inactivated trivalent influenza vaccine (eTIV_f / Evagrip / Fluvirin)

Genomic evolution patterns of influenza A/H1N1 in Iraqi patients revealed by nanopore sequencing.

Owaid Farah M FM, Fadhil Hula Y HY

Influenza viruses have high mutation rates and cause serious health problems worldwide. In our population, no study has examined mutations and their variation relative to the wild-type and vaccine strains. Study focused on whole-genome sequencing to characterize the virus, construct phylogenetic trees, analyze mutations, and assess nucleotide diversity. Nasal swabs were collected from 170 patients with RTI (SARI or ILI) in Baghdad and Wasit from November 2024 to March 2025, and tested for influenza A virus detection and typing by real-time reverse transcription polymerase chain reaction. The 14 positive viral genomes were sequenced using the MinION nanopore platform. 49 influenza viral genomes were identified as positive cases, comprising 48 A/H1N1 and 1 A/H3N2 strain. Nine complete A/H1N1 were sequenced, revealing nonsynonymous mutations, especially in the hemagglutinin (HA), neuraminidase (NA), and nonstructural protein 1 (NS1) genes. Nucleotide diversity analysis revealed negative selection in certain A/H1N1 genes. Mutations were detected in antigenic and functional regions of HA and NA, indicating ongoing antigenic drift in circulating strains. Phylogenetic analysis showed that the Iraqi isolates were closely related to contemporary regional and global strains reported from neighboring countries such as Iran and Saudi Arabia, and were partially genetically related to recent vaccine strains such as A/Wisconsin/67/2022 and A/Missouri/11/2025. By contrast, the older vaccine strains suggest that Iraqi influenza viruses are evolving slowly, accumulating mutations continuously, while the important internal proteins are conserved. Mutations across all eight genome segments will be crucial for elucidating the genetic evolution of influenza A viruses in Iraq.

The Dual Role of Preexisting Immunity in Influenza: Protective Recall Versus Constraint of Novel Responses.

Fox Annette A, Zhu Ziheng Z, Sánchez-Ovando Stephany S

Preexisting immunity to influenza confers rapid protection against antigenically matched viruses but can also constrain responses to drifted variants. This review asks when and why prior infection or vaccination is protective versus detrimental, and which biological mechanisms-epitope masking by circulating antibody, inhibitory FcγRIIb signaling, and competitive dominance by affinity-matured memory B cells-drive these outcomes. We synthesize human cohort, serological, and vaccine-effectiveness data with mechanistic mouse and fate-mapping studies to explore how vaccine formulation, antigen dose, antigenic distance and T cell help modulate the balance between memory recall and recruitment of naïve B cells. Finally, we outline strategies (higher dose, adjuvants, multivalent display, and considered strain selection) to restore de novo responses against escape epitopes and improve vaccine performance.

Respiratory symptoms, vaccination coverage, and antibiotic use among Hajj pilgrims: a multi-season cross sectional study (2023-2025).

Qashqari Fadi S I FSI

Respiratory tract infections are the most frequently reported illnesses during Hajj, one of the world's largest recurring mass gatherings. The convergence of millions of pilgrims from diverse geographic regions in Makkah, Saudi Arabia creates conditions conducive to the transmission of respiratory pathogens. Understanding patterns of infection, vaccination coverage, and antibiotic use across multiple seasons is essential to inform preventive strategies. A multi-season cross-sectional study was conducted during three consecutive Hajj seasons (2023-2025). Adult pilgrims were recruited and interviewed using a standardized structured questionnaire. Data collected included sociodemographic characteristics, vaccination history (meningococcal, influenza, COVID-19, pneumococcal), comorbidities, smoking behavior, respiratory symptoms, healthcare-seeking behavior, and antibiotic use. Multivariable logistic regression analyses were performed to identify factors independently associated with respiratory symptoms and antibiotic consumption. A total of 712 human participants (adult Hajj pilgrims) were enrolled. Overall, 38.9% reported at least one respiratory symptom at the time of assessment, with cough (28.1%), sore throat (23.5%), and runny nose (21.9%) being most common. Chronic lung disease (adjusted odds ratio [aOR] 2.36; 95% CI 1.42-3.92), presence of ≥1 chronic condition (aOR 1.58; 95% CI 1.12-2.24), and current smoking (aOR 1.74; 95% CI 1.15-2.63) were independently associated with respiratory symptoms. Influenza vaccination was associated with reduced odds of multi-symptom respiratory illness (aOR 0.72; 95% CI 0.53-0.98). Among symptomatic participants, 29.6% reported antibiotic use, frequently in the absence of febrile illness. Vaccination coverage was high for meningococcal vaccine (96.1%), while pneumococcal vaccination coverage remained lower. Respiratory symptoms remain a substantial health burden among Hajj pilgrims across consecutive seasons. Chronic lung disease and smoking increase susceptibility, while influenza vaccination appears protective. The frequent use of antibiotics highlights the need for strengthened antimicrobial stewardship. Enhanced vaccination uptake, targeted risk communication, and integrated prevention strategies are critical to mitigating respiratory infection risks during mass gatherings and safeguarding global public health.

Evans syndrome following influenza A presenting with diffuse alveolar hemorrhage managed with extracorporeal membrane oxygenation.

Lu Haotian H, Shi Anke A, Yu Jieqiong J, Zhao Jing J et al.