Contribution of respiratory tract infections to child deaths: a data linkage study

Pediatric tuina for recurrent respiratory tract infection in children: A systematic review and meta-analysis

BACKGROUND

To evaluate the effects and safety of pediatric tuina for recurrent respiratory tract infections (RRTIs).

METHODS

Web of Science, PubMed, Cochrane Library, Embase, CNKI, Wanfang Data, VIP, and CBM databases were searched from inception to September 20 2023. Two authors independently selected studies, collected data, and evaluated methodological quality using the Cochrane Risk of Bias tool. Revman 5.4 was used for the meta-analysis.

RESULTS

Fifteen randomized controlled trials involving 1420 pediatric patients were included in this meta-analysis. The meta-analysis indicated that pediatric tuina significantly reduced the incidence of RRTIs [MD -1.11, 95% confidence interval (CI) (-1.77, -0.46)], decreased infection duration (MD -1.16 days, 95% CI [- 1.66, - 0.66]), improved IgA (MD 0.25 g/L, 95% CI [0.09, 0.41]), IgG (MD 1.64 g/L; 95% CI [0.82, 2.45]), CD3+ (MD 3.33%, 95% CI [0.74, 5.92]), CD4+ (MD 4.78%, 95% CI [2.08, 7.48]), CD4+/CD8+ ratio (MD 0.27%, 95% CI [0.08, 0.47]), and total effective rate (RR 1.19, 95% CI [1.13, 1.25]). However, IgM levels (MD 0.26 g/L, 95% CI [-0.26, 0.81]) and CD8+ (MD -1.36%, 95% CI [- 3.12, 0.41]) were not significantly different between the groups. Moreover, no Tuina-linked adverse reactions were observed.

CONCLUSION

Pediatric tuina has shown positive effects in RRTIs treatment. However, these results should be interpreted with caution owing to study quality. Further large-scale and high-quality randomized controlled trials are warranted to confirm these findings.

Feasibility study of using mobile application to support triage and diagnosis clinical decisions for pediatricians: User-centered design approach

Background

While there is some evidence in the literature demonstrating success in using a triage software application in ED, none of the solution was developed specifically to support a holistic decision of pediatricians in triage and diagnosis purposes to initiate the first treatment properly. To explore the usefulness and possibility of employing a digital-based solution to enhance clinician performance, the mobile application was developed and then assessed in different perspectives.

Objective

The primary objective of this study is to contribute implementation practice of an application to support pediatric triage and diagnoses. The secondary objective is to present the results of the preliminary evaluation of the application.

Methods

The application called Pedicmeter was developed. Formative tests with revisions were applied throughout the development phase. A number of summative extensive evaluations were also conducted to investigate the efficacy of the proposed method. The evaluation focused on measuring the ability of an application to support a pediatric staff's decision to determine an overall severity level and disease diagnosis. Finally, the user's (clinician's) satisfaction of using the application was measured.

Results

The application Pedicmeter enables clinicians to make more accurate decisions in determining emergency level of pediatric patients by 6.66%. The application accurately diagnosed a disease with 73.08% accuracy and 66.67% accuracy for respiratory and infectious diseases, respectively. The diagnostic information that the application suggested shows that it does have an influence on a clinician's diagnosis. Using the app showed improvements in diagnostic accuracy for asthma, croup, sepsis, but it showed a decrease in the accuracy of a clinician's decision for pneumonia. The benefit of the application that satisfies the pediatricians the most is the helpfulness of the features of the application (86%), while the least satisfying factor was the required number of inputs (63%).

Conclusion

The developed application conceptually shows a promising opportunity to enhance clinicians' decisions from the pilot study. However, the study also reveals further tweaks are required and unveils challenging issues and the concerns of clinician users when use the application. Further research will be conducted to investigate and determine the limiting factors and specific issues revealed by this study. Longitudinal data collection and analysis also need to be conducted to investigate the clinical implications.

