{
  "abstract": "During a 2025 hepatitis A outbreak in Portimão, southern Portugal, two Roma communities required different public health responses: whole-community vaccination in Cabeço do Mocho, where hygiene and sanitation conditions were deficient, and mainly reactive household-based vaccination in Vale da Arrancada, where residents had potable water and sanitation. We assessed vaccination effectiveness and the consequences of non-vaccination. We conducted a retrospective comparative observational study nested within an outbreak investigation. Residents were classified as vaccinated only if at least 14 days had elapsed between vaccination and symptom onset; otherwise they were classified as unvaccinated. Infection by vaccination status was compared within each community and overall using Fisher’s exact test. By 23 July 2025, 44 outbreak-related cases had been identified. In Cabeço do Mocho, vaccination coverage was 75/107 (70.1%); infection occurred in 2/75 vaccinated versus 11/32 unvaccinated residents (2.7% vs 34.4%; RR = 0.0776; estimated effectiveness 92.2%; p = 0.000021). In Vale da Arrancada, coverage was 21/70 (30.0%); no vaccinated resident became a case, compared with 8/49 unvaccinated residents (0% vs 16.3%; p = 0.094870). Overall, infection occurred in 2/96 vaccinated and 19/81 unvaccinated residents (2.1% vs 23.5%; RR = 0.0888; estimated effectiveness 91.1%; p = 0.000009). Vaccination was associated with markedly lower hepatitis A infection. Whole-community outreach achieved substantially higher coverage than reactive household-based vaccination, while non-vaccination concentrated cases in both communities. These findings support early context-adapted vaccination strategies in socially vulnerable settings during hepatitis A outbreaks.\n\nKey messages: • Whole-community vaccination in the higher-risk setting achieved greater coverage and was associated with lower hepatitis A infection.\n\n• Considering protection only from 14 days after vaccination, cases were concentrated among non-vaccinated residents in both communities.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": "abstract",
  "arxiv": null,
  "author_total": 8,
  "authors": [
    {
      "name": "I F Medeiros"
    },
    {
      "name": "E A Matias"
    },
    {
      "name": "I C Gonçalves"
    },
    {
      "name": "L T Castêdo"
    },
    {
      "name": "J D Ferreira"
    },
    {
      "name": "P A Correia"
    },
    {
      "name": "L C Cadinha"
    },
    {
      "name": "L P Porojan"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/bewn8e17crcj4.bib",
  "cited_by": 0,
  "doi": "10.1093/eurpub/ckag169.1609",
  "fulltext_url": "https://pmc.ncbi.nlm.nih.gov/articles/PMC13699760/",
  "id": "bewn8e17crcj4",
  "issns": [
    "1101-1262",
    "1464-360X"
  ],
  "landing_url": "https://doi.org/10.1093/eurpub/ckag169.1609",
  "language": "en",
  "licence": "CC-BY-NC-4.0",
  "licence_label": "CC BY-NC 4.0",
  "licence_source": "article",
  "licence_url": "https://creativecommons.org/licenses/by-nc/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "heading",
      "6. Poster Displays"
    ],
    [
      "heading",
      "AcademicSubjects/MED00860"
    ],
    [
      "heading",
      "AcademicSubjects/SOC01210"
    ],
    [
      "heading",
      "AcademicSubjects/SOC02610"
    ],
    [
      "heading",
      "DN. Infectious diseases control"
    ],
    [
      "openalex",
      "2721|Hepatitis Viruses Studies and Epidemiology"
    ]
  ],
  "openalex": "W7223663503",
  "pdf_url": "https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13699760/pdf/?tool=EBI",
  "pmcid": "PMC13699760",
  "pmid": null,
  "published": "2026-10-01",
  "publisher": "Oxford University Press",
  "ris": "https://research.draconitic.com/paper/bewn8e17crcj4.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:20:19Z",
      "native_id": "PMC13699760",
      "source": "pmc",
      "url": "https://doi.org/10.1093/eurpub/ckag169.1609"
    },
    {
      "first_seen": "2026-10-30T12:21:25Z",
      "native_id": "PMC:PMC13699760",
      "source": "europepmc",
      "url": "https://europepmc.org/article/PMC/PMC13699760"
    }
  ],
  "subjects": [
    {
      "field": "medicine",
      "origin": "openalex:2721|Hepatitis Viruses Studies and Epidemiology",
      "subfield": "general"
    }
  ],
  "title": "Vaccination effectiveness under risk-adapted outbreak response in two Roma communities, Portugal",
  "title_text": "Vaccination effectiveness under risk-adapted outbreak response in two Roma communities, Portugal",
  "type": "peer-reviewed",
  "updated_at": "2026-10-30T12:36:17Z",
  "url": "https://research.draconitic.com/paper/bewn8e17crcj4",
  "venue": "The European Journal of Public Health",
  "versions": []
}