{"doi":"10.1038/s41541-025-01331-6","title":"Influenza vaccination post-COVID-19 expands vaccine-specific effector CD4 T-cells and Tregs under positive influence of host trained innate immunity","abstract":"SARS-CoV-2 immunity and innate immune training may influence influenza vaccine immunogenicity. We investigated this in India. Adult volunteers with hybrid SARS-CoV-2 immunity were administered FluarixTM Tetra (GlaxoSmithKlein) 2022/2023 NH Vaccine in 2022. Significant induction of hemagglutinin inhibition-specific antibodies and polyfunctional central memory CD4+ T-cells (TCM) were observed 1-week post-vaccination with variable induction of CD8+T-cell and innate effectors. Vaccination also expanded Flu-specific regulatory T-cells (Treg), which negatively correlated with CD4 responses, highlighting vaccine immunogenicity may be subject to Treg dampening. FluarixTM did not boost SARS-CoV-2 immunity. However, SARS-CoV-2-specific T-cell responses correlated positively with vaccine-induced T-cell responses. We evaluated trained immunity post-COVID-19 as a potential regulatory mechanism linking SARS-CoV-2 and heterologous vaccine immunogenicity. We observed, elevated frequencies of basal bacterial Lipopolysaccharide (LPS)-induced IL-6+IL1β+HLA-DR+CD14+CD16- frequencies post-COVID-19 correlated positively with vaccine-induced Fluarix-specific CD4 T-cell frequencies. Our study highlights a potential positive role for COVID-19-driven immune imprinting on heterologous vaccine immunogenicity in a post-COVID-19 era.","journal":"npj Vaccines","year":2025,"id":587143,"datarank":0.0,"base_score":0.0,"endowment":0.0,"self_citation_contribution":0.0,"citation_network_contribution":0.0,"self_endowment_contribution":0.0,"citer_contribution":0.0,"corpus_percentile":null,"corpus_rank":null,"citation_count":0,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.9553,"is_data_producer":false,"deposit_databanks":null,"is_oa":true,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":"2025-01-01","fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":648741,"name":"Srabanti Rakshit","orcid":null,"position":1,"is_corresponding":false},{"id":647555,"name":"Vasista Adiga","orcid":"0000-0002-6996-4786","position":2,"is_corresponding":false},{"id":1502219,"name":"Asma Ahmed","orcid":"0000-0002-7194-5701","position":3,"is_corresponding":false},{"id":885128,"name":"Nirutha Chetan Kumar","orcid":null,"position":4,"is_corresponding":false},{"id":1502752,"name":"Maria Macrina","orcid":null,"position":5,"is_corresponding":false},{"id":1069405,"name":"Himanshu Tripathi","orcid":"0000-0003-4703-944X","position":6,"is_corresponding":false},{"id":464448,"name":"Francesca Vanni","orcid":null,"position":7,"is_corresponding":false},{"id":549978,"name":"Emanuele Montomoli","orcid":"0000-0001-7595-4974","position":8,"is_corresponding":false},{"id":323265,"name":"Sweety Samal","orcid":"0000-0001-7894-8756","position":9,"is_corresponding":false},{"id":953734,"name":"Sneha Raj","orcid":null,"position":10,"is_corresponding":false},{"id":323262,"name":"Preeti Vishwakarma","orcid":"0000-0001-8530-4860","position":11,"is_corresponding":false},{"id":1502753,"name":"George D’ Souza","orcid":null,"position":12,"is_corresponding":false},{"id":1502754,"name":"Shruthi Sasidharan","orcid":null,"position":13,"is_corresponding":false},{"id":647556,"name":"Mary Dias","orcid":"0000-0002-5313-1819","position":14,"is_corresponding":false},{"id":393223,"name":"Timothy Tree","orcid":"0000-0002-6973-5377","position":15,"is_corresponding":false},{"id":647558,"name":"Annapurna Vyakarnam","orcid":"0000-0003-4260-258X","position":16,"is_corresponding":false},{"id":1309388,"name":"Hima Bindhu","orcid":null,"position":0,"is_corresponding":true}],"reference_count":63,"raw_metadata":null,"created_at":"2026-07-19T02:59:36.020030Z","pmid":"41453905","pmcid":null,"fwci":null,"citation_percentile":null,"influential_citations":0,"oa_status":null,"license":null,"views":0,"total_file_size_bytes":0,"version_count":0,"fair_f":null,"fair_a":null,"fair_i":null,"fair_r":null,"fair_zscore":null,"fair_rationale":null,"fair_model":null,"fair_agent_version":null,"fair_fulltext_source":null,"fair_has_llm":null,"fair_computed_at":null,"clinical_trials":[],"software_tools":[],"db_accessions":[],"linked_datasets":[],"topics":[]}