Bacillus clausii UBBC-07 in the symptom management of upper respiratory tract infections in children: a double blind, placebo-controlled randomised study

In children, upper respiratory tract infections (URTIs) are one of the most common causes of infections which often require outpatient consultations with the doctor. The purpose of this study was to evaluate the effect of probiotic Bacillus clausii UBBC-07 on symptom management of URTIs in children. In this double blind, randomised, placebo-controlled study, 90 children (age 4-7 years) with URTIs were equally divided into two groups, the probiotic and placebo. The children were instructed to take B. clausii UBBC-07 spores (2×109 per 5 ml vial) or placebo suspension daily twice for three months. The total duration of the study was 6 months, 3 months treatment and 3 months follow-up period. The parameters assessed were the mean number of URTIs, duration and severity of URTIs, absenteeism from school/childcare and immunity parameters, such as immunoglobulin (Ig)M, IgG, IgE and salivary IgA levels. At the end of treatment, there was a significant decrease in the number, duration and severity of URTIs in the probiotic treated group as compared to the baseline and placebo. IgE levels were significantly decreased and salivary IgA levels were significantly increased in the probiotic treated group suggesting probiotic mediated Th1/Th2 immune homeostasis to alleviate URTIs in children. In conclusion, B. clausii UBBC-07 may help in the reduction of symptoms of URTIs. The trial was registered prospectively with the Clinical Trial Registry of India (CTRI Reg. No: CTRI/2018/08/015282).

Palivizumab's real-world effectiveness: a population-based study in Ontario, Canada, 1993-2017

OBJECTIVE

To evaluate the effectiveness of two palivizumab programmes targeting high-risk infants, defined by prematurity, diagnosis of comorbidities and geography, and assess potential disparities by neighbourhood income.

DESIGN

Controlled, interrupted time series.

SETTING

Ontario, Canada.

PATIENTS

We used linked health and demographic administrative databases to identify all children born in hospitals 1 January 1993 through 31 December 2016. Follow-up ended at the earliest of second birthday or 30 June 2017.

INTERVENTION

Palivizumab-eligibility: child was born very preterm and ≤6 months old during respiratory syncytial virus (RSV) season; <24 months old with significant chronic lung or congenital heart disease; or ≤6 months, born preterm or residents of remote regions.

MAIN OUTCOME

Severe RSV-related illness, defined as hospitalisation or death with a diagnosis of bronchiolitis, RSV pneumonia or RSV.

RESULTS

3 million births and 87 000 RSV-related events were identified. Over the study period, rates of severe RSV-related illness declined 65.4% among the highest risk group, eligible infants <6 months (230.6 to 79.8 admissions per 1000 child-years). Relative to changes among ineligible infants <6 months, rates dropped 10.4% (95% CI -18.6% to 39.4%) among eligible infants immediately following introduction of a national palivizumab programme in 1998. Initially, rates were considerably higher among infants from low-income neighbourhoods, but income-specific rates converged over time among eligible infants <6 months; such convergence was not seen among other children.

CONCLUSIONS

Incidence of severe RSV-related illness declined over the study period. While we cannot attribute causality, the timing and magnitude of these declines suggest impact of palivizumab in reducing RSV burden and diminishing social inequities among palivizumab-eligible infants.

Data Mining and Systematic Pharmacology to Reveal the Mechanisms of Traditional Chinese Medicine in Recurrent Respiratory Tract Infections' Treatment

Traditional Chinese medicine (TCM) was widely used in the treatment of recurrent respiratory tract infections (RRTIs) in East Asia, but its mechanism was not clear because of its complex prescription rules. This research prospectively collected 100 prescriptions of RRTI children treated with TCM. The characteristics of TCM in prescriptions were described and analyzed, and the rules of prescriptions were analyzed by hierarchical clustering and association rules. The results showed that the principle of RRTI was to pay equal attention to cold and mild, and six new meaningful prescriptions were obtained. Among them, the new prescription composed of Astragali Radix (Huangqi), Atractylodis Macrocephalae Rhizoma (Baizhu), Saposhnikoviae Radix (Fangfeng), Angelicae Sinensis Radix (Danggui), and Paeoniae Radix Rubra (Chishao) was an important method to treat RRTI. In order to explore the mechanism of the new prescription, the research obtained the action target of each herb of the core prescription on Integrative Pharmacology-based Research Platform of Traditional Chinese Medicine, TCMIP v2.0. The target genes were enriched by Metascape, and 93 Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways were obtained. According to the classification and statistics of KEGG type, it was found that the new prescription mainly intervened in the metabolic pathway dominated by amino acid metabolism. In addition, there were also many interventions in the nervous system-, endocrine system-, and digestive system-related pathways. This study summarized the prescription rule of TCM in the treatment of RRTI, analyzed the mechanism of supplementing deficiency, and provided a new idea for the treatment of RRTI.

