Clinical and molecular epidemiology of influenza viruses from Romanian patients hospitalized during the 2019/20 season

The Global Influenza Hospital Surveillance Network: A Multicountry Public Health Collaboration

Respiratory viruses represent a significant public health threat. There is the need for robust and coordinated surveillance to guide global health responses. Established in 2012, the Global Influenza Hospital Surveillance Network (GIHSN) addresses this need by collecting clinical and virological data on persons with acute respiratory illnesses across a network of hospitals worldwide. GIHSN utilizes a standardized patient enrolment and data collection protocol across its study sites. It leverages pre-existing national infrastructures and expert collaborations to facilitate comprehensive data collection. This includes demographic, clinical, epidemiological, and virologic data, and whole genome sequencing (WGS) for a subset of viruses. Sequencing data are shared in the Global Initiative on Sharing All Influenza Data (GISAID). GIHSN uses financing and governance approaches centered around public-private partnerships. Over time, GIHSN has included more than 100 hospitals across 27 countries and enrolled more than 168,000 hospitalized patients, identifying 27,562 cases of influenza and 44,629 of other respiratory viruses. GIHSN has expanded beyond influenza to include other respiratory viruses, particularly since the COVID-19 pandemic. In November 2023, GIHSN strengthened its global impact through a memorandum of understanding with the World Health Organization, aimed at enhancing collaborative efforts and data sharing for improved health responses. GIHSN exemplifies the value of integrating scientific research with public health initiatives through global collaboration and public-private partnerships governance. Future efforts should enhance the scalability of such models and ensure their sustainability through continued public and private support.

Diagnostic Significance of Influenza Symptoms and Signs, and Their Variation by Type/Subtype, in Outpatients Aged ≥ 15 Years: Novi Sad, Serbia

This study assessed the diagnostic performance of influenza-related symptoms and signs and their combinations, as well as differences in patient characteristics based on the type/subtype of influenza, in outpatients at a primary healthcare surveillance system. Our prospective analysis included cases aged ≥ 15 years from two influenza seasons (2022/23 and 2023/24) in Novi Sad, Serbia. Influenza cases were confirmed using polymerase chain reaction (PCR) testing. The mean age of participants with laboratory-confirmed influenza was significantly lower than that of those without influenza (p < 0.0001): 37.90 vs. 54.92 years in 2022/23, and 40.21 vs. 54.17 years in 2023/24. Among the examined symptoms and signs, the highest sensitivity in the 2022/23 season was demonstrated for fever (87.95%, CI: 78.96-94.07), while in the 2023/24 season it was cough (100.00%, CI: 88.06-100.00). In the 2022/23 season, the positive predictive values (PPVs) were highest for fever (34.93%), chills (31.95%), myalgia (30.30%), and malaise (28.57%), but they dropped significantly in 2023/24 for all observed symptoms and signs (ranging from 1.91% to 9.17%). Compared to the World Health Organization's case definition for influenza-like illness (ILI), the case definition provided by the European Centre for Disease Prevention and Control demonstrated higher sensitivity but lower specificity across both seasons. Participants who tested positive between December and February were more likely to have influenza A(H1N1)pdm09 or A(H3N2), whereas those who tested positive between February and April were more likely to have influenza B. This study underscores the importance of seasonal timing, symptom evaluation, and case definitions in improving influenza diagnosis in primary care.

Genomic surveillance and evolutionary dynamics of influenza a virus in Sri Lanka

BACKGROUND

Influenza A has been named as a priority pathogen by the WHO due to the potential to cause pandemics. Genomic sequencing of influenza strains is important to understand the evolution of the influenza strains and also to select the appropriate influenza vaccines to be used in the different influenza seasons in Sri Lanka. Therefore, we sought to understand the molecular epidemiology of the influenza viruses in the Western Province of Sri Lanka, including mutational analysis to investigate the evolutionary dynamics.

METHODOLOGY

A total of 349 individuals presenting with fever and respiratory symptoms were enrolled in this study from November 2022 to May 2024. Nasopharyngeal and oropharyngeal specimens were collected and screened using quantitative PCR to detect Influenza A, Influenza B, and SARS-CoV-2. Subtyping and genomic sequencing was carried out on influenza A strains using Oxford Nanopore Technology.

