{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,18]],"date-time":"2026-08-18T05:15:27Z","timestamp":1787030127152,"version":"build-2736575974"},"reference-count":44,"publisher":"MDPI AG","issue":"5","license":[{"start":{"date-parts":[[2022,5,17]],"date-time":"2022-05-17T00:00:00Z","timestamp":1652745600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Lombardy Region","award":["DGR XI\/3450"],"award-info":[{"award-number":["DGR XI\/3450"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Viruses"],"abstract":"<jats:p>Despite the existence of an effective live-attenuated vaccine, measles can appear in vaccinated individuals. We investigated breakthrough measles cases identified during our surveillance activities within the measles\/rubella surveillance network (MoRoNet) in Milan and surrounding areas (Northern Italy). Between 2017 and 2021, we confirmed measles virus (genotypes B3 or D8) infections in 653 patients and 51 of these (7.8%) were vaccinees. Among vaccinated individuals whose serum was available, a secondary failure was evidenced in 69.4% (25\/36) of cases while 11 patients (30.6%) were non-responders. Non-responders were more frequently hospitalized and had significantly lower Ct values in both respiratory and urine samples. Median age and time since the last immunization were similar in the two groups. Importantly, we identified onward transmissions from vaccine failure cases. Vaccinees were involved in 20 outbreaks, in 10 of them they were able to transmit the virus, and in 8 of them, they were the index case. Comparing viral hemagglutinin sequences from vaccinated and non-vaccinated subjects did not show a specific mutation pattern. These results suggest that vaccination failure was likely due to the poor immune response of single individuals and highlights the importance of identifying breakthrough cases and characterizing their clinical and virologic profiles.<\/jats:p>","DOI":"10.3390\/v14051068","type":"journal-article","created":{"date-parts":[[2022,5,17]],"date-time":"2022-05-17T04:04:19Z","timestamp":1652760259000},"page":"1068","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":29,"title":["Characterization of Vaccine Breakthrough Cases during Measles Outbreaks in Milan and Surrounding Areas, Italy, 2017\u20132021"],"prefix":"10.3390","volume":"14","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-1365-9408","authenticated-orcid":false,"given":"Silvia","family":"Bianchi","sequence":"first","affiliation":[{"name":"Department of Health Sciences, Universit\u00e0 Degli Studi di Milano, 20142 Milan, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6478-2791","authenticated-orcid":false,"given":"Maria","family":"Gori","sequence":"additional","affiliation":[{"name":"Department of Health Sciences, Universit\u00e0 Degli Studi di Milano, 20142 Milan, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1573-5531","authenticated-orcid":false,"given":"Clara","family":"Fappani","sequence":"additional","affiliation":[{"name":"Department of Health Sciences, Universit\u00e0 Degli Studi di Milano, 20142 Milan, Italy"},{"name":"Department of Clinical Sciences and Community Health, Universit\u00e0 Degli Studi di Milano, 20133 Milan, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Giulia","family":"Ciceri","sequence":"additional","affiliation":[{"name":"Department of Health Sciences, Universit\u00e0 Degli Studi di Milano, 20142 Milan, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9959-128X","authenticated-orcid":false,"given":"Marta","family":"Canuti","sequence":"additional","affiliation":[{"name":"Department of Health Sciences, Universit\u00e0 Degli Studi di Milano, 20142 Milan, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Daniela","family":"Colzani","sequence":"additional","affiliation":[{"name":"Department of Health Sciences, Universit\u00e0 Degli Studi di Milano, 20142 Milan, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Marco","family":"Dura","sequence":"additional","affiliation":[{"name":"Department of Health Sciences, Universit\u00e0 Degli Studi di Milano, 20142 Milan, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Mara","family":"Terraneo","sequence":"additional","affiliation":[{"name":"Department of Health Sciences, Universit\u00e0 Degli Studi di Milano, 20142 Milan, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Anna","family":"Lamberti","sequence":"additional","affiliation":[{"name":"Health Protection Agency, Metropolitan Area of Milan, 20121 Milan, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0226-7599","authenticated-orcid":false,"given":"Melissa","family":"Baggieri","sequence":"additional","affiliation":[{"name":"Department of Infectious Diseases, Istituto Superiore di Sanit\u00e0, 00161 Rome, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sabrina","family":"Senatore","sequence":"additional","affiliation":[{"name":"Health Protection Agency, Metropolitan Area of Milan, 20121 Milan, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Marino","family":"Faccini","sequence":"additional","affiliation":[{"name":"Health Protection Agency, Metropolitan Area of Milan, 20121 Milan, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0394-7043","authenticated-orcid":false,"given":"Fabio","family":"Magurano","sequence":"additional","affiliation":[{"name":"Department of Infectious Diseases, Istituto Superiore di Sanit\u00e0, 00161 Rome, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4119-701X","authenticated-orcid":false,"given":"Elisabetta","family":"Tanzi","sequence":"additional","affiliation":[{"name":"Department of Health Sciences, Universit\u00e0 Degli Studi di Milano, 20142 Milan, Italy"},{"name":"Coordinated Research Center \u201cEpiSoMI\u201d, Universit\u00e0 Degli Studi di Milano, 20133 Milan, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0499-8977","authenticated-orcid":false,"given":"Antonella","family":"Amendola","sequence":"additional","affiliation":[{"name":"Department of Health Sciences, Universit\u00e0 Degli Studi di Milano, 20142 Milan, Italy"},{"name":"Coordinated Research Center \u201cEpiSoMI\u201d, Universit\u00e0 Degli Studi di Milano, 20133 Milan, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2022,5,17]]},"reference":[{"key":"ref_1","unstructured":"World Health Organization (2022, January 26). 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