Influenza and Other Respiratory Viruses最新文献

Background

Acute otitis media (AOM) affects over 709 million individuals globally each year, more than half of whom are children < 5 years. Respiratory syncytial virus (RSV) is a leading viral cause of pediatric respiratory illness. We aimed to estimate the burden of RSV in children < 5 years with AOM

Methods

We performed a systematic review of studies reporting RSV identified through laboratory testing in children < 5 years with AOM. We searched eight databases from January 1, 1996, to May 9, 2025. We extracted data on RSV proportion in AOM and on co-detection of bacterial pathogens. We reported pooled proportions using random-effects meta-analysis.

Results

We included 27 studies encompassing 8342 children with AOM. The pooled proportion of RSV in children with AOM was 16.9% (95% CI 11.0–23.8, I² = 94.9%). RSV proportion was higher in inpatient-based studies, in studies conducted during peak RSV seasons, and in children aged < 12 months. Among RSV-positive AOM cases, an estimated 67.4% (95% CI 15.4–100) had at least one bacterial co-detection. The most frequent bacteria co-detected were Streptococcus pneumoniae, followed by Haemophilus influenzae and Moraxella catarrhalis.

Conclusion

RSV is a common contributor to AOM in children < 5 years. Our findings indicate that RSV-associated AOM often involves concurrent bacterial detection. These results highlight the potential impact of recently introduced passive RSV immunization, such as maternal immunization and long-acting monoclonal antibody, in reducing AOM incidence and its complications. Preventing RSV in early childhood could lower the overall burden of AOM and decrease the need for antibiotics.

Background

Influenza transmission is influenced by both individual characteristics and community-level drivers. Understanding how these drivers jointly influence transmission is important to predicting outbreaks and guiding influenza prevention strategies. Our study aimed to assess individual and colony-level influences, including vaccination and environmental factors, on influenza transmission in the Hutterite communities.

Methods

We analyzed data from 3271 individuals in 46 Canadian Hutterite colonies during the 2008 influenza season. Weekly PCR-confirmed Influenza A and B outcomes were examined in relation to demographic, vaccination, geographic, and weather variables using multilevel Bayesian hierarchical models in Integrated Nested Laplace Approximations (INLA), which accounted for colony clustering and temporal autocorrelation.

Results

Of the 3271 participants, 239 (7.3%) had PCR-confirmed influenza (128 Influenza A and 111 Influenza B cases). Older age was found to be protective, especially for Influenza B, while males had slightly lower odds than females. Individual vaccination showed little effect, while colony assignment to influenza vaccination was associated with a lower risk of Influenza A and overall Influenza (A/B). Higher weekly mean temperatures were associated with lower odds of Influenza A but with higher odds of Influenza B. Precipitation showed weak associations, and geographic factors such as elevation and distance to the nearest city suggested possible protective effects, but results were imprecise.

Conclusions

Our findings suggest that influenza risk in Hutterite colonies is associated with local environmental and geographic characteristics in addition to the individual drivers. Incorporating the community-level environmental setting in influenza surveillance may improve preparedness for future outbreaks.

Background

Male sex is a well-known risk factor for respiratory syncytial virus (RSV) hospitalization in children, but there are no data on potential differences in clinical features between boys and girls hospitalized with RSV infection.

Methods

We compared the average population-based rates of hospitalization and the clinical features of the illness between boys and girls hospitalized with virologically confirmed RSV infection during 2006–2020 at Turku University Hospital, Finland. During this period, testing for RSV was routine in all children admitted with respiratory infections. The comparisons were performed in different age groups of children up to 5 years of age.

Results

Among all 1204 children < 5 years of age hospitalized with RSV, the average annual RSV hospitalization rates were 4.0/1000 in boys and 3.3/1000 in girls (incidence rate ratio [IRR] 1.21; 95% CI, 1.07–1.35; p = 0.001). The difference was greatest in children aged 3–23 months, among whom the corresponding rates were 5.4/1000 in boys and 3.6/1000 in girls (IRR, 1.50; 95% CI, 1.25–1.80; p < 0.001). The occurrence of respiratory distress was consistently higher in boys than in girls among children aged 6–17 months. In this group of 233 children, 128 of 141 (90.8%) boys had documented respiratory distress, compared with 70 of 92 (76.1%) girls (p = 0.002).

Conclusions

Except for the first 3 months after birth, boys have a 50% higher risk of RSV hospitalization than girls during the first 2 years of life. In that same age group, boys hospitalized with RSV have also significantly more respiratory distress than girls.

Background

Nonpharmaceutical interventions, implemented during the COVID-19 pandemic, affected the transmission of other respiratory pathogens.

