{"id":2862,"date":"2024-04-11T07:34:43","date_gmt":"2024-04-11T07:34:43","guid":{"rendered":"https:\/\/repo.epiprev.it\/?p=2862"},"modified":"2024-04-11T07:34:43","modified_gmt":"2024-04-11T07:34:43","slug":"a-reanalysis-of-an-italian-study-on-the-effectiveness-of-covid-19-vaccination-suggests-that-it-might-have-unintended-effects-on-total-mortality","status":"publish","type":"post","link":"https:\/\/repo.epiprev.it\/index.php\/2024\/04\/11\/a-reanalysis-of-an-italian-study-on-the-effectiveness-of-covid-19-vaccination-suggests-that-it-might-have-unintended-effects-on-total-mortality\/","title":{"rendered":"A reanalysis of an Italian study on the effectiveness of COVID-19 vaccination suggests that it might have unintended effects on total mortality"},"content":{"rendered":"\n<p class=\"has-small-font-size\"><strong>Publication date:<\/strong> 11\/04\/2024 &#8211;  <strong>E&amp;P Code:<\/strong>  <a aria-label=\" (opens in a new tab)\" rel=\"noreferrer noopener\" href=\"https:\/\/repo.epiprev.it\/2862\" target=\"_blank\">repo.epiprev.it\/2862<\/a>   <br><strong>Authors:<\/strong> Alessandria M.<sup>1<\/sup>, Malatesta G.<sup>2<\/sup>, Donzelli A.<sup>3<\/sup>, Berrino F.<sup>4<\/sup>.<img decoding=\"async\" src=\"\/wp-content\/uploads\/2020\/06\/sottomessione_ep.png\" alt=\"Sottomesso alla peer review sulla rivista Epidemiologia&amp;Prevenzione\"><\/p>\n\n\n\n<p class=\"has-small-font-size\"><strong>Abstract<\/strong>: Immortal-time bias (ITB) is known to be common in cohort studies and distorts the association estimates between treated and untreated groups. We used data from the last of two large studies in an Italian province on COVID-19 vaccines safety and effectiveness incurred this bias, and aligned the entire population on a single index date, to correct the ITB. We considered the &#8220;all-cause deaths&#8221; outcome to compare the survival curves between the unvaccinated group and the various vaccination statuses. The all-cause deaths Hazard Ratios in univariate analysis for unvaccinated (reference) versus vaccinated with 1, 2, 3\/4 doses were 0.88 (CI95: 0.78 \u20131.00; p-value 0.044), 1.23 (1.16\u20131.32; p-value \u22640.001) and 1.21 (1.14\u20131.29; p-value \u22640.001), respectively. The multivariate values were 2.40 (2.00\u20132.88; p-value &lt;0.0001), 1.98 (1.75\u20132.24; p-value &lt;0.0001), 0.99 (0.90\u20131.09; ns). The possible explanations of the trend of the Hazard Ratios as vaccinations increase could be a harvesting effect; a calendar-time bias, accounting for seasonality and pandemic waves; a case-counting windows bias; a healthy-vaccinee bias; or some their combination. With two and even with 3\/4 doses the calculated Restricted Mean Survival Time and Restricted Mean Time Lost have shown a small but significant downside for the vaccinated populations.<\/p>\n\n\n\n<!--more-->\n\n\n\n<p class=\"has-small-font-size\"><strong>Cite as<\/strong>: Alessandria M., Malatesta G., Donzelli A., Berrino F. (2024). A reanalysis of an Italian study on the effectiveness of COVID-19 vaccination suggests that it might have unintended effects on total mortality. E&P Repository <a href='https:\/\/repo.epiprev.it\/2862'>https:\/\/repo.epiprev.it\/2862<\/a><button title=\"Copia citazione\" id=\"copyTextCite\"><span class=\"far fa-copy\"><\/span><\/button><\/p>\n\n\n\n<p class=\"has-small-font-size\"><strong>Topic<\/strong>: <a href='\/index.php\/category\/COVID-19'>COVID-19<\/a><\/p>\n\n\n\n<p class=\"has-small-font-size\"><strong>Key words<\/strong>: <a href=\"https:\/\/repo.epiprev.it\/index.php\/tag\/all-cause-deaths\/\" rel=\"tag\">all-cause deaths<\/a>, <a href=\"https:\/\/repo.epiprev.it\/index.php\/tag\/covid-19-vaccines\/\" rel=\"tag\">COVID-19 vaccines<\/a>, <a href=\"https:\/\/repo.epiprev.it\/index.php\/tag\/healthy-vaccinee-bias\/\" rel=\"tag\">Healthy-vaccinee bias<\/a>, <a href=\"https:\/\/repo.epiprev.it\/index.php\/tag\/immortal-time-bias\/\" rel=\"tag\">immortal-time bias<\/a>, <\/p>\n\n\n\n<p class=\"has-small-font-size\"><strong>AVVERTENZA. GLI ARTICOLI PRESENTI NEL REPOSITORY NON SONO SOTTOPOSTI A PEER REVIEW.