Epidemiology of respiratory syncytial virus infection among paediatric inpatients in northern Taiwan

Respiratory Syncytial Virus Outbreak in Infants and Young Children during COVID-19 Pandemic in Taiwan

Respiratory syncytial virus (RSV) is a major burden of disease in babies and young children, including hospitalizations and deaths. RSV is a seasonal disease that peaks when temperatures decrease in temperate zones and humidity increases in tropical regions. Existing research reveals that RSV hospitalization activity is year-round in Taiwan, which is a subtropical region with small peaks in spring and fall. The monthly distribution and COVID-19 pandemic impact were unclear. The aim of this study was to investigate Taiwan’s RSV hospitalization seasonality and the COVID-19 pandemic effects. The National Health Insurance Database and Death Registration Files from the Center for Health and Welfare Data Science Center were connected to birth data for this study. RSV hospitalization (RSVH) in infants aged 0–1 years ranged from 0.9518% (2009) to 1.7113% (2020), substantially higher than in children aged 1–5. Most years had 2 or 3 RSV epidemic seasons in 0–5-year-olds over the 13-year follow-up. RSVH incidence was low until the autumn of 2020, when a major rise occurred after September and lasted until December 2020. We detected RSVH peaks in February–May and July–August. The 2020 RSV outbreak was found at the end of 2020.

Respiratory viral infections in hospitalised paediatric patients in the tropics

AIM

Respiratory viruses are a huge disease burden globally. An understanding of the seasonal trends and the ability to predict peak periods of respiratory virus disease incidence is useful for clinical care.

METHODS

This is a retrospective analysis of paediatric hospitalizations of laboratory-confirmed viral respiratory tract infections in KK Women's and Children's Hospital, Singapore, from 1 January 2011 to 31 December 2016. Standard direct immunofluorescence was used to detect respiratory syncytial virus (RSV), influenza A and B viruses, parainfluenza 1, 2 and 3 viruses, metapneumovirus and adenovirus.

RESULTS

A total of 97 840 specimens were analysed with a positive detection rate of 23.8%. RSV made up the largest proportion (42% of the total positive results), predominating between May to September. Influenza A had two peaks, June to July and December to January. Type 3 was the most common parainfluenza virus and showed annually recurring peaks. In contrast, parainfluenza 1 and 2, metapneumovirus and adenovirus had a biennial pattern. The test of seasonality detected identifiable seasonality for RSV and parainfluenza 3 virus.

CONCLUSIONS

In conclusion, respiratory viruses have different and overlapping seasonality in tropical Singapore. Respiratory virus testing for patients admitted for acute respiratory infection is useful to target antiviral therapies and appropriate infection control practices.

Mortality in children hospitalised with respiratory syncytial virus infection in Singapore

INTRODUCTION

This study aimed to investigate the trend and seasonality of infection due to respiratory syncytial virus (RSV) at KK Women's and Children's Hospital (KKH) in Singapore and to examine the risk factors for mortality among children with RSV infection requiring admission to the paediatric intensive care unit (PICU).

METHODS

A retrospective study was conducted at KKH on children with RSV infections who were admitted to the PICU between January 2004 and December 2010. The medical records of children who died from RSV infections were reviewed. Linear regression was performed to determine the risk factors of RSV mortality.

RESULTS

RSV infection was documented in 5,785 children during the study period, occurring throughout the year, with a small increase in prevalence between the months of June and August annually. Among 85 (1.5%) of 5,785 children who were admitted to the PICU for RSV infection, 74 (1.3%) survived and there were 11 (0.2%) deaths. Multivariate logistic regression analysis showed that significant haemodynamically significant cardiac disease (odds ratio [OR] 12.2, 95% confidence interval [CI] 0.9-16.7, p = 0.05), immunodeficiency (OR 71.4, 95% CI 8.2-500, p < 0.001) and metabolic disease (OR 71.4, 95% CI 4.3-1,000, p = 0.003) were independent risk factors for mortality in RSV infections. Prematurity increased the risk of admission to the PICU but was not significantly associated with mortality.

CONCLUSION

Children with haemodynamically significant cardiac disease, immunodeficiency and metabolic disease were at higher risk of death after hospitalisation for RSV-related illnesses. These children should be considered for palivizumab prophylaxis.

