Association of COVID-19 with respiratory syncytial virus (RSV) infections in children aged 0-5 years in the USA in 2022: a multicentre retrospective cohort study

Spatial and temporal transmission dynamics of respiratory syncytial virus in New Zealand before and after the COVID-19 pandemic

Human respiratory syncytial virus (RSV) is a major cause of acute respiratory infection. In 2020, RSV was eliminated from New Zealand due to non-pharmaceutical interventions (NPI) used to control the spread of SARS-CoV-2. However, in 2021, following a brief quarantine-free travel agreement with Australia, there was a large-scale nationwide outbreak of RSV that led to reported cases more than five-times higher than typical seasonal patterns. We generated 1470 viral genomes of both RSV-A and RSV-B sampled between 2015-2022 from across New Zealand. Using a phylodynamics approach, we used these data to better understand RSV transmission patterns in New Zealand prior to 2020, and how RSV became re-established in the community following the relaxation of COVID-19 restrictions. We found that in 2021, there was a large epidemic of RSV due to an increase in importations, leading to several large genomic clusters of both RSV-A ON1 and RSV-B BA9 genotypes. However, while a number of viral importations were detected, there was also a major reduction in RSV genetic diversity compared to pre-pandemic years. These data reveal the impact of NPI used during the COVID-19 pandemic on other respiratory infections and highlight the important insights that can be gained from viral genomes.

An Overview of Pediatric Pulmonary Complications During COVID-19 Pandemic: A Lesson for Future

BACKGROUND

The pediatric community is considered a suitable target for controlling the spread and mortality of viral diseases. In late December 2019, a respiratory disease due to the novel coronavirus, later COVID-19, hit the globe. The COVID-19 global disruption had direct and indirect impacts on different aspects of child health. Therefore, surveillance, preventive approaches, and treatment plans for children came into the spotlight.

OBJECTIVE

This study aims to discuss the clinical pictures as well as laboratory and radiological findings of the infected children during the COVID-19 pandemic. The focus of this study is to express the clinical manifestations of respiratory disease in pediatric SARS-CoV-2, available therapeutic options, vaccine recommendations, and long COVID sequelae in affected children. This review could serve as a hint for upcoming challenges in pediatric care during future pandemics.

RESULTS

The clinical presentation of COVID-19 in pediatrics can range from mild pulmonary disease to acute respiratory distress syndrome (ARDS). Supportive care is a crucial component of the management of pediatric COVID-19. However, the importance of specializing in how to treat patients with more severe conditions cannot be overstated. Additionally, clinicians must consider prevention strategies as well as potential complications.

CONCLUSION

Although the infected patients are dipping day by day, there is a lack of clinical guidelines for pediatric SARS-CoV-2-associated pulmonary diseases. Understanding of the physicians about all aspects of pediatric care during the COVID-19 pandemic could lead to enhanced quality of future patient care and safety, reduced costs of health policies, and surveil the risk that patients with respiratory viruses can expose to society.

Aberrations in medically certified sick leave and primary healthcare consultations in Norway in 2023 compared to pre-COVID-19-pandemic trends

BACKGROUND

Since 2022, Norway has employed a vaccine-only COVID-19 strategy. Primary healthcare in Norway uses International Classification of Primary Care version 2 (ICPC-2) codes. This study aims to systematically compare medically certified sick leave and primary healthcare consultations in 2023 with the pre-pandemic 2010-2019 trends, and subsequently estimate the magnitude of these changes.

METHODS

For the respective outcomes of (A) working person-years lost to medically certified sick leave (WYLSL) and (B) number of primary healthcare consultations, 556 and 85 ICPC-2 code combinations were extracted from the Norwegian Labour and Welfare Administration's sick leave registry and the Norwegian Syndromic Surveillance System. For each ICPC-2 code combination, a Bayesian linear regression was performed using data between 2010 and 2019 to estimate an expected baseline for 2023, which was then used to calculate the deviation from the pre-pandemic trend. A false discovery rate of 5% was used to account for multiple testing.

