A delayed resurgence of respiratory syncytial virus (RSV) during the COVID-19 pandemic: An unpredictable outbreak in a small proportion of children in the Southwest of Iran, April 2022

Verapamil inhibits respiratory syncytial virus infection by regulating Ca2+ influx

AIMS

The study evaluated the antiviral effect of Verapamil against respiratory syncytial virus (RSV) and investigated its underlying mechanism.

MATERIALS AND METHODS

RSV-infected BALB/c mice were treated with Verapamil. Body weight, survival rates, viral load, lung damage, inflammatory factors, and the expression of RSV fusion (F) protein were analyzed. In cellular studies, intracellular Ca2+ and viral titers were measured in the presence of Verapamil, Calcium Chloride, and EGTA. A time-of-addition assay assessed the antiviral effect of Verapamil.

KEY FINDINGS

Mice infected with RSV and treated with Verapamil exhibited a significant decrease in weight loss, an increase in survival rates, and reductions in viral titers, RSV F protein expression, inflammatory responses, and lung tissue injury. Verapamil reduced intracellular calcium levels, which correlated with reduced viral titers. The addition of calcium chloride reversed the anti-viral effects mediated by Verapamil, while EGTA potentiated them. The antiviral activity of Verapamil was observed during the early phase of RSV infection, likely by blocking Ca2+ channels and inhibiting virus replication.

SIGNIFICANCE

Verapamil effectively inhibits RSV infection by blocking calcium channels and reducing intracellular calcium levels, thereby impeding viral replication. Thus, Verapamil shows promise as a treatment for RSV.

Inhalation of 2, 4-di-tert-butylphenol-Loaded micelles suppresses respiratory syncytial virus infection in mice

Human respiratory syncytial virus (RSV) is a common cause of respiratory infections in infants, young children, and elderly people. However, there are no effective treatments or vaccines available in most countries. In this study, we explored the anti-RSV potential of 2, 4-Di-tert-butylphenol (2, 4-DTBP), a compound derived from Houttuynia cordata Thunb. To overcome the poor solubility of 2, 4-DTBP, we encapsulated it in polymeric micelles and delivered it by inhalation. We found that 2, 4-DTBP-loaded micelles inhibited RSV infection in vitro and improved survival, lung pathology, and viral clearance in RSV-infected mice. Our results suggested that 2, 4-DTBP-loaded micelle is a promising novel therapeutic agent for RSV infection.

Epidemiological and phylogenetic assessment of human respiratory syncytial virus among pediatric patients presenting acute respiratory infections in Shiraz, Iran during 2015-2016

Background and Objectives

The pediatric population worldwide bears a significant morbidity and death burden due to acute respiratory infections (ARIs). Human Orthopneumovirus, sometimes referred to as the Human Respiratory Syncytial Virus (HRSV), is one of the main causes of ARIs in infants. The main goal of this study was to identify the genetic diversity of HRSV strains that were circulating in the Iranian population at a certain time of year.

Materials and Methods

Two hundred youngsters less than 12 years old with acute respiratory infections had samples taken from their throat and pharynx secretions. Then, external and hemi-nested PCR were employed, using specific primers targeting the G gene region to detect HRSV. Subsequently, nine randomly selected positive samples were subjected to sequencing. The results were then compared with reference strains cataloged in GeneBank, and phylogenetic tree was constructed using Chromes and MEGA7.

Results

Out of 200 samples, 34 were identified as containing HRSV. Subgroup A was predominant, accounting for 61.76% of cases, followed by subgroup BA (35.29%) and subgroup B (2.94%). Phylogenetic analysis revealed five samples associated with subtype B and four with genotype A. Genomic analysis showed three samples under the GA2 subgroup and one under GA1 for subtype A, and four samples in subgroup BA and one in GB2 for subtype B.

Conclusion

In this study, subgroup A strains, particularly genotype GA2, exhibited a higher prevalence compared to subgroup B strains during the specific period under investigation, shedding light on the genetic landscape of HRSV in this region.

