Circulation Of Influenza Research Articles

National Influenza Annual Report, Canada, 2022-2023: Canada's first fall epidemic since the 2019-2020 season.

Coinciding with the beginning of the coronavirus disease 2019 (COVID-19) pandemic in March 2020, Canadian seasonal influenza circulation was suppressed, which was a trend reported globally. Canada saw a brief and delayed return of community influenza circulation during the spring of the 2021-2022 influenza season. Surveillance for Canada's 2022-2023 seasonal influenza epidemic began in epidemiological week 35 (week starting August 28, 2022) and ended in epidemiological week 34 (week ending August 26, 2023). The 2022-2023 season marked the return to pre-pandemic-like influenza circulation. The epidemic began in epidemiological week 43 (week ending October 29, 2022) and lasted 10 weeks. Driven by influenza A(H3N2), the epidemic was relatively early, extraordinary in intensity, and short in length. This season, a total of 74,344 laboratory-confirmed influenza detections were reported out of 1,188,962 total laboratory tests. A total of 93% of detections were influenza A (n=68,923). Influenza A(H3N2) accounted for 89% of the subtyped specimens (n=17,638/19,876). Late-season, Canada saw community circulation of influenza B for the first time since the 2019-2020 season. The 2022-2023 influenza season in Canada had an extraordinary impact on children and youth; nearly half (n=6,194/13,729, 45%) of reported influenza A(H3N2) detections were in the paediatric (younger than 19 years) population. Weekly paediatric influenza-associated hospital admissions were persistently above historical peak levels for several weeks. The total number of influenza-associated paediatric hospitalizations (n=1,792) far exceeded historical averages (n=1,091). With the return of seasonal influenza circulation and endemic co-circulation of multiple high burden respiratory viruses, sustained vigilance is warranted. Annual seasonal influenza vaccination is a key public health intervention available to protect Canadians.

High Influenza Incidence and Disease Severity Among Children and Adolescents Aged

During the 2022-23 influenza season, early increases in influenza activity, co-circulation of influenza with other respiratory viruses, and high influenza-associated hospitalization rates, particularly among children and adolescents, were observed. This report describes the 2022-23 influenza season among children and adolescents aged <18 years, including the seasonal severity assessment; estimates of U.S. influenza-associated medical visits, hospitalizations, and deaths; and characteristics of influenza-associated hospitalizations. The 2022-23 influenza season had high severity among children and adolescents compared with thresholds based on previous seasons' influenza-associated outpatient visits, hospitalization rates, and deaths. Nationally, the incidences of influenza-associated outpatient visits and hospitalization for the 2022-23 season were similar for children aged <5 years and higher for children and adolescents aged 5-17 years compared with previous seasons. Peak influenza-associated outpatient and hospitalization activity occurred in late November and early December. Among children and adolescents hospitalized with influenza during the 2022-23 season in hospitals participating in the Influenza Hospitalization Surveillance Network, a lower proportion were vaccinated (18.3%) compared with previous seasons (35.8%-41.8%). Early influenza circulation, before many children and adolescents had been vaccinated, might have contributed to the high hospitalization rates during the 2022-23 season. Among symptomatic hospitalized patients, receipt of influenza antiviral treatment (64.9%) was lower than during pre-COVID-19 pandemic seasons (80.8%-87.1%). CDC recommends that all persons aged ≥6 months without contraindications should receive the annual influenza vaccine, ideally by the end of October.

Clinical Features and Outcomes of the Association of Co-Infections in Children with Laboratory-Confirmed Influenza during the 2022-2023 Season: A Romanian Perspective.