Cause-specific child and adolescent mortality in the UK and EU15+ countries

OBJECTIVE

To compare cause-specific UK mortality in children and young people (CYP) with EU15+ countries (European Union countries pre-2004, Australia, Canada and Norway).

DESIGN

Mortality estimates were coded from the WHO World Mortality Database. Causes of death were mapped using the Global Burden of Disease mortality hierarchy to 22 cause groups. We compared UK mortality by cause, age group and sex with EU15+ countries in 2015 (or latest available) using Poisson regression models. We then ranked the UK compared with the EU15+ for each cause.

SETTING

The UK and EU15+ countries.

PARTICIPANTS

CYP aged 1-19.

MAIN OUTCOME MEASURE

Mortality rate per 100 000 and number of deaths.

RESULTS

UK mortality in 2015 was significantly higher than the EU15+ for common infections (both sexes aged 1-9, boys aged 10-14 and girls aged 15-19); chronic respiratory conditions (both sexes aged 5-14); and digestive, neurological and diabetes/urological/blood/endocrine conditions (girls aged 15-19). UK mortality was significantly lower for transport injuries (boys aged 15-19). The UK had the worst to third worst mortality rank for common infections in both sexes and all age groups, and in five out of eight non-communicable disease (NCD) causes in both sexes in at least one age group. UK mortality rank for injuries in 2015 was in the top half of countries for most causes.

CONCLUSIONS

UK CYP mortality is higher than a group of comparable countries for common infections and multiple NCD causes. Excess UK CYP mortality may be amenable to health system strengthening.

Deprivation and mortality related to pediatric respiratory tract infection: a cohort study in 3 high-income jurisdictions

BACKGROUND

Deaths from respiratory tract infections (RTIs) in children are preventable through timely access to public health and medical interventions. We aimed to assess whether socioeconomic disparities in mortality related to pediatric RTI persisted after accounting for health status at birth.

METHODS

We compared the prevalence of and risk factors for RTI-related death in singletons aged 28 days to 4 years across Ontario (Canada), Scotland and England (jurisdictions with universal health care) using linked administrative data for 2003-2013. We estimated rates of RTI-related mortality for children living in deprived areas and those born to teenage girls; we estimated both crude rates and those adjusted for health status at birth.

RESULTS

A total of 1 299 240 (Ontario), 547 556 (Scotland) and 3 910 401 (England) children were included in the study. Across all jurisdictions, children born in the most deprived areas experienced the highest rates of RTI-related mortality. After adjustment for high-risk chronic conditions and prematurity, we observed differences in mortality according to area-level deprivation in Ontario and England but not in Scotland. In Ontario, teenage motherhood was also an independent risk factor for RTI-related mortality.

INTERPRETATION

Socioeconomic disparities played a substantial role in child mortality related to RTI in all 3 jurisdictions. Context-specific investigations around the mechanisms of this increased risk and development of programs to address socioeconomic disparities are needed.

Origins of disparities in preventable child mortality in England and Sweden: a birth cohort study

OBJECTIVE

To compare mortality in children aged <5 years from two causes amenable to healthcare prevention in England and Sweden: respiratory tract infection (RTI) and sudden unexpected death in infancy (SUDI).

DESIGN

Birth cohort study using linked administrative health databases from England and Sweden.

SETTING AND PARTICIPANTS

Singleton live births between 2003 and 2012 in England and Sweden, followed up from age 31 days until the fifth birthday, death or 31 December 2013.

MAIN OUTCOME MEASURES

The main outcome measures were HR for RTI-related mortality at 31-364 days and at 1-4 years and SUDI mortality at 31-364 days in England versus Sweden estimated using Cox proportional hazards models. We calculated unadjusted HRs and HRs adjusted for birth characteristics (gestational age, birth weight, sex and congenital anomalies) and socioeconomic factors (maternal age and socioeconomic status).

