Clinical and epidemiological characteristics of human parainfluenza virus infections of children in southern Taiwan

Clinical Characteristics of Pediatric Parainfluenza Virus Infections: A Comparative Analysis of Parainfluenza Virus Serotypes 1-4 From April 2021 to October 2023 in Hokkaido, Japan

BACKGROUND

Parainfluenza virus (PIV) is widely known as a causative virus of acute respiratory tract infections in children, and 4 serotypes (PIV-1-PIV-4) have been identified. The purpose of the present study was to clarify the clinical characteristics of the PIV serotypes in pediatric PIV infections in Japan.

METHODS

Between April 2021 and October 2023, 8821 children aged <16 years who presented with respiratory symptoms underwent multiplex polymerase chain reaction analyses at the Department of Pediatrics, NTT Medical Center Sapporo. All 1490 cases in which PIV was detected were analyzed for their clinical characteristics by PIV serotypes.

RESULTS

Of the 1490 cases, 608 were positive for a single PIV serotype: 91 (13.5%) for PIV-1, 54 (4.8%) for PIV-2, 361 (62.1%) for PIV-3 and 102 (19.6%) for PIV-4. The median ages were 3.5 years for PIV-1, 5.4 years for PIV-2, 1.9 years for PIV-3 and 2.2 years for PIV-4, with a significantly older age for PIV-2. Compared with the other serotypes, croup was significantly more common in PIV-1 and lower respiratory tract infection was significantly more common in PIV-4. Of the 608 cases with a single PIV serotype, 114 were hospitalized. The proportion of hospitalized patients was higher for PIV-4 than for the other PIV serotypes, but the difference was not significant.

CONCLUSIONS

Lower respiratory tract infection was more frequent in PIV-4 than in the other PIV serotypes, and PIV-4 infection may increase the risk of hospitalization.

Clinical characteristics and risk factors of severe human parainfluenza virus infection in hospitalized children

BACKGROUND

Human parainfluenza viruses (HPIVs) commonly cause childhood respiratory illness requiring hospitalization in Taiwan. This study aimed to investigate clinical severity and identify risk factors predisposing to severe disease in hospitalized children with HPIV infection.

METHODS

We included hospitalized patients with lab-confirmed HPIV infection from 2007 to 2018 and collected their demographic and clinical characteristics. Patients with ventilator support, intravenous inotropic agents, and extracorporeal membrane oxygenation were defined as severe cases.

RESULTS

There were 554 children hospitalized for HPIV infection. The median age was 1.2 years; 518 patients had non-severe HPIV infection, whereas 36 patients (6.5%) had severe HPIV infection. 266 (48%) patients had underlying diseases, and 190 patients (34.3%) had bacterial co-detection. Children with severe HPIV infection were more likely to have bacterial co-detection than those without (52.8% vs 33.0%, p = 0.02). Patients with lung patch or consolidation had more invasive bacterial co-infection or co-detection than those without patch or consolidation (43% vs 33%, p = 0.06). Patients with neurological disease (adjusted OR 4.77, 95% CI 1.94-11.68), lung consolidation/patch (adjusted OR 6.64, 95% CI 2.80-15.75), and effusion (adjusted OR 11.59, 95% CI 1.52-88.36) had significantly higher risk to have severe HPIV infection.

CONCLUSION

Neurological disease and lung consolidation/patch or effusion were the most significant predictors of severe HPIV infection.

