solid fuel derived from plant material (biomass) or coal for cooking, heating, or lighting. These fuels are smoky, often used in an open fire or simple stove with incomplete combustion, and result in a large amount of household air pollution when smoke is poorly vented. Air pollution is the biggest environmental cause of death worldwide, with household air pollution accounting for about 3·5-4 million deaths every year. Women and children living in severe poverty have the greatest exposures to household air pollution. In this Commission, we review evidence for the association between household air pollution and respiratory infections, respiratory tract cancers, and chronic lung diseases. Respiratory infections (comprising both upper and lower respiratory tract infections with viruses, bacteria, and mycobacteria) have all been associated with exposure to household air pollution. Respiratory tract cancers, including both nasopharyngeal cancer and lung cancer, are strongly associated with pollution from coal burning and further data are needed about other solid fuels. Chronic lung diseases, including chronic obstructive pulmonary disease and bronchiectasis in women, are associated with solid fuel use for cooking, and the damaging effects of exposure to household air pollution in early life on lung development are yet to be fully described. We also review appropriate ways to measure exposure to household air pollution, as well as study design issues and potential effective interventions to prevent these disease burdens. Measurement of household air pollution needs individual, rather than fixed in place, monitoring because exposure varies by age, gender, location, and household role. Women and children are particularly susceptible to the toxic effects of pollution and are exposed to the highest concentrations. Interventions should target these high-risk groups and be of sufficient quality to make the air clean. To make clean energy available to all people is the long-term goal, with an intermediate solution being to make available energy that is clean enough to have a health impact.

Chronic helminth infections impair pneumococcal vaccine responses

Pneumonia is the leading killer of children and disproportionately affects developing countries. Vaccination campaigns against Streptococcus pneumoniae, the leading cause of pneumonia, have recently been launched with a new conjugate vaccine in Africa. Using a mouse model, we assessed the potential role that the high burden of helminth infections in the countries targeted for vaccine might have on vaccine effectiveness. Mice vaccinated with either commercial conjugate or purified polysaccharide vaccines had impaired antibody responses if they were chronically infected with Taenia crassiceps. This translated to increased susceptibility to pneumococcal pneumonia and high mortality compared to helminth-negative vaccinated animals, which were fully protected from disease and death. Antibodies taken from Taenia-infected, vaccinated mice were unable to effectively opsonize S. pneumoniae for killing by alveolar macrophages, and did not protect against pneumococcal challenge when adoptively transferred into naïve animals. These data may have implications for vaccination programs in countries endemic with helminths.

Population-based incidence of community-acquired pneumonia hospitalization in Hong Kong children younger than 5 years before universal conjugate pneumococcal immunization

OBJECTIVES

We sought to document the incidence of pediatric hospitalization for bacterial pneumonia before universal childhood conjugate pneumococcal vaccination using two different methods of diagnosis.

METHODS

By following the World Health Organization (WHO) chest radiography (CXR) protocol, two radiologists independently read the CXRs of a cohort of systematically recruited children younger than 5 years. The children had acute respiratory infections and were admitted to one of two hospitals that care for 72.5% of all pediatric admissions on Hong Kong Island. Medical records were reviewed for clinical manifestation and to identify bacterial pneumonia diagnosed by pediatricians.

RESULTS

In children younger than 5 years, the incidences of bacterial pneumonia, as diagnosed by pediatricians and by the WHO CXR standard, were 775.7 per 100,000 population [95% confidence interval (CI, 591.8-998.3)] and 439.5 per 100,000 population (95% CI, 304.6-614.5), respectively. The study period was from 2002 to 2004.

CONCLUSION

This study provided a reliable baseline estimate of the hospitalization burden of pneumococcal pneumonia in Hong Kong children before the advent of universal conjugate pneumococcal vaccination.

Serotype-specific effectiveness and correlates of protection for the 13-valent pneumococcal conjugate vaccine: a postlicensure indirect cohort study

BACKGROUND

Efficacy of the 13-valent pneumococcal conjugate vaccine (PCV13) was inferred before licensure from an aggregate correlate of protection established for the seven-valent vaccine (PCV7). We did a postlicensure assessment of serotype-specific vaccine effectiveness and immunogenicity in England, Wales, and Northern Ireland to derive the correlates of protection for individual serotypes.

