Clinical Features of Human Metapneumovirus-Associated Community-acquired Pneumonia Hospitalizations

Clinical and epidemiological characteristics of 96 pediatric human metapneumovirus infections in Henan, China after COVID-19 pandemic: a retrospective analysis

BACKGROUND

In the aftermath of the COVID-19 pandemic, there has been a surge in human metapneumovirus (HMPV) transmission, surpassing pre-epidemic levels. We aim to elucidate the clinical and epidemiological characteristics of HMPV infections in the post-COVID-19 pandemic era.

METHODS

In this retrospective single-center study, participants diagnosed with laboratory confirmed HMPV infection through Targeted Next Generation Sequencing were included. The study encompassed individuals admitted to Henan Children's Hospital between April 29 and June 5, 2023. Demographic information, clinical records, and laboratory indicators were analyzed.

RESULTS

Between April 29 and June 5, 2023, 96 pediatric patients were identified as infected with HMPV with a median age of 33.5 months (interquartile range, 12 ~ 48 months). The majority (87.5%) of infected children were under 5 years old. Notably, severe cases were statistically younger. Predominant symptoms included fever (81.3%) and cough (92.7%), with wheezing more prevalent in the severe group (56% vs 21.1%). Coinfection with other viruses was observed in 43 patients, with Epstein-Barr virus (EBV) (15.6%) or human rhinovirus A (HRV type A) (12.5%) being the most common. Human respiratory syncytial virus (HRSV) coinfection rate was significantly higher in the severe group (20% vs 1.4%). Bacterial coinfection occurred in 74 patients, with Haemophilus influenzae (Hin) and Streptococcus pneumoniae (SNP) being the most prevalent (52.1% and 41.7%, respectively). Severe patients demonstrated evidence of multi-organ damage. Noteworthy alterations included lower concentration of IL-12p70, decreased lymphocytes percentages, and elevated B lymphocyte percentages in severe cases, with statistical significance. Moreover, most laboratory indicators exhibited significant changes approximately 4 to 5 days after onset.

CONCLUSIONS

Our data systemically elucidated the clinical and epidemiological characteristics of pediatric patients with HMPV infection, which might be instructive to policy development for the prevention and control of HMPV infection and might provide important clues for future HMPV research endeavors.

Multicenter epidemiological investigation and genetic characterization of respiratory syncytial virus and metapneumovirus infections in the pre-pandemic 2018-2019 season in northern and central Italy

Respiratory syncytial virus (RSV) and human metapneumovirus (HMPV) cause a high burden of disease, particularly in children and the elderly. With the aim to add knowledge on RSV and HMPV infections in Italy, a prospective, multicenter study was conducted by eight centers of the Working Group on Respiratory Virus Infections (GLIViRe), from December 2018-April 2019. Weekly distribution and patients' demographic and clinical data were compared in 1300 RSV and 222 HMPV-positive cases. Phylogenetic analysis of the G-glycoprotein coding region was performed to characterize circulating strains. RSV positivity ranged from 6.4% in outpatients of all ages to 31.7% in hospitalized children; HMPV positivity was 4-1.2% with no age-association. RSV season peaked in February and ended in mid-April: HMPV circulation was higher when RSV decreased in early spring. RSV was more frequent in infants, whereas HMPV infected comparatively more elderly adults; despite, their clinical course was similar. RSV-B cases were two-thirds of the total and had similar clinical severity compared to RSV-A. Phylogenetic analysis showed the circulation of RSV-A ON1 variants and the predominance of RSV-B genotype BA10. HMPV genotype A2c was the prevalent one and presented insertions of different lengths in G. This first multicenter Italian report on seasonality, age-specific distribution, and clinical presentation of RSV and HMPV demonstrated their substantial disease burden in young patients but also in the elderly. These data may provide the basis for a national respiratory virus surveillance network.

The COVID-19 pandemic as an opportunity for unravelling the causative association between respiratory viruses and pneumococcus-associated disease in young children: a prospective study

BACKGROUND

In young children, rates of lower respiratory infections (LRI) and invasive pneumococcal disease (IPD) have been associated with respiratory syncytial virus (RSV), human metapneumovirus (hMPV), influenza (flu), and parainfluenza (PIV) (collectively termed here as pneumonia and pneumococcal disease-associated viruses [PDA-viruses]). However, their contribution to the pathogenesis of these disease endpoints has not yet been elucidated. The COVID-19 pandemic provided a unique opportunity to examine the question.