<\/strong><\/p>\n\n\n\n<div class='w3eden'><!-- WPDM Link Template: Default Template -->\n\n\n<div class=\"link-template-default card mb-2\">\n    <div class=\"card-body\">\n        <div class=\"media stack-xs\">\n            <div class=\"media-body\">\n                <div class=\"media\">\n                    <div class=\"mr-3 img-48\"><img decoding=\"async\" class=\"wpdm_icon\" alt=\"Icona\" src=\"https:\/\/repo.epiprev.it\/wp-content\/plugins\/download-manager\/assets\/file-type-icons\/pdf.svg\" onError='this.src=\"https:\/\/repo.epiprev.it\/wp-content\/plugins\/download-manager\/assets\/file-type-icons\/unknown.svg\";' \/><\/div>\n                    <div class=\"media-body\">\n                        <h3 class=\"package-title\"><a href='https:\/\/repo.epiprev.it\/index.php\/download\/a-reanalysis-of-an-italian-study-on-the-effectiveness-of-covid-19-vaccination-suggests-that-it-might-have-unintended-effects-on-total-mortality\/'>A reanalysis of an Italian study on the effectiveness of COVID-19 vaccination suggests that it might have unintended effects on total mortality<\/a><\/h3>\n                        <div class=\"text-muted text-small\"><i class=\"fas fa-file-download\"><\/i> 297 Download <i class=\"fas fa-hdd ml-3\"><\/i> 387.83 KB<\/div>\n                    <\/div>\n                <\/div>\n            <\/div>\n            <div class=\"ml-3 wpdmdl-btn\">\n                <a class='wpdm-download-link btn btn-primary ' rel='nofollow' href='#' onclick=\"location.href='https:\/\/repo.epiprev.it\/index.php\/download\/a-reanalysis-of-an-italian-study-on-the-effectiveness-of-covid-19-vaccination-suggests-that-it-might-have-unintended-effects-on-total-mortality\/?wpdmdl=2867&refresh=69e91469eb0c91776882793';return false;\">Scarica<\/a>\n            <\/div>\n        <\/div>\n\t\t\n    <\/div>\n<\/div>\n\n\n<\/div>\n\n\n\n<h4 class=\"wp-block-heading\">Info<\/h4>\n\n\n\n<p class=\"has-small-font-size\"><strong>Affiliations<\/strong>: <br><sup>1<\/sup> Department of Life Sciences and Systems Biology, University of Turin, Turin (Italy);<br><sup>2<\/sup> Scientific Committee Foundation \u201cAllineare Sanit\u00e0 e Salute\u201d, Pistoia, Italy;<br><sup>3<\/sup> Specialist in Hygiene and Preventive Medicine, independent Medical-Scientific Commission; President of Foundation \u201cAllineare Sanit\u00e0 e Salute\u201d, Milan, Italy;<br><sup>4<\/sup> Past Director, Department of Predictive and Preventive Medicine, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy<\/p>\n\n\n\n<p class=\"has-small-font-size\"><strong>Authors&#8217; contributions: <\/strong><br>Conceptualization A.M., M.G., D.A., B.F.<br>Data Curation A.M., M.G., D.A., B.F<br>Formal Analysis A.M., M.G., D.A., B.F<br>Funding Acquisition D.A.<br>Investigation A.M., M.G., D.A., B.F<br>Methodology A.M., M.G., D.A., B.F<br>Resources A.M., M.G., D.A., B.F<br>Software A.M<br>Supervision A.M., M.G., D.A., B.F<br>Validation A.M., M.G., D.A., B.F<br>Visualization A.M., M.G., D.A., B.F<br>Writing \u2013 Original Draft Preparation A.M., M.G., D.A., B.F<br>Writing \u2013 Review &amp; Editing A.M., M.G., D.A., B.F<\/p>\n\n\n\n<p><strong>Competing interests: <\/strong>&#8211;<\/p>\n\n\n\n<p class=\"has-small-font-size\"><strong>Funding disclosure:<\/strong> None<\/p>\n\n\n\n<p class=\"has-small-font-size\"><strong>Ethics committee approval: <\/strong>The study was based on publicly available aggregate data. No Ethics committee approval was necessary. <\/p>\n\n\n\n<p class=\"has-small-font-size\"><strong>Copyright<\/strong>:  Il detentore del copyright \u00e8 l\u2019autore\/finanziatore, che ha concesso a \u201cE&amp;P Repository\u201d una licenza per rendere pubblico questo preprint. The copyright holder for this preprint is the author\/funder, who has granted E&amp;P Repository a license to display the preprint in perpetuity.