RESULTS

All years from 2020 to 2023 had excess WYLSL, corresponding to 14,491 (90% PI: 8,935 to 20,016) in 2020, 12,911 (90% PI: 5,916 to 19,996) in 2021, 21,263 (90% PI: 12,627 to 29,864) in 2022, and 24,466 (90% PI: 14,023 to 34,705) in 2023. This corresponded to an economic loss of approximately 1.5 billion USD in 2023. Excess WYLSL due to A* (General and unspecified) increased from 2020 to 2023, with an estimated excess of 4,136 WYLSL in 2023 (69% higher than expected). More than half of this increase was explained by A04 (Weakness/tiredness general), whose excess WYLSL in 2023 were estimated at 2,640 (80% higher than expected). The excess in A04 (Weakness/tiredness general) corresponded to an economic loss of 161 million USD and accounted for 11% of the total excess WYLSL in 2023. The excess WYLSL in R* (Respiratory) in 2023 was 3,408, which correspond to an economic loss of 207 million USD and accounted for 14% of the total excess in 2023.

CONCLUSIONS

Significant excesses in working person-years lost to medically certified sick leave and primary healthcare consultations in 2023. A sizable proportion of the excesses were due to diseases/symptoms associated with acute and post-acute sequelae of COVID-19.

The Impact of COVID-19 Pandemic on Respiratory Syncytial Virus Infection in Children

Background/Objective: Respiratory syncytial virus (RSV) is a major cause of bronchiolitis in infants and young children. Bronchiolitis, an acute inflammation of the lower respiratory tract, can lead to pneumonia, respiratory failure, and death. We aimed to compare the incidence and severity of RSV infection in children aged 0-60 months before and during the coronavirus disease 2019 (COVID-19) pandemic. Methods: A retrospective chart review was conducted on patients aged 0-60 months who tested positive for RSV between May 1, 2018, and May 31, 2022, in a community hospital in Queens County, New York City, United States. Comparisons were made between seasons 2018-2019 and 2019-2020 as before, and seasons 2020-2021 and 2021-2022 as during the COVID-19 pandemic. Severity of RSV infection was assessed using the Bronchiolitis Severity Score (BSS). Data were analyzed using R software, a p value of < 0.05 was considered statistically significant. Results: The incidence of RSV infection in seasons 2018-2019 and 2019-2020 peaked from mid-October to February, whereas the first season during the COVID-19 pandemic (2020-2021) was truncated with a very low incidence of RSV infection, and season 2021-2022 peaked from September to January, with the highest incidence (37%) and lower frequency of RSV infection at any given point. Patients during the season 2021-2022 were older (H [2, 196.6] = 12.5, p < 0.001, 95% CI = [5.4, 25.6]) and had milder illness (H [2, 187.5] = 7.5, p < 0.01, 95% CI = [2.1, 19.2]). Conclusions: We observed a lower incidence of RSV infection and a lower rate of hospitalization for RSV during the COVID-19 pandemic. The second RSV season during the COVID-19 pandemic began earlier, lasted longer, and had a lower frequency. Older children with milder illnesses were affected most during this season. RSV epidemiology and disease burden were impacted by the COVID-19 pandemic and could have significant ramifications for its prevention and control strategies.

Prevalence of Human Adenovirus Type 3 Associated with Pharyngoconjunctival Fever in Children in Osaka, Japan during and after the COVID-19 Pandemic

