Viral Respiratory Tract Infections in Adult Patients Attending Outpatient and Emergency Departments, Taiwan, 2012-2013: A PCR/Electrospray Ionization Mass Spectrometry Study

Burden of respiratory syncytial virus in older adults in Taiwan: An expert perspective on knowledge gaps

The burden of respiratory syncytial virus (RSV) infection among older adults in Taiwan is not well understood due to a scarcity of published epidemiological data. Nonetheless, the increasing proportion of older adults is anticipated to translate to increased burden of RSV infection, presenting a challenge to the healthcare system. Thus, an expert meeting was convened among a panel of infectious disease specialists from Taiwan to evaluate the existing local evidence and data gaps related to RSV infection in older adults (aged ≥50 years), and propose steps to generating evidence on disease burden among this population. Overall, there are few studies on the clinical and economic burden of RSV infection in Taiwan, and existing data are limited by small sample sizes and highly selected populations. Inconsistent RSV testing practices among older adults contribute to under-diagnosis and under-reporting, driven by limitations to reimbursement policies that discourage proactive RSV testing in older adults, and the lack of appropriate, targeted RSV treatment. Crucially, the paucity of epidemiological data may perpetuate a lack of awareness of RSV among clinicians and the public, hinder investments into RSV testing at a policymaker level, and thereby impede implementation of consistent diagnostic practices, precluding a deeper understanding of RSV. To overcome these challenges, it is imperative to prioritize generation of epidemiological data to establish the burden of RSV infection among older adults in Taiwan. Such data would also support a multi-stakeholder group in assessing the impact of future RSV-related interventions, such as educational initiatives and preventative strategies including vaccines.

Impact of FilmArray respiratory panel test for hospitalized pediatric respiratory tract infection in Taiwan: A 3-year single-center cohort study

Respiratory tract infections are prevalent and clinically significant in pediatric populations globally. However, pathogen testing often involves time-consuming processes, resulting in delays in diagnosis. To date, commercial testing machines, such as the FilmArray respiratory panel, have been proposed for hospitals. Therefore, this study aimed to investigate the impact of the FilmArray respiratory panel at a single center. This study utilized the medical records of our hospital to select pediatric inpatients with respiratory tract infections who underwent the FilmArray respiratory panel between September 2020 and April 2021 and those who did not undergo nucleic acid detection (a rapid test group) between September 2019 and April 2020. FilmArray is a polymerase chain reaction-based diagnostic tool. The FilmArray respiratory panel group was scheduled to recruit 150 patients (final 137 patients), whereas the rapid test group was scheduled to recruit 300 patients (final 267 patients). Differences in continuous variables between the 2 groups were analyzed using independent Student t tests. The FilmArray respiratory panel group had a longer length of inpatient days, longer duration of antibiotic use, and higher proportion of pathogens that tested positive, with significant differences than those in the rapid test group. Fever duration showed no significant difference between the 2 groups. For the polymerase chain reaction method, respiratory syncytial virus was the most commonly detected pathogen causing pneumonia, followed by human rhinovirus/enterovirus and parainfluenza virus. Mycoplasma was detected using the rapid test but not with the FilmArray respiratory panel. The FilmArray respiratory panel provides clinicians with a rapid and useful diagnostic tool. The effect was quite good for virus detection, but not for bacteria. Given its limited adoption, the tool may not aid clinicians in the diagnosis of mild cases.

Developing and validating clinical features-based machine learning algorithms to predict influenza infection in influenza-like illness patients

BACKGROUND

Seasonal influenza poses a significant risk, and patients can benefit from early diagnosis and treatment. However, underdiagnosis and undertreatment remain widespread. We developed and compared clinical feature-based machine learning (ML) algorithms that can accurately predict influenza infection in emergency departments (EDs) among patients with influenza-like illness (ILI).

MATERIAL AND METHODS

We conducted a prospective cohort study in five EDs in the US and Taiwan from 2015 to 2020. Adult patients visiting the EDs with symptoms of ILI were recruited and tested by real-time RT-PCR for influenza. We evaluated seven ML algorithms and compared their results with previously developed clinical prediction models.