Diagnostic value of routine blood tests in differentiating between SARS-CoV-2, influenza A, and RSV infections in hospitalized children: a retrospective study

BACKGROUND

The Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), influenza A, and respiratory syncytial virus (RSV) infections have similar modes of transmission and clinical symptoms. There is a need to identify simple diagnostic indicators to distinguish these three infections, particularly for community hospitals and low- and middle-income countries that lack nucleic acid detection kits. This study used clinical data to assess the diagnostic value of routine blood tests in differentiating between SARS-CoV-2, influenza A, and RSV infections in children.

METHODS

A total of 1420 children treated at the Hangzhou Children's Hospital between December 2022 and June 2023 were enrolled in this study, of whom 351 had SARS-CoV-2, 671 had influenza, and 398 had RSV. In addition, 243 healthy children were also collected. The blood test results of SARS-CoV-2 patients were compared to those of patients with influenza A and RSV and the healthy controls. The area under the receiver operating characteristic curve (AUC-ROC) was employed to evaluate each blood parameter's diagnostic value.

RESULTS

Children with SARS-CoV-2 exhibited notably elevated levels of white blood cell (WBC) count, platelet (PLT) count, neutrophil count, and neutrophil-to-lymphocyte ratio (NLR) compared to influenza A patients (P < 0.05). In contrast, SARS-CoV-2 patients exhibited a decrease in the mean platelet volume to platelet count ratio (MPV/PLT) and the lymphocyte-to-monocyte ratio (LMR) when compared to other individuals (P < 0.05). These parameters had an AUC between 0.5 and 0.7. Compared to patients with RSV, SARS-CoV-2 patients had significantly higher MPV/PLT and significantly lower WBC, lymphocyte, PLT, LMR, and lymphocyte multiplied by platelet (LYM*PLT) values (P < 0.05). However, only LYM*PLT had an acceptable diagnostic value above 0.7 for all age groups. Compared to healthy children, children with COVID-19 exhibited elevated NLR and MPV/PLT levels, alongside decreased lymphocyte, PLT, LMR, and LYM*PLT values. (P < 0.05). The AUC of the LMR, LYM*PLT, and PLT were above 0.7 in all age groups, indicating promising diagnostic values.

CONCLUSIONS

The routine blood parameters among patients with COVID-19, influenza A, and RSV differ significantly early in the disease and could be used by clinicians to discriminate between the 3 types of infection.

Epidemiological characteristics of respiratory viruses in children during the COVID-19 epidemic in Chengdu, China

IMPORTANCE

During the coronavirus disease 2019 epidemic, the Chinese government launched and used a series of nonpharmaceutical interventions (NPIs), including banning social gatherings, wearing face masks, home isolation, and maintaining hand hygiene, to control the disease spread. Whether and how NPIs influence other respiratory viruses in children remain unclear. In this article, we analyzed relative data and found that the number of samples and positive proportion of respiratory viruses decreased significantly compared with that before the epidemic. Clinicians and public health policymakers should pay attention to changes in the epidemic trends and types of respiratory viruses and maintain monitoring of respiratory-related viruses to avoid possible abnormal rebounds and epidemic outbreaks of these viruses.

Epidemiology and clinical features of respiratory syncytial virus (RSV) infection in hospitalized children during the COVID-19 pandemic in Gorgan, Iran

Background and Aims

Respiratory syncytial virus (RSV) is a leading cause of acute respiratory infection in infants and young children. Given the altered circulation patterns of respiratory viruses during the coronavirus disease pandemic-2019 (COVID-19), the study aimed to evaluate epidemiology and clinical features of RSV infections in hospitalized children during the COVID-19 pandemic in Gorgan, northeastern Iran. Molecular epidemiology studies on respiratory viral infections are necessary to monitor circulating viruses, disease severity, and clinical symptoms, in addition to early warning of new outbreaks.