The 2022-2023 influenza season in Romania was characterized by high pediatric hospitalization rates, predominated due to influenza A subtypes (H1N1) pdm09 and H3N2. The lowered population immunity to influenza after the SARS-CoV-2 pandemic and the subsequent stoppage of influenza circulation, particularly in children who had limited pre-pandemic exposures, influenced hospitalization among immunosuppressed children and patients with concurrent medical conditions who are at an increased risk for developing severe forms of influenza. This study focused on the characteristics of influenza issues among pediatric patients, as well as the relationship between different influenza virus types/subtypes and viral and bacterial co-infections, as well as illness severity in the 2022-2023 season after the SARS-CoV-2 pandemic. We conducted a retrospective clinical analysis on 301 cases of influenza in pediatric inpatients (age ≤ 18 years) who were hospitalized at the National Institute of Infectious Diseases "Prof. Dr. Matei Balș" IX Pediatric Infectious Diseases Clinical Section between October 2022 and February 2023. The study group's median age was 4.7 years, and the 1-4 year age group had the highest representation (57.8%). Moderate clinical forms were found in 61.7% of cases, whereas severe versions represented 18.2% of cases. Most of the complications were respiratory (acute interstitial pneumonia, 76.1%), hematological (72.1%, represented by intra-infectious and deficiency anemia, leukopenia, and thrombocytopenia), and 33.6% were digestive, such as diarrheal disease, liver cytolysis syndrome, and the acute dehydration syndrome associated with an electrolyte imbalance (71.4%). Severe complications were associated with a risk of unfavorable evolution: acute respiratory failure and neurological complications (convulsions, encephalitis). No deaths were reported. We noticed that the flu season of 2022-2023 was characterized by the association of co-infections (viral, bacterial, fungal, and parasitic), which evolved more severely, with prolonged hospitalization and more complications (p < 0.05), and the time of use of oxygen therapy was statistically significant (p < 0.05); the number of influenza vaccinations in this group was zero. In conclusion, co-infections with respiratory viruses increase the disease severity of the pediatric population to influenza, especially among young children who are more vulnerable to developing a serious illness. We recommend that all people above the age of six months should receive vaccinations against influenza to prevent the illness and its severe complications.

A-292 The Use of Third-Party Controls During Covid-19 Pandemic: An Alternative to the Lack of Other Respiratory Infections

Abstract Background Since SARS-CoV-2 spread widely around the world, previously well-established infectious patterns have changed. The introduction of a new respiratory pathogen, together with changes in human behaviour, such as restrictions on social interactions and the use of facemasks, led to a decrease in the circulation of influenza and respiratory syncytial viruses. This phenomenon, together with the collapse of the healthcare system, significantly decreased the availability of certain types of samples for use in clinical studies to evaluate the performance of in vitro diagnostic products. To overcome this issue, EQA programmes are an excellent alternative. This material has been designed to be used in any equipment, kit or following any specific protocol, as the aim is to mimic human specimens. Thus, the CE-IVD Vitassay qPCR FluA + FluB + RSV, an assay for the detection and differentiation of Flu A, Flu B and RSV, has been routinely tested with material from QCMD programmes containing different strains and serotypes of Influenza and RSV. Methods Vitassay qPCR FluA + FluB + RSV (Vitassay Healthcare SLU, Huesca, Spain) is a commercial kit consisting in a ready-to-use lyophilized master mix. This kit has been blindly tested with controls from 4 QCMD panels including RSV, influenza A and B (2020–2022). Each panel consist of 10 specimens in transport media, which were handled following the programme indications. RNA was extracted using automatic extraction (MagDEA Dx SV kit on the 12gC or Vitassay Microorganism-NA Isolation kit on the KingFisher Flex Automatic platform). Amplification was performed on BioRad systems (CFX96 and CFX96 OPUS). Interpretation of the results was done following manufacturer’s instructions. Sensitivity, specificity, and Likelihood Ratio have been calculated with a 95% confidence interval using the software MetaDiSC 1.4. Results In total, 40 human-like samples from QCMD EQA programmes were analysed with Vitassay qPCR Flu A + Flu B + RSV during Covid-19 Pandemic. Vitassay reported 14 Influenza A positive samples, 11 influenza B and 12 RSV positive samples; all of them were correctly detected when compared the initial characterisation. For Flu A sensitivity and specificity were of 1 (0,76–1) and 1 (0.86–1), LR+ 52.2 (3.34–814.62), LR− 0.034 (0.002–0.51). For Flu B sensitivity and specificity were of 1 (0.71–1) and 1 (0.88–1), LR+ 57.5 (3.67–900.49), LR− 0.042 (0.003–0.63). For RSV sensitivity and specificity were of 1 (0,73–1) and 1 (0.87–1), LR+ 55.76 (3.56–872.35), LR− 0.039 (0.003–0.59). Conclusions Third party controls are an excellent alternative to clinical samples, especially in extraordinary circumstances. In addition, they allow to introduce different strains and variants, such as the QCMD specimens tested. Among these, we could find a such as H1N1 and H3N2 Influenza A serotypes, Influenza B Yamagata and Victoria and RSV A and B, which were properly detected by Vitassay multiplex. In addition, Vitassay extraction kit showed satisfactory results as all samples were properly detected when used in combination with Vitassay qPCR Flu A + Flu B + RSV.