RESULTS

Out of the 2189 enrolled patients, 1104 tested positive for influenza. The eXtreme Gradient Boosting achieved superior performance with an area under the receiver operating characteristic curve of 0.82 (95% confidence interval [CI] = 0.79-0.85), with a sensitivity of 0.92 (95% CI = 0.88-0.95), specificity of 0.89 (95% CI = 0.86-0.92), and accuracy of 0.72 (95% CI = 0.69-0.76) in the testing set over cut-offs of 0.4, 0.6 and 0.5, respectively. These results were superior to those of previously proposed clinical prediction models. The model interpretation revealed that body temperature, cough, rhinorrhea, and exposure history were positively associated with and the days of illness and influenza vaccine were negatively associated with influenza infection. We also found the week of the influenza season, pulse rate, and oxygen saturation to be associated with influenza infection.

CONCLUSIONS

The clinical feature-based ML model outperformed conventional models for predicting influenza infection.

Phylogenetic characteristics of Non-SARS human coronavirus in southern Taiwan, 2012-2013

This study characterizes the phylogenetic relatedness of non-SARS human coronaviruses (HCoVs) in southern Taiwan by sequencing the nucleocapsid (N), spike (S), and RNA-dependent RNA polymerase (RdRp) genes directly from ten HCoV PCR-positive respiratory samples collected during 2012-2013. In the N, S1, and RdRp phylogeny, HCoV-OC43 in one and three samples was clustered with genotypes F and G, respectively, and HCoV-OC43 in sample YC101/TWN/2013 represented a recombination event between genotypes F and G. Amino acid substitutions in the S1 protein of HCoV-OC43 were also identified. In the N phylogeny, HCoV-HKU1 in one and two samples clustered with genotypes A and B, respectively, and HCoV-229E in two samples was clustered with genogroup 6. The genotypes and genogroup detected here were in line with the prevalent phylogenetic lineages reported outside of Taiwan during the contemporary period. In summary, three species of non-SARS HCoVs with different genotypes cocirculated in the community, with genetic evolution observed in HCoV-OC43.

Targeted Literature Review of the Burden of Respiratory Syncytial Infection among High-Risk and Elderly Patients in Asia Pacific Region

INTRODUCTION

The burden of respiratory syncytial virus (RSV), which causes acute respiratory illness, is well recognized among the pediatric population but also imposes a significant risk to the elderly (age ≥ 60) and those with underlying comorbidities. The study aimed to review the most recent data on epidemiology and burden (clinical and economic) of RSV in the elderly/high-risk populations in China, Japan, South Korea, Taiwan, and Australia.

METHODS

A targeted review was conducted of English, Japanese, Korean, and Chinese language articles published from 1 January 2010 to 7 October 2020 relevant for the purpose.

RESULTS

A total of 881 studies were identified, and 41 were included. The median proportion of elderly patients with RSV in all adult patients with acute respiratory infection (ARI) or community acquired pneumonia was 79.78% (71.43-88.12%) in Japan, 48.00% (3.64-80.00%) in China, 41.67% (33.33-50.00%) in Taiwan, 38.61% in Australia, and 28.57% (22.76-33.33%) in South Korea. RSV was associated with a high clinical burden on those patients with comorbidities such as asthma and chronic obstructive pulmonary disease. In China, inpatients with ARI showed a significantly higher rate of RSV-related hospitalization than outpatients (13.22% versus 4.08%, p < 0.01). The median length of hospital stay among elderly patients with RSV was longest in Japan (30 days) and shortest in China (7 days). Mortality data varied by region with some studies reporting rates as high as 12.00% (9/75) in hospitalized elderly patients. Finally, data on the economic burden was only available for South Korea, with the median cost of a medical admission for an elderly patient with RSV being US dollar (USD) 2933.

CONCLUSION

RSV infection is a major source of disease burden among elderly patients, especially in regions with aging populations. It also complicates the management of those with underlying diseases. Appropriate prevention strategies are required to reduce the burden among the adult, especially the elderly, population. Data gaps regarding economic burden of RSV infection in the Asia Pacific region indicates the need for further research to increase our understanding on the burden of this disease in this region.

Applying symptom dynamics to accurately predict influenza virus infection: An international multicenter influenza-like illness surveillance study

BACKGROUND

Public health organizations have recommended various definitions of influenza-like illnesses under the assumption that the symptoms do not change during influenza virus infection. To explore the relationship between symptoms and influenza over time, we analyzed a dataset from an international multicenter prospective emergency department (ED)-based influenza-like illness cohort study.

METHODS

We recruited patients in the US and Taiwan between 2015 and 2020 with: (1) flu-like symptoms (fever and cough, headache, or sore throat), (2) absence of any of the respiratory infection symptoms, or (3) positive laboratory test results for influenza from the current ED visit. We evaluated the association between the symptoms and influenza virus infection on different days of illness. The association was evaluated among different subgroups, including different study countries, influenza subtypes, and only patients with influenza.