The incidence and type distribution of human adenovirus (HAdV) infections among children with pharyngoconjunctival fever (PCF) in Osaka, Japan between 2019 and 2023 were analyzed to assess the effect of the coronavirus disease 2019 (COVID-19) pandemic. The number of reported PCF cases in Osaka decreased from 2020 to 2022, followed by an unprecedented increase in 2023. HAdV-C strains, including types C1, C2, and C5, were detected in throughout the study period. Conversely, HAdV-B3 was not detected for 2 years and 9 months from March 2020 to December 2022, but the number of detections increased from July 2023. Overall, HAdV-B3 was the most frequently detected type (27 of 52 strains), and genetic analysis of its hexon hypervariable regions showed that, except for one strain, the HAdV-B3 strains identified after 2022 had different amino acid substitutions to those identified in 2019 and 2020. These results suggest that the PCF epidemic in 2023 was predominantly caused by variant strains of HAdV-B3, and that children were susceptible owing to a lack of exposure to HAdV-B3 between 2020 and 2022. Ongoing surveillance is needed to evaluate the impact of COVID-19 on the prevalence of HAdV infection.

EHR-based Case Identification of Pediatric Long COVID: A Report from the RECOVER EHR Cohort

Objective

Long COVID, marked by persistent, recurring, or new symptoms post-COVID-19 infection, impacts children's well-being yet lacks a unified clinical definition. This study evaluates the performance of an empirically derived Long COVID case identification algorithm, or computable phenotype, with manual chart review in a pediatric sample. This approach aims to facilitate large-scale research efforts to understand this condition better.

Methods

The algorithm, composed of diagnostic codes empirically associated with Long COVID, was applied to a cohort of pediatric patients with SARS-CoV-2 infection in the RECOVER PCORnet EHR database. The algorithm classified 31,781 patients with conclusive, probable, or possible Long COVID and 307,686 patients without evidence of Long COVID. A chart review was performed on a subset of patients (n=651) to determine the overlap between the two methods. Instances of discordance were reviewed to understand the reasons for differences.

Results

The sample comprised 651 pediatric patients (339 females, M age = 10.10 years) across 16 hospital systems. Results showed moderate overlap between phenotype and chart review Long COVID identification (accuracy = 0.62, PPV = 0.49, NPV = 0.75); however, there were also numerous cases of disagreement. No notable differences were found when the analyses were stratified by age at infection or era of infection. Further examination of the discordant cases revealed that the most common cause of disagreement was the clinician reviewers' tendency to attribute Long COVID-like symptoms to prior medical conditions. The performance of the phenotype improved when prior medical conditions were considered (accuracy = 0.71, PPV = 0.65, NPV = 0.74).

Conclusions

Although there was moderate overlap between the two methods, the discrepancies between the two sources are likely attributed to the lack of consensus on a Long COVID clinical definition. It is essential to consider the strengths and limitations of each method when developing Long COVID classification algorithms.

Spatial and temporal transmission dynamics of respiratory syncytial virus in New Zealand before and after the COVID-19 pandemic

Human respiratory syncytial virus (RSV) is a major cause of acute respiratory infection. In 2020, RSV was effectively eliminated from the community in New Zealand due to non-pharmaceutical interventions (NPI) used to control the spread of COVID-19. However, in April 2021, following a brief quarantine-free travel agreement with Australia, there was a large-scale nationwide outbreak of RSV that led to reported cases more than five times higher, and hospitalisations more than three times higher, than the typical seasonal pattern. In this study, we generated 1,471 viral genomes of both RSV-A and RSV-B sampled between 2015 and 2022 from across New Zealand. Using a phylodynamics approach, we used these data to better understand RSV transmission patterns in New Zealand prior to 2020, and how RSV became re-established in the community following the relaxation of COVID-19 restrictions. We found that in 2021, there was a large epidemic of RSV in New Zealand that affected a broader age group range compared to the usual pattern of RSV infections. This epidemic was due to an increase in RSV importations, leading to several large genomic clusters of both RSV-A ON1 and RSV-B BA9 genotypes in New Zealand. However, while a number of importations were detected, there was also a major reduction in RSV genetic diversity compared to pre-pandemic seasonal outbreaks. These genomic clusters were temporally associated with the increase of migration in 2021 due to quarantine-free travel from Australia at the time. The closest genetic relatives to the New Zealand RSV genomes, when sampled, were viral genomes sampled in Australia during a large, off-season summer outbreak several months prior, rather than cryptic lineages that were sustained but not detected in New Zealand. These data reveal the impact of NPI used during the COVID-19 pandemic on other respiratory infections and highlight the important insights that can be gained from viral genomes.