METHODS

We assessed vaccine effectiveness against invasive pneumococcal disease using the indirect cohort method. We measured serotype-specific IgG concentration in infants after they were given two priming doses of PCV7 (n=126) or PCV13 (n=237) and opsonophagocytic antibody titre from a subset of these infants (n=100). We derived correlates of protection by relating percentage protection to a threshold antibody concentration achieved by an equivalent percentage of infants. We used multivariable logistic regression to estimate vaccine effectiveness and reverse cumulative distribution curves to estimate correlates of protection.

FINDINGS

For the 706 cases of invasive pneumococcal disease included in the study, PCV13 vaccine effectiveness after two doses before age 12 months or one dose from 12 months was 75% (95% CI 58-84). Vaccine effectiveness was 90% (34-98) for the PCV7 serotypes and 73% (55-84) for the six additional serotypes included in PCV13. Protection was shown for four of the six additional PCV13 serotypes (vaccine effectiveness for serotype 3 was not significant and no cases of serotype 5 infection occurred during the observation period). The vaccine effectiveness for PCV13 and PCV7 was lower than predicted by the aggregate correlate of protection of 0·35 μg/mL used during licensing. Calculated serotype-specific correlates of protection were higher than 0·35 μg/mL for serotypes 1, 3, 7F, 19A, 19F, and lower than 0·35 μg/mL for serotypes 6A, 6B, 18C, and 23F. Opsonophagocytic antibody titres of 1 in 8 or higher did not predict protection.

INTERPRETATION

PCV13 provides significant protection for most of the vaccine serotypes. Although use of the aggregate correlate of protection of 0·35 μg/mL has enabled the licensing of effective new PCVs, serotype-specific correlates of protection vary widely. The relation between IgG concentration after priming and long-term protection needs to be better understood.

FUNDING

Public Health England and UK Department of Health Research and Development Directorate.

Effectiveness of 7-valent pneumococcal conjugate vaccine against invasive pneumococcal disease in HIV-infected and -uninfected children in south africa: a matched case-control study

A 2 + 1 seven-valent pneumococcal conjugate vaccine schedule is effective against vaccine-serotype invasive pneumococcal disease (IPD) in HIV-uninfected children and HIV-exposed but -uninfected children and against all-serotype multidrug-resistant IPD in HIV-uninfected children.

Background. South Africa introduced 7-valent pneumococcal conjugate vaccine (PCV7) in April 2009 using a 2 + 1 schedule (6 and 14 weeks and 9 months). We estimated the effectiveness of ≥2 PCV7 doses against invasive pneumococcal disease (IPD) in human immunodeficiency virus (HIV)–infected and -uninfected children.

Methods. IPD (pneumococcus identified from a normally sterile site) cases were identified through national laboratory-based surveillance. Specimens were serotyped by Quellung or polymerase chain reaction. Four controls, matched for age, HIV status, and hospital were sought for each case. Using conditional logistic regression, we calculated vaccine effectiveness (VE) as 1 minus the adjusted odds ratio for vaccination.

Results. From March 2010 through November 2012, we enrolled 187 HIV-uninfected (48 [26%] vaccine serotype) and 109 HIV-infected (43 [39%] vaccine serotype) cases and 752 HIV-uninfected and 347 HIV-infected controls aged ≥16 weeks. Effectiveness of ≥2 PCV7 doses against vaccine-serotype IPD was 74% (95% confidence interval [CI], 25%–91%) among HIV-uninfected and −12% (95% CI, −449% to 77%) among HIV-infected children. Effectiveness of ≥3 doses against vaccine-serotype IPD was 90% (95% CI, 14%–99%) among HIV-uninfected and 57% (95% CI, −371% to 96%) among HIV-infected children. Among HIV-exposed but -uninfected children, effectiveness of ≥2 doses was 92% (95% CI, 47%–99%) against vaccine-serotype IPD. Effectiveness of ≥2 doses against all-serotype multidrug-resistant IPD was 96% (95% CI, 62%–100%) among HIV-uninfected children.