RESULTS

Among the 2471 recruited patients, 45.7% tested positive for influenza virus. Cough was the most predictive symptom throughout the week (odds ratios [OR]: 7.08-11.15). In general, all symptoms were more predictive during the first 2 days (OR: 1.55-10.28). Upper respiratory symptoms, such as sore throat and productive cough, and general symptoms, such as body ache and fatigue, were more predictive in the first half of the week (OR: 1.51-3.25). Lower respiratory symptoms, such as shortness of breath and wheezing, were more predictive in the second half of the week (OR: 1.52-2.52). Similar trends were observed for most symptoms in the different subgroups.

CONCLUSIONS

The time course is an important factor to be considered when evaluating the symptoms of influenza virus infection.

Detection of respiratory pathogens by application of multiplex PCR panel during early period of COVID-19 pandemic in a tertiary hospital in Central Taiwan

BACKGROUND

Respiratory tract infections (RTIs) represent a major cause of clinical visits worldwide. Viral epidemiology of RTIs in adults has been less studied compared to children. FilmArray respiratory panel (FA-RP), a multiplex, real time polymerase chain reaction method can simultaneously detect the nucleic acids of multiple pathogens. The purpose of this study is to analyze the epidemiology and clinical presentations of an RTI cohort.

METHODS

This retrospective cohort study was conducted at China Medical University Hospital (CMUH) and China Medical University Children's Hospital (CMUCH), from January 2020 to June 2020. The FA-RP results were collected and analyzed according to upper versus lower RTIs.

RESULTS

Among 253 respiratory samples tested, 135 (53.4%) were from adults and 118 (46.6%) from children. A total positive rate of 33.9% (86/253) was found, with 21.48% (29/135) in adults and 48.31% (57/118) in children. Human rhinovirus/Enterovirus (HRV/EV) was detected in most of the age groups and was more common in URIs. HRV/EV was found as a frequent co-detection virus. Among children, HRV/EV was the most detected pathogen of URIs, while the most predominant pathogen in LRIs was Mycoplasma pneumoniae.

CONCLUSIONS

FA-RP has the potential to improve the detection rate of respiratory pathogens. The positive rate of FA-RP was higher in children compared to adults, which likely corresponds to the higher incidence of viral RTIs in children. Different pathogens may lead to different types of respiratory infections.

Visual Detection of COVID-19 from Materials Aspect

ABSTRACT

In the recent COVID-19 pandemic, World Health Organization emphasized that early detection is an effective strategy to reduce the spread of SARS-CoV-2 viruses. Several diagnostic methods, such as reverse transcription-polymerase chain reaction (RT-PCR) and lateral flow immunoassay (LFIA), have been applied based on the mechanism of specific recognition and binding of the probes to viruses or viral antigens. Although the remarkable progress, these methods still suffer from inadequate cellular materials or errors in the detection and sampling procedure of nasopharyngeal/oropharyngeal swab collection. Therefore, developing accurate, ultrafast, and visualized detection calls for more advanced materials and technology urgently to fight against the epidemic. In this review, we first summarize the current methodologies for SARS-CoV-2 diagnosis. Then, recent representative examples are introduced based on various output signals (e.g., colorimetric, fluorometric, electronic, acoustic). Finally, we discuss the limitations of the methods and provide our perspectives on priorities for future test development.

Early Warning Measurement of SARS-CoV-2 Variants of Concern in Wastewaters by Mass Spectrometry

Wastewater surveillance has rapidly emerged as an early warning tool to track COVID-19. However, the early warning measurement of new SARS-CoV-2 variants of concern (VOCs) in wastewaters remains a major challenge. We herein report a rapid analytical strategy for quantitative measurement of VOCs, which couples nested polymerase chain reaction and liquid chromatography-mass spectrometry (nPCR-LC-MS). This method showed a greater selectivity than the current allele-specific quantitative PCR (AS-qPCR) for tracking new VOC and allowed the detection of multiple signature mutations in a single measurement. By measuring the Omicron variant in wastewaters across nine Ontario wastewater treatment plants serving over a three million population, the nPCR-LC-MS method demonstrated a better quantification accuracy than next-generation sequencing (NGS), particularly at the early stage of community spreading of Omicron. This work addresses a major challenge for current SARS-CoV-2 wastewater surveillance by rapidly and accurately measuring VOCs in wastewaters for early warning.

