An off-season outbreak of human metapneumovirus infections after ending of a COVID-19 lockdown

Clinical manifestations, para-clinical features and outcome of Iranian adults with respiratory syncytial virus (RSV) infection: a report from hospitalized patients

BACKGROUND

Respiratory syncytial virus (RSV) is an important cause of children's pulmonary infections. However, there are fewer studies on RSV infections in adults. The purpose of this study was to describe the clinical manifestations, para-clinical characteristics, and outcome of RSV infection among adult patients who were referred to the Imam Khomeini Hospital Complex during the winter and spring of 2022-2023.

METHODS

From December 21, 2022, to May 20, 2023, we conducted a cross-sectional study on hospitalized adults having positive RT-PCR results for RSV. We further assessed the clinical and para-clinical characteristics and outcomes of the RSV groups.

RESULTS

We screened 1375 adults with suspected acute respiratory infections (ARIs) and confirmed RSV infections in 59 of them (4.3%). Of these, 23 patients were excluded from further analysis due to outpatient management, leaving 36 hospitalized patients with confirmed RSV infection (61.01%). The mean age of the hospitalized patients was 53.28 ± 20.37 years (range: 15-83), with a slightly higher proportion of females (52.80%) compared to males (47.20%). Dyspnea, productive cough, and fever were the most common symptoms, with a mean symptom duration of 10.50 days. Ischemic heart disease, hypertension, and liver failure were common underlying conditions. Notably, biochemical and inflammatory markers such as CRP, ESR, and LDH were significantly elevated beyond the normal range. Finally, five patients (13.9%) who received intensive care treatments died.

CONCLUSIONS

Although the rate of RSV infection was not high among Iranian adults, a greater proportion of patients required hospitalization (61%). There was a significant link between liver failure, an elevated INR, more than 30% bilateral pulmonary involvement, abdominal pain, longer ICU stays, and immunodeficiency cases with increased mortality from RSV infection. We suggest that RSV infection may act as a secondary factor in decompensating pre-existing liver failure, which was present in certain patients with underlying conditions, potentially leading to life-threatening consequences.

A Re-emerging Respiratory Virus: Human Metapneumovirus (hMPV)

Human metapneumovirus (hMPV) is identified as a pathogenic agent responsible for respiratory tract infections in paediatric, adult and elderly populations. It is a spherical, enveloped virus with a diameter of 209nm, consisting of a single-stranded, non-segmented, and negative-sense RNA genome of around 13.3 kb in length. hMPV infection is prevalent all around the globe, with peak positivity rates detected mostly during later winter and spring seasons. Mostly transmitted through droplet or aerosol contamination, this viral infection may manifest clinical characteristics indicative of both upper and lower respiratory tract infections like fever, cough, rhinorrhea, pneumonia, bronchiolitis, and croup. The recommended laboratory diagnostic approach is reverse transcription polymerase chain reaction, given the challenges associated with culturing the virus. This review article focuses on the structure, replication, genotype, epidemiology, seasonality, transmission methods, clinical manifestations in humans, treatment methodology, and outbreaks of hMPV that have been reported worldwide.

Impact of COVID-19 pandemic measures on hospitalizations and epidemiological patterns of twelve respiratory pathogens in children with acute respiratory infections in southern China

OBJECTIVES

To investigate the impact of COVID-19 pandemic measures on hospitalizations and the alterations and persistence of the epidemiological patterns of 12 common respiratory pathogens in children during the COVID-19 pandemic and after the cessation of the "zero-COVID-19" policy in southern China.

METHODS

Respiratory specimens were collected from hospitalized children with acute respiratory infections at Shenzhen Children's Hospital from January 2020 to June 2024. Twelve common respiratory pathogens were detected using multiplex PCR. Data on demographic characteristics, pathogen detection rates, epidemiological patterns, co-infections, and ICU admission rates were compared between the 'during COVID-19' period (Phase 1: January 2020 to December 2022) and the 'post COVID-19' period (Phase 2: January 2023 to June 2024).

RESULTS

In Phase 2, there was a significant increase in average annual cases, with a higher median age of affected children, higher pathogen detection rates, and increased co-infection rates compared to Phase 1. The epidemiological patterns of most pathogens were altered by the COVID-19 pandemic. Human Parainfluenza Virus, Human Metapneumovirus, Human Bocavirus (HBOV), and Human Coronavirus remained active during Phase 1, while Mycoplasma pneumoniae (Mp) and Adenovirus (ADV) were low, and Respiratory Syncytial Virus (RSV) lacked a seasonal peak in 2022. In Phase 2, Mp, ADV, and RSV experienced outbreaks, with Mp's high prevalence continuing into 2024. RSV showed out-of-season epidemics for two consecutive years. Influenza A (H1N1), Influenza A (H3N2), and InfB lost their seasonal patterns during Phase 1 but reemerged and regained their seasonal characteristics in 2023-2024. ICU admission rates did not significantly differ between the two phases, except for HBOV, which had higher rates in Phase 2.

