{"doi":"10.3389/fimmu.2025.1514845","title":"Adjuvanted subunit intranasal vaccine reduces SARS-CoV-2 onward transmission in hamsters","abstract":"Introduction: Most COVID-19 vaccine trials have focused on recipient protection, not protection of their contacts, a critical need. As a subunit intranasal COVID-19 vaccine reduced nasopharyngeal virus more than did an intramuscular (IM) vaccine, we hypothesized that this vaccine might reduce onward transmission to others. Methods: We vaccinated hamsters with either the IM-administrated licensed mRNA vaccine twice or one dose of mRNA IM followed by adjuvanted subunit intranasal vaccine. 24 hours after SARS-CoV-2 challenge, these animals were housed with naïve recipients in a contactless chamber that allows airborne transmission. Results: Onward airborne transmission was profoundly blocked: the donor and recipients of the intranasal vaccine-boosted group had lower oral and lung viral loads (VL), which correlated with mucosal ACE2 inhibition activity. Notably, in this head-to-head comparison of COVID-19 booster vaccines on SARS-CoV-2 onward transmission, we found that statistically significant viral reduction in the lung tissues and oral swabs was observed only in the intranasal S1 nanoparticle vaccine-boosted group, but not in the systemic mRNA vaccine-boosted group, suggesting the superior protection of this intranasal vaccine, which could act as an attractive vaccine booster candidate to complement the current licensed systemic vaccines. Discussion: Overall, our study strongly supports the use of the intranasal vaccine as a boost to protect not only the vaccinated person, but also people exposed to the vaccinated person, a key public health goal.","journal":"Frontiers in Immunology","year":2025,"id":520520,"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":5,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.9578,"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":618561,"name":"Swagata Kar","orcid":"0000-0003-3702-6207","position":1,"is_corresponding":false},{"id":1390068,"name":"Bhavna Chawla","orcid":"0009-0001-7759-122X","position":2,"is_corresponding":false},{"id":384494,"name":"Tanya Hoang","orcid":null,"position":3,"is_corresponding":false},{"id":1390461,"name":"YuanKai Yu","orcid":null,"position":4,"is_corresponding":false},{"id":909320,"name":"Shannon M. Wallace","orcid":"0009-0008-6735-4969","position":5,"is_corresponding":false},{"id":106758,"name":"Hanné Andersen","orcid":null,"position":6,"is_corresponding":false},{"id":388227,"name":"Jay A. Berzofsky","orcid":"0000-0002-0342-3194","position":7,"is_corresponding":false},{"id":456627,"name":"Yongjun Sui","orcid":"0000-0002-1568-4607","position":0,"is_corresponding":true}],"reference_count":17,"raw_metadata":null,"created_at":"2026-07-19T02:49:28.470782Z","pmid":"39981227","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":[]}