The Etiological Role of Common Respiratory Viruses in Acute Respiratory Infections in Older Adults: A Systematic Review and Meta-analysis

Acute respiratory tract infections (ARI) constitute a substantial disease burden in adults and elderly individuals. We aimed to identify all case-control studies investigating the potential role of respiratory viruses in the etiology of ARI in older adults aged ≥65 years. We conducted a systematic literature review (across 7 databases) of case-control studies published from 1996 to 2017 that investigated the viral profile of older adults with and those without ARI. We then computed a pooled odds ratio (OR) with a 95% confidence interval and virus-specific attributable fraction among the exposed (AFE) for 8 common viruses: respiratory syncytial virus (RSV), influenza virus (Flu), parainfluenza virus (PIV), human metapneumovirus (HMPV), adenovirus (AdV), rhinovirus (RV), bocavirus (BoV), and coronavirus (CoV). From the 16 studies included, there was strong evidence of possible causal attribution for RSV (OR, 8.5 [95% CI, 3.9-18.5]; AFE, 88%), Flu (OR, 8.3 [95% CI, 4.4-15.9]; AFE, 88%), PIV (OR, not available; AFE, approximately 100%), HMPV (OR, 9.8 [95% CI, 2.3-41.0]; AFE, 90%), AdV (OR, not available; AFE, approximately 100%), RV (OR, 7.1 [95% CI, 3.7-13.6]; AFE, 86%) and CoV (OR, 2.8 [95% CI, 2.0-4.1]; AFE, 65%) in older adults presenting with ARI, compared with those without respiratory symptoms (ie, asymptomatic individuals) or healthy older adults. However, there was no significant difference in the detection of BoV in cases and controls. This review supports RSV, Flu, PIV, HMPV, AdV, RV, and CoV as important causes of ARI in older adults and provides quantitative estimates of the absolute proportion of virus-associated ARI cases to which a viral cause can be attributed. Disease burden estimates should take into account the appropriate AFE estimates (for older adults) that we report.

Comparison of the Clinical Characteristics and Severity of Influenza and Non-influenza Respiratory Virus-Related Pneumonia in China: A Multicenter, Real-World Study

Purpose

Respiratory viruses are important etiologies of community-acquired pneumonia (CAP). However, the impact of different RVs on the outcomes of CAP is not well elucidated. This study aims to compare the clinical features and severity of influenza (Flu-p) and non-influenza respiratory viruses-related pneumonia (NIRVs-p) onset in the community among immunocompetent adults.

Methods

The data of the patients hospitalized with laboratory-confirmed RVs-p were retrospectively reviewed from five teaching hospitals in China from January 2013 to May 2019. Univariate and multivariate logistic regressions were performed to compare the clinical characteristics and outcomes between Flu-p and NIRVs-p.

Results

A total of 1079 patients with Flu-p and 341 patients with NIRVs-p were included in this study. A multivariate logistic regression model revealed chronic pulmonary disease [odd ratio (OR) 0.341, 95% confidence interval (CI) 0.225–0.515, p < 0.001], solid malignant tumor (OR 0.330, 95% CI 0.163–0.668, p = 0.002), myalgia (OR 1.697, 95% CI 1.236–2.330, p < 0.001), lymphocytes <0.8×10⁹/L (OR 10.811, 95% CI 6.949–16.818, p < 0.001) and blood albumin <35 g/L (OR 0.327, 95% CI 0.242–0.442, p < 0.001) were predictors for Flu-p. After adjusting for confounders, the multivariate logistic regression analysis confirmed that influenza B-related pneumonia (FluB-p) (OR 0.419, 95% CI 0.272–0.646, p < 0.001) and NIRVs-p (OR 0.260, 95% CI 0.158–0.467, p < 0.001) were associated with a decreased risk of 30-day mortality compared with the influenza A-related pneumonia (FluA-p).

Conclusion

Our results showed that patients with FluA-p experience a more severe disease than those with FluB-p and NIRVs-p. Some clinical features are helpful to distinguish between NIRVs-p and Flu-p.

Detection of respiratory viruses in adults with respiratory tract infection using a multiplex PCR assay at a tertiary center

Background

Respiratory viruses (RVs) are among the most common pathogens for both upper and lower respiratory tract infections (RTIs). However, the viral epidemiology of RV-associated RTIs in adults has long been under-recognized. Through a sensitive molecular assay, it would be possible to have a better understanding of the epidemiology of RV-associated RTIs.

