Viral etiology of medically attended influenza-like illnesses in children less than five years old in Suzhou, China, 2011-2014

Epidemiology and diagnosis technologies of human metapneumovirus in China: a mini review

Human metapneumovirus (HMPV) is a newly identified pathogen causing acute respiratory tract infections in young infants worldwide. Since the initial document of HMPV infection in China in 2003, Chinese scientists have made lots of efforts to prevent and control this disease, including developing diagnosis methods, vaccines and antiviral agents against HMPV, as well as conducting epidemiological investigations. However, effective vaccines or special antiviral agents against HMPV are currently not approved, thus developing early diagnosis methods and knowing its epidemiological characteristics will be beneficial for HMPV control. Here, we summarized current research focused on the epidemiological characteristics of HMPV in China and its available detection methods, which will be beneficial to increase the public awareness and disease control in the future.

Epidemiological characteristics of respiratory viruses in hospitalized children during the COVID-19 pandemic in southwestern China

Background

Multinational studies have reported that the implementation of nonpharmaceutical interventions (NPIs) to control severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transmission coincided with the decline of other respiratory viruses, such as influenza viruses and respiratory syncytial virus.

Objective

To investigate the prevalence of common respiratory viruses during the coronavirus disease 2019 (COVID-19) pandemic.

Methods

Respiratory specimens of children with lower respiratory tract infections (LRTIs) hospitalized at the Children's Hospital of Chongqing Medical University from January 1, 2018 to December 31, 2021 were collected. Seven common pathogens, including respiratory syncytial virus (RSV), adenovirus (ADV), influenza virus A and B (Flu A, Flu B), and parainfluenza virus types 1-3 (PIV1-3), were detected by a multiplex direct immunofluorescence assay (DFA). Demographic data and laboratory test results were analyzed.

Results

1) A total of 31,113 children with LRTIs were enrolled, including 8141 in 2018, 8681 in 2019, 6252 in 2020, and 8059 in 2021.The overall detection rates decreased in 2020 and 2021 (P < 0.001). The detection rates of RSV, ADV, Flu A, PIV-1, and PIV-3 decreased when NPIs were active from February to August 2020, with Flu A decreasing most predominantly, from 2.7% to 0.3% (P < 0.05). The detection rates of RSV and PIV-1 resurged and even surpassed the historical level of 2018-2019, while Flu A continued decreasing when NPIs were lifted (P < 0.05). 2) Seasonal patterns of Flu A completely disappeared in 2020 and 2021. The Flu B epidemic was observed until October 2021 after a long period of low detection in 2020. RSV decreased sharply after January 2020 and stayed in a nearly dormant state during the next seven months. Nevertheless, the detection rates of RSV were abnormally higher than 10% in the summer of 2021. PIV-3 decreased significantly after the COVID-19 pandemic; however, it atypically surged from August to November 2020.

Conclusion

The NPIs implemented during the COVID-19 pandemic affected the prevalence and seasonal patterns of certain viruses such as RSV, PIV-3, and influenza viruses. We recommend continuous surveillance of the epidemiological and evolutionary dynamics of multiple respiratory pathogens, especially when NPIs are no longer necessary.

Clinical Evaluation of a Multiplex PCR Assay for Simultaneous Detection of 18 Respiratory Pathogens in Patients with Acute Respiratory Infections

Reliable diagnostics are necessary to identify influenza infections, and coronavirus disease 2019 (COVID-19) highlights the need to develop highly specific and sensitive viral detection methods to distinguish severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and other respiratory pathogens to prevent their further spread. In this prospective study, 1070 clinical respiratory samples were collected from patients with acute respiratory infections from January 2019 to February 2021 to evaluate the diagnostic performance of a multiplex probe amplification (MPA) assay, designed to screen 18 pathogens, mainly those causing acute respiratory infections. Ninety-six positive samples and twenty negative samples for the 18 respiratory pathogens defined by the MPA assay and reverse transcription polymerase chain reaction (RT-PCR) were further confirmed by reference next-generation sequencing (NGS). The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of the MPA assay were 95.00%, 93.75%, 98.96% and 75.00%, respectively. Additionally, the co-infection rate for these positive samples were 25% (24/95). The MPA assay demonstrated a highly concordant diagnostic performance with NGS in the diagnosis of 18 respiratory pathogens and might play an important role in clinical respiratory pathogen diagnosis.