Conclusions. A 2 + 1 PCV7 schedule was effective in preventing vaccine-serotype IPD in HIV-uninfected and HIV-exposed, uninfected children. This finding supports the World Health Organization recommendation for this schedule as an alternative to a 3-dose primary series among HIV-uninfected individuals.

Global control of pneumococcal infections by pneumococcal vaccines

Streptococcus pneumoniae is a major worldwide cause of morbidity and mortality. Pneumococcal carriage is considered to be an important source of horizontal spread of this pathogen within the community. Pneumococcal conjugate vaccine (PCV) is capable of inducing serotype-specific antibodies in sera of infants, and has been suggested to reduce nasopharyngeal carriage of vaccine-type pneumococci in children. PCV is generally immunogenic for pediatric patients with invasive pneumococcal disease, with an exception for the infecting serotypes. Based on evidences from the clinical trials of PCV, the health impact of childhood pneumococcal pneumonia appears to be high in developing countries where most of global childhood pneumonia deaths occur. PCV vaccination may prevent hundreds of deaths per 100,000 children vaccinated in developing countries, while PCV vaccination is expected to prevent less than 10 deaths per 100,000 children vaccinated in the developed countries. Therefore, the WHO has proposed a strategy to reduce the incidence of severe pneumonia by 75% in child less than 5 years of age compared to 2010 levels by 2025.

Efficacy of pneumococcal nontypable Haemophilus influenzae protein D conjugate vaccine (PHiD-CV) in young Latin American children: A double-blind randomized controlled trial

BACKGROUND

The relationship between pneumococcal conjugate vaccine-induced antibody responses and protection against community-acquired pneumonia (CAP) and acute otitis media (AOM) is unclear. This study assessed the impact of the ten-valent pneumococcal nontypable Haemophilus influenzae protein D conjugate vaccine (PHiD-CV) on these end points. The primary objective was to demonstrate vaccine efficacy (VE) in a per-protocol analysis against likely bacterial CAP (B-CAP: radiologically confirmed CAP with alveolar consolidation/pleural effusion on chest X-ray, or non-alveolar infiltrates and C-reactive protein ≥ 40 µg/ml); other protocol-specified outcomes were also assessed.

METHODS AND FINDINGS

This phase III double-blind randomized controlled study was conducted between 28 June 2007 and 28 July 2011 in Argentine, Panamanian, and Colombian populations with good access to health care. Approximately 24,000 infants received PHiD-CV or hepatitis control vaccine (hepatitis B for primary vaccination, hepatitis A at booster) at 2, 4, 6, and 15-18 mo of age. Interim analysis of the primary end point was planned when 535 first B-CAP episodes, occurring ≥2 wk after dose 3, were identified in the per-protocol cohort. After a mean follow-up of 23 mo (PHiD-CV, n = 10,295; control, n = 10,201), per-protocol VE was 22.0% (95% CI: 7.7, 34.2; one-sided p = 0.002) against B-CAP (conclusive for primary objective) and 25.7% (95% CI: 8.4%, 39.6%) against World Health Organization-defined consolidated CAP. Intent-to-treat VE was 18.2% (95% CI: 5.5%, 29.1%) against B-CAP and 23.4% (95% CI: 8.8%, 35.7%) against consolidated CAP. End-of-study per-protocol analyses were performed after a mean follow-up of 28-30 mo for CAP and invasive pneumococcal disease (IPD) (PHiD-CV, n = 10,211; control, n = 10,140) and AOM (n = 3,010 and 2,979, respectively). Per-protocol VE was 16.1% (95% CI: -1.1%, 30.4%; one-sided p = 0.032) against clinically confirmed AOM, 67.1% (95% CI: 17.0%, 86.9%) against vaccine serotype clinically confirmed AOM, 100% (95% CI: 74.3%, 100%) against vaccine serotype IPD, and 65.0% (95% CI: 11.1%, 86.2%) against any IPD. Results were consistent between intent-to-treat and per-protocol analyses. Serious adverse events were reported for 21.5% (95% CI: 20.7%, 22.2%) and 22.6% (95% CI: 21.9%, 23.4%) of PHiD-CV and control recipients, respectively. There were 19 deaths (n = 11,798; 0.16%) in the PHiD-CV group and 26 deaths (n = 11,799; 0.22%) in the control group. A significant study limitation was the lower than expected number of captured AOM cases.

