{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,2,6]],"date-time":"2026-02-06T23:28:08Z","timestamp":1770420488993,"version":"3.49.0"},"reference-count":25,"publisher":"Wiley","issue":"1","license":[{"start":{"date-parts":[[2023,9,14]],"date-time":"2023-09-14T00:00:00Z","timestamp":1694649600000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by-nc-nd\/4.0\/"}],"funder":[{"DOI":"10.13039\/100012504","name":"Royal Melbourne Hospital Neuroscience Foundation","doi-asserted-by":"publisher","id":[{"id":"10.13039\/100012504","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":["onlinelibrary.wiley.com"],"crossmark-restriction":true},"short-container-title":["Euro J of Neurology"],"published-print":{"date-parts":[[2024,1]]},"abstract":"<jats:title>Abstract<\/jats:title><jats:sec><jats:title>Background and purpose<\/jats:title><jats:p>This study was undertaken to retrospectively compare rates of John Cunningham virus (JCV) seroconversion in natalizumab\u2010treated patients before and during COVID\u201019\u2010related community restrictions. Natalizumab is highly effective therapy for relapsing\u2013remitting multiple sclerosis. Prolonged exposure to natalizumab in JCV\u2010positive patients can cause progressive multifocal leukoencephalopathy, a potentially fatal brain infection. Serial assessment of JCV status is required for patients receiving natalizumab.<\/jats:p><\/jats:sec><jats:sec><jats:title>Methods<\/jats:title><jats:p>Patients receiving natalizumab at the Royal Melbourne Hospital were assessed for change in JCV serostatus and duration of exposure to natalizumab in two discrete time periods: from 1 February 2012 until 1 February 2017 (\u201cpre\u2010COVID\u201d; <jats:italic>n<\/jats:italic>\u2009=\u2009128) and from 1 April 2020 until 12 October 2022 (\u201cCOVID\u201d; <jats:italic>n<\/jats:italic>\u2009=\u2009214). A Poisson regression model adjusted for age at natalizumab commencement and sex was used to model seroconversion rate between the two time periods.<\/jats:p><\/jats:sec><jats:sec><jats:title>Results<\/jats:title><jats:p>The pre\u2010COVID JCV seroconversion rate among natalizumab\u2010treated patients at the Royal Melbourne Hospital was 9.08%. Conversely, we found a precipitous decline in JCV seroconversion during COVID lockdown. Annualized seroconversion during COVID\u201019\u2010related restrictions was 2.01%. The annualized seroconversion rate was 4.7 times higher during the pre\u2010COVID\u201019 period (95% confidence interval\u2009=\u20092.96\u20137.45, <jats:italic>p<\/jats:italic>\u2009&lt;\u20090.0001) compared to the annualized seroconversion rate during COVID lockdown. Males had a 2\u00d7 higher rate of seroconversion compared to females.<\/jats:p><\/jats:sec><jats:sec><jats:title>Conclusions<\/jats:title><jats:p>JCV seroconversion among natalizumab\u2010treated patients was markedly lower during COVID\u201019\u2010related community restrictions. Restrictions observed in Melbourne were among the longest and most comprehensive implemented worldwide. This suggests the presence of modifiable risk factors that could lower rates of JCV seroconversion among natalizumab\u2010treated patients.<\/jats:p><\/jats:sec>","DOI":"10.1111\/ene.16059","type":"journal-article","created":{"date-parts":[[2023,9,14]],"date-time":"2023-09-14T17:48:18Z","timestamp":1694713698000},"update-policy":"https:\/\/doi.org\/10.1002\/crossmark_policy","source":"Crossref","is-referenced-by-count":4,"title":["Rates of John Cunningham virus seroconversion greatly reduced in natalizumab\u2010treated patients during COVID\u201019\u2010related lockdowns"],"prefix":"10.1111","volume":"31","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-6387-6585","authenticated-orcid":false,"given":"Chris","family":"Dwyer","sequence":"first","affiliation":[{"name":"Neuroimmunology Centre, Department of Neurology Royal Melbourne Hospital  Parkville Victoria Australia"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Sifat","family":"Sharmin","sequence":"additional","affiliation":[{"name":"Clinical Outcomes Research Unit (CORe), Department of Medicine University of Melbourne  Parkville Victoria Australia"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3778-1376","authenticated-orcid":false,"given":"Tomas","family":"Kalincik","sequence":"additional","affiliation":[{"name":"Neuroimmunology Centre, Department of Neurology Royal Melbourne Hospital  Parkville Victoria Australia"},{"name":"Clinical Outcomes Research Unit (CORe), Department of Medicine University of Melbourne  Parkville Victoria Australia"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"311","published-online":{"date-parts":[[2023,9,14]]},"reference":[{"key":"e_1_2_10_2_1","doi-asserted-by":"publisher","DOI":"10.1056\/NEJMoa044397"},{"key":"e_1_2_10_3_1","doi-asserted-by":"publisher","DOI":"10.1056\/NEJMoa020696"},{"key":"e_1_2_10_4_1","doi-asserted-by":"publisher","DOI":"10.1212\/NXI.0000000000000235"},{"key":"e_1_2_10_5_1","doi-asserted-by":"publisher","DOI":"10.1002\/ana.24286"},{"key":"e_1_2_10_6_1","doi-asserted-by":"publisher","DOI":"10.1002\/ana.22128"},{"key":"e_1_2_10_7_1","doi-asserted-by":"publisher","DOI":"10.1371\/journal.ppat.1000363"},{"key":"e_1_2_10_8_1","doi-asserted-by":"publisher","DOI":"10.1111\/apm.12128"},{"key":"e_1_2_10_9_1","doi-asserted-by":"publisher","DOI":"10.1111\/ene.12988"},{"key":"e_1_2_10_10_1","doi-asserted-by":"publisher","DOI":"10.1177\/1352458515599681"},{"key":"e_1_2_10_11_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.jns.2016.03.050"},{"key":"e_1_2_10_12_1","doi-asserted-by":"publisher","DOI":"10.1128\/JVI.72.12.9918-9923.1998"},{"key":"e_1_2_10_13_1","doi-asserted-by":"publisher","DOI":"10.1128\/JVI.75.21.10290-10299.2001"},{"issue":"3","key":"e_1_2_10_14_1","first-page":"179","article-title":"John Cunningham virus: an overview on biology and disease of the etiological agent of the progressive multifocal leukoencephalopathy","volume":"41","author":"Pietropaolo V","year":"2018","journal-title":"New Microbiol"},{"key":"e_1_2_10_15_1","doi-asserted-by":"publisher","DOI":"10.1002\/ana.22366"},{"key":"e_1_2_10_16_1","doi-asserted-by":"publisher","DOI":"10.1016\/S1474-4422(17)30470-2"},{"key":"e_1_2_10_17_1","unstructured":"Ltd BP.Product Information TYSABRI(natalizumab). 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