<\/p>\n\n\n\n<p class=\"has-small-font-size\"><strong>Terms of distribution<\/strong>: No riutilizzo <\/p>\n\n\n\n<hr \/><img src='https:\/\/repo.epiprev.it\/wp-content\/uploads\/2024\/04\/doctor-5947535_1280-1280x765.png' alt=\"doctor-5947535_1280\" class='attachment-post-thumbnail size-post-thumbnail wp-post-image' \/><p class='has-small-font-size'>Immagine di redazione. Foto di <a href=\"https:\/\/pixabay.com\/it\/users\/elf-moondance-19728901\/?utm_source=link-attribution&utm_medium=referral&utm_campaign=image&utm_content=5947535\">Moondance<\/a> da <a href=\"https:\/\/pixabay.com\/it\/\/?utm_source=link-attribution&utm_medium=referral&utm_campaign=image&utm_content=5947535\">Pixabay<\/a><\/p><hr \/>\n\n\n\n<div style=\"height:20px\" aria-hidden=\"true\" class=\"wp-block-spacer\"><\/div>\n\n\n\n<p class=\"has-background has-small-font-size has-light-gray-background-color\"><strong>References &amp; Citations<\/strong><br><a rel=\"noreferrer noopener\" aria-label=\" (opens in a new tab)\" href=\"https:\/\/scholar.google.com\/scholar?q=A reanalysis of an Italian study on the effectiveness of COVID-19 vaccination suggests that it might have unintended effects on total mortality\" target=\"_blank\">Google Scholar<\/a><\/p>\n\n\n\n<p><a href=\"http:\/\/www.facebook.com\/sharer.php?u=https:\/\/www.repo.epiprev.it\/2862\" target=\"_blank\" rel=\"noopener noreferrer\" title=\"Condividi su Facebook\"><img decoding=\"async\" src=\"\/wp-content\/uploads\/2020\/04\/icon_facebook.png\"><\/a><a href=\"https:\/\/twitter.com\/intent\/tweet?url=https:\/\/www.repo.epiprev.it\/2862\" target=\"_blank\" rel=\"noopener noreferrer\" title=\"Condividi su Twitter\"><img decoding=\"async\" src=\"\/wp-content\/uploads\/2020\/04\/icon_twitter.png\"><\/a><a class=\"icon_whatsapp\" href=\"https:\/\/api.whatsapp.com\/send?text=https%3A%2F%2Frepo.epiprev.it\/2862&amp;attribution=AMPhtml&amp;url=https%3A%2F%2Frepo.epiprev.it\/2862\" target=\"_blank\" rel=\"noopener noreferrer\" title=\"Invia con WhatsApp\"><img decoding=\"async\" src=\"\/wp-content\/uploads\/2020\/04\/icon_whatsapp.png\"><\/a><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Immortal-time bias (ITB) is known to be common in cohort studies and distorts the association estimates between treated and untreated groups. We used data from the last of two large studies in an Italian province on COVID-19 vaccines safety and effectiveness incurred this bias, and aligned the entire population on a single index date, to correct the ITB. We considered the &#8220;all-cause deaths&#8221; outcome to compare the survival curves between the unvaccinated group and the various vaccination statuses.<\/p>\n","protected":false},"author":1,"featured_media":2865,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[13],"tags":[245,243,244,241],"class_list":["post-2862","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-covid-19","tag-all-cause-deaths","tag-covid-19-vaccines","tag-healthy-vaccinee-bias","tag-immortal-time-bias"],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v27.0 - https:\/\/yoast.com\/product\/yoast-seo-wordpress\/ -->\n<title>A reanalysis of an Italian study on the effectiveness of COVID-19 vaccination suggests that it might have unintended effects on total mortality - E&amp;P Repository<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/repo.epiprev.it\/index.php\/2024\/04\/11\/a-reanalysis-of-an-italian-study-on-the-effectiveness-of-covid-19-vaccination-suggests-that-it-might-have-unintended-effects-on-total-mortality\/\" \/>\n<meta property=\"og:locale\" content=\"it_IT\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"A reanalysis of an Italian study on the effectiveness of COVID-19 vaccination suggests that it might have unintended effects on total mortality - E&amp;P Repository\" \/>\n<meta property=\"og:description\" content=\"Immortal-time bias (ITB) is known to be common in cohort studies and distorts the association estimates between treated and untreated groups. We used data from the last of two large studies in an Italian province on COVID-19 vaccines safety and effectiveness incurred this bias, and aligned the entire population on a single index date, to correct the ITB. We considered the &quot;all-cause deaths&quot; outcome to compare the survival curves between the unvaccinated group and the various vaccination statuses.