CONCLUSIONS

Efficacy was demonstrated against a broad range of pneumococcal diseases commonly encountered in young children in clinical practice.

TRIAL REGISTRATION

www.ClinicalTrials.gov NCT00466947.

Population effect of 10-valent pneumococcal conjugate vaccine on nasopharyngeal carriage of Streptococcus pneumoniae and non-typeable Haemophilus influenzae in Kilifi, Kenya: findings from cross-sectional carriage studies

Background

The effect of 7-valent pneumococcal conjugate vaccine (PCV) in developed countries was enhanced by indirect protection of unvaccinated individuals, mediated by reduced nasopharyngeal carriage of vaccine-serotype pneumococci. The potential indirect protection of 10-valent PCV (PCV10) in a developing country setting is unknown. We sought to estimate the effectiveness of introduction of PCV10 in Kenya against carriage of vaccine serotypes and its effect on other bacteria.

Methods

PCV10 was introduced into the infant vaccination programme in Kenya in January, 2011, accompanied by a catch-up campaign in Kilifi County for children aged younger than 5 years. We did annual cross-sectional carriage studies among an age-stratified, random population sample in the 2 years before and 2 years after PCV10 introduction. A nasopharyngeal rayon swab specimen was collected from each participant and was processed in accordance with WHO recommendations. Prevalence ratios of carriage before and after introduction of PCV10 were calculated by log-binomial regression.

Findings

About 500 individuals were enrolled each year (total n=2031). Among children younger than 5 years, the baseline (2009–10) carriage prevalence was 34% for vaccine-serotype Streptococcus pneumoniae, 41% for non-vaccine-serotype Streptococcus pneumoniae, and 54% for non-typeable Haemophilus influenzae. After PCV10 introduction (2011–12), these percentages were 13%, 57%, and 40%, respectively. Adjusted prevalence ratios were 0·36 (95% CI 0·26–0·51), 1·37 (1·13–1·65), and 0·62 (0·52–0·75), respectively. Among individuals aged 5 years or older, the adjusted prevalence ratios for vaccine-serotype and non-vaccine-serotype S pneumoniae carriage were 0·34 (95% CI 0·18–0·62) and 1·13 (0·92–1·38), respectively. There was no change in prevalence ratio for Staphylococcus aureus (adjusted prevalence ratio for those <5 years old 1·02, 95% CI 0·52–1·99, and for those ≥5 years old 0·90, 0·60–1·35).

Interpretation

After programmatic use of PCV10 in Kilifi, carriage of vaccine serotypes was reduced by two-thirds both in children younger than 5 years and in older individuals. These findings suggest that PCV10 introduction in Africa will have substantial indirect effects on invasive pneumococcal disease.

Funding

GAVI Alliance and Wellcome Trust.

Antibiotic therapy versus no antibiotic therapy for children aged two to 59 months with WHO-defined non-severe pneumonia and wheeze

BACKGROUND

Worldwide, pneumonia is the leading cause of death among children under five years of age and accounts for approximately two million deaths annually. The World Health Organization (WHO) has developed case management guidelines based on simple clinical signs to help clinicians decide on the appropriate pneumonia treatment. Children and infants who exhibit fast breathing (50 breaths per minute or more in infants two months to 12 months of age and 40 or more in children 12 months to five years of age) and cough are presumed to have non-severe pneumonia and the WHO recommends antibiotics. Implementation of these guidelines to identify and manage pneumonia at the community level has been shown to reduce acute respiratory infection (ARI)-related mortality by 36%, although apprehension exists regarding these results due to the questionable quality of evidence. As WHO guidelines do not make a distinction between viral and bacterial pneumonia, these children continue to receive antibiotics because of the concern that it may not be safe to do otherwise. Therefore, it is essential to explore the role of antibiotics in children with WHO-defined non-severe pneumonia and wheeze and to develop effective guidelines for initial antibiotic treatment.