RESULTS

Influenza A was detected in 49 (14%) patients, influenza B in 20 (5.7%) and SARS-CoV-2 in 41 (11.7%). Co-infections were observed in five participants. The phylogenetic analysis assigned the H1N1 HA gene sequences within the 6B.1 A.5a.2a clade. The HA gene of the H1N1 sequences in 2023 were assigned as belonging to the subclades C.1, C.1.2, and C.1.8, while the 2024 sequences were assigned to subclades C.1.8 and C.1.9. The H3N2 sequences from 2023 were assigned to the 3 C.2a1b.2a.2a.1b clade and subclade G.1.1.2, while the 2024 sequences were assigned to the 3 C.2a1b.2a.2a.3a.1 clade and subclade J.2. The K54Q, A186T, Q189E, E224A, R259K, K308R, I418V, and X215A amino acid substitutions were seen in the H1N1 in the 2023 and 2024 sequences. The 2024 H1N1 sequences additionally exhibited further substitutions, such as V47I, I96T, T120A, A139D, G339X, K156X, and T278S.

CONCLUSION

In this first study using genomic sequencing to characterize the influenza A strains in Sri Lanka, which showed different influenza A viruses circulating in an 18-month period. As the Sri Lankan strains also had certain mutations of unknown significance, it would be important to continue detailed surveillance of the influenza strains in Sri Lanka to choose the most suitable vaccines for the population and the timing of vaccine administration.

Antigenic Divergence from the Seasonal Vaccine of the Influenza Virus Strains Circulating in Romania During Three Successive Seasons (2021-2024)

Influenza viruses continue to be an important public health threat. Vaccination is the most effective measure to control the influenza virus circulation. However, these viruses are continuously evolving through antigenic drift/shift, and thus the vaccine efficiency is affected. The aim of this study was to characterize the viral strains circulating in Romania, in a population with declining vaccination coverage, during the last three cold seasons by evaluating the hemagglutinin antigenic relatedness to the vaccine strains. All the available sequences collected between August 2021 and June 2024 were analyzed by using phylogenetic analysis and the Pepitope model to predict vaccine efficacy. The results showed that the 2021/2022 influenza season was dominated by the circulation of highly diverse clades of A(H3N2) viruses with high mutational divergence as compared to the vaccine strain, which might contribute to the reduction in vaccine efficacy. During the 2022/2023 influenza season, both influenza A and B viruses were reported, with few antigenic site mutations. The 2023/2024 influenza season was dominated by the circulation of influenza A viruses: A/H1N1pdm09 clade 6B.1A.5a.2a and A/H3N2 clade 2a.3a.1. The clade 2a.3a.1 also showed high variability when compared to the vaccine strain, presumably leading to reduced vaccine efficacy. This study illustrates the high diversity of influenza viruses circulating in a population with low vaccination coverage during the previous cold seasons. The viral diversity impacted vaccine efficacy, hence the need for public health programs to increase vaccine uptake and improve vaccine formulation in order to limit viral transmission.

Exploring the Clinical Characteristics and Outcomes of Rhinovirus Infection in Hospitalized Children Compared with Other Respiratory Viruses

BACKGROUND

Acute viral respiratory tract infections constitute a significant challenge in pediatric healthcare globally, with rhinovirus representing one of the primary etiological agents. In this context, we conducted a study with the objective of identifying the clinical characteristics and outcomes of rhinovirus infection in comparison with other respiratory viruses in children hospitalized in one of the largest pediatric hospitals in the capital of Romania.

METHODS

We conducted a retrospective study among children hospitalized for influenza-like illness symptoms and who were tested by multiplex RT-PCR with a nasopharyngeal swab between May 2020 and December 2021.

RESULTS

A total of 496 children were eligible for inclusion in the study, and the positivity rate for at least one virus was 58.5%. The rhinovirus was identified in 138 patients (median age 12.5 months), representing 27.8% of all children tested and 49.3% of all positive samples. Although the clinical features of children with rhinovirus were dominated by cough (63.7%) and dyspnea (51.6%), no symptoms were identified that were strongly associated with rhinovirus infection in comparison to other respiratory viruses. The probability of receiving an antibiotic prescription was 1.92 times lower (p = 0.011) in children who tested positive for rhinovirus compared to children with negative RT-PCR results. The incidence of acute bronchiolitis or acute bronchitis, acute respiratory failure, and acute otitis media was higher among rhinovirus-positive children than among those who tested negative via RT-PCR. However, the incidence of these conditions was similar among children who tested positive for other respiratory viruses.