Risk of Swine influenza for veterinary medicine and human health in Ukraine

The article provides a brief review of the literature on influenza viruses, including their prevalence, classification, pathogenicity, ability to mutate and reassort, and some peculiarities of their biological properties. Special attention is given to swine influenza, since interspecies transmission of influenza viruses between pigs and humans can have serious consequences for both human and veterinary medicine. The results of pilot studies conducted at the NSC ‘IECVM’ prove the circulation of influenza A viruses among pigs in Ukraine — 324 samples of blood sera from pigs of different age groups from different regions of Ukraine were tested using an ELISA test system, 48 (14.8%) positive samples were found. Seroprevalence reached 100% in some farms and antibodies were detected in animals aged 24–73 days. The prospect of further work is to conduct surveillance studies (serological, molecular biological, virological) of pigs in both large breeding complexes and private households to detect antibodies to influenza A and, based on the results obtained, to draw conclusions about the circulation of influenza A viruses in Ukraine

Effect of the COVID-19 pandemic on the pediatric infectious disease landscape.

This narrative review aims to present an overview of the COVID-19 pandemic's effects on the landscape of pediatric infectious diseases. While COVID-19 generally results in mild symptoms and a favorable prognosis in children, the pandemic brought forth significant consequences. These included persistent symptoms among infected children ("long COVID"), a profound transformation in healthcare utilization (notably through the widespread adoption of telemedicine), and the implementation of optimization strategies within healthcare settings. Furthermore, the pandemic resulted in alterations in the circulation patterns of respiratory pathogens, including influenza, RSV, and Streptococcus pneumoniae. The possible reasons for those changes are discussed in this review. COVID-19 effect was not limited to respiratory infectious diseases, as other diseases, including urinary tract and gastrointestinal infections, have displayed decreased transmission rates, likely attributable to heightened hygiene measures and shifts in care-seeking behaviors. Finally, the disruption of routine childhood vaccination programs has resulted in reduced immunization coverage and an upsurge in vaccine hesitancy. In addition, the pandemic was associated with issues of antibiotic misuse and over-prescription. Conclusion: In conclusion, the COVID-19 pandemic has left a profound and multifaceted impact on the landscape of pediatric infectious diseases, ranging from the emergence of "long COVID" in children to significant changes in healthcare delivery, altered circulation patterns of various pathogens, and concerning disruptions in vaccination programs and antibiotic usage. What is Known: •COVID-19 usually presents with mild symptoms in children, although severe and late manifestations are possible. •The pandemic resulted in a dramatically increased use of health care services, as well as alterations in the circulation patterns of respiratory pathogens, decreased rates of other, non-respiratory, infections, disruption of routine childhood vaccination programs, and antibiotic misuse. What is New: •Possible strategies to tackle future outbreaks are presented, including changes in health care services utilization, implementation of updated vaccine programs and antibiotic stewardship protocols. •The decline in RSV and influenza circulation during COVID-19 was probably not primarily related to NPI measures, and rather related to other, non-NPI measures implementation, including specific pathogen-host interactions on the level of the biological niche (the nasopharynx).

Influenza epidemics in Europe, nursing homes and vaccination of healthcare workers

During the 2022-2023 season, influenza circulation levels in the European Union (EU) have increased substantially compared to the 2021-2022 season but were still generally somewhat lower compared to pre-pandemic influenza seasons. Studies have shown that influenza epidemics in the EU countries were associated with a heavy toll of mortality for different principal causes of death including respiratory, cardiac and other causes. Mortality data also suggest that residents of long-term care facilities represent a sizeable share of all cases of death in the EU, and an even higher share among deaths stemming from infections with respiratory viruses, including influenza. Influenza vaccination coverage for healthcare workers in nursing homes in many EU countries is moderate to low, whereas evidence in the literature suggests that higher influenza vaccination coverage levels for healthcare workers result in a significant reduction in all-cause mortality during influenza seasons, both in nursing home residents as well as in hospital patients, though the magnitude of that effect varies with influenza season. Here, we review the above evidence, and as well as the effect of different strategies for boosting influenza vaccination coverage in healthcare workers, such as mandatory vaccination, educational initiatives/outreach activities and availability of on-sight vaccination.