Understanding Post Entry Sorting of Adenovirus Capsids; A Chance to Change Vaccine Vector Properties

Adenovirus vector-based genetic vaccines have emerged as a powerful strategy against the SARS-CoV-2 health crisis. This success is not unexpected because adenoviruses combine many desirable features of a genetic vaccine. They are highly immunogenic and have a low and well characterized pathogenic profile paired with technological approachability. Ongoing efforts to improve adenovirus-vaccine vectors include the use of rare serotypes and non-human adenoviruses. In this review, we focus on the viral capsid and how the choice of genotypes influences the uptake and subsequent subcellular sorting. We describe how understanding capsid properties, such as stability during the entry process, can change the fate of the entering particles and how this translates into differences in immunity outcomes. We discuss in detail how mutating the membrane lytic capsid protein VI affects species C viruses' post-entry sorting and briefly discuss if such approaches could have a wider implication in vaccine and/or vector development.

Epidemiological and virological characteristics of respiratory tract infections in children during COVID-19 outbreak

Background

To investigate the impact of protective measures and isolation on respiratory tract infections in children during the COVID-19 outbreak.

Methods

We extracted data on outpatient visits and respiratory infection visits, and tests of respiratory viruses (adenovirus (ADV), influenza A (FluA), influenza B (FluB) and respiratory syncytial virus (RSV)) from electronic healthcare records in Children’s Hospital, Zhejiang University School of Medicine during the COVID-19 outbreak (January–April, 2020), compared with those in 2018 and 2019 during the same periods.

Results

We found that outpatient visits in January, 2020 was comparable with those in 2018 and 2019, but decreased by 59.9% (288,003 vs. 717,983) and 57.4% (288,003 vs. 676,704), respectively during the period of February-April, 2020, as compared with the same periods in 2018 and 2019. The total number of respiratory tract infections from January to April 2020 decreased by 65.7% (119,532 vs.348,762) and 59.0% (119,532 vs.291,557), respectively compared with the same periods in 2018 and 2019. The proportion of respiratory tract infections during the outbreak also dropped compared with the same periods in 2018 and 2019 (P<0.001). We also found significantly decreased number of completed tests for respiratory viruses and positive cases of ADV, FluA, FluB, and RSV during February-April, 2020.

Conclusions

In this study, we found that outpatient visits and respiratory tract infections in children significantly decreased during COVID-19 outbreak. Adequate protective measures and isolation in children may help to prevent respiratory virus infections in children.

Estimated influenza illnesses and hospitalizations averted by influenza vaccination among children aged 6-59 months in Suzhou, China, 2011/12 to 2015/16 influenza seasons

BACKGROUND

There are few estimates of vaccination-averted influenza-associated illnesses in China.

METHODS

We used a mathematical model and Monte Carlo algorithm to estimate numbers and 95% confidence intervals (CI) of influenza-associated outcomes (hospitalization, illness, and medically-attended (MA) illness) averted by vaccination among children aged 6-59 months in Suzhou from October 2011-September 2016. Influenza illnesses included non-hospitalized MA influenza illnesses and non-MA influenza illnesses. The numbers of influenza-associated outcomes averted by vaccination were the difference between the expected burden if there were no vaccination given and the observed burden with vaccination. The model incorporated the disease burden estimated based on surveillance data from Suzhou University Affiliated Children's Hospital (SCH) and data from health utilization surveys conducted in the catchment area of SCH, age-specific estimates of influenza vaccination coverage in Suzhou from the Expanded Program on Immunization database, and influenza vaccine effectiveness estimates from previous publications. Averted influenza estimations were presented as absolute numbers and in terms of the prevented fraction (PF). A hypothetical scenario with 50% coverage (but identical vaccine effectiveness) over the study period was also modeled.