OBJECTIVES

To evaluate the efficacy of antibiotic therapy versus no antibiotic therapy for children aged two to 59 months with WHO-defined non-severe pneumonia and wheeze.

SEARCH METHODS

We searched CENTRAL (2014, Issue 1), MEDLINE (1946 to March week 3, 2014), EMBASE (January 2010 to March 2014), CINAHL (1981 to March 2014), LILACS (1982 to March 2014), Networked Digital Library of Theses and Dissertations (23 July 2013) and Web of Science (1985 to March 2014).

SELECTION CRITERIA

Randomised controlled trials (RCTs) evaluating the efficacy of antibiotic therapy versus no antibiotic therapy for children aged two to 59 months with non-severe pneumonia and wheeze. We considered studies that defined non-severe pneumonia as cough or difficulty in breathing with a respiratory rate above the WHO-defined age-specific values (respiratory rate of 50 breaths per minute or more for children aged two to 12 months, or a respiratory rate of 40 breaths per minute or more for children aged 12 to 59 months) and wheeze for inclusion. We have excluded non-RCTs (quasi-RCTs).

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed the search results and extracted data.

MAIN RESULTS

We did not identify any study that completely fulfilled our inclusion criteria.

AUTHORS' CONCLUSIONS

There is a clear need for RCTs to address this question in representative populations. We do not currently have evidence to support or challenge the continued use of antibiotics for the treatment of non-severe pneumonia, as suggested by WHO guidelines.

Use of vaccines as probes to define disease burden

Vaccine probe studies have emerged in the past 15 years as a useful way to characterise disease. By contrast, traditional studies of vaccines focus on defining the vaccine effectiveness or efficacy. The underlying basis for the vaccine probe approach is that the difference in disease burden between vaccinated and unvaccinated individuals can be ascribed to the vaccine-specific pathogen. Vaccine probe studies can increase understanding of a vaccine's public health value. For instance, even when a vaccine has a seemingly low efficacy, a high baseline disease incidence can lead to a large vaccine-preventable disease burden and thus that population-based vaccine introduction would be justified. So far, vaccines have been used as probes to characterise disease syndromes caused by Haemophilus influenzae type b, pneumococcus, rotavirus, and early infant influenza. However, vaccine probe studies have enormous potential and could be used more widely in epidemiology, for example, to define the vaccine-preventable burden of malaria, typhoid, paediatric influenza, and dengue, and to identify causal interactions between different pathogens.

Placebo use in vaccine trials: recommendations of a WHO expert panel

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Placebo controls may be acceptable even when an efficacious vaccine exists, in the following four possible situations:

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When developing a locally affordable vaccine.

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When evaluating the local safety and efficacy of an existing vaccine.

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When testing a new vaccine when an existing vaccine is not considered appropriate locally.

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When determining the local burden of disease.

Vaccines are among the most cost-effective interventions against infectious diseases. Many candidate vaccines targeting neglected diseases in low- and middle-income countries are now progressing to large-scale clinical testing. However, controversy surrounds the appropriate design of vaccine trials and, in particular, the use of unvaccinated controls (with or without placebo) when an efficacious vaccine already exists. This paper specifies four situations in which placebo use may be acceptable, provided that the study question cannot be answered in an active-controlled trial design; the risks of delaying or foregoing an efficacious vaccine are mitigated; the risks of using a placebo control are justified by the social and public health value of the research; and the research is responsive to local health needs. The four situations are: (1) developing a locally affordable vaccine, (2) evaluating the local safety and efficacy of an existing vaccine, (3) testing a new vaccine when an existing vaccine is considered inappropriate for local use (e.g. based on epidemiologic or demographic factors), and (4) determining the local burden of disease.