Methods

Overall, 411 respiratory swab samples from hospitalized children from October 2021 to March 2022 were collected at Taleghani Children's Hospital, Gorgan, Iran. The incidence of RSV, as well as the circulating subgroups and genotypes, were investigated and confirmed using PCR methods. Additionally, all samples tested for severe acute respiratory syndrome-associated coronavirus 2 (SARS-CoV-2) and influenza, and demographic and clinical data were analyzed using SPSS software.

Results

The share of RSV, SARS-CoV-2, and influenza among hospitalized children with acute lower respiratory infections (ALRI) were 27%, 16.5%, and 4.1%, respectively. The RSV subgroup A (genotype ON1) was dominant over subgroup B (genotype BA9), with more severe clinical symptoms. Compared with the prepandemic era there were high numbers of hospitalized SARS-CoV-2 positive children and low numbers of other respiratory viruses. Despite this, the prevalence of ALRI-related RSV-disease among hospitalized children in our specialized pediatric center was higher than COVID-19 disease in the same cohort.

Conclusions

Studying the epidemiology of respiratory viruses and determining the circulating strains can contribute to effective infection control and treatment strategies.

Multicenter study to describe viral etiologies, clinical profiles, and outcomes of hospitalized children with severe acute respiratory infections, Egypt 2022

In late 2022, severe acute respiratory infections (SARI) surveillance reported an abrupt increase in non-COVID-19 infections among children after three years of drastic reductions. Signals of increased absenteeism due to respiratory symptoms among primary and preparatory school children were detected by Event-Based Surveillance. We conducted a hospital-based survey of children who were admitted with SARI to identify the causative pathogen(s) and estimate the burden of infection. A survey was conducted among children < 16 years in 21 referral hospitals in the three governorates with the highest SARI rates. Patients' demographics, clinical symptoms, and severity were collected from medical records using a line list. Patients were swabbed and tested for a panel of 33 respiratory pathogens by RT-PCR at the Central Laboratory in Cairo. Descriptive data analysis was performed for demographic data. Patients' characteristics were compared by causative agents' clinical picture and severity using Chi2 with a p < 0.05 significance. Overall, 317 patients were enrolled, 58.3% were ≤ 1 year of age, 61.5% were males. Of 229 (72.7%) of positively tested patients, viruses caused 92.1% including RSV 63.8%, Rhinovirus 10.0%, Influenza 9.2%, Adenovirus 5.2%, and 1.3% co-infected with two viruses. Bacteria caused 3.5% of cases and 4.4% had mixed viral-bacterial infections. Rhinovirus was the most common cause of death among children with SARI, followed by RSV (8.7% and 1.4%), whereas influenza and Adenovirus did not result in any deaths. Patients with viral-bacterial infections are more likely to be admitted to ICU and die at the hospital than bacterial or viral infections (60% and 20% vs. 31.8% and 1.9% vs. 12.5% and 12.5%, p < 0.001). Viruses particularly RSV are the leading cause of SARI causing significant health problem among children < 16 years in Egypt. Bacterial on top of viral infection can worsen disease courses and outcomes. Studies are required to estimate the SARI burden accurately among Egyptian children and a comprehensive approach tailored to Egypt is necessary to reduce its burden.

Impact of COVID-19 on the changing pattern of human orthopneumovirus (respiratory syncytial virus) infection in Iran

BACKGROUND

Human orthopneumovirus (HOPV) or respiratory syncytial virus (RSV) is one of the important causes of acute respiratory infections (ARIs) during the cold months of the year worldwide. Many countries have reported an absence of ARIs due to HOPV during the winter of 2020-2021 associated with preventive measures to reduce the spread of SARS-CoV2. However, with the reduction of COVID-19 public health restrictions and the absence of immunity in the community due to the lack of exposure in the previous season, many countries had a delayed HOPV outbreak. Here we reported the impact of COVID-19 on the changing pattern of HOPV infection in Iran.

METHODS

Throat and nasopharyngeal swab samples were collected from patients (children and adults) with ARIs and sent to the Iran National Influenza Center. After RNA extraction, Real time RT-PCR was performed for HOPV detection.

RESULTS

In 260 samples collected from patients with ARIs in three different groups, which included children in March 2021, pilgrims in July 2022, and outpatients during November and December 2022, no HOPV was detected in any group.