RESULTS

In ~250,000 children, influenza vaccination prevented an estimated 731 (CI: 549-960) influenza hospitalizations (PF: 6.2% of expected, CI: 5.8-6.6%) and 10,024 (7593-12,937) influenza illnesses (PF: 6.5%, 6.4-6.7%), of which 8342 (6338-10,768) were MA (PF: 6.6%, 6.4-6.7%) from 2011 to 2016. The PFs declined each year along with decreasing influenza vaccination coverage. If 50% of the study population had been vaccinated over time, the estimated numbers of averted cases during the study period would have been 4059 (3120-5762) influenza hospitalizations (PF: 27.2%, 26.4-27.9%) and 56,215 (42,925-78,849) influenza illnesses (PF: 28.5%, 28.3-28.7%), of which 46,596 (35,662-65,234) would be MA (PF: 28.5%, 28.3-28.7%).

CONCLUSION

Influenza vaccination is estimated to have averted influenza-associated illness outcomes even with low coverage in children aged 6-59 months in Suzhou. Increasing influenza vaccination coverage in this population could further reduce illnesses and hospitalizations.

Molecular epidemiology of influenza, RSV, and other respiratory infections among children in Qatar: A six years report (2012-2017)

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Throughout a five years period, HRV, RSV, and influenza viruses were responsible for two-thirds of acute respiratory infections among children in Qatar.

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RSV, influenza, and HMPV circulated in winter, whereas HRV was highly active during other seasons.

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RSV is more prevalent among infants, while influenza circulates more among children above five years of age.

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Influenza–RSV co-infections are significantly associated with age.

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Gender-dependent differences affect infection rates.

Background

Studies on the etiology of respiratory infections among children in Qatar and surrounding countries are limited.

Objectives

To describe the prevalence and seasonality of RSV, influenza, and other respiratory pathogens among children in Qatar.

Methods

We retrospectively collected and analyzed data of 33,404 children (<15 years) presented with influenza-like illness from 2012 to 2017.

Results

At least one respiratory pathogen was detected in 26,138 (78%) of patients. Together, human rhinoviruses (HRV), respiratory syncytial virus (RSV), and influenza viruses comprised nearly two-thirds of all cases, affecting 24%, 19.7%, and 18.5%, respectively. A prevalence of 5-10% was recorded for adenovirus, parainfluenza viruses (PIVs), human bocavirus (HboV), and human coronaviruses (HCoVs). Human metapneumovirus (HMPV), enteroviruses, M. pneumonia, and parechovirus had prevalences below 5%. While RSV, influenza, and HMPV exhibited strong seasonal activity in the winter, HRV was active during low RSV and influenza circulation. The burden of RSV exceeds that of influenza among young age groups, whereas influenza correlated positively with age. Further, HRV, adenovirus, influenza, and RSV infection rates varied significantly between male and females.

Conclusion

This comprehensive multi-year study provides insights into the etiology of ILI among children in Qatar, which represents the Gulf region. Our results reinforce the significance of active surveillance of respiratory pathogens to improve infection prevention and control strategies, particularly among children.

Etiology and characteristics of community-acquired pneumonia in an influenza epidemic period

PURPOSE

The etiology of community-acquired pneumonia (CAP) in hospital patients is often ambiguous due to the limited pathogen detection. Lack of a microbiological diagnosis impairs precision treatment in CAP.

METHODS

Specimens collected from the lower respiratory tract of 195 CAP patients, viruses were measured by the Single-plex real-time PCR assay and the conventional culture method was exploited for bacteria.

RESULTS

Among the 195 patients, there were 46 (23.59%) pure bacterial infections, 20 (10.26%) yeast infections, 32 (16.41%) pure viral infections, 8 (4.10%) viral-yeast co-infections, and 17 (8.72%) viral-bacterial co-infections. The two most abundant bacteria were Acinetobacter baumannii and klebsiella pneumoniae, whereas the most common virus was influenza A.

CONCLUSIONS

Non-influenza respiratory microorganisms frequently co-circulated during the epidemic peaks of influenza, which easily being ignored in CAP therapy. In patients with bacterial and viral co-infections, identifying the etiologic agent is crucial for patient's therapy.

Characteristics of hospitalized adult patients with laboratory documented Influenza A, B and Respiratory Syncytial Virus - A single center retrospective observational study

Introduction

The epidemiology, clinical features and outcomes of hospitalized adult patients with Influenza A (FluA), Influenza B (FluB) and Respiratory Syncytial Virus (RSV) have not been thoroughly compared. The aim of this study was to describe the differences between these viruses during 3 winter seasons.