Hospitalization rates of complicated pneumococcal community-acquired pneumonia is increasing in Tuscan children

To provide epidemiological data on community-acquired pneumonia (CAP) and complicated CAP, a retrospective study was conducted on a partially vaccinated paediatric population. Data from children hospitalized for CAP in Tuscan hospitals between January 1st, 1999 and December 31st, 2009 were analysed. A total of 5,450 children with CAP were hospitalized. Annual hospitalization rates for CAP did not change significantly over the study period (X2 for trend= 0.652; p=0.419). The total annual hospitalization rate for pneumococcal CAP varied according to age (28.04 per 100,000 children aged less than 5 years, 10.06 per 100,000 children aged 6-12 years and 0.98 per 100,000 children aged greater than13years). Hospitalization rates for pneumococcal CAP increased from12.84 (95 percent CI:7.35-18.34) in 2001 to 45.4 (95 percent CI:35.93-54.90) per 100,000 children aged less than 5 years in 2009 (p less than 0.0001). In addition, a significant increase of hospitalization rates for complicated CAP (from 6.07 in 1999 to 13.66 in 2009 per 100,000 children; P less than 0.0001) and pneumococcal complicated CAP (from 0.19 in 1999 to 3.41 in 2009 per 100,000 children) over the study period were highlighted. Our epidemiological data confirm the decision to introduce the PCV13 vaccine, to satisfy the need to prevent a wider group of pneumococcal serotypes.

Vaccine preventable disease incidence as a complement to vaccine efficacy for setting vaccine policy

Traditionally, vaccines have been evaluated in clinical trials that establish vaccine efficacy (VE) against etiology-confirmed disease outcomes, a measure important for licensure. Yet, VE does not reflect a vaccine's public health impact because it does not account for relative disease incidence. An additional measure that more directly establishes a vaccine's public health value is the vaccine preventable disease incidence (VPDI), which is the incidence of disease preventable by vaccine in a given context. We describe how VE and VPDI can vary, sometimes in inverse directions, across disease outcomes and vaccinated populations. We provide examples of how VPDI can be used to reveal the relative public health impact of vaccines in developing countries, which can be masked by focus on VE alone. We recommend that VPDI be incorporated along with VE into the analytic plans of vaccine trials, as well as decisions by funders, ministries of health, and regulatory authorities.

Increased risk for respiratory syncytial virus-associated, community-acquired alveolar pneumonia in infants born at 31-36 weeks of gestation

BACKGROUND

We compared hospitalization and pediatric intensive care unit (PICU) admission rates for community-acquired alveolar pneumonia (CAAP) and respiratory syncytial virus (RSV)-associated CAAP (RSV-CAAP) in non-RSV-immunized children <24-month-old born at 31-36 weeks gestational age (GA) versus those born at term (>36 weeks GA).

METHODS

Nasopharyngeal samples for RSV were obtained prospectively (2004-2011) during RSV season, from hospitalized children with radiographic-diagnosed CAAP. Soroka University Medical Center is the only hospital in the region, enabling population-based rate calculation. Relative risks (RR) and 95% confidence intervals (95% CI) were calculated comparing RSV-CAAP incidence in 31-36 weeks GA with >36 weeks GA children.

RESULTS

CAAP hospitalization incidences (per 1000 population) were 23.6 and 9.4 (RR: 2.52; 95% CI: 2.13-2.68), respectively; the respective incidences of PICU admission for overall CAAP were 1.8 and 0.2 (RR: 7.88; 95% CI: 4.59-11.83). The RRs (and 95% CI) for RSV-CAAP hospitalizations and PICU admission rates were (after extrapolation) 15.2 and 5.8 (RR: 2.79; 95% CI: 2.31-3.06) and 1.1 and 0.1 (RR: 9.14; 95% CI: 4.93-16.96), respectively. In a multiregression analysis in patients with RSV-CAAP versus CAAP, 31-36 weeks GA was an independent risk factor for hospitalization (RR: 1.485; 95% CI: 1.03-2.14).

CONCLUSIONS

Children <24-month-old born at 31-36 weeks GA are at increased risk for hospitalization and PICU admission for both overall CAAP and RSV-associated CAAP compared with those born at >36 weeks GA. Moreover, in late premature children, RSV represented a 50% increased risk for CAAP compared with infants born at term.

Efficacy of different pneumococcal conjugate vaccine schedules against pneumonia, hospitalisation, and mortality: re-analysis of a randomised trial in the Gambia

BACKGROUND

Pneumococcal conjugate vaccines (PCV) reduce disease due to Streptococcus pneumoniae. We aimed to determine the efficacy of different PCV schedules in Gambian children.