CONCLUSIONS

The lack of HOPV activity in Iran during the winter of 2020-2021 and then the resurgence in spring 2022 and again the absence of activity in summer and autumn 2022 was extraordinary in the HOPV epidemiology, and probably due to the implementation of public health non-pharmaceutical interventions to reduce the spread of SARS-CoV2. Although it is not possible to keep such restrictions, similar methods can be taken to control outbreaks caused by respiratory viruses.

The long-term boomerang effect of COVID-19 on admissions for non-COVID diseases: the ECIEN-2022 study

Since COVID-19 pandemic started, many changes have been seen in the cycling patterns of pediatric pathologies. On year 2020, we described the initial effects of COVID-19, with a significant decrease in emergency visits and admissions, but 2 years later the situation seems to be reversed. Our study bridges a literature gap by exploring the lasting effects of COVID-19 on pediatric non-COVID admissions, particularly the resurgence of respiratory illnesses. ECIEN-2022 is a single-center, retrospective, observational-study conducted 3 years after the pandemic onset, to describe the long-term effects of COVID-19 in pediatric admissions for non-COVID diseases. Admissions during year 2022 were compared with the Pre-Pandemic Period (PPP: 2015-2019). Pediatric Emergency Department (P-ED) visits, hospital, and Intensive Care Unit (P-ICU) admissions were compared across pre- and post-pandemic periods. Monthly distribution and year-waves are presented. P-ED monthly visits (mean and Standard deviation (SD) raised from 3521 (533) in the PPP to 3775 (996) in 2022 (p < 0.001). Monthly hospital admissions in the 3rd quarter of the Pre-Pandemic Period were 111.7/month (SD:29), dropped to 88.5(SD:6.5) in 2020 and raised to 149(SD:38.8) in 2022 (p = 0.036). An increase in respiratory illnesses was observed in 2022 compared to PPP; Bronchiolitis increased 38%, bronchitis 56%, and admissions for Respiratory Syncytial Virus 67%.  Conclusion: COVID-19 pandemic has had a significant impact on the use and nature of pediatric health services. The initial decrease has been followed by a boomerang effect with an increase of cases, mainly due to an increase in respiratory infections when pandemic control measures and social restrictions have been lifted. It is essential to maintain an active surveillance and monitorization of these patterns to ensure appropriate healthcare access and utilization. What is Known: • COVID-19 pandemic initially led to a significant decrease in emergency visits and admissions for non-COVID diseases. What is New: • ECIEN-2022 study investigated the long-term effects of COVID-19 on pediatric admissions for non-COVID diseases, detecting a "boomerang effect" with an increase in pediatric admissions for non-COVID diseases in year 2022. • Pediatric Emergency Department visits and hospital admissions for non-COVID diseases, especially those due to respiratory infections, increased significantly in 2022 when compared to the Pre-Pandemic Period.

The age profile of respiratory syncytial virus burden in preschool children of low- and middle-income countries: A semi-parametric, meta-regression approach

BACKGROUND

Respiratory syncytial virus (RSV) infections are among the primary causes of death for children under 5 years of age worldwide. A notable challenge with many of the upcoming prophylactic interventions against RSV is their short duration of protection, making the age profile of key interest to the design of prevention strategies.