Resurgence of pertussis in Taiwan during 2009-2015 and its impact on infants

BACKGROUND/PURPOSE

Pertussis incidence markedly decreased due to universal vaccination, but outbreaks had been noted worldwide in recent decade. This study was conducted to know the epidemiology of pertussis and its impact on infants in Taiwan.

METHODS

Epidemiologic parameters for confirmed pertussis cases were collected from the Taiwan Centers for Disease Control. The incidence of each age group over years was calculated using population data. We also did retrospective reviews of laboratory-confirmed pertussis cases in NTUH to analyze clinical characteristics and disease severity.

RESULTS

A total of 668 confirmed pertussis cases were obtained from the Taiwan CDC open database between 2003 and 2017. There was higher incidence during the period 2009-2015, with a mean incidence of 0.27 cases per 100,000 population, about 2-fold increase compared with mean incidence of 0.12 cases per 100,000 population during the period 2003-2008. Infants accounted for the highest proportion of all cases (49.8%), with mean incidence of 16.1 cases per 100,000 people per year during 2009-2015, and a trend of increase was found from 2003 to 2015. In NTUH, a total of 17 laboratory-confirmed pertussis cases were diagnosed during 2012-2016, and 14 cases were young infants. Among them, 9 infants had been admitted to intensive care unit and 2 infant needed invasive ventilator support.

CONCLUSION

There was a resurgence of pertussis during 2009-2015 and it had significant impact on infants. Young infants with pertussis may be severe and need intensive care, so preventive strategy may be advocated for them.

Seasonality of respiratory viruses causing hospitalizations for acute respiratory infections in children in Nha Trang, Vietnam

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Hospitalizations for respiratory viruses are seasonal in Vietnam

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Respiratory syncytial virus peaks in the late summer months, and inuenza A in April to June

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No clear seasonality is seen for human rhinovirus

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Human parainuenza 3 and human rhinovirus are positively associated with dew point

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This work can inform the timing of inuenza and RSV vaccination and the judicious use of antibiotics in Vietnam

Background

Acute respiratory infections (ARIs) are the most common causes of death in children under 5 years of age. While the etiology of most pneumonia and ARI episodes is undiagnosed, a broad range of ARI-causing viruses circulate widely in South East Asia. However, the patterns and drivers of the seasonal transmission dynamics are largely unknown. Here we identify the seasonal patterns of multiple circulating viruses associated with hospitalizations for ARIs in Nha Trang, Vietnam.

Methods

Hospital based enhanced surveillance of childhood ARI is ongoing at Khanh Hoa General Hospital in Nha Trang. RT-PCR was performed to detect 13 respiratory viruses in nasopharyngeal samples from enrolled patients. Seasonal patterns of childhood ARI hospital admissions of various viruses were assessed, as well as their association with rainfall, temperature, and dew point.

Results

Respiratory syncytial virus peaks in the late summer months, and influenza A in April to June. We find significant associations between detection of human parainfluenza 3 and human rhinovirus with the month's mean dew point. Using a cross-wavelet transform we find a significant out-of-phase relationship between human parainfluenza 3 and temperature and dew point.

Conclusions

Our results are important for understanding the temporal risk associated with circulating pathogens in Southern Central Vietnam. Specifically, our results can inform timing of routing seasonal influenza vaccination and for when observed respiratory illness is likely viral, leading to judicious use of antibiotics in the region.

Comparisons of etiology and diagnostic tools of lower respiratory tract infections in hospitalized young children in Southern Taiwan in two seasons

BACKGROUND

Lower respiratory tract infections (LRTIs) play an important role in pediatric diseases; however, there are limited data about LRTIs in Southern Taiwan. This study aimed to investigate the clinical and epidemiological data of LRTIs in this area.

METHODS

Children aged under 5 years who were hospitalized at a medical center in Southern Taiwan with acute LRTIs from July 2010 to October 2010 (summer) and from March 2011 to May 2011 (spring) were prospectively enrolled. Nasopharyngeal aspirates were obtained and sent for viral cultures, multiplex polymerase chain reaction (PCR), and traditional quick tests. The clinical features, laboratory data, and imaging findings were recorded and analyzed.

