{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,11,2]],"date-time":"2025-11-02T08:50:58Z","timestamp":1762073458502,"version":"build-2065373602"},"reference-count":32,"publisher":"MDPI AG","issue":"21","license":[{"start":{"date-parts":[[2022,10,25]],"date-time":"2022-10-25T00:00:00Z","timestamp":1666656000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["IJERPH"],"abstract":"<jats:p>The duration of protection of vaccines against SARS-CoV-2 infection has been evaluated in previous studies, but uncertainty remains about the persistence of effectiveness over time and the ideal timing for booster doses. Therefore, the aim of this study was to evaluate BNT162b2 vaccine effectiveness against SARS-CoV-2 infection in health care workers (HCWs) at a tertiary hospital depending on time elapsed since the completion of a two-dose vaccination regimen. We conducted a case\u2013control with negative test study between 25 January and 12 December 2021 that included 1404 HCWs who underwent an active infection diagnostic test (AIDT) to rule out SARS-CoV-2 infection due to COVID-19 suspicion or prior close contact with patients diagnosed with COVID-19. The adjusted vaccine effectiveness (aVE) for the prevention of SARS-CoV-2 infection 12 to 120 days after completing the full two-dose vaccination regimen was 91.9%. Then, aVE decreased to 63.7% between 121 to 240 days after completing the full two-dose regimen and to 37.2% after 241 days since the second dose. Vaccination against SARS-CoV-2 infection in HCWs remains highly effective after 12 to 120 days have elapsed since the administration of two doses of the BNT162b2 vaccine; however, effectiveness decreases as time elapses since its administration.<\/jats:p>","DOI":"10.3390\/ijerph192113884","type":"journal-article","created":{"date-parts":[[2022,10,25]],"date-time":"2022-10-25T21:58:06Z","timestamp":1666735086000},"page":"13884","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":2,"title":["The Waning of BNT162b2 Vaccine Effectiveness for SARS-CoV-2 Infection Prevention over Time: A Test-Negative Study in Health Care Professionals of a Health Department from January 2021 to December 2021"],"prefix":"10.3390","volume":"19","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-2405-0884","authenticated-orcid":false,"given":"Natali","family":"Jim\u00e9nez-Sep\u00falveda","sequence":"first","affiliation":[{"name":"Epidemiology Unit, Department of Preventive Medicine, Alicante Institute for Health and Biomedical Research (ISABIAL), General University Hospital Dr. Balmis, 03010 Alicante, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2809-8751","authenticated-orcid":false,"given":"Pablo","family":"Chico-S\u00e1nchez","sequence":"additional","affiliation":[{"name":"Epidemiology Unit, Department of Preventive Medicine, Alicante Institute for Health and Biomedical Research (ISABIAL), General University Hospital Dr. Balmis, 03010 Alicante, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4412-0149","authenticated-orcid":false,"given":"Jos\u00e9 Miguel","family":"Castro-Garc\u00eda","sequence":"additional","affiliation":[{"name":"Department of Medical Imaging, General University Hospital Dr. Balmis, 03010 Alicante, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Isabel","family":"Escribano-Ca\u00f1adas","sequence":"additional","affiliation":[{"name":"Department of Microbiology, Alicante Institute for Health and Biomedical Research (ISABIAL), General University Hospital Dr. Balmis, 03010 Alicante, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3854-4874","authenticated-orcid":false,"given":"Esperanza","family":"Merino-Lucas","sequence":"additional","affiliation":[{"name":"Unit of Infectious Diseases, Alicante Institute for Health and Biomedical Research (ISABIAL), General University Hospital Dr. Balmis, 03010 Alicante, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1886-466X","authenticated-orcid":false,"given":"Elena","family":"Ronda-P\u00e9rez","sequence":"additional","affiliation":[{"name":"Preventive Medicine and Public Health Area, Faculty of Health Sciences, University of Alicante, 03690 Alicante, Spain"},{"name":"Centre of Networked Biomedical Research in Epidemiology and Public Health (CIBERESP), 28029 Madrid, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Jos\u00e9","family":"S\u00e1nchez-Pay\u00e1","sequence":"additional","affiliation":[{"name":"Epidemiology Unit, Department of Preventive Medicine, Alicante Institute for Health and Biomedical Research (ISABIAL), General University Hospital Dr. Balmis, 03010 Alicante, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3505-3244","authenticated-orcid":false,"given":"Paula","family":"Gras-Valent\u00ed","sequence":"additional","affiliation":[{"name":"Epidemiology Unit, Department of Preventive Medicine, Alicante Institute for Health and Biomedical Research (ISABIAL), General University Hospital Dr. Balmis, 03010 Alicante, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"name":"on behalf of the COVID-19 Preventive Medicine Group","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2022,10,25]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1761","DOI":"10.1056\/NEJMoa2110345","article-title":"Safety and Efficacy of the BNT162b2 mRNA COVID-19 Vaccine through 6 Months","volume":"385","author":"Thomas","year":"2021","journal-title":"N. 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