Shifting Patterns of Influenza Circulation during the COVID-19 Pandemic, Senegal.

Historically low levels of seasonal influenza circulation were reported during the first years of the COVID-19 pandemic and were mainly attributed to implementation of nonpharmaceutical interventions. In tropical regions, influenza's seasonality differs largely, and data on this topic are scarce. We analyzed data from Senegal's sentinel syndromic surveillance network before and after the start of the COVID-19 pandemic to assess changes in influenza circulation. We found that influenza shows year-round circulation in Senegal and has 2 distinct epidemic peaks: during January-March and during the rainy season in August-October. During 2021-2022, the expected January-March influenza peak completely disappeared, corresponding to periods of active SARS-CoV-2 circulation. We noted an unexpected influenza epidemic peak during May-July 2022. The observed reciprocal circulation of SARS-CoV-2 and influenza suggests that factors such as viral interference might be at play and should be further investigated in tropical settings.

Circulation of influenza and other respiratory viruses during the COVID-19 pandemic in Australia and New Zealand, 2020–2021

Circulation of influenza and other respiratory viruses during the COVID-19 pandemic in Australia and New Zealand, 2020–2021

Circulation of influenza C virus of C/Sao Paulo/378/82 lineage among pediatric acute respiratory cases, Shandong, China

Influenza C virus (ICV) was identified in five pediatric acute respiratory cases in Shandong. Co-infection with other respiratory viruses was detected in four of these cases. Two ICV genomes were obtained and clustered in the S1-sublineage of C/Sao Paulo/378/82, indicating that genetically diverse ICV strains have been circulating in mainland China.

Global variability of influenza activity and virus subtype circulation from 2011 to 2023

BackgroundAlthough decreased influenza activity has been reported in many countries during the COVID-19 pandemic, it remains unknown how global influenza activity has changed. We described the global variability of influenza...

Increased influenza severity in children in the wake of SARS-CoV-2.

The SARS-CoV-2 pandemic and subsequent interruption of influenza circulation has lowered population immunity to influenza, especially among children with few prepandemic exposures. Using data from a prospective pediatric cohort study based in Managua, Nicaragua, we compared the incidence and severity of influenza A/H3N2 and influenza B/Victoria between 2022 and two prepandemic seasons. We found a higher incidence of A/H3N2 in older children in 2022 compared with pre-2020 and a higher proportion of severe influenza in 2022, primarily among children aged 0-4, suggesting an influence of the SARS-CoV-2 pandemic on influenza incidence and severity in children.

Clinical challenge of co-infection of SARS-CoV-2 with influenza during the influenza circulation season: suggestions for prevention.

Clinical challenge of co-infection of SARS-CoV-2 with influenza during the influenza circulation season: suggestions for prevention.

Spatial timing of circulating seasonal influenza A and B viruses in China from 2014 to 2018

Major outbreaks of influenza virus occurred in China in 2017–2018. To describe the pattern of influenza circulation and timing of seasonal epidemics, we analyzed data from influenza-like illness (ILI) specimens on surveillance wards of sentinel hospitals during 2014–2018. Among 1,890,084 ILI cases, 324,211 (17.2%) tested positive for influenza. Influenza A virus (particularly A/H3N2), which circulates annually, was detected in 62% of cases, compared with influenza B virus in 38% of cases. The detection rate of A/H1N1, A/H3N2, B/Victoria, and B/Yamagata viruses were 3.56%, 7.07%, 2.08%, and 3.45%, respectively. Influenza prevalence was generally stable over the four years analyzed, but obvious outbreaks occurred in 2015–2016 (17.28%) and 2017–2018 (22.67%), with B/Victoria and B/Yamagata contributing to these outbreaks, respectively. In the south, a characteristic peak in infections was detected in the summer (week 23–38), which was not detected in the north. Influenza B was found high frequency in school-age children (5–14 years) with 4.78% of B/Victoria and 6.76% of B/Yamagata. Therefore, the epidemiological characteristics of seasonal influenza were complex in China during 2014–2018, presenting distinctions in region, season, and susceptible population. These findings underline the importance of enhancing year-round influenza surveillance and provide a reference for the timing and variety of influenza vaccination.