METHODS AND FINDINGS

We leverage the RSV data collected on cases, hospitalizations, and deaths in a systematic review in combination with flexible generalized additive mixed models (GAMMs) to characterize the age burden of RSV incidence, hospitalization, and hospital-based case fatality rate (hCFR). Due to the flexible nature of GAMMs, we estimate the peak, median, and mean incidence of infection to inform discussions on the ideal "window of protection" of prophylactic interventions. In a secondary analysis, we reestimate the burden of RSV in all low- and middle-income countries. The peak age of community-based incidence is 4.8 months, and the mean and median age of infection is 18.9 and 14.7 months, respectively. Estimating the age profile using the incidence coming from hospital-based studies yields a slightly younger age profile, in which the peak age of infection is 2.6 months and the mean and median age of infection are 15.8 and 11.6 months, respectively. More severe outcomes, such as hospitalization and in-hospital death have a younger age profile. Children under 6 months of age constitute 10% of the population under 5 years of age but bear 20% to 29% of cases, 28% to 39% of hospitalizations, and 38% to 50% of deaths. On an average year, we estimate 28.23 to 31.34 million cases of RSV, between 2.95 to 3.35 million hospitalizations, and 16,835 to 19,909 in-hospital deaths in low, lower- and upper middle-income countries. In addition, we estimate 17,254 to 23,875 deaths in the community, for a total of 34,114 to 46,485 deaths. Globally, evidence shows that community-based incidence may differ by World Bank Income Group, but not hospital-based incidence, probability of hospitalization, or the probability of in-hospital death (p ≤ 0.01, p = 1, p = 0.86, 0.63, respectively). Our study is limited mainly due to the sparsity of the data, especially for low-income countries (LICs). The lack of information for some populations makes detecting heterogeneity between income groups difficult, and differences in access to care may impact the reported burden.

CONCLUSIONS

We have demonstrated an approach to synthesize information on RSV outcomes in a statistically principled manner, and we estimate that the age profile of RSV burden depends on whether information on incidence is collected in hospitals or in the community. Our results suggest that the ideal prophylactic strategy may require multiple products to avert the risk among preschool children.

Parental Attitude, Knowledge, and Practices Regarding the Usage of Antibiotics for Upper Respiratory Tract Infections in Children During the COVID-19 Pandemic

BACKGROUND

The COVID-19 pandemic has raised knowledge of the proper antibiotic dosage for treating childhood upper respiratory tract infections (URTIs). In order to ensure proper antibiotic usage and prevent the establishment of illnesses that is antibiotic-resistant during the COVID-19 pandemic, parental attitudes, knowledge, and behaviour surrounding antibiotic use for URTIs in children are essential. The goal of this study was to find out the parental attitude, knowledge, and practices regarding the usage of antibiotics for URTIs in children during the COVID-19 epidemic.

METHODOLOGY

This cross-sectional was conducted in the Department of Paediatric Medicine, Central Hospital, Ganesh Nagar, New Delhi, India from September 2022 to February 2023. The study analysed a total of 500. All the children had URTIs. A structured questionnaire was randomly distributed among parents. Socio-demographic information like gender, age, occupation, monthly family income, and age of the children were noted at the time of enrollment. Outcomes were recorded in terms of responses to questions regarding attitude, knowledge, and practices regarding the use of antibiotics for URTIs in children during the COVID-19 epidemic.  Results: Of a total of 500 parents, 380 (76.0%) were male. The mean age was 39.9±8.3 years while 280 (56.0%) participants were aged between 31 to 45 years. Relatively older age (p<0.0001) and occupational status as unemployed (p<0.0001) were found to have a significant association with response to "virus being the cause of COVID-19". Females (p=0.0004) and increasing age (p<0.0001) were found to have significant associations with incorrect responses to "antibiotics are essential for managing the symptoms in children with COVID-19". Incorrect responses to "without the use of antibiotics, children usually suffer from greater periods of sickness" were associated with females and increasing age (p<0.0001). Incorrect responses to "not using antibiotics will prove beneficial for the children suffering from COVID-19" were significantly associated with female gender (p=0.0016) and increasing age (p<0.0001). The incorrect responses to "how often are antibiotics being prescribed to the COVID-19 children" was significantly linked with females and relatively older age (p<0.0001).

CONCLUSIONS

Parental attitude, knowledge, and practices regarding the usage of antibiotics for URTIs in children during the COVID-19 epidemic showed variations. Parental attitude, knowledge, and practices were associated with gender, age, and socio-economic status.