METHODS

This prospective study comprised all children <5 years, living in southern Israel, during 2016 through 2021. The data were previously collected in multiple ongoing prospective surveillance programs and include: hospital visits for community-acquired alveolar pneumonia (CAAP), non-CAAP LRI; nasopharyngeal pneumococcal carriage (<3 years of age); respiratory virus activity; and nationwide, all-ages COVID-19 episodes and IPD in children <5 years. A hierarchical statistical model was developed to estimate the proportion of the different clinical endpoints attributable to each virus from monthly time series data, stratified by age and ethnicity. A separate model was fit for each endpoint, with covariates that included a linear time trend, 12-month harmonic variables to capture unexplained seasonal variations, and the proportion of tests positive for each virus in that month.

FINDINGS

During 2016 through 2021, 3,204, 26,695, 257, and 619 episodes of CAAP, non-CAAP LRI, pneumococcal bacteremic pneumonia and non-pneumonia IPD, respectively, were reported. Compared to 2016-2019, broad declines in the disease endpoints were observed shortly after the pandemic surge, coincident with a complete disappearance of all PDA-viruses and continued circulation of rhinovirus (RhV) and adenovirus (AdV). From April 2021, off-season and abrupt surges of all disease endpoints occurred, associated with similar dynamics among the PDA-viruses, which re-emerged sequentially. Using our model fit to the entire 2016-2021 period, 82% (95% CI, 75-88%) of CAAP episodes in 2021 were attributable to the common respiratory viruses, as were 22%-31% of the other disease endpoints. Virus-specific contributions to CAAP were: RSV, 49% (95% CI, 43-55%); hMPV, 13% (10-17%); PIV, 11% (7-15%); flu, 7% (1-13%). RhV and AdV did not contribute. RSV was the main contributor in all endpoints, especially in infants. Pneumococcal carriage prevalence remained largely stable throughout the study.

INTERPRETATION

RSV and hMPV play a critical role in the burden of CAAP and pneumococcal disease in children. Interventions targeting these viruses could have a secondary effect on the burden of disease typically attributed to bacteria.

FUNDING

There was no funding for this study.

Using Precision Medicine for the Diagnosis and Treatment of Viral Pneumonia

The COVID-19 pandemic has drawn considerable attention to viral pneumonia from clinicians, public health authorities, and the general public. With dozens of viruses able to cause pneumonia in humans, differentiating viral from bacterial pneumonia can be very challenging in clinical practice using traditional diagnostic methods. Precision medicine is a medical model in which decisions, practices, interventions, and therapies are adapted to the individual patient on the basis of their predicted response or risk of disease. Precision medicine approaches hold promise as a way to improve outcomes for patients with viral pneumonia. This review describes the latest advances in the use of precision medicine for diagnosing and treating viral pneumonia in adults and discusses areas where further research is warranted.

Involvement of IL-33 in the Pathogenesis and Prognosis of Major Respiratory Viral Infections: Future Perspectives for Personalized Therapy

Interleukin (IL)-33 is a key cytokine involved in type-2 immunity and allergic airway disease. At the level of lung epithelial cells, where it is clearly expressed, IL-33 plays an important role in both innate and adaptive immune responses in mucosal organs. It has been widely demonstrated that in the course of respiratory virus infections, the release of IL-33 increases, with consequent pro-inflammatory effects and consequent exacerbation of the clinical symptoms of chronic respiratory diseases. In our work, we analyzed the pathogenetic and prognostic involvement of IL-33 during the main respiratory viral infections, with particular interest in the recent SARS-CoV-2 virus pandemic and the aim of determining a possible connection point on which to act with a targeted therapy that is able to improve the clinical outcome of patients.

A rare case of metapneumovirus-induced rhabdomyolysis and multi-organ dysfunction in a 4-year-old child

Human metapneumovirus (hMPV) is a common cause of acute respiratory tract infections in children. In immunocompetent individuals, the course of hMPV infection is usually benign and self-limiting. A developmentally normal, previously healthy 4-year-old girl presented with pneumonia and later developed rhabdomyolysis and multi-organ dysfunction syndrome (MODS) which was fatal. Extensive microbiological investigation for a possible viral aetiology was positive only for hMPV, thus making it the first reported case of hMPV infection-related rhabdomyolysis.Abbreviations: ARDS, acute respiratory distress syndrome; CK, creatinine kinase; hMPV, human metapneumovirus; MODS, multi-organ dysfunction syndrome; RSV, respiratory syncytial virus.

