Liang En Wee, Enoch Xue Heng Loy, Jue Tao Lim, Wei Hao Kwok, Calvin Chiew, Christopher Lien, Barbara Helen Rosario, Ian Yi Onn Leong, Reshma Aziz Merchant, David Chien Boon Lye, Kelvin Bryan Tan
{"title":"Real-World Effectiveness of Boosting Against Omicron Hospitalization in Older Adults, Stratified by Frailty.","authors":"Liang En Wee, Enoch Xue Heng Loy, Jue Tao Lim, Wei Hao Kwok, Calvin Chiew, Christopher Lien, Barbara Helen Rosario, Ian Yi Onn Leong, Reshma Aziz Merchant, David Chien Boon Lye, Kelvin Bryan Tan","doi":"10.3390/vaccines13060565","DOIUrl":null,"url":null,"abstract":"<p><strong>Background/objectives: </strong>Older adults with frailty are at-risk of worse outcomes following respiratory-viral-infections such as COVID-19. Data on effectiveness of vaccination/boosting in frail older adults during Omicron is lacking.</p><p><strong>Methods: </strong>National healthcare-claims data and COVID-19 registries were utilized to enroll a cohort of older Singaporeans (≥60 years) as of 1 January 2022, divided into low/intermediate/high-risk for frailty; matching weights were utilized to adjust for sociodemographic differences/vaccination uptake at enrolment across frailty categories. Competing-risk-regression (Fine-Gray) taking death as a competing risk, with matching weights applied, was utilized to compare risks of COVID-19-related hospitalizations and severe COVID-19 across frailty levels (low/intermediate/high-risk), with estimates stratified by booster status. Individuals were followed up until study end-date (20 December 2023).</p><p><strong>Results: </strong>874,160 older adults were included during Omicron-predominant transmission; ~10% had intermediate/high-frailty-risk. Risk of hospitalization/severe COVID-19 was elevated in those with intermediate/high-frailty-risk up to XBB/JN.1 transmission. Boosting was associated with decreased risk of COVID-19-related hospitalization across all frailty categories in infection-naïve individuals. However, in infection-naïve older adults with high-frailty-risk, while receipt of first boosters was associated with lower risk of COVID-19-hospitalization/severe COVID-19, additional booster doses did not reduce risk. In reinfected older adults, first boosters were still associated with lower hospitalization risk (adjusted-hazards-ratio, aHR = 0.55, 95% CI = 0.33-0.92) among the non-frail, but not in the intermediate/high-frailty-risk minority.</p><p><strong>Conclusions: </strong>First boosters were associated with reduced adverse COVID-19 outcomes across all frailty categories in infection-naïve older adults during Omicron. However, in the high-frailty minority, boosting did not additionally reduce risk in reinfected individuals with hybrid immunity, and beyond the first booster for infection-naïve individuals.</p>","PeriodicalId":23634,"journal":{"name":"Vaccines","volume":"13 6","pages":""},"PeriodicalIF":5.2000,"publicationDate":"2025-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12197443/pdf/","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Vaccines","FirstCategoryId":"3","ListUrlMain":"https://doi.org/10.3390/vaccines13060565","RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"IMMUNOLOGY","Score":null,"Total":0}
引用次数: 0
Abstract
Background/objectives: Older adults with frailty are at-risk of worse outcomes following respiratory-viral-infections such as COVID-19. Data on effectiveness of vaccination/boosting in frail older adults during Omicron is lacking.
Methods: National healthcare-claims data and COVID-19 registries were utilized to enroll a cohort of older Singaporeans (≥60 years) as of 1 January 2022, divided into low/intermediate/high-risk for frailty; matching weights were utilized to adjust for sociodemographic differences/vaccination uptake at enrolment across frailty categories. Competing-risk-regression (Fine-Gray) taking death as a competing risk, with matching weights applied, was utilized to compare risks of COVID-19-related hospitalizations and severe COVID-19 across frailty levels (low/intermediate/high-risk), with estimates stratified by booster status. Individuals were followed up until study end-date (20 December 2023).
Results: 874,160 older adults were included during Omicron-predominant transmission; ~10% had intermediate/high-frailty-risk. Risk of hospitalization/severe COVID-19 was elevated in those with intermediate/high-frailty-risk up to XBB/JN.1 transmission. Boosting was associated with decreased risk of COVID-19-related hospitalization across all frailty categories in infection-naïve individuals. However, in infection-naïve older adults with high-frailty-risk, while receipt of first boosters was associated with lower risk of COVID-19-hospitalization/severe COVID-19, additional booster doses did not reduce risk. In reinfected older adults, first boosters were still associated with lower hospitalization risk (adjusted-hazards-ratio, aHR = 0.55, 95% CI = 0.33-0.92) among the non-frail, but not in the intermediate/high-frailty-risk minority.
Conclusions: First boosters were associated with reduced adverse COVID-19 outcomes across all frailty categories in infection-naïve older adults during Omicron. However, in the high-frailty minority, boosting did not additionally reduce risk in reinfected individuals with hybrid immunity, and beyond the first booster for infection-naïve individuals.
VaccinesPharmacology, Toxicology and Pharmaceutics-Pharmacology
CiteScore
8.90
自引率
16.70%
发文量
1853
审稿时长
18.06 days
期刊介绍：
Vaccines (ISSN 2076-393X) is an international, peer-reviewed open access journal focused on laboratory and clinical vaccine research, utilization and immunization. Vaccines publishes high quality reviews, regular research papers, communications and case reports.
求助内容：
应助结果提醒方式：
京公网安备 11010802042870号