CONCLUSION

The epidemiological patterns of various respiratory pathogens were affected by the COVID-19 pandemic to varying degrees. Pathogens suppressed during the pandemic experienced outbreaks or out-of-season epidemics after the lifting of non-pharmaceutical interventions, with Mp and RSV continuing into the second year and HBOV associated ICU admission rates increasing in the post-pandemic era. Continuous monitoring of these patterns is essential to understand the duration of these effects and to inform effective response strategies.

Changes in the epidemiological patterns of respiratory syncytial virus and human metapneumovirus infection among pediatric patients and their correlation with severe cases: a long-term retrospective study

Objectives

We aim to investigate the prevalence of respiratory syncytial virus (RSV) and human metapneumovirus (hMPV) among pediatric patients with acute respiratory tract illness (ARTI) in southern China both pre- and post-COVID-19 pandemic, as well as identify associated risk factors for severe infections.

Methods

The study conducted a real-time PCR analysis on hospitalized children with ARTI from 2012 to 2023, specifically targeting RSV, hMPV, and other respiratory pathogens. Additionally, demographic data was collected during this analysis.

Results

The prevalence of RSV occurs triennially, and likewise, the temporal pattern of hMPV outbreaks mirrors that of RSV. The peak infection rates of RSV and hMPV occurred during and following the implementation of COVID-19 epidemic prevention and control measures. The incidence of RSV infection exhibited bimodal peaks in 2022, while hMPV demonstrated seasonal peaks during the spring, fall, and winter periods post-COVID-19 pandemic. After the COVID-19 outbreak, there has been an upward trend in the proportion of female patients and patients aged one year and older presenting with ARTI, RSV infections, and hMPV infections. Infant (OR = 4.767, 95%CI: [3.888-5.846], p < 0.0001), presence of co-infection (OR = 0.540, 95%CI: [0.404-0.722], p < 0.0001), and existence of comorbidities (OR = 1.582, 95%CI: [1.285-1.949], p < 0.0001) was the risk ratio for the severity of RSV infection. Children infected with hMPV under the age of 1 year (OR = 0.322, 95%CI: [0.180 - 0.575], p < 0.0001), as well as those with comorbidities (OR = 8.809, 95%CI: [4.493 - 17.272], p < 0.0001), have a higher risk of developing severe illness.

Conclusion

The changing epidemiological patterns have the potential to lead to widespread severe outbreaks among children, particularly those with underlying medical conditions who may experience more severe symptoms. Conducting surveillance for pneumoviridae viruses in children is an imperative measure to establish a robust foundation for future epidemic prevention and treatment strategies.

The impact of non-pharmaceutical interventions on community non-SARS-CoV-2 respiratory infections in preschool children

BACKGROUND

Effects of non-pharmaceutical interventions during the pandemic were mainly studied for severe outcomes. Among children, most of the burden of respiratory infections is related to infections which are not medically attended. The perspective on infections in the community setting is necessary to understand the effects of the pandemic on non-pharmaceutical interventions.

METHODS

In the unique prospective LoewenKIDS cohort study, we compared the true monthly incidence of self-reported acute respiratory infections (ARI) in about 350 participants (aged 3-4 years old) between October 2019 to March 2020 (pre-pandemic period) and October 2020 to March 2021 (pandemic period). Parents reported children's symptoms using a diary. Parents were asked to take a nasal swab of their child during all respiratory symptoms. We analysed 718 swabs using Multiplex PCR for 25 common respiratory viruses and bacteria.

RESULTS

During the pre-pandemic period, on average 44.6% (95% CI: 39.5-49.8%) of children acquired at least one ARI per month compared to 19.9% (95% CI: 11.1-28.7%) during the pandemic period (Incidence Rate Ratio = 0.47; 95% CI: 0.41-0.54). The detection of influenza virus decreased absolute by 96%, respiratory syncytial virus by 65%, metapneumovirus by 95%, parainfluenza virus by 100%, human enterovirus by 96% and human bocavirus by 70% when comparing the pre-pandemic to the pandemic period. However, rhinoviruses were nearly unaffected by NPI. Co-detection (detection of more than one virus in a single symptomatic swab) was common in the pre-pandemic period (222 of 390 samples with viral detection; 56.9%) and substantially less common during the pandemic period (46 of 216 samples; 21.3%).

CONCLUSION

Non-pharmaceutical interventions strongly reduced the incidence of all respiratory infections in preschool children but did not affect rhinovirus.