CONCLUSIONS

Rhinovirus was the most prevalent virus identified in children hospitalized with influenza-like illness symptoms. The utilization of multiplex RT-PCR molecular tests is instrumental in elucidating etiology with precision and implementation of these advanced diagnostic methods, which can bring significant benefits in practice. A positive result for rhinovirus helps to reduce the unnecessary administration of antibiotics and optimizes patient management, thus decreasing the risk of severe complications such as acute respiratory failure and acute otitis media.

Genomic Surveillance and Evolutionary Dynamics of Influenza A Virus in Sri Lanka

Background

Influenza A has been named as a priority pathogen by the WHO due to the potential to cause pandemics. Genomic sequencing of influenza strains is important to understand the evolution of the influenza strains and also to select the appropriate influenza vaccines to be used in the different influenza seasons in Sri Lanka. Therefore, we sought to understand the molecular epidemiology of the influenza viruses in the Western Province of Sri Lanka, including mutational analysis to investigate the evolutionary dynamics.

Methods

A total of 349 individuals presenting with fever and respiratory symptoms were enrolled in this study from November 2022 to May 2024. Nasopharyngeal and oropharyngeal specimens were collected and screened using quantitative PCR to detect Influenza A, Influenza B, and SARS-CoV-2. Subtyping and genomic sequencing was carried out on influenza A strains using Oxford Nanopore Technology.

Results

Influenza A was detected in 49 (14%) patients, influenza B in 20 (5.7%) and SARS-CoV-2 in 41 (11.7%). Co-infections were observed in five participants. The phylogenetic analysis assigned the H1N1 HA gene sequences within the 6B.1A.5a.2a clade. The HA gene of the H1N1 sequences in 2023 were assigned as belonging to the subclades C.1, C.1.2, and C.1.8, while the 2024 sequences were assigned to subclades C.1.8 and C.1.9. The H3N2 sequences from 2023 were assigned to the 3C.2a1b.2a.2a.1b clade and subclade G.1.1.2, while the 2024 sequences were assigned to the 3C.2a1b.2a.2a.3a.1 clade and subclade J.2. The K54Q, A186T, Q189E, E224A, R259K, K308R, I418V, and X215A amino acid substitutions were seen in the H1N1 in the 2023 and 2024 sequences. The 2024 H1N1 sequences additionally exhibited further substitutions, such as V47I, I96T, T120A, A139D, G339X, K156X, and T278S.

Conclusion

In this first study using genomic sequencing to characterize the influenza A strains in Sri Lanka, which showed different influenza A viruses circulating in an 18-month period. As the Sri Lankan strains also had certain mutations of unknown significance, it would be important to continue detailed surveillance of the influenza strains in Sri Lanka to choose the most suitable vaccines for the population and the timing of vaccine administration.

Influenza B Virus Vaccine Innovation through Computational Design

As respiratory pathogens, influenza B viruses (IBVs) cause a significant socioeconomic burden each year. Vaccine and antiviral development for influenza viruses has historically viewed IBVs as a secondary concern to influenza A viruses (IAVs) due to their lack of animal reservoirs compared to IAVs. However, prior to the global spread of SARS-CoV-2, the seasonal epidemics caused by IBVs were becoming less predictable and inducing more severe disease, especially in high-risk populations. Globally, researchers have begun to recognize the need for improved prevention strategies for IBVs as a primary concern. This review discusses what is known about IBV evolutionary patterns and the effect of the spread of SARS-CoV-2 on these patterns. We also analyze recent advancements in the development of novel vaccines tested against IBVs, highlighting the promise of computational vaccine design strategies when used to target both IBVs and IAVs and explain why these novel strategies can be employed to improve the effectiveness of IBV vaccines.

Genomic Surveillance and Evolutionary Dynamics of Influenza A Virus in Sri Lanka

Background

Influenza A has been named as a priority pathogen by the WHO due to the potential to cause pandemics. Genomic sequencing of influenza strains is important to understand the evolution of the influenza strains and also to select the appropriate influenza vaccines to be used in the different influenza seasons in Sri Lanka. Therefore, we sought to understand the molecular epidemiology of the influenza viruses in the Western Province of Sri Lanka, including mutational analysis to investigate the evolutionary dynamics.

Methodology

A total of 349 individuals presenting with fever and respiratory symptoms were enrolled in this study from November 2022 to May 2024. Nasopharyngeal and oropharyngeal specimens were collected and screened using quantitative PCR to detect Influenza A, Influenza B, and SARS-CoV-2. Subtyping and genomic sequencing was carried out on influenza A strains using Oxford Nanopore Technology.