RESULTS

A total of 90 children were enrolled, 70 of whom had detectable pathogens. The positive rate of conventional viral and bacterial cultures was 25.6%, which increased to 77.77% after combining with the two multiplex PCR methods. Adenovirus and enterovirus were the most common viral etiologies identified (26.5% of cases) and Streptococcus pneumoniae was the leading bacterial etiology (46.4%). The seasonal trend of viral infections in Southern Taiwan was different from Northern Taiwan. There were no differences in demographic data, severity of disease, or hospital stay between single and mixed infections. A similar result was found between nonpneumococcal and pneumococcal infections.

CONCLUSION

Viral infections were the main etiologies of LRTIs in young children. Multiplex PCR methods are rapid assays that can increase the diagnostic yield rate. Mixed infections do not seem to affect the severity of disease. Early detection may aid clinicians in appropriate decision-making and treatment.

Prolonged seasonality of respiratory syncytial virus infection among preterm infants in a subtropical climate

Objective

There is limited epidemiological data on the seasonality of respiratory syncytial virus (RSV) infection in subtropical climates, such as in Taiwan. This study aimed to assess RSV seasonality among children ≤24 months of age in Taiwan. We also assessed factors (gestational age [GA], chronologic age [CA], and bronchopulmonary dysplasia [BPD]) associated with RSV-associated hospitalization in preterm infants to confirm the appropriateness of the novel Taiwanese RSV prophylactic policy.

Study Design

From January 2000 to August 2010, 3572 children aged ≤24-months were admitted to Taipei Mackay Memorial Hospital due to RSV infection. The monthly RSV-associated hospitalization rate among children aged ≤24 months was retrospectively reviewed. Among these children, 378 were born preterm. The associations between GA, CA, and BPD and the incidence of RSV-associated hospitalization in the preterm infants were assessed.

Results

In children aged ≤24 months, the monthly distribution of RSV-associated hospitalization rates revealed a prolonged RSV season with a duration of 10 months. Infants with GAs ≤32 weeks and those who had BPD had the highest rates of RSV hospitalization (P<0.001). Preterm infants were most vulnerable to RSV infection within CA 9 months.

Conclusions

Given that Taiwan has a prolonged (10-month) RSV season, the American Academy of Pediatrics' recommendations for RSV prophylaxis are not directly applicable. The current Taiwanese guidelines for RSV prophylaxis, which specify palivizumab injection (a total six doses until CA 8–9 months) for preterm infants (those born before 28^6/7 weeks GA or before 35^6/7 weeks GA with BPD), are appropriate. This prophylaxis strategy may be applicable to other countries/regions with subtropical climates.

Close correlation between season of birth and the prevalence of bronchial asthma in a Taiwanese population

Background

Bronchial asthma (BA), atopic dermatitis (AD), and allergic rhinitis (AR) are common allergic diseases. Environmental factors were indicated to influence the development of allergic diseases.

Objective

To evaluate the correlation between the month of birth and the prevalence of allergic diseases in Taiwan.

Methods

Data from 104,455 children were collected from the National Insurance Research Database of Taiwan. Subjects were identified by at least two service claims for ambulatory care or one claim for inpatient care. All of the enrolled patients were aged 7∼15 years in 2010. In a bio-clinical data analysis, total immunoglobulin E (IgE) and ImmunoCAP™ allergen data (CAP) from mothers and infants were collected in a medical center in Taiwan. Correlations between children's allergic factors and the season of birth were assessed.

Results

A significant difference in the prevalence of BA according to the month of birth (Χ² = 18.2, p<0.001) was found in the Taiwanese population. The fewest schoolchildren with were born in May (7.21%), and the most were born in October (10.59%). However, no tendency for the prevalence of AD (Χ² = 4.6, P = 0.204) or AR (Χ² = 4.3 P = 0.229) was found. In addition, we found that children born in autumn (August to October) had a higher prevalence of BA compared to those born in spring (February to April) (odds ratio: 1.13; 95% confidence interval: 1.05∼1.21). In a bio-clinical data study, markers of maternal and childhood allergies including IgE and CAP were detected in a risk analysis section. Children who were born in autumn had higher levels of CAP and total IgE.