Modulation of innate immunity related genes resulting in prophylactic antimicrobial and antiviral properties

BACKGROUND

The innate immunity acts during the early phases of infection and its failure in response to a multilayer network of co-infections is cause of immune system dysregulation. Epidemiological SARS-CoV-2 infections data, show that Influenza Virus (FLU-A-B-C) and Respiratory Syncytial Virus (RSV) are co-habiting those respiratory traits. These viruses, especially in children (mostly affected by 'multi-system inflammatory syndrome in children' [MIS-C] and the winter pandemic FLU), in the aged population, and in 'fragile' patients are causing alteration in immune response. Then, bacterial and fungal pathogens are also co-habiting the upper respiratory traits (e.g., Staphylococcus aureus and Candida albicans), thus contributing to morbidity in those COVID-19 affected patients.

METHODS

Liquid chromatography coupled with high-resolution mass spectrometry using the quadrupole orbital ion trap analyser (i.e., UHPLC-Q-Orbitrap HRMS) was adopted to measure the polyphenols content of a new nutraceutical formula (Solution-3). Viral infections with SARS-CoV-2 (EG.5), FLU-A and RSV-A viruses (as performed in BLS3 authorised laboratory) and real time RT-PCR (qPCR) assay were used to test the antiviral action of the nutraceutical formula. Dilution susceptibility tests have been used to estimate the minimum inhibitory and bactericidal concentration (MIC and MBC, respectively) of Solution-3 on a variety of microorganisms belonging to Gram positive/ negative bacteria and fungi. Transcriptomic data analyses and functional genomics (i.e., RNAseq and data mining), coupled to qPCR and ELISA assays have been used to investigate the mechanisms of action of the nutraceutical formula on those processes involved in innate immune response.

RESULTS

Here, we have tested the combination of natural products containing higher amounts of polyphenols (i.e., propolis, Verbascum thapsus L., and Thymus vulgaris L.), together with the inorganic long chain polyphosphates 'polyPs' with antiviral, antibacterial, and antifungal behaviours, against SARS-CoV-2, FLU-A, RSV-A, Gram positive/ negative bacteria and fungi (i.e., Candida albicans). These components synergistically exert an immunomodulatory action by enhancing those processes involved in innate immune response (e.g., cytokines: IFNγ, TNFα, IL-10, IL-6/12; chemokines: CXCL1; antimicrobial peptides: HBD-2, LL-37; complement system: C3).

CONCLUSION

The prophylactic antimicrobial success of this nutraceutical formula against SARS-CoV-2, FLU-A and RSV-A viruses, together with the common bacteria and fungi co-infections as present in human oral cavity, is expected to be valuable.

Increased Pediatric Respiratory Syncytial Virus Case Counts Following the Emergence of SARS-CoV-2 Can Be Attributed to Changes in Testing

BACKGROUND

Respiratory syncytial virus (RSV) circulation dropped markedly early in the COVID-19 pandemic, followed by a resurgence with heightened case counts. The "immunity debt" hypothesis proposes that the RSV-naїve pediatric population increased during the period of low transmission. However, the evidence supporting this hypothesis is limited, and the role of changing testing practices in the perceived surge has not been comprehensively evaluated.

METHODS

We conducted a multicenter, retrospective analysis of 342 530 RSV encounters and 980 546 RSV diagnostic tests occurring at 32 US pediatric hospitals in 2013-2023. We used interrupted time series analysis to estimate pandemic-associated changes in RSV patient and test volume and to quantify changes in the proportions of patients requiring hospitalization, intensive care, or mechanical ventilation. We quantified the fraction of the shifts in case counts and in the age of diagnosed patients attributable to changes in testing.