Results

Influenza A was detected in 49 (14 %) patients, influenza B in 20 (5.7%) and SARS-CoV-2 in 41 (11.7%). Co-infections were observed in five participants. The phylogenetic analysis assigned the H1N1 HA gene sequences within the 6B.1A.5a.2a clade. The HA gene of the H1N1 sequences in 2023 were assigned as belonging to the subclades C.1, C.1.2, and C.1.8, while the 2024 sequences were assigned to subclades C.1.8 and C.1.9. The H3N2 sequences from 2023 were assigned to the 3C.2a1b.2a.2a.1b clade and subclade G.1.1.2, while the 2024 sequences were assigned to the 3C.2a1b.2a.2a.3a.1 clade and subclade J.2. The K54Q, A186T, Q189E, E224A, R259K, K308R, I418V, and X215A amino acid substitutions were seen in the H1N1 in the 2023 and 2024 sequences. The 2024 H1N1 sequences additionally exhibited further substitutions, such as V47I, I96T, T120A, A139D, G339X, K156X, and T278S.

Conclusion

In this first study using genomic sequencing to characterize the influenza A strains in Sri Lanka, which showed different influenza A viruses circulating in an 18-month period. As the Sri Lankan strains also had certain mutations of unknown significance, it would be important to continue detailed surveillance of the influenza strains in Sri Lanka to choose the most suitable vaccines for the population and the timing of vaccine administration.

Probable extinction of influenza B/Yamagata and its public health implications: a systematic literature review and assessment of global surveillance databases

Early after the start of the COVID-19 pandemic, the detection of influenza B/Yamagata cases decreased globally. Given the potential public health implications of this decline, in this Review, we systematically analysed data on influenza B/Yamagata virus circulation (for 2020-23) from multiple complementary sources of information. We identified relevant articles published in PubMed and Embase, and data from the FluNet, Global Initiative on Sharing All Influenza Data, and GenBank databases, webpages of respiratory virus surveillance systems from countries worldwide, and the Global Influenza Hospital Surveillance Network. A progressive decline of influenza B/Yamagata detections was reported across all sources, in absolute terms (total number of cases), as positivity rate, and as a proportion of influenza B detections. Sporadically reported influenza B/Yamagata cases since March, 2020 were mostly vaccine-derived, attributed to data entry errors, or have yet to be definitively confirmed. The likelihood of extinction necessitates a rapid response in terms of reassessing the composition of influenza vaccines, enhanced surveillance for B/Yamagata, and a possible change in the biosafety level when handling B/Yamagata viruses in laboratories.

Incidence and Characteristics of Pediatric Patients with Acute Otitis Hospitalized in a Romanian Infectious Diseases Hospital

BACKGROUND

Otic involvement is common in children during acute infectious diseases, and is an important cause of morbidity and health service utilization.

METHODS

We performed a retrospective analysis of pediatric cases hospitalized in the largest infectious disease hospital in Romania between 2018 and 2023, with the aim of quantifying the incidence and impact of acute otitis (AO) according to pediatric age subgroups.

RESULTS

A total of 1118 cases diagnosed with AO were eligible and included in the analysis. Acute congestive otitis media was the most common subtype, identified in 53.3% of cases, followed by acute purulent otitis media (APOM) in 26.7% of children. The majority of AO cases (69.9%) were diagnosed in the pre-pandemic period (2018-2019), and infants (10.6%), toddlers (49.4%), and preschoolers (29.2%) were the most affected age groups. A viral infection associated with the AO episode was documented in 49.6% of cases. Influenza viruses were most commonly reported (20.5%), followed by SARS-CoV-2 (5.8%), and adenovirus (4.9%). A total of 38 cases of AO were identified in children with measles. In 15.9% of APOM cases, Streptococcus pneumoniae was isolated by culture from otic secretions. The duration of hospitalization was longer in children with APOM and acute otitis externa compared to the other subtypes of AO (p < 0.001).

CONCLUSIONS

Our study highlights the importance of ENT (ear, nose, and throat) monitoring in children hospitalized for acute infectious diseases, as the majority of AO cases occur in the context of a viral infection. These findings emphasize the necessity for tailored assessment and intervention in suspected cases of AO, especially in young children under 5 years of age.