Material and methods

Respiratory tract (RT) specimens from adults hospitalized due to RTIs were tested for RVs, using the multiplex PCR-based Luminex xTAG® Respiratory Viral Panel assay. A total of nineteen RVs, including influenza viruses and non-influenza respiratory viruses (NIRVs) were detected. Positive rates were compared using a chi-square test.

Results

A total of 2292 samples from adult patients hospitalized with RTIs were screened for RVs. The overall positive rate was 22%, with 17.8% samples positive for at least one NIRV. NIRVs had a higher positive rate in non-winter seasons. As many as 12.7% (46/363) of the samples collected through broncho-alveolar lavage and 20.5% (176/859) of the samples collected in ICUs were positive for RVs. Distribution of corona virus (CoV), human metapneumovirus (hMPV) and parainfluenza virus (PIV) demonstrated seasonal variation. Also, temperature was associated with the positive rates of specific viruses, including CoV, respiratory syncytial virus (RSV), hMPV and PIV.

Conclusion

Respiratory viruses, notably NIRVs, were frequently detected in adults hospitalized with RTIs. Several RVs were detected with distinctive seasonal variations. A substantial number of RVs were identified in lower RT specimens or from patients admitted to ICU, highlighting their important role in causing severe respiratory infection.

SARS-CoV-2 diagnostic diary: from rumors to the first case. Early reports of molecular tests from the military research and diagnostic institute of Rio de Janeiro

Corona virus disease (COVID-19) presents a serious threat to global health. A historical timeline of early molecular diagnostics from government alert (January 22) (D) was presented. After in silico analysis, Brazilian Army Institute of Biology (IBEx-RJ) tested samples in house using real-time reverse transcriptase polymerase chain reaction (RT-PCR) (fast mode) based on Centers for Disease Control and Prevention (CDC) recommendations. First cases from Brazil, Rio de Janeiro, IBEx, and diagnosis team were reported in D36, D44, D66, and D74 respectively. Therefore, after 1300 tests, we recommend N1/N2 primer sets (CDC) for preliminary and Charité protocol confirmation in case of positive results. Moreover, every professional should be tested before starting work, in addition to weekly tests for everyone involved.

Advances in laboratory assays for detecting human metapneumovirus

Human metapneumovirus (HMPV) is one of the major causes of acute respiratory tract infection (ARI) and shows high morbidity and mortality, particularly in children and immunocompromised patients. Various methods for detecting HMPV have been developed and applied in clinical laboratories. When reviewing the literature, we found that polymerase chain reaction (PCR)-based assays have been most frequently and consistently used to detect HMPV. The most commonly used method was multiplex reverse transcriptase-PCR (RT-PCR; 57.4%), followed by real-time RT-PCR (38.3%). Multiplex RT-PCR became the more popular method in 2011-2019 (69.7%), in contrast to 2001-2009 (28.6%). The advent of multiplex PCR in detecting broader viral pathogens in one run and coinfected viruses influenced the change in user preference. Further, newly developed microarray technologies and ionization mass spectrometry were introduced in 2011-2019. Viral culture (including shell vial assays) and fluorescent immunoassays (with or without culture) were once the mainstays. However, the percentage of studies employing culture and fluorescent immunoassays decreased from 21.4% in 2001-2010 to 15.2% in 2011-2019. Meanwhile, the use of PCR-based methods of HMPV detection increased from 78.6% in 2001-2010 to 84.8% in 2011-2019. The increase in PCR-based methods might have occurred because PCR methods demonstrated better diagnostic performance, shorter hands-on and run times, less hazards to laboratory personnel, and more reliable results than traditional methods. When using these assays, it is important to acquire a comprehensive understanding of the principles, advantages, disadvantages, and precautions for data interpretation. In the future, the combination of nanotechnology and advanced genetic platforms such as next-generation sequencing will benefit patients with HMPV infection by facilitating efficient therapeutic intervention. Analytical and clinical validation are required before using new techniques in clinical laboratories.

