Recent increase in the detection of human parainfluenza virus during the coronavirus disease-2019 pandemic in the Republic of Korea

Trends in human parainfluenza virus in Scotland before and after the peak of the COVID-19 pandemic, January 2017 to October 2023

BackgroundHuman parainfluenza viruses (HPIV) commonly cause upper respiratory tract infections, with potential for severe lower respiratory complications. Understanding seasonal increases informs strategies to prevent HPIV spreading.AimWe examined the impact of COVID-19 on HPIV epidemiological and clinical patterns in Scotland using non-sentinel and sentinel surveillance data.MethodsInformation on HPIV swab positivity (January 2017-October 2023) and demographic data was obtained from the Electronic Communication of Surveillance in Scotland (ECOSS) non-sentinel surveillance sources (laboratory-based data from hospital and community) and the Community Acute Respiratory Infection (CARI) sentinel surveillance programme (enhanced surveillance and symptom data).ResultsIn 2020 during early COVID-19 waves, HPIV detection decreased aligning with lockdowns and preventive measures. In summer 2021, HPIV positivity increased, with HPIV-3 possibly reverting to pre-pandemic seasonality, but HPIV-1 not yet re-establishing alternate-year peaks. Most positive results from non-sentinel sources came from hospital tests. Sentinel surveillance (CARI) complemented non-sentinel data, offering community-level insights. There was no significant difference in CARI swab positivity by sex in any age group. Consistent with historical trends, children under five years exhibited highest test positivity: 9.3% (95% CI: 7.6-11.2) in females and 8.5% (95% CI 7.0-10.2) in males.ConclusionThe COVID-19 pandemic impacted HPIV detection in Scotland. The decline during the pandemic peak and subsequent partial resurgence underscores the complex interplay between viral epidemiology and public health measures. Combining diverse surveillance systems provides a comprehensive understanding of HPIV dynamics. Insights into age-specific and symptom-associated patterns contribute to understanding HPIV epidemiology and refining public health strategies.

The structural basis of protective and nonprotective human monoclonal antibodies targeting the parainfluenza virus type 3 hemagglutinin-neuraminidase

Parainfluenza virus 3 (PIV3) infection poses a substantial risk to vulnerable groups including infants, the elderly, and immunocompromised individuals, and lacks effective treatments or vaccines. This study focuses on targeting the hemagglutinin-neuraminidase (HN) protein, a structural glycoprotein of PIV3 critical for viral infection and egress. With the objective of targeting these activities of HN, we identified eight neutralizing human monoclonal antibodies (mAbs) with potent effects on viral neutralization, cell-cell fusion inhibition, and complement deposition. Three epitopes on PIV3 HN were delineated and one epitope, Site 2, elicits a mAb with cross-neutralizing ability against PIV1 and PIV3. Cryo-EM revealed the cross-neutralizing mAb utilizes a long CDR3 loop to bind inside the pocket of the sialic acid binding site. Additionally, we resolved the structure of a non-protective mAb binding to Site 1 near the HN:F-interaction site. The potent Site 2-directed mAb demonstrated clinical efficacy in hamsters, reducing viral replication prophylactically and therapeutically. These findings advance our understanding of PIV3 immunity and underscore the significance of targeting HN for clinical therapeutic development against PIV3.

Epidemiology of respiratory pathogens in patients with acute respiratory infections during the COVID-19 pandemic and after easing of COVID-19 restrictions