Age, comorbidity burden and late presentation are significant predictors of hospitalization length and acute respiratory failure in patients with influenza

Influenza viruses are responsible for a high number of infections and hospitalizations every year. In this study, we aimed to identify clinical and host-specific factors that influence the duration of hospitalization and the progression to acute respiratory failure (ARF) in influenza. We performed an analysis of data from a prospective active influenza surveillance study that was conducted over five seasons (2018/19 to 2022/23). A total of 1402 patients with influenza were included in the analysis, the majority of which (64.5%) were children (under 18 years), and 9.1% were elderly. At least one chronic condition was present in 29.2% of patients, and 9.9% of patients developed ARF. The median hospital stay was 4 days (IQR: 3, 6 days). The most important predictors of prolonged hospital stay and development of ARF were extremes of age (infants and elderly), presence of chronic diseases, particularly the cumulus of at least 3 chronic diseases, and late presentation to hospital. Among the chronic diseases, chronic obstructive pulmonary disease, cardiovascular disease, cancer, diabetes, obesity, and chronic kidney disease were strongly associated with a longer duration of hospitalization and occurrence of ARF. In this context, interventions aimed at chronic disease management, promoting influenza vaccination, and improving awareness and access to health services may contribute to reducing the impact of influenza not only in Romania but globally. In addition, continued monitoring of the circulation of influenza viruses is essential to limit their spread among vulnerable populations.

Hospitalizations for Acute Otitis and Sinusitis in Patients Living with HIV: A Retrospective Analysis of a Tertiary Center in Romania

Background/Objectives: Acute or chronic ear, nose and throat (ENT) conditions in people living with HIV can lead to hospitalization and affect their quality of life. The aim of our study was to determine the frequency and characteristics of hospitalizations for acute sinusitis (AS) and acute otitis (AO) in people living with HIV. Methods: We performed a retrospective analysis over the course of six years (from January 2018 to December 2023), assessing all hospitalizations for AS and/or AO occurring in patients living with HIV, at the largest infectious diseases hospital in Romania. Results: We identified a total of 179 cases, among which 149 cases (83.2%) were attributed to AS and 41 cases (22.9%) were due to AO. Among cases of AS, maxillary sinuses were most frequently involved (n = 140/149, 94.0%), and among cases of AO, acute congestive otitis media (n = 14, 34.1%) and acute purulent otitis media (n = 13, 31.7%) were the most common forms. The underlying HIV infection was classified as stage C3 in 57.5% of cases. In 19.6% of cases, it was possible to identify either the trigger or the etiological agent, and the most frequent bacterial pathogens were Streptococcus pneumoniae, Staphylococcus aureus, Haemophilus influenzae and Pseudomonas aeruginosa. Conclusions: In conclusion, this study highlights that hospitalizations due to acute sinus and ear involvement are not isolated events in people living with HIV. A prospective follow-up is needed to gain a deeper and more dynamic understanding of how ENT health is affected in people with HIV infection. Furthermore, promoting prevention through vaccination may reduce to a certain extent the burden of ENT infections in this population.

Nucleic acid-based electrochemical biosensor for detection of influenza B by gold nanoparticles

The influenza virus is a pervasive pathogen that exhibits increased prevalence during colder seasons, resulting in a significant annual occurrence of infections. Notably, pharmaceutical interventions effective against influenza A strains often exhibit limited efficacy against influenza B variants. Against this backdrop, the need for innovative approaches to accurately and swiftly differentiate and detect influenza B becomes evident. Biosensors play a pivotal role in this detection process, offering rapid, specific, and sensitive identification of the virus, facilitating timely intervention and containment efforts. Oligonucleotide sequences targeting the conserved B/Victoria/2/87 influenza virus NP region were designed. Nasopharyngeal swabs were collected from patients suspected of influenza virus infection, and viral RNA was extracted. RNA quality was assessed through one-step PCR. cDNA synthesis was performed using random hexamers, and real-time PCR quantified the influenza genome. Gold nanoparticles were immobilized on a surface to immobilize the specific DNA probe, and electrochemical hybridization was electrochemically followed. The biosensor exhibited high selectivity and effective distinction of complementary sequences from mismatches and influenza virus cDNA genome. The biosensor successfully detected the influenza B virus genome in real samples. Non-influenza samples yielded no significant hybridization signals. The comparison between the results obtained from the biosensor and real-time PCR revealed full agreement of these methods. The biosensor utilized electrochemical detection of hybridization and proved effective in detecting the influenza B virus genome with high specificity, sensitivity, and selectivity. Comparative analysis with real-time PCR underscored the accuracy and potential applicability of the biosensor in rapid and specific virus detection. This innovative approach holds promise for future diagnostic and epidemiological applications in detecting influenza B virus and other pathogens.