Molecular characterization of human respiratory syncytial virus in Seoul, South Korea, during 10 consecutive years, 2010-2019

Respiratory syncytial virus (RSV) is the leading cause of lower respiratory tract infections and hospitalization in infants and young children. Here, we analyzed the genetic diversity of RSV using partial G gene sequences in 84 RSV-A and 78 RSV- B positive samples collected in Seoul, South Korea, for 10 consecutive years, from 2010 to 2019. Our phylogenetic analysis revealed that RSV-A strains were classified into either the ON1 (80.9%) or NA1 (19.0%) genotypes. On the other hand, RSV-B strains demonstrated diversified clusters within the BA genotype. Notably, some sequences designated as BA-SE, BA-SE1, and BA-DIS did not cluster with previously identified BA genotypes in the phylogenetic trees. Despite this, they did not meet the criteria for the assignment of a new genotype based on recent classification methods. Selection pressure analysis identified three positive selection sites (amino acid positions 273, 274, and 298) in RSV-A, and one possible positive selection site (amino acid position 296) in RSV-B, respectively. The mean evolutionary rates of Korean RSV-A from 1999 to 2019 and RSV-B strains from 1991 and 2019 were estimated at 3.51 × 10-3 nucleotides (nt) substitutions/site/year and 3.32 × 10-3 nt substitutions/site/year, respectively. The population dynamics in the Bayesian skyline plot revealed fluctuations corresponding to the emergence of dominant strains, including a switch of the dominant genotype from NA1 to ON1. Our study on time-scaled cumulative evolutionary analysis contributes to a better understanding of RSV epidemiology at the local level in South Korea.

Surveillance of endemic coronaviruses during the COVID‐19 pandemic in Iran, 2021–2022

Background

Human coronaviruses (HCoVs) 229E, OC43, HKU1, and NL63 are common viruses that continuously circulate in the human population. Previous studies showed the circulation of HCoVs during the cold months in Iran. We studied the circulation of HCoVs during coronavirus disease 2019 (COVID‐19) pandemic to find the impact of pandemic on the circulation of these viruses.

Methods

As a cross‐sectional survey conducted during 2021 to 2022, of all throat swabs sent to Iran National Influenza Center from patients with severe acute respiratory infection, 590 samples were selected to test for HCoVs using one‐step real‐time RT‐PCR.

Results

Overall, 28 out of 590 (4.7%) tested samples were found to be positive for at least one HCoVs. HCoV‐OC43 was the most common (14/590 or 2.4%), followed by HCoV‐HKU1 (12/590 or 2%) and HCoV‐229E (4/590 or 0.6%), while HCoV‐NL63 was not detected. HCoVs were detected in patients of all ages and throughout the study period with peaks in the cold months of the year.

Conclusions

Our multicenter survey provides insight into the low circulation of HCoVs during the COVID‐19 pandemic in Iran in 2021/2022. Hygiene habits and social distancing measures might have important role in decreasing of HCoVs transmission. We believe that surveillance studies are needed to track the pattern of HCoVs distributions and detect changes in the epidemiology of such viruses to set out strategies in order to timely control the future outbreaks of HCoVs throughout the nation.

The Impact of the COVID-19 Pandemic on Respiratory Syncytial Virus Infection: A Narrative Review

Respiratory syncytial virus (RSV) is one of the most common respiratory viruses. It not only affects young children but also the elderly and immunocompromised patients. After the emergence of SARS-CoV-2 and the corona virus disease 2019 (COVID-19) era, a dramatic reduction in RSV activity was found, which coincided with the implementation of public health and social measures (PHSMs). However, the correlation is more complicated than we initially thought. After PHSMs were gradually lifted, a seasonality shift and a delayed RSV outbreak with greater number of infected patients were found in numerous countries, such as Israel, Australia, South Africa, New Zealand, France, United States, and Japan. Several hypotheses and possible reasons explaining the interaction between SARS-CoV-2 and RSV were mentioned. Since RSV vaccinations are still under investigation, administration of palivizumab should be considered in high-risk patients. In the post-COVID-19 era, greater attention should be paid to a further resurgence of RSV. In this narrative review, we conducted a thorough review of the current knowledge on the epidemiology of RSV during the COVID-19 era, the out-of-season outbreak of RSV, and the data on co-infection with RSV and SARS-CoV-2.