We aimed to investigate the epidemiological characteristics of non-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) respiratory pathogens among patients with acute respiratory infections (ARIs) in Shijiazhuang, China, during the coronavirus disease 2019 (COVID-19) pandemic (January 2021--December 2022) and after the relaxation of COVID-19 restrictive measures (January 2022--December 2023). This retrospective study enrolled 6,633 ARIs patients who visited the Hebei General Hospital between 2021- and 2023. Nasopharyngeal swabs samples were collected for multiplex PCR detection of 13 common respiratory pathogens. Respiratory pathogens were detected in 31.58% of individuals diagnosed with ARIs, whileereas a co-infection with multiple pathogens was observed in 8.5% of the ARI patients. In the years 2021 and 2022, 326 (27.63%) and 283 (24.38%) respiratory pathogens were found to be positive, respectively, during the COVID-19 pandemic. However, in 2023, subsequent to the easing of COVID-19 restrictions, the positivity rate significantly rose to 34.62%, with 4,292 cases identified. The majority of positive cases over the last three3 years were concentrated in patients under 14 years old. The predominant pathogens identified were human rhinovirus (HRVs) (15.08%) in 2021, mycoplasma pneumonia (MP) (6.46%) in 2022, and influenza A virus (FluA) (11.35%) in 2023. Seasonal prevalence patterns of most pathogens were affected, except for parainfluenza virus (PIV). There was a simultaneous increase in the positive cases and positivity rates of FluA and adenovirus (ADV) Iin 2023, compared to 2021 and 2022. Additionally, the infection rates of respiratory syncytial virus (RSV), MP, and coronavirus (CoV) in 2023 either exceeded or were comparable to those in 2021 and 2022. Conversely, the positivity rates of PIV, RVs, metapneumovirus (MPV), and influenza B virus (FluB) were lower in 2023 compared to 2021 or 2022.

IMPORTANCE

The implementation of strict non-pharmaceutical interventions (NPIs) during the coronavirus disease 2019 (COVID-19) pandemic may lead to changes in the epidemiological features of respiratory pathogens, as well as the occurrence of immune debt, potentially causing a resurgence in respiratory pathogen activity following the easing of strict NPIs measures. There are limited reports on the epidemiological characteristics of respiratory pathogens among patients of all ages with acute respiratory infections (ARIs) during the COVID-19 pandemic and after the easing of COVID-19 restrictions. Our study investigated the epidemiology of 13 respiratory pathogens in Shijiazhuang, China, from January 2021 to December 2023. Thisese data isare crucial for the ongoing surveillance of epidemiological shifts in respiratory pathogens during and post the -COVID-19 pandemic, and serves as a scientific foundation for the prevention and management of ARIs.

Seasonality of common respiratory viruses: Analysis of nationwide time-series data

BACKGROUND AND OBJECTIVE

Understanding the seasonal behaviours of respiratory viruses is crucial for preventing infections. We evaluated the seasonality of respiratory viruses using time-series analyses.

METHODS

This study analysed prospectively collected nationwide surveillance data on eight respiratory viruses, gathered from the Korean Influenza and Respiratory Surveillance System. The data were collected on a weekly basis by 52 nationwide primary healthcare institutions between 2015 and 2019. We performed Spearman correlation analyses, similarity analyses via dynamic time warping (DTW) and seasonality analyses using seasonal autoregressive integrated moving average (SARIMA).

RESULTS

The prevalence of rhinovirus (RV, 23.6%-31.4%), adenovirus (AdV, 9.2%-16.6%), human coronavirus (HCoV, 3.0%-6.6%), respiratory syncytial virus (RSV, 11.7%-20.1%), influenza virus (IFV, 11.7%-21.5%), parainfluenza virus (PIV, 9.2%-12.6%), human metapneumovirus (HMPV, 5.6%-6.9%) and human bocavirus (HBoV, 5.0%-6.4%) were derived. Most of them exhibited a high positive correlation in Spearman analyses. In DTW analyses, all virus data from 2015 to 2019, except AdV, exhibited good alignments. In SARIMA, AdV and RV did not show seasonality. Other viruses showed 12-month seasonality. We describe the viruses as winter viruses (HCoV, RSV and IFV), spring/summer viruses (PIV, HBoV), a spring virus (HMPV) and all-year viruses with peak incidences during school periods (RV and AdV).

CONCLUSION

This is the first study to comprehensively analyse the seasonal behaviours of the eight most common respiratory viruses using nationwide, prospectively collected, sentinel surveillance data.