Occurrence of acute otitis and sinusitis in patients hospitalized for influenza

Introduction

Acute otitis and sinusitis are common complications in patients with influenza and are responsible for increased hospitalization rates.

Methods

A five-year retrospective study (2018-2023) was conducted including all patients hospitalized for influenza (etiologic diagnosis by RT-PCR) to identify the incidence and characteristics of cases complicated with otitis and/or sinusitis. Cases associated with other viral co-infections were excluded from the analysis.

Results

We identified a cumulative rate of 20.6% (324 cases) of acute otitis (AO) and acute sinusitis (AS) among patients with influenza. Of these, 62.3% had AO, 28.1% AS, and 9.6% concomitant AO and AS. Cases of AO were predominant in the pediatric population (97.0%), while cases of AS were more common in adults (56.1%). Influenza A viruses were identified in 67.2% of patients. The infection with influenza B viruses increased the risk of acute congestive otitis media 2.1-fold (p=0.020), and influenza A viruses increased the risk of acute maxillary sinusitis 2.7-fold (p=0.029). Late presentation to the hospital, with a median of 4 days from the onset of influenza symptoms, was identified as a factor in the occurrence of AO and AS.

Conclusions

The risk of AO and AS is increased in patients with influenza, especially in the pediatric population and in late hospital presentations. These findings highlight the importance of proper monitoring and management of patients with influenza to prevent the development of complications, as well as the need to better understand the mechanisms whereby influenza viruses contribute to these secondary conditions.

The Impact of Obesity on the Host-Pathogen Interaction with Influenza Viruses - Novel Insights: Narrative Review

After exposure to a viral pathogen, the host-pathogen interaction is essential to determine whether or not infection will ensue, and what the clinical outline of the infection will be. Recent research has shown that the patient with obesity presents a set of particular pathophysiological changes that lead to higher severity of viral infections, and this is particularly true for infection with influenza viruses. Herein, we describe the main metabolic, endocrine, and immune dysregulations that occur in the presence of obesity and their impact on driving intra-host viral diversity, leading to heightened severity and virulence of influenza. We show that obesity is linked to modified responses of both the innate and adaptive immune systems during viral infections, including influenza. Due to chronic inflammation and metabolic, endocrine, and signaling pathway disruptions, individuals with obesity have a suboptimal immune response. This results in longer illness duration, increased virus shedding, higher risk of hospitalization and complications, and greater mortality rates. Additionally, they may have a blunted response to vaccination and a higher likelihood of genetic mutation selection. Understanding the intricate interplay between obesity and viral pathogenesis is crucial for developing efficacious therapeutic approaches and public health policies, particularly in light of the escalating worldwide incidence of obesity.

Genome characterization of influenza A and B viruses in New South Wales, Australia, in 2019: A retrospective study using high-throughput whole genome sequencing

BACKGROUND

During the 2019 severe influenza season, New South Wales (NSW) experienced the highest number of cases in Australia. This study retrospectively investigated the genetic characteristics of influenza viruses circulating in NSW in 2019 and identified genetic markers related to antiviral resistance and potential virulence.

METHODS

The complete genomes of influenza A and B viruses were amplified using reverse transcription-polymerase chain reaction (PCR) and sequenced with an Illumina MiSeq platform.

RESULTS

When comparing the sequencing data with the vaccine strains and reference sequences, the phylogenetic analysis revealed that most NSW A/H3N2 viruses (n = 68; 94%) belonged to 3C.2a1b and a minority (n = 4; 6%) belonged to 3C.3a. These viruses all diverged from the vaccine strain A/Switzerland/8060/2017. All A/H1N1pdm09 viruses (n = 20) showed genetic dissimilarity from vaccine strain A/Michigan/45/2015, with subclades 6B.1A.5 and 6B.1A.2 identified. All B/Victoria-lineage viruses (n = 21) aligned with clade V1A.3, presenting triple amino acid deletions at positions 162-164 in the hemagglutinin protein, significantly diverging from the vaccine strain B/Colorado/06/2017. Multiple amino acid substitutions were also found in the internal proteins of influenza viruses, some of which have been previously reported in hospitalized influenza patients in Thailand. Notably, the oseltamivir-resistant marker H275Y was present in one immunocompromised patient infected with A/H1N1pdm09 and the resistance-related mutation I222V was detected in another A/H3N2-infected patient.