RESULTS

The English cohort comprised 3 928 483 births, 768 RTI-related deaths at 31-364 days, 691 RTI-related deaths at 1-4 years and 1166 SUDIs; the corresponding figures for the Swedish cohort were 1 012 682, 131, 118 and 189. At 31-364 days, unadjusted HR for RTI-related death in England versus Sweden was 1.52 (95% CI 1.26 to 1.82). After adjusting for birth characteristics, the HR reduced to 1.16 (95% CI 0.96 to 1.40) and for socioeconomic factors to 1.11 (95% CI 0.92 to 1.34). At 1-4 years, unadjusted HR was 1.58 (95% CI 1.30 to 1.92) and decreased to 1.32 (95% CI 1.09 to 1.61) after adjusting for birth characteristics and to 1.30 (95% CI 1.07 to 1.59) after further adjustment for socioeconomic factors. For SUDI, the respective HRs were 1.59 (95% CI 1.36 to 1.85) in the unadjusted model, and 1.40 (95% CI 1.20 to 1.63) after accounting for birth characteristics and 1.19 (95% CI 1.02 to 1.39) in the fully adjusted model.

CONCLUSION

Interventions that improve maternal health before and during pregnancy to reduce the prevalence of adverse birth characteristics and address poverty could reduce child mortality due to RTIs and SUDIs in England.

Avoidable mortality from respiratory tract infection and sudden unexplained death in children with chronic conditions: a data linkage study

OBJECTIVE

To determine the risk of death from two potentially avoidable causes with different aetiologies: respiratory tract infection (RTI) and sudden unexplained death (SUD) in children with and without chronic conditions.

DESIGN

Whole-country, birth cohort study using linked administrative health databases from Scotland.

SETTING AND PARTICIPANTS

Children aged 2 months to less than 5 years in Scotland between 2000 and 2014.

MAIN OUTCOME MEASURES

Relative risk of death (expressed as the HR) related to RTIs or SUD, in children with and without chronic conditions. We separately analysed deaths at ages 2-11 months and at 1-4 years and adjusted for birth characteristics, socioeconomic status and vaccination uptake using Cox regression.

RESULTS

The cohort comprised 761 172 children. Chronic conditions were recorded in 9.6% (n=72 901) of live births, 82.4% (n=173) of RTI-related deaths and 17.4% (n=49) of SUDs. Chronic conditions were very strongly associated with RTI mortality (2-11 months: HR 68.48, 95% CI (40.57 to 115.60), 1-4 years: HR 38.32, 95% CI (23.26 to 63.14)) and strongly associated with SUD (2-11 months: HR 2.42, 95% CI (1.67 to 3.63), 1-4 years: HR 2.53, 95% CI (1.36 to 4.71)).

CONCLUSIONS

The very strong association with chronic conditions suggests that RTI-related mortality may sometimes be a consequence of a terminal decline and not possible to defer or prevent in all cases. Recording whether death was expected on death certificates could indicate which RTI-related deaths might be avoidable through healthcare and public health measures.

Social contact patterns of infants in deciding vaccination strategy: a prospective, cross-sectional, single-centre study

Social contact between individuals is believed to be a fundamental cause in the transmission of many respiratory tract infections. Because they have not yet been fully vaccinated, infants are at high risk for contracting whooping cough, influenza and their serious complications. Therefore, determining infant social contact patterns is an important step in protecting them from respiratory tract infection. This study included 1200 healthy infants (<12 months of age). Social contact diaries were used to estimate the frequency and nature of the infants’ social contacts. This survey also gathered information regarding the infants’ respiratory symptoms and their frequency of attendance at crowded places over a period of 1 week. The diary return rate was 83.8% (N = 1006), and there was a total of 4706 contacts reported for these infants. The median daily contact number per capita was 4 (range 1–18). The median number of contacts with adolescents was 0 (range 0–7). Of the infants, 50.3% had contact with non-household individuals. The mothers had the longest contacts with their babies. Contacts with school children, frequency of attendance at crowded places and age were determined to be significant effective factors for reporting respiratory symptoms. Results suggest that school-age siblings and the mothers should be primarily vaccinated, and parents should keep their babies away from crowded places for protecting their infants.

Using record linkage to validate notification and laboratory data for a more accurate assessment of notifiable infectious diseases

BACKGROUND

Infectious disease burden is commonly assessed using notification data. Using retrospective record linkage in Western Australia, we described how well notification data captures laboratory detections of influenza, pertussis and invasive pneumococcal disease (IPD).