Effects of COVID-19 pandemic on epidemiological features of viral respiratory tract infections in children: a single-centre study

The epidemiology of respiratory infections may vary depending on factors such as climate changes, geographical features, and urbanization. Pandemics also change the epidemiological characteristics of not only the relevant infectious agent itself but also other infectious agents. This study aims to assess the impact of the COVID-19 pandemic on the epidemiology of viral respiratory infections in children. We retrospectively reviewed the medical records of children aged ≤18 years with laboratory-confirmed viral respiratory infections other than COVID-19 from January 2018 to March 2023. Data on demographic characteristics, month and year of admission, and microbiological results were collected. During the study period, 1,829 respiratory samples were sent for polymerase chain reaction testing. Rhinovirus was identified in 24% of the patients, mixed infections in 21%, influenza virus in 20%, and respiratory syncytial virus in 12.5%. A 38.6% decrease in viral respiratory infections was observed in 2020, followed by a 188% increase in 2021. The respiratory syncytial virus was significantly more common in the post-pandemic period (13.8%) compared to the pre-pandemic period (8.1%), but no seasonal shift in respiratory syncytial virus infection was observed. There was also a yearly increase in influenza infections in the post-pandemic period compared to the pre-pandemic period. After the COVID-19 pandemic, the frequency of parainfluenza virus infections increased during the summer months, and this finding provides a new contribution to the existing literature.

Epidemiology of Human Parainfluenza Virus Infections among Pediatric Patients in Hainan Island, China, 2021-2023

Human parainfluenza viruses (HPIVs) are the leading causes of acute respiratory tract infections (ARTIs), particularly in children. During the COVID-19 pandemic, non-pharmaceutical interventions (NPIs) significantly influenced the epidemiology of respiratory viruses. This study analyzed 19,339 respiratory specimens from pediatric patients with ARTIs to detect HPIVs using PCR or tNGS, focusing on the period from 2021 to 2023. HPIVs were identified in 1395 patients (7.21%, 1395/19,339), with annual detection rates of 6.86% (303/4419) in 2021, 6.38% (331/5188) in 2022, and 7.82% (761/9732) in 2023. Notably, both the total number of tests and HPIV-positive cases increased in 2023 compared to 2021 and 2022. Seasonal analysis revealed a shift in HPIV prevalence from winter and spring in 2021-2022 to spring and summer in 2023. Most HPIV-positive cases were in children aged 0-7 years, with fewer infections among those aged 7-18 years. Since June 2022, HPIV-3 has been the most prevalent serotype (59.55%, 524/880), whereas HPIV-2 had the lowest proportion (0.80%, 7/880). The proportions of HPIV-1 (24.89%, 219/880) and HPIV-4 (15.45%, 136/880) were similar. Additionally, the incidence of co-infections with other common respiratory pathogens has increased since 2021. This study highlights rising HPIV detection rates post-COVID-19 and underscores the need for continuous surveillance of HPIVs to inform public health strategies for future epidemic seasons.

Immunoinformatics-aided rational design of multiepitope-based peptide vaccine (MEBV) targeting human parainfluenza virus 3 (HPIV-3) stable proteins

BACKGROUND

Human parainfluenza viruses (HPIVs) are common RNA viruses responsible for respiratory tract infections. Human parainfluenza virus 3 (HPIV-3) is particularly pathogenic, causing severe illnesses with no effective vaccine or therapy available.

RESULTS

The current study employed a systematic immunoinformatic/reverse vaccinology approach to design a multiple epitope-based peptide vaccine against HPIV-3 by analyzing the virus proteome. On the basis of a number of therapeutic features, all three stable and antigenic proteins with greater immunological relevance, namely matrix protein, hemagglutinin neuraminidase, and RNA-directed RNA polymerase L, were chosen for predicting and screening suitable T-cell and B-cell epitopes. All of our desired epitopes exhibited no homology with human proteins, greater population coverage (99.26%), and high conservancy among reported HPIV-3 isolates worldwide. All of the T- and B-cell epitopes are then joined by putative ligands, yielding a 478-amino acid-long final construct. Upon computational refinement, validation, and thorough screening, several programs rated our peptide vaccine as biophysically stable, antigenic, allergenic, and non-toxic in humans. The vaccine protein demonstrated sufficiently stable interaction as well as binding affinity with innate immune receptors TLR3, TLR4, and TLR8. Furthermore, codon optimization and virtual cloning of the vaccine sequence in a pET32a ( +) vector showed that it can be readily expressed in the bacterial system.

CONCLUSION

The in silico designed HPIV-3 vaccine demonstrated potential in evoking an effective immune response. This study paves the way for further preclinical and clinical evaluation of the vaccine, offering hope for a future solution to combat HPIV-3 infections.