Methods

Systematically collected respiratory illness surveillance data and consistent case definitions were used to describe changes in influenza and respiratory syncytial virus (RSV)–associated outpatient visits and hospitalisations in South Africa during the first 3 years of the COVID-19 pandemic relative to a pre-COVID-19 pandemic period (2017–2019).

Results

In 2020, influenza circulation almost ceased. In 2021 an out-of-season circulation was observed with a return to prepandemic timing, albeit with a higher peak in 2022. During the pandemic period, influenza-associated influenza-like illness (ILI) was more common in those aged ≥ 5 years compared to < 6 months. Patients with influenza-associated severe respiratory illness (SRI) were less likely to be ≥ 45 years versus < 6 months and less likely to be admitted to ICU (aOR 0.2, 95% CI 0.04–0.8).

RSV circulation declined at the start of the pandemic, with an out-of-season spring resurgence in 2020 followed by a return to prepandemic timing in 2021 and a higher peak in 2022. During the pandemic, compared to the prepandemic period, patients with RSV-associated SRI were more likely to be aged 1–4 years (aOR 1.5, 95% CI 1.2–1.8) versus < 6 months and less likely to be admitted to ICU (aOR 0.5, 95% CI 0.3–0.8).

Conclusion

We report low levels of influenza circulation and out-of-season RSV circulation in 2020 with changes in the age distribution of cases and risk of ICU admission. Return to prepandemic timing was earlier for RSV, with higher seasonal peaks for influenza-associated ILI and RSV-associated SRI in 2022.

Background

Surveillance of influenza infections and virus characterisation are essential to guide prevention strategies. In the Central African Republic (CAR), data on influenza viruses are patchy and poorly documented.

Objective

To study the clinical, seasonal, genetic and phenotypic characteristics of influenza viruses circulating in the CAR population.

Materials and Methods

From January 2015 to December 2018, the presence of influenza A and B viruses in patients presenting with influenza-like illness (ILI) symptoms or severe acute respiratory infections (SARI) was investigated by RT-qPCR. Influenza genetic diversity was evaluated by phylogenetic analyses, and antigenic properties were investigated by haemagglutination inhibition assays, whereas reduced susceptibility to neuraminidase inhibitors was assessed through the presence of known genetic markers and neuraminidase assay. The relationship between patients' clinical characteristics and infection status was investigated using statistical analyses.

Results

Over the surveillance period influenza viruses were detected in 9.7% of samples (n = 6134), with the highest intensity of circulation occurring in 2016 (15.8%), attributed mainly to A(H3N2). Periods of increased influenza transmission (June to October) generally coincided with rainy seasons; however, variations in terms of monthly distribution of cases between years were evident. Hospitalisation rates (SARI) were most frequent in infants (0–11 months, 37.9%) and young children (1–4 years, 24.8%), whereas influenza prevalences were highest in the 15–49 (12.0%) and ≥ 50 (15.2%) years old categories. A new A(H1N1)pdm09 6B.1 hemagglutinin subgroup characterised by amino acid substitutions S84N, S162N and I216T was detected in 2015, with associated antigenic drift, and subsequently, two of these viruses showed highly reduced inhibition by oseltamivir.

Conclusion

This study showcases the value of local influenza sentinel networks to specifically inform vaccination strategies and highlights the need for improved strain characterisation in tropical regions.

Background and Objectives

Different COVID-19 vaccine platforms elicit variable immune responses, influenced by prior infection and booster vaccination. We aimed to compare the humoral immune responses elicited by mRNA and adenoviral vector (Ad-vector) COVID-19 vaccines in hospital employees and to assess the possible impact of prior SARS-CoV-2 infection on these responses.

Methods

We performed a prospective observational cohort study by recruiting employees of the Universitair Ziekenhuis Brussel who were vaccinated with an mRNA or Ad-vector vaccine. We assessed anti-spike (S) IgG and neutralising capacity at 1, 6 and 12 months (post-mRNA booster). Anti-S and anti-NCP IgG were measured by chemiluminescent microparticle immunoassay, and neutralising capacity was assessed using Genscript's cPASS. Non-parametric group comparisons used the Mann–Whitney U test, complemented by multiple linear regression.

Results

Following RVR, mRNA-vaccinated individuals (n = 380) exhibited higher anti-S IgG titres and neutralising capacity compared to those who received Ad-vector vaccines (n = 200). After the booster, anti-spike IgG remained higher in mRNA-vaccinated individuals than in Ad-vector recipients (q < 0.001); Ad-vector vaccinated individuals showed superior neutralising capacity. Natural SARS-CoV-2 infection prior to vaccination had varying impact on anti-S IgG and neutralising capacity, depending on vaccination type and time points.

Conclusion

Our findings underscore that both vaccine platforms and prior infections shape the magnitude and quality of the humoral immune response, highlighting the importance of considering priming strategy, booster design and hybrid immunity when optimising COVID-19 vaccination schedules for durable protection.