RESULTS

RSV patient volume increased 2.4-fold (95% confidence interval [CI]: 1.7, 3.5) in 2021-2023 relative to the pre-pandemic phase and was accompanied by an 18.9-fold increase (95% CI: 15.0, 23.9) in RSV test volume. Shifts in patient volume and in patient age were largely attributable to increased testing. The proportions of patients with RSV that required hospitalization, intensive care, or mechanical ventilation declined significantly across all patient age groups.

CONCLUSIONS

A surge in RSV testing, rather than in viral circulation, likely underlies the increased case counts observed in 2021-2023. These findings warrant a critical assessment of the immunity debt hypothesis and highlight the importance of considering the testing denominator when surveillance strategies are dynamic.

Increased Hyperactivity with Decreased Parental Perceived Social Support Among Turkish Children with Autism Spectrum Disorder during Coronavirus Disease 2019 Pandemic

Objective

The aim of the present study is to investigate the change in emotional/behavioral problems of children with autism spectrum disorder (ASD) and the perceived social support of parents during the coronavirus disease 2019 (COVID-19) pandemic.

Methods

A total of 51 children with ASD aged between 6 and 18 years took part in the study. The Aberrant Behavior Checklist (ABC), the Strengths and Difficulties Questionnaire (SDQ), and the Multidimensional Scale of Perceived Social Support (MSPSS) were used to evaluate ASD symptoms, emotional/behavioral problems, and perceived social support, respectively. The cases were assessed before and 6 months after the pandemic.

Results

Our findings indicated that after the onset of the pandemic hyperactivity scores of children with ASD increased, whereas perceived social support of their parents decreased, compared to their pre-pandemic levels (P-value < .05). The increase in hyperactivity and irritability levels among children were positively associated with the presence of a chronic illness in the family and medication discontinuation (P-value < .05).

Conclusion

Quarantine in the COVID-19 pandemic may cause or worsen behavioral problems among children with ASD possibly due to problems related to poor medication adherence and lowered perceived social support among their parents. Clinicians working with children with special needs may be pro-active to assess and manage emotional/behavioral problems among this special population particularly during difficult times such as pandemic.

The Changing Landscape of Respiratory Viruses Contributing to Hospitalizations in Quebec, Canada: Results From an Active Hospital-Based Surveillance Study

BACKGROUND

A comprehensive description of the combined effect of SARS-CoV-2 and respiratory viruses other than SARS-CoV-2 (ORVs) on acute respiratory infection (ARI) hospitalizations is lacking.

OBJECTIVE

This study aimed to compare the viral etiology of ARI hospitalizations before the pandemic (8 prepandemic influenza seasons, 2012-13 to 2019-20) and during 3 pandemic years (periods of increased SARS-CoV-2 and ORV circulation in 2020-21, 2021-22, and 2022-23) from an active hospital-based surveillance network in Quebec, Canada.

METHODS

We compared the detection of ORVs and SARS-CoV-2 during 3 pandemic years to that in 8 prepandemic influenza seasons among patients hospitalized with ARI who were tested systematically by the same multiplex polymerase chain reaction (PCR) assay during periods of intense respiratory virus (RV) circulation. The proportions of infections between prepandemic and pandemic years were compared by using appropriate statistical tests.