METHODS

We reanalysed data from a randomised placebo-controlled trial. Infants aged 6-51 weeks were allocated to three doses of nine-valent PCV (n=8718) or placebo (n=8719) and followed until age 30 months. We categorised participants to compare: (a) a first dose at age 6 or 10 weeks, (b) intervals of 1 or 2 months between doses, and (c) different intervals between second and third doses. The primary endpoint was first episode of radiologic pneumonia; other endpoints were hospitalisation and mortality. Using the placebo group as the reference population, Poisson regression models were used with follow-up after the first dose to estimate the efficacy of each schedule and from age 6 weeks to estimate the incidence rate difference between schedules.

RESULTS

Predicted efficacy in the groups aged 6 weeks (n=2467, 154 events) or 10 weeks (n=2420, 106 events) at first dose against radiologic pneumonia were 32% (95% CI 19-43%) and 33% (95% CI 21-44%), against hospitalisation 14% (95% CI 3-23%) and 17% (95% CI 7-26%), and against mortality 17% (95% CI -3 to 33%) and 16% (95% CI -3 to 32%) respectively. Predicted efficacy in the groups with intervals of 1 month (n=2701, 133 events) or 2 months (n=1351, 58 events) between doses against radiologic pneumonia were 33% (95% CI 20-44%) and 36% (95% CI 24-46%), against hospitalisation 15% (95% CI 5-24%) and 18% (95% CI 8-27%), and against mortality 17% (95% CI -2 to 33%) and 13% (95% CI -8 to 29%) respectively. Efficacy did not differ by interval between second and third doses, nor did the incidence rate difference between schedules.

CONCLUSIONS

We found no evidence that efficacy or effectiveness of PCV9 differed when doses were given with modest variability around the scheduled ages or intervals between doses.

Pneumococcal vaccines and the prevention of community-acquired pneumonia

Community-acquired pneumonia (CAP) is a disease that frequently affects children and adults throughout the world. As it places a considerable burden on society and, particularly, healthcare resources, any means of reducing its incidence and impact arouses great interest. A substantial number of paediatric and adult CAP cases are due to Streptococcus pneumoniae but, fortunately, there are effective vaccines available that are likely to have a significant impact on CAP-related medical, social and economic problems. The main aim of this paper is to evaluate the published evidence concerning the impact of pneumococcal vaccines on CAP in children and adults. The original 7-valent pneumococcal conjugate vaccine (PCV-7) completely modified the total burden of pneumococcal diseases in vaccinated children and unvaccinated contacts of any age. However, the existence of some problems moderately reducing its preventive efficacy has led to the development of PCVs with a larger number of pneumococcal serotypes, including those that were previously of marginal importance but now cause of severe disease. It is reasonable to think that these PCVs (particularly PCV13, which includes all of the most important serotypes emerging since the introduction of PCV7) will further reduce the importance of pneumococcal diseases, although it is still not clear whether the replacement of the 23-valent polysaccharide vaccine with PCV13 would be more protective in adults.

The effect of distance on observed mortality, childhood pneumonia and vaccine efficacy in rural Gambia

We investigated whether straight-line distance from residential compounds to healthcare facilities influenced mortality, the incidence of pneumonia and vaccine efficacy against pneumonia in rural Gambia. Clinical surveillance for pneumonia was conducted on 6938 children living in the catchment areas of the two largest healthcare facilities. Deaths were monitored by three-monthly home visits. Children living >5 km from the two largest healthcare facilities had a 2·78 [95% confidence interval (CI) 1·74–4·43] times higher risk of all-cause mortality compared to children living within 2 km of these facilities. The observed rate of clinical and radiological pneumonia was lower in children living >5 km from these facilities compared to those living within 2 km [rate ratios 0·65 (95% CI 0·57–0·73) and 0·74 (95% CI 0·55–0·98), respectively]. There was no association between distance and estimated pneumococcal vaccine efficacy. Geographical access to healthcare services is an important determinant of survival and pneumonia in children in rural Gambia.