Comparative Clinical Evaluation of a Novel FluA/FluB/SARS-CoV-2 Multiplex LAMP and Commercial FluA/FluB/SARS-CoV-2/RSV RT-qPCR Assays

Influenza and coronaviruses cause highly contagious respiratory diseases that cause millions of deaths worldwide. Public health measures implemented during the current coronavirus disease (COVID-19) pandemic have gradually reduced influenza circulation worldwide. As COVID-19 measures have relaxed, it is necessary to monitor and control seasonal influenza during this COVID-19 pandemic. In particular, the development of rapid and accurate diagnostic methods for influenza and COVID-19 is of paramount importance because both diseases have significant public health and economic impacts. To address this, we developed a multi-loop-mediated isothermal amplification (LAMP) kit capable of simultaneously detecting influenza A/B and SARS-CoV-2. The kit was optimized by testing various ratios of primer sets for influenza A/B (FluA/FluB) and SARS-CoV-2 and internal control (IC). The FluA/FluB/SARS-CoV-2 multiplex LAMP assay showed 100% specificity for uninfected clinical samples and sensitivities of 90.6%, 86.89%, and 98.96% for LAMP kits against influenza A, influenza B, and SARS-CoV-2 clinical samples, respectively. Finally, the attribute agreement analysis for clinical tests indicated substantial agreement between the multiplex FluA/FluB/SARS-CoV-2/IC LAMP and commercial AllplexTM SARS-CoV-2/FluA/FluB/RSV assays.

How human ecology landscapes shape the circulation of H5N1 avian influenza: A case study in Indonesia

BackgroundHighly pathogenic avian influenza H5N1 virus consistently threatens global public health. A better understanding of the virus' circulation mechanism is needed for future epidemic prevention. Previous studies have focused on the correlations between the presence of H5N1 virus and wild bird populations, domestic poultry production, and sociodemographic factors. However, human cultural landscapes and their impact on H5N1 spread have not been adequately explored. MethodsUsing 196 HA gene sequences of H5N1 influenza viruses from Indonesia with district-level geographic information, we performed Monmonier barrier and Louvain community detection analyses to explore how human ecological factors impact the circulation of virus and identify barriers to or corridors of dispersal. ResultsSpatial discontinuity in the genetic characteristics identified by the Monmonier algorithm were found to mirror the differences in key landscape factors. Our Louvain community detection analysis also found the co-existence of different geographic circulation patterns. The community detection analysis suggests that direct human-related interactions such as poultry transportations between remote areas may result in similar viruses spreading in two distant regions whilst dense localities supported genetically heterogeneous viruses in geographically adjacent areas. ConclusionHuman ecological landscapes shape the circulation mechanism of H5N1 virus in multiple ways contingent upon local context. Physical and cultural barriers may impede its movement between adjacent areas, while natural or human-induced corridors such as wild bird flyways and poultry production networks facilitate its spread between geographically distant areas. Further focus on the importance of cultural landscapes has great potential for increasing our understanding of the circulation of pathogenic H5N1 avian influenza virus in Southeast Asia.

First Dominant Circulation of Influenza A/H3 among Patients with Acute Respiratory Tract Infections in a Tertiary Care Hospital in Dhaka 2022

The seasonal circulation of influenza viruses varies from year to year. We have retrospectively analyzed our hospital data of respiratory pathogens among patients of respiratory tract infections and extracted circulation of influenza viruses and characterized patients with influenza attended to a tertiary care hospital in Dhaka from July 2021 to September 2022. We have analyzed data of real-time reverse transcription polymerase chain reaction testing of respiratory panel done in QIAstatDx (Qiagen, Germany) using nasopharyngeal samples to identify the presence of influenza viruses and to determine the subtypes. A total of 547 patient’s data were analyzed in this study, with an influenza positivity rate of 15.62% in 2021 and 23.63% in 2022. We identified an exclusive circulation of influenza A/H3 viruses in 2022 while cocirculation of Influenza A (H1N1 pdm 09 – 10.15%, H3– 2.34%, A not subtyped – 2.34%) and influenza B (0.78%) was observed in 2021 in our cohort. Further, subtyping data showed that both Influenza A/H1N1 pdm09 and Influenza A/H3 was equally observed in influenza like illness (ILI) and severe acute respiratory infection (SARI) patients. This small study in our cohort warrants further elaborate investigation to know circulating influenza A subtyping in the country which may assist health care providers in making treatment decisions and hence, appropriate patient management. J MEDICINE 2023; 24: 37-42