Clinical impact of human parainfluenza virus infections before and during the COVID-19 pandemic in Southern China

Human parainfluenza viruses (HPIVs) are a leading cause of acute respiratory tract infections (ARTIs). Non-pharmaceutical interventions (NPIs) were widely administered to combat the pandemic of the coronavirus disease 2019 (COVID-19). Respiratory specimens were obtained from 10,454 hospitalized children with ARTIs to detect HPIV. We investigated differences in epidemiological and clinical characteristics of HPIV infections before (2017-2019) and during the COVID-19 pandemic (2020-2022). HPIVs were detected in 392 (3.75%, 392/10,454) patients, of whom 70 (17.86%), 48 (12.24%), and 274 (69.90%) were positive for HPIV1, HPIV2, and HPIV3, respectively. Detection rates of HPIV3 were higher in 2020-2022 than in 2017-2019 (3.38% vs. 2.24%). The seasonal distribution of HPIV1 showed no difference, but HPIV3 peaked between September and December during the COVID-19 pandemic, which differed from previous epidemiological patterns. Compared to the period before the COVID-19 pandemic, there has been a noticeable decrease in the incidence of asthma, moist rales, and emesis in patients infected with HPIV1 and in asthma, expectoration, and severe pneumonia in patients infected with HPIV3 during 2020-2022. The detection rates of HPIV increased in Southern China during the COVID-19 outbreak, which underlines the importance of continuous surveillance of HPIV in the next epidemic season.

Circulating pediatric respiratory pathogens in Taiwan during 2020: Dynamic change under low COVID-19 incidence

BACKGROUND

In Taiwan, there were only 799 confirmed COVID-19 cases in 2020. The unique backdrop amidst a pandemic and promotion of nonpharmaceutical interventions generated some distinct changes in the epidemiology of common respiratory pathogens. In this study, we aimed to investigate the dynamic changes in respiratory pathogens in children during 2020.

METHODS

We performed a retrospective cohort study at a tertiary hospital in southern Taiwan during 2020. Patients aged 0-18 years who visited the pediatric emergency department were enrolled. Children who presented with clinical symptoms (fever or respiratory illness) and received nasopharyngeal swabs for multiplex polymerase chain reaction (PCR) were included in our analysis. We also compared respiratory syncytial virus (RSV) trends from previous years by PCR and lateral flow immunochromatographic assays from 2017 to 2020.

RESULTS

A total of 120 children were tested. The overall detection rate was 55%. With strengthened restrictions, the detection rate dropped from 70% to 30%. However, non-enveloped viruses (rhinovirus/enterovirus and adenovirus) were in constant circulation. Upon easing prevention measures, the detection rate remained above 60%, and an outbreak of an enveloped virus (RSV and parainfluenza virus) was noted. Compared with 2017-2019, the cyclical RSV epidemic was delayed, with a large surge in late 2020.

CONCLUSIONS

We observed a constant circulation of non-enveloped viruses when strict nonpharmaceutical interventions were employed and a delayed surge of enveloped viruses during the easing of restrictions. Continuous surveillance and monitoring of the evolutionary dynamics of respiratory viruses is important, while easing restrictions requires balanced judgment.

The epidemiology and etiologies of respiratory tract infection in Northern Taiwan during the early phase of coronavirus disease 2019 (COVID-19) outbreak

Background

Coronavirus disease 2019 (COVID-19) manifests symptoms as common etiologies of respiratory tract infections (RTIs). During the pandemic of COVID-19, identifying the etiologies correctly from patients with RTI symptoms was crucial in not only disease control but preventing healthcare system from collapsing. By applying sensitive PCR-based molecular assays, we detected the etiologic agents and delineated the epidemiologic picture of RTIs in the early phase of COVID-19 pandemic.

Methods

From December 2019 to February 2020, we screened patients presented with RTIs using multiplex PCR-based diagnostic assays. Data from pediatric and adult patients were compared with different months and units in the hospital.

Results

Of all 1631 patients including 1445 adult and 186 pediatric patients screened, 8 viruses and 4 bacteria were identified. Positive rates were 25% in December, 37% in January, and 20% in February, with pediatric patients having higher positive rates than adults (Ps < 0.001). In pediatric patients, RhV/EnV was the most commonly detected, followed by parainfluenza viruses. Most Mycoplasma pneumoniae infection occurred in pediatric patients. RhV/EnV was the most commonly detected agent in pediatric patients admitted to intensive care units (ICUs), while influenza accounted for the majority of adult cases with critical illness. Noticeably, seasonal coronavirus ranked second in both adult and pediatric patients with ICU admission.