The Clinical Characteristics and Outcomes of Adult Patients With Pneumonia Related to Three Paramyxoviruses

Background: Respiratory syncytial virus (RSV), human metapneumovirus (hMPV), and human parainfluenza virus (hPIV) are paramyxoviruses (PMVs) that are important etiologies of community-acquired pneumonia. However, current knowledge about the clinical features and outcomes of PMV-related pneumonia (PMV-p) is limited. We aimed to investigate the clinical characteristics and disease severity in immunocompetent adults hospitalized with hMPV-related pneumonia (hMPV-p), hPIV-related pneumonia (hPIV-p), or RSV-related pneumonia (RSV-p).

Methods: We retrospectively recruited 488 patients with PMV-p (153 with RSV-p, 137 with hMPV-p, and 198 with hPIV-p) from five teaching hospitals in China during 2011–2019. Univariate and multivariate analyses were performed to identify predictors to distinguish hMPV-p/hPIV-p from RSV-p and evaluate the effects of virus types on the clinical outcomes.

Results: Compared with RSV-p, sputum production [odds ratio (OR) 5.029, 95% confidence interval (CI) 2.452–10.312, P < 0.001] was positively associated with hMPV-p, while solid malignant tumor (OR 0.346, 95% CI 0.126–0.945, P = 0.038), nasal congestion (OR 0.102, 95% CI 0.041–0.251, P < 0.001), and respiratory rate ≥ 30 breaths/min (OR 0.296, 95% CI 0.136–0.640, P = 0.002) were negatively related to hMPV-p. Sputum production (OR 13.418, 95% CI 6.769–26.598, P < 0.001) was positively associated with hPIV-p, while nasal congestion (OR 0.194, 95% CI 0.098–0.387, P < 0.001), dyspnea (OR 0.469, 95% CI 0.272–0.809, P < 0.001), and respiratory rate ≥30 breaths/min (OR 0.090, 95% CI 0.032–0.257, P < 0.001) on admission were negatively related to hPIV-p. After adjustment for confounders, multivariate logistic regression analysis suggested that hMPV-p (OR 0.355, 95% CI 0.135–0.932, P = 0.035) and hPIV-p (OR 0.311, 95% CI 0.121–0.784, P = 0.013) were associated with decreased 30-day mortality compared with RSV-p. RSV infection (OR 4.183, 95% CI 1.709–10.236, P = 0.002) was identified as an independent predictor of 30-day mortality in patients with PMV-p.

Conclusion: RSV-p caused more severe disease than hMPV-p and hPIV-p. Although some clinical features are helpful for distinguishing the diseases, etiologic diagnosis is critical in the management of the PMV-p.

Clinical characteristics and outcomes in adult patients hospitalized with influenza, respiratory syncytial virus and human metapneumovirus infections

Objectives: To compare the clinical characteristics and outcomes of patients hospitalized with respiratory syncytial virus (RSV), human metapneumovirus (hMPV), and influenza infections.Methods: This study prospectively enrolled 594 patients hospitalized with influenza-like illness (ILI) and laboratory-confirmed RSV, hMPV, or influenza infections over three consecutive influenza seasons at a tertiary hospital in China.Results: While certain clinical features were of value as predictors of infection type, none exhibited good predictive performance as a means of discriminating between these three infections (area under the receiver-operating characteristic curve < 0.70). After controlling for potential confounding variables, RSV infections in pneumonia patients were found to be associated with a 30-day mortality risk comparable to that of influenza patients [odds ratio (OR) 1.016, 95% confidence interval (CI) 0.267-3.856, p = 0.982], whereas hMPV infection was associated with a reduced risk of mortality (OR 0.144, 95% CI 0.027-0.780, p = 0.025). Among those without pneumonia, the 30-day mortality risk in patients with influenza was comparable to that in patients infected with RSV (OR 1.268, 95% CI 0.172-9.355, p = 0.816) or hMPV (OR 1.128, 95% CI 0.122-10.419, p = 0.916).Conclusion: Disease severity associated with these three types of viral infection was inconsistent when comparing patients with and without pneumonia, highlighting the importance of etiologic testing.