Conclusions

The findings of this study showed that the month of birth was closely correlated with the prevalence of BA and higher levels of CAP and IgE.

Molecular epidemiology and phylodynamics of the human respiratory syncytial virus fusion protein in northern Taiwan

BACKGROUND AND AIMS

The glycoprotein (G protein) and fusion protein (F protein) of respiratory syncytial virus (RSV) both show genetic variability, but few studies have examined the F protein gene. This study aimed to characterize the molecular epidemiology and phylodynamics of the F protein gene in clinical RSV strains isolated in northern Taiwan from 2000-2011.

METHODS

RSV isolates from children presenting with acute respiratory symptoms between July 2000 and June 2011 were typed based on F protein gene sequences. Phylogeny construction and evaluation were performed using the neighbor-joining (NJ) and maximum likelihood (ML) methods. Phylodynamic patterns in RSV F protein genes were analyzed using the Bayesian Markov Chain Monte Carlo framework. Selection pressure on the F protein gene was detected using the Datamonkey website interface.

RESULTS

From a total of 325 clinical RSV strains studied, phylogenetic analysis showed that 83 subgroup A strains (RSV-A) could be further divided into three clusters, whereas 58 subgroup B strains (RSV-B) had no significant clustering. Three amino acids were observed to differ between RSV-A and -B (positions 111, 113, and 114) in CTL HLA-B*57- and HLA-A*01-restricted epitopes. One positive selection site was observed in RSV-B, while none was observed in RSV-A. The evolution rate of the virus had very little change before 2000, then slowed down between 2000 and 2005, and evolved significantly faster after 2005. The dominant subtypes of RSV-A in each epidemic were replaced by different subtypes in the subsequent epidemic.

CONCLUSIONS

Before 2004, RSV-A infections were involved in several small epidemics and only very limited numbers of strains evolved and re-emerged in subsequent years. After 2005, the circulating RSV-A strains were different from those of the previous years and continued evolving through 2010. Phylodynamic pattern showed the evolutionary divergence of RSV increased significantly in the recent 5 years in northern Taiwan.

Viral etiology of bronchiolitis among pediatric inpatients in northern Taiwan with emphasis on newly identified respiratory viruses

Purpose

Viral etiology of bronchiolitis in children in Taiwan has been fragmentary. We conducted a prospective study to figure out the viral epidemiology of bronchiolitis in Taiwan.

Materials and methods

From January 2009 to March 2011, a total of 113 children with bronchiolitis, aged <2 years, hospitalized in Chang Gung Children’s Hospital were randomly selected for viral etiology investigation. Nasopharyngeal aspirates were obtained from each case and sent for viral detection by tissue culture, antigen test, and polymerase chain reaction.

Results

A total of 120 viruses were detected from 113 children. Positive viral etiology was identified in 86 (76%) children. Mixed viral pathogens were found in 28 cases (25%). Respiratory syncytial virus (RSV) was the most common pathogen and was identified in 43.4% of the cases. Human bocavirus (hBoV) was the second most common identified virus (in 19.5%), followed by human metapneumovirus (hMPV), rhinovirus, influenza viruses, and coronavirus OC43. In terms of clinical characteristics, no significant difference was found among the children with bronchiolitis either caused by different single or mixed viral infection.

Conclusion

RSV was the most common etiologic agent for children with bronchiolitis in Taiwan. Newly identified viruses, including hMPV and hBoV, were also among the common causative agents. Clinical characteristics were not significantly different among the children with bronchiolitis caused by different viruses.

Influenza-associated morbidity in subtropical Taiwan

OBJECTIVES

The purpose of this study was to assess the characteristics of influenza-associated morbidity in subtropical Taiwan, corresponding to the seasonal patterns, weather, and co-circulation of influenza (sub)types, and other respiratory viruses, where the burden of influenza is poorly quantified.

METHODS

This study applied the virus variation-guided Poisson seasonal regression models to evaluate the impact of epidemic influenza on morbidity in Taiwan for 1999-2006. The models allow for the adjusting of influenza-associated morbidity for factors such as annual trend, seasonality, temperature, relative humidity, influenza A (H1N1), A (H3N2), B, and respiratory syncytial virus.