Methods

A retrospective observational study was conducted consisting of all the polymerase chain reaction (PCR)-based diagnoses of FluA, FluB and RSV among adults during 2015–2018, in one regional hospital. Epidemiology, clinical symptoms and outcome-related data were comparatively analyzed.

Results

Between November 2015 and April 2018, 759 patients were diagnosed with FluA, FluB or RSV. Study cohort included 539 adult patients (306 FluA, 148 FluB and 85 RSV). FluB was predominant during the winter of 2017–18. RSV caused 15.7% of hospitalizations with diagnosed viral infection and in comparison to influenza, had distinct epidemiological, clinical features and outcomes, including older age (74.2 vs 66.2, p = 0.001) and higher rates of co-morbidities; complications including bacterial pneumonia (31 vs 18%, p = 0.02), mechanical ventilation (20 vs 7%, p = 0.001), and viral-related death (13 vs 6.6%, p = 0.04). FluA and FluB had similar epidemiology, clinical symptoms and outcomes, but vaccinated patients were less prone to be hospitalized with FluB as compared with FluA (3 vs 14%, p = 0.001). Paroxysmal atrial fibrillation and falls were common (8.7 and 8.5% respectively).

Conclusions

FluA and FluB had similar epidemiological, clinical features and contributed equally to hospitalization burden and complications. RSV had a major impact on hospitalizations, occurring among the more elderly and sick populations and causing significantly worse outcomes, when compared to influenza patients. Vaccination appeared as a protective factor against hospitalizations with FluB as compared with FluA.

Preventive Effects of Vitamin D on Seasonal Influenza A in Infants: A Multicenter, Randomized, Open, Controlled Clinical Trial

OBJECTIVES

This study aimed to evaluate the clinical efficacy and safety of vitamin D for preventing influenza A in 400 infants in a multicenter, randomized, open, controlled clinical trial.

METHODS

The infants were randomized into low-dose and high-dose vitamin D groups, and serum calcium, inorganic phosphorus and 25-hydroxyvitamin D levels were detected thrice in 4 months. Infants infected with influenza A were monitored for symptoms including fever, cough and wheezing. Pathogen levels and safety of vitamin D treatment were also evaluated.

RESULTS

Of 121 cases in total, 78 and 43 cases of influenza A infection occurred in the low-dose and high-dose vitamin D groups, respectively. There was a significant difference between the groups (χ = 14.6324, P = 0.0001). Among the cases of influenza infection, the median durations for fever, cough and wheezing were shorter in the high-dose vitamin D group than in the low-dose vitamin D group. The viral loads showed a downward trend in both groups and were significantly different between the groups at the second and third detections. Additionally, the incidences of adverse events and severe adverse events were very low and not significantly different between the 2 groups.

CONCLUSION

High-dose vitamin D (1200 IU) is suitable for the prevention of seasonal influenza as evidenced by rapid relief from symptoms, rapid decrease in viral loads and disease recovery. In addition, high-dose vitamin D is probably safe for infants.

Molecular diagnosis of microbial copathogens with influenza A(H1N1)pdm09 in Oaxaca, Mexico

Background

Multiple factors have been associated with the severity of infection by influenza A(H1N1)pdm09. These include H1N1 cases with proven coinfections showing clinical association with bacterial contagions.

Purpose

The objective was to identify H1N1 and copathogens in the Oaxaca (Mexico) population. A cross-sectional survey was conducted from 2009 to 2012. A total of 88 study patients with confirmed H1N1 by quantitative RT-PCR were recruited.

Methods

Total nucleic acid from clinical samples of study patients was analyzed using a TessArray RPM-Flu microarray assay to identify other respiratory pathogens.

Results

High prevalence of copathogens (77.3%; 68 patients harbored one to three pathogens), predominantly from Streptococcus, Haemophilus, Neisseria, and Pseudomonas, were detected. Three patients (3.4%) had four or five respiratory copathogens, whereas others (19.3%) had no copathogens. Copathogenic occurrence with Staphylococcus aureus was 5.7%, Coxsackie virus 2.3%, Moraxella catarrhalis 1.1%, Klebsiella pneumoniae 1.1%, and parainfluenza virus 3 1.1%. The number of patients with copathogens was four times higher to those with H1N1 alone (80.68% and 19.32%, respectively). Four individuals (4.5%; two males, one female, and one infant) who died due to H1N1 were observed to have harbored such copathogens as Streptococcus, Staphylococcus, Haemophilus, and Neisseria.