\" \/>\n<meta property=\"og:url\" content=\"https:\/\/repo.epiprev.it\/index.php\/2024\/04\/11\/a-reanalysis-of-an-italian-study-on-the-effectiveness-of-covid-19-vaccination-suggests-that-it-might-have-unintended-effects-on-total-mortality\/\" \/>\n<meta property=\"og:site_name\" content=\"E&amp;P Repository\" \/>\n<meta property=\"article:publisher\" content=\"https:\/\/www.facebook.com\/epiprev\/\" \/>\n<meta property=\"article:published_time\" content=\"2024-04-11T07:34:43+00:00\" \/>\n<meta property=\"og:image\" content=\"https:\/\/repo.epiprev.it\/wp-content\/uploads\/2024\/04\/doctor-5947535_1280.png\" \/>\n\t<meta property=\"og:image:width\" content=\"1280\" \/>\n\t<meta property=\"og:image:height\" content=\"853\" \/>\n\t<meta property=\"og:image:type\" content=\"image\/png\" \/>\n<meta name=\"author\" content=\"administrator\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:label1\" content=\"Scritto da\" \/>\n\t<meta name=\"twitter:data1\" content=\"administrator\" \/>\n\t<meta name=\"twitter:label2\" content=\"Tempo di lettura stimato\" \/>\n\t<meta name=\"twitter:data2\" content=\"2 minuti\" \/>\n<script type=\"application\/ld+json\" class=\"yoast-schema-graph\">{\"@context\":\"https:\/\/schema.org\",\"@graph\":[{\"@type\":\"Article\",\"@id\":\"https:\/\/repo.epiprev.it\/index.php\/2024\/04\/11\/a-reanalysis-of-an-italian-study-on-the-effectiveness-of-covid-19-vaccination-suggests-that-it-might-have-unintended-effects-on-total-mortality\/#article\",\"isPartOf\":{\"@id\":\"https:\/\/repo.epiprev.it\/index.php\/2024\/04\/11\/a-reanalysis-of-an-italian-study-on-the-effectiveness-of-covid-19-vaccination-suggests-that-it-might-have-unintended-effects-on-total-mortality\/\"},\"author\":{\"name\":\"administrator\",\"@id\":\"https:\/\/repo.epiprev.it\/#\/schema\/person\/2a184e8c4e97508ef5111e78c8d0a59c\"},\"headline\":\"A reanalysis of an Italian study on the effectiveness of COVID-19 vaccination suggests that it might have unintended effects on total mortality\",\"datePublished\":\"2024-04-11T07:34:43+00:00\",\"mainEntityOfPage\":{\"@id\":\"https:\/\/repo.epiprev.it\/index.php\/2024\/04\/11\/a-reanalysis-of-an-italian-study-on-the-effectiveness-of-covid-19-vaccination-suggests-that-it-might-have-unintended-effects-on-total-mortality\/\"},\"wordCount\":500,\"commentCount\":0,\"publisher\":{\"@id\":\"https:\/\/repo.epiprev.it\/#organization\"},\"image\":{\"@id\":\"https:\/\/repo.epiprev.it\/index.php\/2024\/04\/11\/a-reanalysis-of-an-italian-study-on-the-effectiveness-of-covid-19-vaccination-suggests-that-it-might-have-unintended-effects-on-total-mortality\/#primaryimage\"},\"thumbnailUrl\":\"https:\/\/repo.epiprev.it\/wp-content\/uploads\/2024\/04\/doctor-5947535_1280.png\",\"keywords\":[\"all-cause deaths\",\"COVID-19 vaccines\",\"Healthy-vaccinee bias\",\"immortal-time bias\"],\"articleSection\":[\"COVID-19\"],\"inLanguage\":\"it-IT\",\"potentialAction\":[{\"@type\":\"CommentAction\",\"name\":\"Comment\",\"target\":[\"https:\/\/repo.epiprev.it\/index.php\/2024\/04\/11\/a-reanalysis-of-an-italian-study-on-the-effectiveness-of-covid-19-vaccination-suggests-that-it-might-have-unintended-effects-on-total-mortality\/#respond\"]}]},{\"@type\":\"WebPage\",\"@id\":\"https:\/\/repo.epiprev.it\/index.php\/2024\/04\/11\/a-reanalysis-of-an-italian-study-on-the-effectiveness-of-covid-19-vaccination-suggests-that-it-might-have-unintended-effects-on-total-mortality\/\",\"url\":\"https:\/\/repo.epiprev.it\/index.php\/2024\/04\/11\/a-reanalysis-of-an-italian-study-on-the-effectiveness-of-covid-19-vaccination-suggests-that-it-might-have-unintended-effects-on-total-mortality\/\",\"name\":\"A reanalysis of an Italian study on the effectiveness of COVID-19 vaccination suggests that it might have unintended effects on total mortality - 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