METHODS

We linked data from the Western Australian Notifiable Infectious Diseases Database (WANIDD) and the PathWest Laboratory Database (PathWest) pertaining to the Triple I birth cohort, born in Western Australia in 1996-2012. These were combined to calculate the number of unique cases captured in each dataset alone or in both datasets. To assess the impact of under-ascertainment, we compared incidence rates calculated using WANIDD data alone and using combined data.

RESULTS

Overall, there were 5550 influenza, 513 IPD (2001-2012) and 4434 pertussis cases (2000-2012). Approximately 2% of pertussis and IPD cases and 7% of influenza cases were solely recorded in PathWest. Notification of influenza and pertussis cases to WANIDD improved over time. Overall incidence rates of influenza in children aged <5 years using both datasets was 10% higher than using WANIDD data alone (IRR = 1.1, 95% CI = 1.1-1.2).

CONCLUSIONS

This is the first time WANIDD data have been validated against routinely collected laboratory data. We anticipated all cases would be captured in WANIDD but found additional laboratory-confirmed cases that were not notified. Studies investigating pathogen-specific infectious disease would benefit from using multiple data sources.

Managing acute respiratory tract infections in children

Respiratory tract infections (RTIs), including community-acquired pneumonia (CAP), bronchiolitis, viral-induced wheeze and croup, account for more primary care consultations than any other illness group and are the most likely reason for a parent or carer to contact a health professional. The majority of RTIs in fully immunised children are usually self-limiting. However, in a small percentage of children RTIs may become life threatening and it is crucial that all front-line health professionals are able to recognise and identify these children who are at risk of deterioration. To ensure this, fast recognition of symptoms is important, with care taken to exclude any 'red flag' features that may prompt a referral to secondary care. Nurses are well placed to reassure and support families, and to provide education regarding the facts about fever, the appropriate use of a single antipyretic medication, how to avoid dehydration in children with RTIs, and the beneficial role of immunisation in preventing infection. It is also important to explain in cases of CAP where antibiotics are necessary about how soon to expect a response, any side effects from antibiotics, and to provide 'safety net advice' on when to consider reassessment for the child. An illustrative case study is included to highlight some of the challenges that are likely to be encountered in clinical practice.

Low Serum Levels of Vitamins A, D, and E Are Associated with Recurrent Respiratory Tract Infections in Children Living in Northern China: A Case Control Study

Background

This study aimed to investigate the association of serum concentrations of vitamin A, D, and E with recurrent respiratory tract infections (RRTIs).

Methods

A total of 1200 children aged at 0.5–14 years were selected via a face-to-face survey in Harbin, China. Among the participants, 600 children with RRTIs comprised the symptomatic group (RRTI group), whereas 600 healthy children were used as controls (control group). Blood samples were collected to measure serum levels of vitamins A and E by HPLC; the serum level of 25-hydroxycholecalciferol (25(OH)D), was measured by HPLC-MS/MS.

Results

Serum levels of vitamins A and E, as well as 25(OH)D, were significantly lower in the RRTI group than the control group. The conditional logistic regression model and the receiver-operating characteristic curve showed that the insufficiency or deficiency of vitamins A, D, and E was positively correlated with RRTI occurrence (p < 0.05).

Conclusions

Low serum concentrations of vitamins A, D, and E were associated with RRTIs in children from northern China.

Adjuvant Treatment with Yupingfeng Formula for Recurrent Respiratory Tract Infections in Children: A Meta-analysis of Randomized Controlled Trials

This meta-analysis aimed to evaluate the immunomodulating function of Yupingfeng Formula (YPFF) in children with recurrent respiratory tract infections (RRTIs). The PubMed, EMBASE, Cochrane Library, CNKI and WanFang databases were searched for randomized controlled trials comparing with and without YPFF for RRTIs in children. Twelve trials with 1236 patients were identified. Adjuvant treatment with YPFF significantly increased serum levels of IgA (weighted mean difference [WMD] 0.33 mg/mL; 95% confidence interval [CI] 0.20 to 0.45), IgG (WMD 1.36 mg/mL; 95% CI 1.06 to 1.65), IgM (WMD 0.16 mg/mL; 95% CI 0.02 to 0.31), and CD3(+) T-lymphocytes (WMD 10.16%; 95% CI 4.62 to 15.69) but not CD4(+) T-lymphocytes (WMD 3.16%; 95% CI -0.27 to 6.59) and CD8(+) T-lymphocytes (WMD -0.84%; 95% CI -2.50 to 0.81). YPFF also reduced the frequency of RRTIs (WMD -3.80 times; 95% CI -4.86 to -2.74) and increased total effective rates of symptom improvement (risk ratio: 1.44; 95% CI 1.19 to 1.75). Adjuvant treatment with YPFF could improve total clinical effective rate and decrease the frequency of respiratory tract infections in children with RRTIs. The beneficial effects of YPFF may be correlated to its immunomodulating action. More well-designed trials with larger sample sizes are needed to evaluate its efficacy and safety. Copyright © 2016 John Wiley & Sons, Ltd.