Using Discarded Facial Tissues to Monitor and Diagnose Viral Respiratory Infections.

Molecular biology amplification enables sensitive detection of most respiratory viruses through nasopharyngeal swabbing. We developed an innovative approach to detect viral genomes on used facial tissues. In 2 communities of children, used tissues were collected once weekly for 1 year. Pooled analysis of tissues enabled detection of successive virus circulation in 4 age groups over time and forecasted by several weeks the circulation of influenza in the general population. At the individual level, in a proof-of-concept study of 30 volunteers with influenza-like signs/symptoms, we identified common respiratory viruses. The signals for SARS-CoV-2 obtained in parallel from 15 facial tissues and swab samples were similar and often higher for the tissues (11/15). Individual analysis of tissues offers a noninvasive, sensitive, and affordable alternative to self-sampling without a medical care requirement. Pooled analyses may be used to detect virus spread in specific communities, predict seasonal epidemics, and alert the population to viral infections.

Whole-Genome Analysis of Influenza A(H3N2) and B/Victoria Viruses Detected in Myanmar during the COVID-19 Pandemic in 2021.

An influenza circulation was observed in Myanmar between October and November in 2021. Patients with symptoms of influenza-like illness were screened using rapid diagnostic test (RDT) kits, and 147/414 (35.5%) upper respiratory tract specimens presented positive results. All RDT-positive samples were screened by a commercial multiplex real-time polymerase chain reaction (RT-PCR) assay, and 30 samples positive for influenza A(H3N2) or B underwent further typing/subtyping for cycle threshold (Ct) value determination based on cycling probe RT-PCR. The majority of subtyped samples (n = 13) were influenza A(H3N2), while only three were B/Victoria. Clinical samples with low Ct values obtained by RT-PCR were used for whole-genome sequencing via next-generation sequencing technology. All collected viruses were distinct from the Southern Hemisphere vaccine strains of the corresponding season but matched with vaccines of the following season. Influenza A(H3N2) strains from Myanmar belonged to clade 2a.3 and shared the highest genetic proximity with Bahraini strains. B/Victoria viruses belonged to clade V1A.3a.2 and were genetically similar to Bangladeshi strains. This study highlights the importance of performing influenza virus surveillance with genetic characterization of the influenza virus in Myanmar, to contribute to global influenza surveillance during the COVID-19 pandemic.

A recent experience on the role of influenza vaccination on cardiovascular events.

The purpose of this review is to update the recent information regarding the role of influenza vaccination (IV) as a strategy to reduce cardiovascular (CV) events. During the last 2 years, new meta-analysis, guidelines, and two randomized controlled trials (RCTs) were published. The IAMI trial added information regarding the safety and efficacy of IV right after an acute myocardial infarction hospitalization. A significant reduction in the primary endpoint-including mortality-was observed. More recently, the influenza vaccine to prevent vascular events trial (IVVE) trial did not meet the primary CV endpoint in patients with heart failure (HF). However, a significant reduction was observed during the seasonal peaks of Influenza circulation. COVID-19 pandemic provoked recruitment difficulties in these trials, as well as an altered influenza seasonality and incidence. Further analysis of IVVE trial is needed to clarify the precise role of IV in patients with HF. A recent meta-analysis of RCTs and observational studies indicated that IV was safe and effective to reduce CV events, and it was included in the most updated guideline. Despite these benefits, and the recommendations for its prescription by scientific societies and health regulatory agencies, the vaccination rate remains below than expected globally. The correct understanding of implementation barriers, which involve doctors, patients, and their context, is essential when continuous improvement strategies are planned, in order to improve the IV rate in at-risk subjects.