CONCLUSIONS

Considering antigenic drift and the constant evolution of circulating A and B strains, we believe continuous monitoring of influenza viruses in NSW via the high-throughput sequencing approach provides timely and pivotal information for both public health surveillance and clinical treatment.

Phylogenetic analysis of HA and NA genes of influenza A viruses in immunosuppressed inpatients in Beijing during the 2018-2020 influenza seasons

BACKGROUND

Influenza A viruses have undergone rapid evolution with virulent; however, complete and comprehensive data on gene evolution and amino acid variation of HA and NA in immunosuppressed patients was few. In this study, we analysed molecular epidemiology and evolution of influenza A viruses in immunosuppressed population, and immunocompetent population were used as controls.

METHODS

Full sequences of HA and NA of A(H1N1)pdm09 and A(H3N2) were acquired through reverse transcription-polymerase chain reaction (RT-PCR). HA and NA genes were sequenced using the Sanger method and phylogenetically analysed using ClustalW 2.10 and MEGA software version 11.0.

RESULTS

During the 2018-2020 influenza seasons, 54 immunosuppressed and 46 immunocompetent inpatients screened positive for influenza A viruses by using the quantitative real-time PCR (qRT-PCR) were enrolled. 27 immunosuppressed and 23 immunocompetent nasal swab or bronchoalveolar lavage fluid samples were randomly selected and sequenced using the Sanger method. A(H1N1)pdm09 were detected in 15 samples and the remaining 35 samples were A(H3N2) positive. By analyzing the HA and NA gene sequences of these virus strains, we found that all A(H1N1)pdm09 viruses shared high similarities to each other and the HA and NA genes of these viruses exclusively belonged to subclade 6B.1A.1. Some NA genes of A(H3N2) viruses were not in the same clade as those of A/Singapore/INFIMH-16-0019/2016 and A/Kansas/14/2017, which may have led to A(H3N2) being the dominant strain in the 2019-2020 influenza season. Both A(H1N1)pdm09 and A(H3N2) viruses showed similar evolutionary lineages patterns of HA and NA between immunosuppressed and immunocompetent patients. Compared with the vaccine strains, there were no statistically significant of HA and NA genes and amino acid sequences of influenza A viruses in immunosuppressed and immunocompetent patients. However, the oseltamivir resistance substitution of NA-H275Y and R292K have been observed in immunosuppressed patients.

CONCLUSIONS

A(H1N1)pdm09 and A(H3N2) viruses showed similar evolutionary lineages patterns of HA and NA between immunosuppressed and immunocompetent patients. Both immunocompetent and immunosuppressed patients have some key substitutions, which should be of note monitored, especially those with potential to affect the viral antigen.

Omicron in Infants-Respiratory or Digestive Disease?

The Omicron variant of SARS-CoV-2 has caused a large number of cases and hospitalizations in the pediatric population. Infants due to their age are susceptible to viral infections that may have a worse prognosis. Therefore, the aim of the current study has been to characterize the clinical features and the outcome of infants hospitalized with confirmed SARS-CoV-2 infection during the Omicron wave. We conducted a retrospective study of all consecutive infants hospitalized with symptomatic COVID-19 and no other co-infections, from January to September 2022 in one of the largest infectious diseases hospitals from Bucharest, Romania. A total of 613 infants were included in the analysis. The median age was 5 months (IQR: 3, 8 months). The clinical features were dominated by fever (96.4%), cough (64.8%) and loss of appetite (63.3%), and overall, respiratory symptoms were the most numerous (76.0%). Infants between 1-3 months old had a 1.5-fold increased risk of elevated alanine aminotransferase (ALT) values, and a longer length of hospitalization as compared to older infants. Infants between 7-9 months of age had 1.5-fold higher odds of loss of appetite, 1.7-fold more frequent cough and 1.6-fold more frequent digestive symptoms compared to infants in other age groups. The presence of digestive symptoms increased the probability of hepatic cytolysis (increased ALT) by 1.9-fold. Continued monitoring of COVID-19 among infants is very necessary, given the progressive character of SARS-CoV-2, in order to take correct and rapid therapeutic measures and to adapt to clinical changes driven by viral variant change.

