COVID-19 vaccine effectiveness against hospitalizations and severe outcomes in Kosovo, 2022-2024: a test negative case–control study

COVID-19 vaccine effectiveness against hospitalizations and severe outcomes in Kosovo, 2022-2024: a test negative case–control study | Authorea try { document.documentElement.classList.add('js'); } catch (e) { } var _gaq = _gaq || []; _gaq.push(['_setAccount', 'G-8VDV14Y67G']); _gaq.push(['_trackPageview']); (function() { var ga = document.createElement('script'); ga.type = 'text/javascript'; ga.async = true; ga.src = ('https:' == document.location.protocol ? 'https://ssl' : 'http://www') + '.google-analytics.com/ga.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(ga, s); })(); Skip to main content Preprints Collections Wiley Open Research IET Open Research Ecological Society of Japan All Collections About About Authorea FAQs Contact Us Quick Search anywhere Search for preprint articles, keywords, etc. Search Search ADVANCED SEARCH SCROLL Influenza and other respiratory viruses This is a preprint and has not been peer reviewed. Data may be preliminary. 7 April 2025 V1 Latest version Share on COVID-19 vaccine effectiveness against hospitalizations and severe outcomes in Kosovo, 2022-2024: a test negative case–control study Authors : Besfort Kryeziu 0000-0002-9529-0770 [email protected] , Sandra COHUET , Ariana Kalaveshi , Zana Kaçaniku-Deva , Pranvera Kaçaniku-Gunga , Iris Finci , Miguel Angel Sanchez Ruiz , … Show All … , James Humphreys , Naser Ramadani , Edita Haxhiu , Kostas Danis , Angela Rose 0000-0002-2493-8082 , Isme Humolli , and Mark Katz 0000-0002-5532-7276 Show Fewer Authors Info & Affiliations https://doi.org/10.22541/au.174404165.50421516/v1 Published Influenza and Other Respiratory Viruses Version of record Peer review timeline 417 views 214 downloads Contents Abstract Supplementary Material Information & Authors Metrics & Citations View Options References Figures Tables Media Share Abstract Background: Few studies have evaluated COVID-19 vaccine effectiveness (VE) in middle-income countries, particularly in eastern Europe. We aimed to estimate COVID-19 VE against SARS-CoV-2-confirmed hospitalizations and severe outcomes in Kosovo. Methods: We conducted a test-negative case-control study using data from Kosovo’s severe acute respiratory infection (SARI) sentinel surveillance system from January 2022 to June 2024. We enrolled adult patients aged ≥18 years hospitalized with SARI. From all patients, we collected clinical data, vaccination history and a nasopharyngeal specimen, which was tested for SARS-CoV-2 using RT-PCR. SARS-CoV-2-positive patients were cases; those testing negative were controls. We estimated VE overall and against severe outcomes (requiring oxygen, intensive care admission, or in-hospital death) using logistic regression, adjusting for age, sex, and comorbidities, calculating VE as (1–adjusted odds ratio)×100. Results: We included 564 SARI patients; 218 (39%) tested positive for SARS-CoV-2. Overall, 24% of SARI patients had received at least one COVID-19 vaccine dose in the previous 12 months. VE against SARS-CoV-2-confirmed SARI hospitalization among all adults was 75% (95%CI:37–90%) at 14–179 days post-vaccination, and 24% (95% CI:-35–58%) at 180–364 days. In adults ≥60 years, VE was 59% (95%CI:-10–84%) at 14–179 days post-vaccination, and -37% (95%CI:-188–5%) at 180–364 days. VE against severe outcomes was 70% (95% CI:-2–91%) at 14–179 days, and 8% (95%CI:-128–63%) at 180–364 days. Conclusions: In Kosovo, COVID-19 vaccination offered significant protection against hospitalization and severe outcomes. Effectiveness waned after 6 months, highlighting the need for periodic booster doses. Supplementary Material File (covid-19 ve against hospitalizations and severe outcomes in kosovo, 2022-2024_final.docx) Download 599.22 KB Information & Authors Information Version history V1 Version 1 07 April 2025 Peer review timeline Published Influenza and Other Respiratory Viruses Version of Record 8 Sep 2025 Published Copyright This work is licensed under a Non Exclusive No Reuse License. Collection Influenza and other respiratory viruses Keywords covid-19 hospitalization kosovo severe outcomes vaccine effectiveness Authors Affiliations Besfort Kryeziu 0000-0002-9529-0770 [email protected] National Institute of Public Health of Kosovo View all articles by this author Sandra COHUET Epiconcept View all articles by this author Ariana Kalaveshi National Institute of Public Health of Kosovo View all articles by this author Zana Kaçaniku-Deva National Institute of Public Health of Kosovo View all articles by this author Pranvera Kaçaniku-Gunga National Institute of Public Health of Kosovo View all articles by this author Iris Finci World Health Organization Regional Office for Europe View all articles by this author Miguel Angel Sanchez Ruiz Epiconcept View all articles by this author James Humphreys Epiconcept View all articles by this author Naser Ramadani National Institute of Public Health of Kosovo View all articles by this author Edita Haxhiu Universiteti i Prishtines Hasan Prishtina View all articles by this author Kostas Danis European Centre for Disease Prevention and Control (ECDC View all articles by this author Angela Rose 0000-0002-2493-8082 Epiconcept View all articles by this author Isme Humolli Universiteti i Prishtines Hasan Prishtina View all articles by this author Mark Katz 0000-0002-5532-7276 World Health Organization Regional Office for Europe View all articles by this author Metrics & Citations Metrics Article Usage 417 views 214 downloads .FvxKWukQNSOunydq8rnd { width: 100px; } Citations Download citation Besfort Kryeziu, Sandra COHUET, Ariana Kalaveshi, et al. COVID-19 vaccine effectiveness against hospitalizations and severe outcomes in Kosovo, 2022-2024: a test negative case–control study. Authorea . 07 April 2025. DOI: https://doi.org/10.22541/au.174404165.50421516/v1 If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download. For more information or tips please see 'Downloading to a citation manager' in the Help menu . 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