Conclusion

While we focused on the pandemic of COVID-19, common etiologies still accounted for the majority of RTIs and lead to severe diseases, including other seasonal coronaviruses.

A review on disease burden and epidemiology of childhood parainfluenza virus infections in Asian countries

Human parainfluenza viruses (HPIVs) are an important cause of acute respiratory tract infections (ARTIs) in children less than 5 years, second only to human respiratory syncytial viruses (HRSVs). Generally, patients infected with HPIVs are treated in outpatient clinics, yet also contribute to ARTI-associated hospitalization in children. Although HPIV infections are well studied in developed countries, these infections remain under-investigated and not considered in the routine laboratory diagnosis of childhood ARTI in many developing countries in Asia. We performed an extensive literature search on the prevalence, epidemiology, and burden of HPIV infections in children less than 5 years in Asia using PubMed and PubMed Central search engines. Based on the literature, the prevalence of HPIV infection in Asia ranges from 1% to 66%. According to many studies, HPIV-3 is the major virus circulating among children; however, several studies failed to detect HPIV-4 due to unavailability of diagnostic tools. In Asian countries, HPIV contributes a substantial disease burden in children. The data in this review should assist researchers and public health authorities to plan preventive measures, including accelerating research on vaccines and antiviral drugs.

Etiological analysis of virus, mycoplasma pneumoniae and chlamydia pneumoniae in hospitalized children with acute respiratory infections in Huzhou

BACKGROUND

Acute respiratory infections are a common disease in children with high mortality and morbidity. Multiple pathogens can cause acute respiratory infections. A 2-year survey of hospitalized children was conducted to understand the epidemic situation, seasonal spread of pathogens and the improvement of clinical diagnosis, treatment and prevention of disease in Huzhou, China.

METHODS

From September 2017 to August 2019, 3121 nasopharyngeal swabs from hospitalized children with acute respiratory infections were collected, and real-time PCR was used to detect various pathogens. Then, pathogen profiles, frequency and seasonality were analyzed.

RESULTS

Of the 3121 specimens, 14.45% (451/3121) were positive for at least one pathogen. Of the single-pathogen infections, RSV (45.61%, 182/399) was the most frequent pathogen, followed by PIVs (14.79%, 59/399), ADV (14.54%, 58/399), MP (10.78%, 43/399), and IAV (5.26%, 21/399). Of the 52 coinfections, RSV + PIVs viruses were predominantly identified and accounted for 40.38% (21/52) of cases. RSV was the most frequent pathogen in all four groups. The highest positive rate of the pathogens occurred in the winter (21.26%), followed by autumn (14.98%), the summer (14.11%) and the spring (12.25%).

CONCLUSION

Viruses are the main pathogens in hospitalized children with acute respiratory infections in Huzhou city, Zhejiang Province, China. Among the pathogens, RSV had the highest detection rate, and MP is also a common pathogen among children with acute respiratory infections. This study provided a better understanding of the distribution of pathogens in children of different ages and seasons, which is conducive to the development of more reasonable treatment strategies and prevention and control measures.

Viral etiologies of acute respiratory tract infections among hospitalized children - A comparison between single and multiple viral infections

Background

Acute respiratory tract infections are commonly caused by viruses in children. The differences in clinical data and outcome between single and multiple viral infections in hospitalized children were analyzed.

Methods

We retrospectively reviewed the medical records of hospitalized children who had fever and a xTAG Respiratory Virus Panel (RVP) test over a 2-year period. The clinical data were analyzed and compared between single and multiple viral infections. Viral etiologies in upper and lower respiratory infections were analyzed and compared.