RESULTS

Influenza-associated morbidity was associated more strongly with temperature than relative humidity. Influenza A (H3N2) was more coordinated with other virus (sub)types than A (H1N1). Type B dominated simultaneously with A (H3N2) at times, whereas A (H3N2) and A (H1N1) rarely dominated simultaneously with each other. Epidemiologically, A (H3N2) appeared to be the dominant subtype (51%), followed by type B (39%) and then A (H1N1) (10%) for influenza-associated morbidity.

CONCLUSIONS

This study suggests that seasonality and influenza (sub)types contribute significantly to influenza morbidity in subtropical Taiwan. This is important for influenza control managers who are involved actively in using epidemic and climate information to achieve influenza-reduction targets in subtropical regions.

Surveillance of respiratory viral infections among pediatric outpatients in northern Taiwan

BACKGROUND

Viruses are a frequent cause of upper respiratory tract infections in children. Like Taiwan, there were few virological surveillance systems for respiratory viral infections among children in developing countries.

MATERIALS AND METHODS

During August 1995 and July 1997, 6-10 throat swab specimens per week were taken from pediatric outpatients with acute, febrile upper respiratory tract infections (URTI). The specimens were randomly obtained by two pediatricians at Chang Gung Children's Hospital and sent for virus isolation and identification.

RESULTS

A total of 910 specimens were collected and 365 specimens (40%) were positive for at least 1 virus and included 81 enterovirus, 73 adenovirus, 58 influenza B virus, 54 influenza A virus, 48 cytomegalovirus (CMV), 25 herpes simplex virus-1 (HSV-1), 7 parainfluenza virus, 3 respiratory syncytial virus (RSV) and 16 mixed viruses. Adenovirus and enterovirus were identified throughout the study period. No seasonal variation was noted for adenovirus while enterovirus peaked between May and July and also during September and November. Influenza viruses, both A and B, were identified during two periods, respectively and altogether, influenza viruses could be detected almost throughout the year. An association between the virus type identified and the mean age of patients was found (P-value = 0.0001 by ANOVA test). The mean age of patients infected with influenza viruses, either A or B, was significantly higher than those of patients infected with adenovirus, HSV-1, CMV and enterovirus.

CONCLUSION

The results of this study demonstrate that adenovirus and enterovirus are the two most common viruses isolated from pediatric outpatients with acute, febrile URTIs and can be identified throughout the year in northern Taiwan. Influenza viruses also can be identified throughout the year and during the epidemic, a child older than 5 years of age with acute febrile URTI is likely to be a case of influenza.

Epidemiology and seasonality of respiratory tract virus infections in the tropics

Acute viral respiratory tract infections are a significant cause of morbidity worldwide. Information on the epidemiology and seasonality of these infections is important in planning vaccination and treatment strategies. In temperate climes, there are distinct seasonal peaks in the winter months. This paper reviews the seasonal trends of respiratory viral infections in the tropics. Despite the absence of a winter season, consistent seasons of infection, albeit less distinct, have been observed. With few exceptions, respiratory syncytial virus and influenza infections have been observed mainly during the rainy seasons in Asian, African and South American countries.

Respiratory syncytial virus epidemics: the ups and downs of a seasonal virus

Respiratory syncytial virus (RSV) is the most common pathogen causing lower respiratory tract infections in infants worldwide. Lower respiratory tract infections caused by RSV occur epidemically, and the appearance of epidemics seems to vary with latitude, altitude and climate. This study uses a review of the literature on RSV seasonality to investigate whether a global pattern in RSV epidemics can be found. A comparison of morbidity and mortality caused by RSV in developed vs. developing countries is also presented. The seasons in which RSV epidemics occur typically depend on geographic location and altitude. During these seasons the epidemics tend to appear in clusters. Although the appearance pattern of these epidemics varies from one continent to another, they usually begin in coastal areas. RSV is the cause of one-fifth of lower respiratory infections worldwide. Generally RSV mortality is low, with a median value of zero. However, RSV mortality in developing countries is significantly higher than RSV mortality in developed countries.