RESULTS

During prepandemic influenza seasons, overall RV detection was 92.7% (1384/1493) (respiratory syncytial virus [RSV]: 721/1493, 48.3%; coinfections: 456/1493, 30.5%) in children (<18 years) and 62.8% (2723/4339) (influenza: 1742/4339, 40.1%; coinfections: 264/4339, 6.1%) in adults. Overall RV detection in children was lower during pandemic years but increased from 58.6% (17/29) in 2020-21 (all ORVs; coinfections: 7/29, 24.1%) to 90.3% (308/341) in 2021-22 (ORVs: 278/341, 82%; SARS-CoV-2: 30/341, 8.8%; coinfections: 110/341, 32.3%) and 88.9% (361/406) in 2022-23 (ORVs: 339/406, 84%; SARS-CoV-2: 22/406, 5.4%; coinfections: 128/406, 31.5%). In adults, overall RV detection was also lower during pandemic years but increased from 43.7% (333/762) in 2020-21 (ORVs: 26/762, 3.4%; SARS-CoV-2: 307/762, 40.3%; coinfections: 7/762, 0.9%) to 57.8% (731/1265) in 2021-22 (ORVs: 179/1265, 14.2%; SARS-CoV-2: 552/1265, 43.6%; coinfections: 42/1265, 3.3%) and 50.1% (746/1488) in 2022-23 (ORVs: 409/1488, 27.5%; SARS-CoV-2: 337/1488, 22.6%; coinfections: 36/1488, 2.4%). No influenza or RSV was detected in 2020-21; however, their detection increased in the 2 subsequent years but did not reach prepandemic levels. Compared to the prepandemic period, the peaks of RSV hospitalization shifted in 2021-22 (16 weeks earlier) and 2022-23 (15 weeks earlier). Moreover, the peaks of influenza hospitalization shifted in 2021-22 (17 weeks later) and 2022-23 (4 weeks earlier). Age distribution was different compared to the prepandemic period, especially during the first pandemic year.

CONCLUSIONS

Significant shifts in viral etiology, seasonality, and age distribution of ARI hospitalizations occurred during the 3 pandemic years. Changes in age distribution observed in our study may reflect modifications in the landscape of circulating RVs and their contribution to ARI hospitalizations. During the pandemic period, SARS-CoV-2 had a low contribution to pediatric ARI hospitalizations, while it was the main contributor to adult ARI hospitalizations during the first 2 seasons and dropped below ORVs during the third pandemic season. Evolving RVs epidemiology underscores the need for increased scrutiny of ARI hospitalization etiology to inform tailored public health recommendations.

JC Virus in Kidney Transplant Population: Are We Cautious Enough?

The John Cunningham virus (JCV) is a polyomavirus that usually infects people at a young age and does not cause any symptoms in immunocompetent individuals. However, in immunocompromised individuals, such as kidney transplant recipients, JCV can cause severe and potentially fatal disease. Unfortunately, JCV has not been researched as extensively as the BK virus and is not mentioned in relevant kidney transplant guidelines. This lack of attention to JCV can lead to less consideration in kidney transplant patients' care. Surveillance using locally available diagnostic methods is of the utmost importance. The presence of JCV can be diagnosed with urine decoy cells, viruria, or viremia verified by the PCR method. A low threshold for considering JCV as a possible cause of any neurological or renal dysfunction in kidney transplant recipients must be maintained. In such cases, kidney and brain biopsy are indicated. Maintaining the appropriate immunosuppression while avoiding over-immunosuppression to prevent JCV disease is crucial, and the approach should be individual, according to overall immunological risk. We hypothesize that the presence of the JCV can indicate overt immunosuppression and identify kidney transplant recipients more prone to opportunistic infections and diseases, including some malignancies. To explore that, future observational studies are needed.