Changes in endemic patterns of respiratory syncytial virus infection in pediatric patients under the pressure of nonpharmaceutical interventions for COVID-19 in Beijing, China

A series of nonpharmaceutical interventions (NPIs) was launched in Beijing, China, on January 24, 2020, to control coronavirus disease 2019. To reveal the roles of NPIs on the respiratory syncytial virus (RSV), respiratory specimens collected from children with acute respiratory tract infection between July 2017 and Dec 2021 in Beijing were screened by capillary electrophoresis-based multiplex PCR (CEMP) assay. Specimens positive for RSV were subjected to a polymerase chain reaction (PCR) and genotyped by G gene sequencing and phylogenetic analysis using iqtree v1.6.12. The parallel and fixed (paraFix) mutations were analyzed with the R package sitePath. Clinical data were compared using SPSS 22.0 software. Before NPIs launched, each RSV endemic season started from October/November to February/March of the next year in Beijing. After that, the RSV positive rate abruptly dropped from 31.93% in January to 4.39% in February 2020; then, a dormant state with RSV positive rates ≤1% from March to September, a nearly dormant state in October (2.85%) and November (2.98%) and a delayed endemic season in 2020, and abnormal RSV positive rates remaining at approximately 10% in summer until September 2021 were detected. Finally, an endemic RSV season returned in October 2021. There was a game between Subtypes A and B, and RSV-A replaced RSV-B in July 2021 to become the dominant subtype. Six RSV-A and eight RSV-B paraFix mutations were identified on G. The percentage of severe pneumonia patients decreased to 40.51% after NPIs launched. NPIs launched in Beijing seriously interfered with the endemic season of RSV.

Epidemiological characteristics of respiratory viruses in hospitalized children during the COVID-19 pandemic in southwestern China

Background

Multinational studies have reported that the implementation of nonpharmaceutical interventions (NPIs) to control severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transmission coincided with the decline of other respiratory viruses, such as influenza viruses and respiratory syncytial virus.

Objective

To investigate the prevalence of common respiratory viruses during the coronavirus disease 2019 (COVID-19) pandemic.

Methods

Respiratory specimens of children with lower respiratory tract infections (LRTIs) hospitalized at the Children's Hospital of Chongqing Medical University from January 1, 2018 to December 31, 2021 were collected. Seven common pathogens, including respiratory syncytial virus (RSV), adenovirus (ADV), influenza virus A and B (Flu A, Flu B), and parainfluenza virus types 1-3 (PIV1-3), were detected by a multiplex direct immunofluorescence assay (DFA). Demographic data and laboratory test results were analyzed.

Results

1) A total of 31,113 children with LRTIs were enrolled, including 8141 in 2018, 8681 in 2019, 6252 in 2020, and 8059 in 2021.The overall detection rates decreased in 2020 and 2021 (P < 0.001). The detection rates of RSV, ADV, Flu A, PIV-1, and PIV-3 decreased when NPIs were active from February to August 2020, with Flu A decreasing most predominantly, from 2.7% to 0.3% (P < 0.05). The detection rates of RSV and PIV-1 resurged and even surpassed the historical level of 2018-2019, while Flu A continued decreasing when NPIs were lifted (P < 0.05). 2) Seasonal patterns of Flu A completely disappeared in 2020 and 2021. The Flu B epidemic was observed until October 2021 after a long period of low detection in 2020. RSV decreased sharply after January 2020 and stayed in a nearly dormant state during the next seven months. Nevertheless, the detection rates of RSV were abnormally higher than 10% in the summer of 2021. PIV-3 decreased significantly after the COVID-19 pandemic; however, it atypically surged from August to November 2020.

Conclusion

The NPIs implemented during the COVID-19 pandemic affected the prevalence and seasonal patterns of certain viruses such as RSV, PIV-3, and influenza viruses. We recommend continuous surveillance of the epidemiological and evolutionary dynamics of multiple respiratory pathogens, especially when NPIs are no longer necessary.