Results

A total of 442 patients were enrolled. Patients with positive viral detection (N = 311) had a significantly lower rate of leukocytosis (p = 0.03), less evidence of bacterial infection (p = 0.004), and shorter duration of hospitalization (p = 0.019) than those with negative viral detection. The age of patients with multiple viral infections was younger than those with single viral infection; however, there were no significant differences in duration of fever, antibiotics treatment and hospitalization between these two groups.

The most commonly identified virus was human rhinovirus. About 27% (n = 83) of patients had multiple viral infections. Overall, the highest percentage of human bocavirus infection was detected in multiple viral infections (79%). Lower respiratory tract infection (LRTI) was independently associated with multiple viral infections (p = 0.022), respiratory syncytial virus (RSV) infection (p = 0.001) and longer hospitalization duration (p = 0.011).

Conclusion

Multiple viral infections were associated with younger age and a higher risk of developing LRTI. However, multiple viral infections did not predict a worse disease outcome. More studies are needed to unveil the interplay between the hosts and different viruses in multiple viral infections.

Immunological association of inducible bronchus-associated lymphoid tissue organogenesis in Ag85B-rHPIV2 vaccine-induced anti-tuberculosis mucosal immune responses in mice

We previously reported that Ag85B-expressing human parainfluenza type 2 virus (Ag85B-rHPIV2) was effective as a nasal vaccine against tuberculosis in mice; however, the mechanism by which it induces an immune response remains to be investigated. In the present study, we found that organogenesis of inducible bronchus-associated lymphoid tissue (iBALT) played a role in the induction of antigen-specific T cells and IgA antibody responses in the lung of mice intra-nasally administered Ag85B-rHPIV2. We found that expression of Ag85B was dispensable for the development of iBALT, suggesting that HPIV2 acted as an iBALT-inducing vector. When iBALT organogenesis was disrupted in Ag85B-rHPIV2-immunized mice, either by neutralization of the lymphotoxin pathway or depletion of CD11b⁺ cells, Ag85B-specific immune responses (i.e. IFN γ-producing T cells and IgA antibody) were diminished in the lung. Furthermore, we found that immunization with Ag85B-rHPIV2 induced neutrophil and eosinophil infiltration temporally after the immunization in the lung. Thus, our results show that iBALT organogenesis contributes to the induction of antigen-specific immune responses by Ag85B-rHPIV2 and that Ag85B-rHPIV2 provokes its immune responses without inducing long-lasting inflammation.

Clinical characteristics of the lower respiratory tract infection caused by a single infection or coinfection of the human parainfluenza virus in children

BACKGROUND

Human parainfluenza virus (HPIV), usually combined with other pathogens, causes lower respiratory tract infection (LRTI) in children. However, clinical characteristics of HPIV coinfection with other pathogens were unclear. This study aimed to investigate the viral and atypical bacterial etiology of LRTI in children and compare the clinical characteristics of HPIV single infection with those of coinfection.

METHODS

This study included 1335 patients, aged between 1 to 71 months, diagnosed with LRTI in Yuying Children's Hospital, Zhejiang, China, from December 2013 to June 2015. Nasopharyngeal secretions were collected, and respiratory pathogens were detected using Multiplex polymerase chain reaction. The clinical data of patients were collected and analyzed.

RESULTS

At least 1 pathogen was detected in 1181/1335 (88.5%) patients. The pathogens identified most frequently were respiratory syncytial virus, human rhinovirus, HPIV, adenovirus, and human metapneumovirus. The coinfection rate was 24.8%. HPIV coinfection with other viruses was more associated with running nose, shortness of breath, and oxygen support compared with HPIV single infection. Moreover, HPIV coinfection with atypical bacteria was more related to running nose, moist rales, and longer hospital duration compared with HPIV single infection, and also to longer hospital duration compared with coinfection with other viruses.

CONCLUSIONS

This study demonstrated that viral infections were highly associated with LRTI and the rate of coinfection was high. HPIV single infection was milder than coinfection with other viruses. Moreover, HPIV coinfection with atypical bacteria was more serious than HPIV single infection and coinfection with other viruses.