Conclusion

In summary, copathogens were found in a significant number (>50%) of cases of influenza in Oaxaca. Timely detection of coinfections producing increased acuity or severity of disease and treatment of affected patients is urgently needed.

Literature review of the epidemiology of influenza B disease in 15 countries in the Asia-Pacific region

Influenza control strategies focus on the use of trivalent influenza vaccines containing two influenza A virus subtypes and one of the two circulating influenza type B lineages (Yamagata or Victoria). Mismatches between the vaccine B lineage and the circulating lineage have been regularly documented in many countries, including those in the Asia‐Pacific region. We conducted a literature review with the aim of understanding the relative circulation of influenza B viruses in Asia‐Pacific countries. PubMed and Western Pacific Region Index Medicus were searched for relevant articles on influenza type B published since 1990 in English language for 15 Asia‐Pacific countries. Gray literature was also accessed. From 4834 articles identified, 121 full‐text articles were analyzed. Influenza was reported as an important cause of morbidity in the Asia‐Pacific region, affecting all age groups. In all 15 countries, influenza B was identified and associated with between 0% and 92% of laboratory‐confirmed influenza cases in any one season/year. Influenza type B appeared to cause more illness in children aged between 1 and 10 years than in other age groups. Epidemiological data for the two circulating influenza type B lineages remain limited in several countries in the Asia‐Pacific, although the co‐circulation of both lineages was seen in countries where strain surveillance data were available. Mismatches between circulating B lineages and vaccine strains were observed in all countries with available data. The data suggest that a shift from trivalent to quadrivalent seasonal influenza vaccines could provide additional benefits by providing broader protection.

Risk factors of respiratory syncytial virus infection among pediatric influenza-like illness and severe acute respiratory infections in Suzhou, China

The characteristics and risk factors of respiratory syncytial virus (RSV) infection among children has not yet been fully understood. To address the characteristics of RSV-associated illness and risk factors of RSV infection among children under 5 years of age in Suzhou, China. From April 2011 to March 2014, we conducted a prospective surveillance among children in Suzhou, China. Nasal or throat swabs were collected from outpatients with influenza-like illness (ILI) and inpatients with severe acute respiratory infections (SARI). RSV was detected by reverse-transcriptase polymerase chain reaction and direct fluorescent antibody assay for children with ILI and SARI, respectively. Multivariable logistic-regression models were constructed to explore risk factors and symptoms of RSV infection. Of 3267 ILI and 1838 SARI children enrolled in the study, 192 (5.9%) and 287 (15.6%) tested positive for RSV, respectively. Among ILI patients, children with RSV infections visited clinics more often (P = 0.005) and had longer duration of fever (P = 0.032) than those without RSV infection. All RSV-positive children had an increased risk of having cough (OR = 2.9), rhinorrhea (OR = 1.6), breathing difficulty (OR = 3.4), wheezing (OR = 3.3), and irritability (OR = 2.7). Children aged <2 years, had history of prematurity (OR = 2.0) and recent respiratory infections (OR = 1.3) were more likely to get infected by RSV. Children with SARI had higher positive rate of RSV than those with ILI. Cough, rhinorrhea, and wheezing were the most common symptoms in RSV infection. Children aged <2 years, had history of prematurity and recent respiratory infections were the potential risk factors for RSV infection.

Etiology of community-acquired pneumonia in 1500 hospitalized children

Childhood community‐acquired pneumonia (CAP) is a common illness; however, comprehensive studies of hospitalizations for CAP among children in China based on prospective and multicenter data collection are limited. The aim of this investigation was to determine the respiratory pathogens responsible for CAP in hospitalized children. From January to December 2015, oropharyngeal swabs and blood serum were collected from hospitalized children with CAP symptoms ranging in age from 6 months to 14 years at 10 hospitals across China. We used immunofluorescence to detect antibodies for eight respiratory viruses and passive agglutination to detect specific IgM against Mycoplasma pneumoniae (M. pneumoniae). Of 1500 children presenting with CAP, 691 (46.1%) tested positive for at least one pathogen (virus or M. pneumoniae). M. pneumoniae (32.4%) was detected most frequently, followed by respiratory syncytial virus (11.5%), adenovirus (5.0%), influenza A virus (4.1 %), influenza B virus (3.4%), parainfluenza virus types 2 and 3 type (3.1 %), parainfluenza virus type 1 (2.9%), and human metapneumovirus (0.3%). Co‐infections were identified in 128 (18.5%) of the 691 cases. These data provide a better understanding of viral etiology and M. pneumoniae in CAP in children between 6 months and 14 years in China. More study of the etiologic investigations that would further aid the management of pneumonia is required. With effective immunization for RSV, ADV, and M. pneumoniae infections, more than one‐half of the pneumonia cases in this study could have been prevented.