Re-Emergence of HMPV in Gwangju, South Korea, after the COVID-19 Pandemic

The non-pharmaceutical interventions implemented to prevent the spread of COVID-19 have affected the epidemiology of other respiratory viruses. In South Korea, Human metapneumovirus (HMPV) typically occurs from winter to the following spring; however, it was not detected for two years during the COVID-19 pandemic and re-emerged in the fall of 2022, which is a non-epidemic season. To examine the molecular genetic characteristics of HMPV before and after the COVID-19 pandemic, we analyzed 427 HMPV-positive samples collected in the Gwangju area from 2018 to 2022. Among these, 24 samples were subjected to whole-genome sequencing. Compared to the period before the COVID-19 pandemic, the incidence rate of HMPV in 2022 increased by 2.5-fold. Especially in the age group of 6-10 years, the incidence rate increased by more than 4.5-fold. In the phylogenetic analysis results, before the COVID-19 pandemic, the A2.2.2 lineage was predominant, while in 2022, the A2.2.1 and B2 lineage were observed. The non-pharmaceutical interventions implemented after COVID-19, such as social distancing, have reduced opportunities for exposure to HMPV, subsequently leading to decreased acquisition of immunity. As a result, HMPV occurred during non-epidemic seasons, influencing the age distribution of its occurrences.

Changes in hospitalizations and emergency department respiratory viral diagnosis trends before and during the COVID-19 pandemic in Ontario, Canada

INTRODUCTION

Population-level surveillance systems have demonstrated reduced transmission of non-SARS-CoV-2 respiratory viruses during the COVID-19 pandemic. In this study, we examined whether this reduction translated to reduced hospital admissions and emergency department (ED) visits associated with influenza, respiratory syncytial virus (RSV), human metapneumovirus, human parainfluenza virus, adenovirus, rhinovirus/enterovirus, and common cold coronavirus in Ontario.

METHODS

Hospital admissions were identified from the Discharge Abstract Database and exclude elective surgical admissions and non-emergency medical admissions (January 2017-March 2022). Emergency department (ED) visits were identified from the National Ambulatory Care Reporting System. International Classification of Diseases (ICD-10) codes were used to classify hospital visits by virus type (January 2017-May 2022).

RESULTS

At the onset of the COVID-19 pandemic, hospitalizations for all viruses were reduced to near-trough levels. Hospitalizations and ED visits for influenza (9,127/year and 23,061/year, respectively) were nearly absent throughout the pandemic (two influenza seasons; April 2020-March 2022). Hospitalizations and ED visits for RSV (3,765/year and 736/year, respectively) were absent for the first RSV season during the pandemic, but returned for the 2021/2022 season. This resurgence of hospitalizations for RSV occurred earlier in the season than expected, was more likely among younger infants (age ≤6 months), more likely among older children (aged 6.1-24 months), and less likely to comprise of patients residing in higher areas of ethnic diversity (p<0.0001).

CONCLUSION

During the COVID-19 pandemic, there was a reduced the burden of other respiratory infections on patients and hospitals. The epidemiology of respiratory viruses in the 2022/23 season remains to be seen.

Comparison of 14 respiratory pathogens among hospitalized children during and after the COVID-19 outbreak in Chaoshan area

BACKGROUND

Since January 2020, measures has been adopted in the Chaoshan area to limit the spread of COVID-19. Restrictions were removed after August 2020. At the same time, children returned to school. We previously reported the changes of 14 main respiratory pathogens in hospitalized children before and during the COVID-19 outbreak in Chaoshan area. However, the changes of respiratory pathogen spectrum in hospitalized children after the epidemic are still unknown, which will be elucidated in this study.

METHODS

There are 6201 children hospitalized with respiratory tract infection were enrolled in the study, which were divided into two groups: 2533 from outbreak group (1 January 2020-31 December 2020), and 3668 from post-outbreak group (1 January 2021-31 December 2021). Pharyngeal swab samples were collected. 14 respiratory tract pathogens were detected by liquid chip technology.

RESULTS

The positive rate of pathogen detection is significantly lower in the outbreak group (65.42%, 1657/2533) than that in the post-outbreak group (70.39%, 2582/3668; χ² = 17.15, P < 0.05). The Influenza A virus (FluA) detection rate was 1.9% (49) in 2020, but 0% (0) in 2021. The detection rates of Bordetella pertussis (BP) decreased from 1.4% (35) in 2020 to 0.5% (17) in 2021. In contrast, the detection rates of  Influenza B virus (FluB), Cytomegalovirus (CMV), Haemophilus influenzae (HI), Streptococcus pneumoniae (SP) increased from 0.3% (8), 24.7% (626), 2.0% (50) and 19.4% (491) in 2020 to 3.3% (121), 27.9% (1025), 4.6% (169), 22.8% (836) in 2021, respectively (P < 0.01).

CONCLUSIONS

The detection rates of pathogens such as FluA, FluB, CMV, HI, SP, BP were statistically different between 2020 and 2021. From 2020 to 2021, the positive rates of Flu, CMV, HI and SP increased, while the positive rates of FluA and BP decreased. After the COVID-19 prevention and control measures are gradually relaxed, the positive rate of respiratory pathogens in children aged from 6 months to 6 years will increase.