ArticleBMC infectious diseases2026
Genetic characterization of influenza A (A/H3N2) viruses reveals antigenic drift in receptor binding domain and possible vaccine mismatch in strains circulating in Riyadh, Saudi Arabia, 2024-2025.
Article in BMC infectious diseases, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 1 paper.
What it found
Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.
The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.
Who cites it
1 citing paper in PubMed.
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
8 authors.
Funding
Abstract
introductionInfluenza A/H3N2 viruses undergo continuous antigenic evolution, necessitating ongoing surveillance for informed vaccine strain selection. This study characterized the molecular epidemiology of A/H3N2 viruses circulating in Riyadh, Saudi Arabia, during the winter season of 2024-2025 and assessed their compatibility with current vaccine strains.
methodsNasopharyngeal samples (NPAs) (n=363) were collected from patients presenting with influenza-like illness at King Khalid University Hospital in Riyadh. Influenza A/H3N2 detection and subtyping were performed using RT-PCR. Complete hemagglutinin (HA) and neuraminidase (NA) genes sequencing was conducted on confirmed A/H3N2 strains (n=7), followed by phylogenetic analysis, amino acid substitution mapping, and glycosylation site prediction.
resultsOf 363 samples tested, 110 (30.3%) were positive for influenza A, with 42 (38.2%) identified as A/H3N2 and 68 (61.8%) as A/H1N1pdm09. Phylogenetic analysis revealed that all seven sequenced A/H3N2 strains belonged to clade 2a.3a.1, which is identical to the current vaccine strain clade. However, molecular analysis identified four amino acid substitutions in the HA glycoprotein that distinguished circulating strains from the A/H3N2 vaccine strain A/Croatia/10136RV/2023. The NA gene was homologous to the study isolates, indicating a possible match with the vaccine. Notably, all study strains showed the same N-glycosylation sites that are present in the vaccine strain.
conclusionsWhile phylogenetic clade compatibility suggests potential vaccine effectiveness, the observed amino acid differences highlight the importance of continued molecular surveillance to monitor antigenic drift and assess vaccine performance in the Saudi Arabian population.
Indexed as
Identifiers
What OpenQuestion holds
Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.