Frequency of human Parvovirus B19 among patients with respiratory infection in Iran

Background: Human parvovirus B19 was known as one of the possible cause of mild respiratory tract diseases in previous studies. However, there are some reports of acute obstructive respiratory disease and severe pneumonia. The purpose of current study was to assess the prevalence and clinical features of parvovirus B19 in respiratory infection. Methods: This study was conducted on 156 patients diagnosed with respiratory infection at the Iran University of Medical Sciencesaffiliated hospitals. After extraction of viral DNA from swab samples, detection of parvovirus B19 was performed by real-time PCR assay. Results: In 156 patient's samples, parvovirus B19 was found in 8 (5.1 %) cases including 5 males (5.9%) and 3 females (4.1%). The most common clinical symptoms were wheezing (100%), tachypnea (100%), fever (75%) and rhinorrhea/pharyngitis (75%). Conclusion: This is the first attempt to assess the prevalence of parvovirus B19 infection in Iranian patients with respiratory infection. The low frequency of parvovirus B19 detected in our study does not support the role of this virus in the development of respiratory infection. However, further studies are needed to better evaluate the etiological role of parvovirus B19 in respiratory infection.

Analysis of viral infection and biomarkers in patients with acute exacerbation of chronic obstructive pulmonary disease

OBJECTIVE

To investigate viral infection in patients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD) in Shanghai, and to analyze the clinical characteristics and biomarkers in viral infection.

METHODS

This study included all consecutive patients who were admitted for a diagnosis of AECOPD during June 2013 to May 2015. Thirty-one stable COPD patients and 31 healthy controls were also recruited. Oropharyngeal samples were assessed, PCR for respiratory viruses were performed. Patients were divided into AECOPD virus-positive (+) group and AECOPD virus-negative (-) group according to viral detection. Luminex was used to detect the concentrations of inflammatory cytokines in the serum.

RESULTS

A total of 264 patients were included with a mean age of 75 ± 0.5 years. There were 72 patients (27.3%) identified with viral positive, of whom two patients were detected with double viral infections (FluA + FluB and RSVA + HRV, respectively). The rate of viral detection was associated with season, highest in winter. Comparisons of clinical characteristics showed no significant differences between AECOPD virus+ group and AECOPD virus- group. However, serum concentrations of interferon-inducible protein-10 (IP-10) and interferon-gamma (IFN-γ) in virus+ AECOPD patients were significantly higher than those in the virus- AECOPD, stable COPD and healthy control groups (P < .05).

CONCLUSION

Viral infection was an important pathogen in AECOPD patients; the most common viruses included FluA, HRV and FluB. It was very difficult to diagnose the viral infection according to clinical characteristics. The increased of serum IP-10 and IFN-γ levels might be value to indicate viral infection in AECOPD.

Prevalence and Seasonal Distribution of Respiratory Viruses During the 2014 - 2015 Season in Istanbul

Background

Acute respiratory tract infection (ARTI) is one of the most common infections worldwide, causing significant morbidity and mortality.

Objectives

This study was conducted to determine the prevalence and seasonal distribution of respiratory viruses in our region, in children and adults with a pre-diagnosis of ARTI.

Methods

A total of 845 nasopharyngeal swab specimens were analyzed with the RespiFinder Smart 22 kit (PathoFinder BV, Netherlands) and the Rotor-Gene 6000 real-time PCR system.

Results

At least one pathogen was detected in 612 (72.4%) of the specimens. Overall, 902 pathogens were detected; 821 (91%) were viruses and 81 (9%) were bacteria. The most commonly detected pathogens were influenza A virus (IFV-A) (n = 219), influenza B virus (IFV-B) (n=157), rhinovirus/enterovirus (n = 107), human bocavirus (HBoV) (n = 91), respiratory syncytial virus (RSV) A/B (n = 64), adenovirus (n = 56), human coronaviruses (n = 51), Mycoplasma pneumoniae (n = 49), parainfluenza viruses (n = 40), human metapneumovirus (n = 36), Bordetella pertussis (n = 15), Legionella pneumophila (n = 11), and Chlamydophila pneumoniae (n = 6), respectively. Among the 215 (25.4%) co-infected cases, IFV-A/HBoV and IFV-A/IFV-B were the most common co-infections. IFV-A was the most prevalent agent in all age groups except for children under 5 years of age, in whom RSV A/B was the most common pathogen. Approximately two thirds of the respiratory viruses were detected in early spring and winter, with peaks in January, March, and April.

Conclusions

With regard to the prevalence and seasonal distribution of respiratory viruses, our epidemiological data for the 2014 - 2015 season in Istanbul showed a predominance of IFV-A infections with a peak activity in early spring. Enhanced surveillance and early detection of respiratory viral pathogens can be useful in the diagnosis, treatment, and prevention of ARTIs, and for guiding the development of appropriate public health strategies.