Efficient isolation of human metapneumovirus using MNT-1, a human malignant melanoma cell line with early and distinct cytopathic effects

Isolation of human metapneumovirus (HMPV) from clinical specimens is currently inefficient because of the lack of a cell culture system in which a distinct cytopathic effect (CPE) occurs. The cell lines LLC-MK2, Vero and Vero E6 are used for isolation of HMPV; however, the CPE in these cell lines is subtle and usually requires a long observation period and sometimes blind passages. Thus, a cell line in which an early and distinct CPE occurs following HMPV inoculation is highly desired by clinical virology laboratories. In this study, it was demonstrated that, in the human malignant melanoma cell line MNT-1, obvious syncytium formation occurs shortly after inoculation with HMPV-positive clinical specimens. In addition, the growth and efficiency of isolation of HMPV were greater using MNT-1 than using any other conventional cell line. Addition of this cell line to our routine viral isolation system for clinical specimens markedly enhanced isolation frequency, allowing isolation-based surveillance. MNT-1 has the potential to facilitate clinical and epidemiological studies of HMPV.

Prevalence and seasonality of six respiratory viruses during five consecutive epidemic seasons in Belgium

BACKGROUND

Acute Respiratory Infections (ARIs) are a major health problem, especially in young children and the elderly.

OBJECTIVES

Insights into the seasonality of respiratory viruses can help us understand when the burden on society is highest and which age groups are most vulnerable.

STUDY DESIGN

We monitored six respiratory viruses during five consecutive seasons (2011-2016) in Belgium. Patient specimens (n=22876), tested for one or more of the following respiratory viruses, were included in this analysis: Influenza viruses (IAV & IBV), Human respiratory syncytial virus (hRSV), Human metapneumovirus (hMPV), Adenovirus (ADV) and Human parainfluenza virus (hPIV). Data were analysed for four age categories: <6y, 6-17y, 18-64y and ≥65y.

RESULTS

Children <6y had the highest infection rates (39% positive vs. 20% positive adults) and the highest frequency of co-infections. hRSV (28%) and IAV (32%) caused the most common respiratory viral infections and followed, like hMPV, a seasonal pattern with winter peaks. hRSV followed an annual pattern with two peaks: first in young children and ±7 weeks later in elderly. This phenomenon has not been described in literature so far. hPIV and ADV occurred throughout the year with higher rates in winter.

CONCLUSIONS

Children <6y are most vulnerable for respiratory viral infections and have a higher risk for co-infections. hRSV and IAV are the most common respiratory infections with peaks during the winter season in Belgium.

Child pneumonia - focus on the Western Pacific Region

Worldwide, pneumonia is the leading cause of death in infants and young children (aged <5 years). We provide an overview of the global pneumonia disease burden, as well as the aetiology and management practices in different parts of the world, with a specific focus on the WHO Western Pacific Region. In 2011, the Western Pacific region had an estimated 0.11 pneumonia episodes per child-year with 61,900 pneumonia-related deaths in children less than 5 years of age. The majority (>75%) of pneumonia deaths occurred in six countries; Cambodia, China, Laos, Papua New Guinea, the Philippines and Viet Nam. Historically Streptococcus pneumoniae and Haemophilus influenzae were the commonest causes of severe pneumonia and pneumonia-related deaths in young children, but this is changing with the introduction of highly effective conjugate vaccines and socio-economic development. The relative contribution of viruses and atypical bacteria appear to be increasing and traditional case management approaches may require revision to accommodate increased uptake of conjugated vaccines in the Western Pacific region. Careful consideration should be given to risk reduction strategies, enhanced vaccination coverage, improved management of hypoxaemia and antibiotic stewardship.