Exploring association between gastrointestinal heat retention syndrome and recurrent respiratory tract infections in children: a prospective cohort study

BACKGROUND

Recurrent respiratory tract infections (RRTIs) have a negative impact on both children's health and family wellbeing. Deficiency of ZhengQi used to be an instinct factor driving RRTI in Traditional Chinese Medicine (TCM). Our clinical observations suggest that children with gastrointestinal heat retention syndrome (GHRS) may have a greater risk of catching respiratory tract infections (RTIs). GHRS is a new predisposing factor for RRTI and it is dietary related. This study is aimed to explore association between GHRS and RRTI.

METHODS

A prospective cohort study has been conducted in Beijing, China; children aged 1-18 were enrolled. TCM symptoms, demographic and physiological characteristics were recorded by using semi-structured questionnaire. GHRS was considered as a predisposing factor. Children were followed up for next 12 months. We contacted with their parents using a face-to-face questionnaire survey, via email or phone every 3 months. Episodes of RTIs were recorded in detail.

RESULTS

Three hundred thirty four children were enrolled and 307 (91.92%) followed up for 12 months. The incidence of RTI was 4.32 episodes per child-year (95 % CI 4.03-4.61). 69 (43.13%) children in the group with GHRS suffered from RRTI; there were 48 (32.65%) children in group without GHRS. The risk ratio (RR) value of RRTI occurrence was 1.32 (95 % CI 0.91-1.91, P = 0.139), and the attributable risk percent (AR%) was 24.28%. Dry stool and irritability were positively correlated with RTI episodes, age and BMI were negatively correlated with RTI episodes in a linear regression model. Dry stool (OR = 1.510) was positively correlated with RRTI occurrence, age (OR = 0.889) and BMI (OR = 0.858) were negatively correlated with RRTI occurrence in our logistic regression model.

CONCLUSIONS

GHRS is associated with RRTI in this cohort. Dry stool was positively associated with RRTI, and BMI was negatively associated with RRTI. Studies with larger sample size and longer follow up are needed to further evaluate this association. Relieving GHRS should be considered when TCM practitioners treat RRTI children, and this may protect children from suffering RTIs.

TRIAL REGISTRATION

Chinese Clinical Trial Registry Number: ChiCTR-CCH-13003756.

Probiotics for the treatment of upper and lower respiratory-tract infections in children: systematic review based on randomized clinical trials

OBJECTIVES

Evaluate the effect of probiotics on the symptoms, duration of disease, and the occurrence of new episodes of upper and lower respiratory infections in healthy children.

SOURCES

In order to identify eligible randomized controlled trials, two reviewers accessed four electronic databases [MEDLINE/PubMed, Scopus (Elsevier), Web of Science, and Cochrane (Cochrane VHL)], as well as ClinicalTrials.gov until January 2015. Descriptors were determined by using the Medical Subject Headings tool, following the same search protocol.

SUMMARY OF THE FINDINGS

Studies showed to be heterogeneous regarding strains of probiotics, the mode of administration, the time of use, and outcomes. The present review identified 11 peer-reviewed, randomized clinical trials, which analyzed a total of 2417 children up to 10 incomplete years of age. In the analysis of the studies, reduction in new episodes of disease was a favorable outcome for the use of probiotics in the treatment of respiratory infections in children. It is noteworthy that most of these studies were conducted in developed countries, with basic sanitation, health care, and strict, well-established and well-organized guidelines on the use of probiotics. Adverse effects were rarely reported, demonstrating probiotics to be safe.

CONCLUSIONS

Despite the encouraging results - reducing new episodes of respiratory infections - the authors emphasize the need for further research, especially in developing countries, where rates of respiratory infections in children are higher when compared to the high per capita-income countries identified in this review.