From COVID-19 to Influenza-Real-Life Clinical Practice in a Pediatric Hospital

The COVID-19 pandemic, through the restrictions and the non-pharmaceutical interventions implemented, has importantly impacted the circulation and epidemiology of respiratory viruses. Specifically, the 2020/21 season was entirely dominated by SARS-CoV-2, while influenza activity reached an all-time low, despite initial warnings that a double concurrent epidemic could be possible. The current season, 2021/22, started with the shift of circulating SARS-CoV-2 variants from delta to omicron, which then rapidly spread globally, as most countries, including Romania, removed all restrictions and compulsory non-pharmaceutical interventions. In this report we present the clinical reality observed in March 2022 in a tertiary paediatric hospital in Bucharest, Romania, where we observed a sudden surge in influenza cases, after two consecutive years (March 2020 to March 2022) when influenza had stopped circulating in our country. Thus, in March 2022 the positivity rate of rapid influenza antigen tests unexpectedly increased to 33.5%, paralleled by a decrease to 7.5% in the positivity rate of rapid SARS-CoV-2 antigen tests. This significant increase in the influenza attack rate was observed from the first week (14.9% positivity rate), through the fourth week of March (42.1% positivity rate, p < 0.001), while the COVID-19 attack rate displayed a significant decreasing trend (from 11.2% to 4.8%, p < 0.001). These data serve as a warning about relaxing restrictions in a precipitous approach with minimised vigilance. The evolution of these observations needs to be followed very carefully in all countries, particularly in settings where epidemiological interactions and non-pharmaceutical interventions have so far led to the extensive circulation of only one of these viruses, and we should now be prepared to perform a correct differential diagnosis between influenza and COVID-19, in order to ensure the best quality of care and personalized management of each case of respiratory infection. The results of active influenza surveillance studies for the whole 2021/22 season are awaited, in order to quantify the joint influenza—COVID-19 burden among children.

Optional Vaccines in Children—Knowledge, Attitudes, and Practices in Romanian Parents

Vaccination is one of the most useful medical interventions for controlling certain infectious diseases. The aim of current research is to identify some of the drivers of vaccine hesitancy or acceptance in a rather skeptical European population by addressing parental perception on optional vaccination (OV) perception. Novel tools, delivered by social media, were used in our research attempt. A validated questionnaire was distributed online among parents. Parental knowledge, attitudes and perceptions of OV were analyzed. The majority of parent respondents (55.1%) showed very good knowledge about vaccination and vaccine-preventable diseases, and 76.0% stated that they had given at least one optional vaccine to at least one of their children. The most common optional vaccine administered was the rotavirus vaccine. The level of knowledge appeared to be related to compliance with OV. Concurrently, the rate of vaccine acceptance in the NIP (National Immunization Program) was not correlated with the level of parental knowledge. In total, a high percentage of parents (77.6%) believed that OV can bring an additional health safety benefit to their children. This study shows the need to involve the medical community in a steady dialogue with parents about OV. Raising awareness by presenting clear and understandable information could be a game-changing intervention in mitigating the public health impact of OV-preventable diseases.

Comparative Analysis of Clinical and Epidemiological Characteristics in Patients with SARI Confirmed as Influenza or COVID-19 Admitted in a Tertiary Care Hospital in Bucharest, Romania

The COVID-19 pandemic has influenced the epidemiology of other respiratory pathogens, and this was most evident in the 2020–2021 season, which was characterized by a low circulation of influenza viruses. We aim to present a comparative analysis of clinical and epidemiological characteristics of 2018–2019 influenza cases and 2020–2021 COVID-19 cases, hospitalized at a tertiary infectious diseases hospital in Bucharest. We used data collected from patients admitted for severe acute respiratory infection (SARI) and subsequently confirmed with either influenza or COVID-19. During the 2018–2019 season, 208 patients over 18 years of age were confirmed with influenza (median age = 53 years, 59.6% were female) and 6.7% had been vaccinated against influenza. The most frequent symptoms were fever (97.1%) and cough (94.7%), and 77.4% had at least one chronic condition. 90.4% received influenza antiviral therapy. During the 2020–2021 season, 191 patients were confirmed with COVID-19 (median age = 56 years, 67% were male). The most frequent symptoms were cough (85.9%) and fever (80.6%), and 75.9% had at least one chronic condition. This analysis highlights the main similarities and differences between influenza and COVID-19 and could help to optimize the management of cases.