Long COVID's Impact on Patients, Workers, & Society: A review

The incidence of long COVID in adult survivors of an acute SARS-CoV-2 infection is approximately 11%. Of those afflicted, 26% have difficulty with day-to-day activities. The majority of long COIVD cases occur after mild or asymptomatic acute infection. Children can spread SARS-CoV-2 infections and can also develop long-term neurological, endocrine (type I diabetes), and immunological sequelae. Immunological hypofunction is exemplified by the recent large outbreaks of respiratory syncytial virus and streptococcal infections. Neurological manifestations are associated with anatomical brain damage demonstrated on brain scans and autopsy studies. The prefrontal cortex is particularly susceptible. Common symptoms include brain fog, memory loss, executive dysfunction, and personality changes. The impact on society has been profound. Fewer than half of previously employed adults who develop long COVID are working full-time, and 42% of patients reported food insecurity and 20% reported difficulties paying rent. Vaccination not only helps prevent severe COVID-19, but numerous studies have found beneficial effects in preventing and mitigating long COVID. There is also evidence that vaccination after an acute infection can lessen the symptoms of long COVID. Physical and occupational therapy can also help patients regain function, but the approach must be "low and slow." Too much physical or mental activity can result in post-exertional malaise and set back the recovery process by days or weeks. The complexity of long COVID presentations coupled with rampant organized disinformation, have caused significant segments of the public to ignore sound public health advice. Further research is needed regarding treatment and effective public communication.

Increased pediatric RSV case counts following the emergence of SARS-CoV-2 are attributable to increased testing

Background

The incidence of respiratory syncytial virus (RSV) dropped markedly early in the COVID-19 pandemic, followed by a resurgence with heightened case counts. The "immunity debt" hypothesis proposes that the RSV-naive pediatric population increased during the period of low transmission, resulting in a subsequent increased risk of infection. However, the evidence supporting this hypothesis is limited, and no studies have comprehensively evaluated the role of changing respiratory viral testing practices in the perceived surge.

Methods

We conducted a multicenter, retrospective analysis of 342,530 RSV encounters and 980,546 RSV diagnostic tests occurring at 32 United States pediatric hospitals between 2013 and 2023. We used interrupted time series analysis to estimate pandemic-associated changes in RSV patient and testing volume, and to quantify changes in the proportions of patients admitted from the emergency department (ED), admitted to the intensive care unit (ICU), and receiving mechanical ventilation. We quantified the fraction of the observed shifts in case counts and in the age of diagnosed patients attributable to changes in RSV testing practices. Finally, we analyzed 524,404 influenza virus encounters and 1,768,526 influenza diagnostic tests to address the specificity of the findings to RSV.

Findings

RSV patient volume increased 2.4-fold (95% CI: 1.7, 3.5) in 2021-2023 relative to the pre-pandemic phase, and was accompanied by an 18.9-fold increase (95% CI: 15.0, 23.9) in RSV test volume. Over two-thirds of the apparent shifts in patient volume and in patient age were attributable to increased testing, which was concentrated among older pediatric patients. The proportions of patients with RSV requiring hospitalization, intensive care, or mechanical ventilation declined significantly across all patient age groups. These declines were not observed for patients with influenza virus.

Interpretation

A surge in RSV testing, rather than in viral circulation, likely underlies the increased case counts observed in 2021-2023. We identify expected consequences of increased testing, including the diagnosis of less severe cases and a shift in the patient age distribution. These findings warrant a critical assessment of the immunity debt hypothesis, while highlighting the importance of considering the testing denominator when surveillance strategies are dynamic.

Funding

National Institutes of Health & Howard Hughes Medical Institute.

Editorial: Outbreaks of Post-Pandemic Childhood Pneumonia and the Re-Emergence of Endemic Respiratory Infections

In October and November 2023, hospitals in the major cities of Beijing and Liaoning in northern China reported a surge in cases of pneumonia in children, with some hospitals being overwhelmed by pediatric emergency admissions. Similar outbreaks of childhood pneumonia had been reported in the autumn of 2022 in Europe and North America. Therefore, increased reports of childhood pneumonia could be driven by post-pandemic changes in the pathogenesis of endemic respiratory infections other than COVID-19, including Mycoplasma pneumoniae, respiratory syncytial virus (RSV), and influenza, rather than emerging novel pathogens. However, the recent reports of increased hospitalizations for children with pneumonia warrant continued infection surveillance and monitoring to exclude new respiratory pathogens or more virulent variants of known pathogens, including SARS-CoV-2. This editorial aims to present what is known about the re-emergence of endemic respiratory infections, which may be the cause of the recently reported outbreaks of childhood pneumonia.