Background: Influenza is a major cause of morbidity and mortality in the elderly worldwide. Influenza vaccination can prevent morbidity/mortality from influenza infection. A gap of 1-2 years, before an epidemic strain is recommended by the World Health Organization (WHO) to be the vaccine strain in Southeast Asia, has been reported; this results in a high rate of vaccine mismatch and excess influenza-associated morbidity. The aim of the current study was to evaluate the effect of repeated vaccination on vaccine effectiveness (VE) among the elderly in Taiwan, during years with and without early appearance of antigenically drifted strains.
Methods: A historical cohort study was conducted to evaluate the impact of repeated vaccination on the reduction of influenza-associated hospitalization among persons older than 64 years over two influenza seasons: 2007-08, with all circulating virus strains mismatched, and 2008-09, with all virus strains matched with the vaccine strains, considering four exposure effects, namely current vaccine effect, sequential vaccination effect, residual protection effect and no vaccination effect. Propensity score matching on vaccination status was performed to ensure similar baseline characteristics between the groups that received and did not receive vaccination.
Results: Only current-year vaccination in combination with prior history of annual revaccination significantly reduced the risk of hospitalization, with adjusted hazard ratios of 0.68 (95% CI: 0.54, 0.85) and 0.74 (95% CI: 0.57, 0.95) during the 2007-08 and 2008-09 influenza seasons, respectively. Further stratification showed that even during the 2007-08 influenza season, when all vaccinations were mismatched with the circulating strains, sequential vaccinations still significantly reduced influenza-associated hospitalization in the female population aged 68-74 and 75-84 years, with adjusted VE of 25.2% (95% CI: -9.6, 49.0%) and 36.9% (95% CI: 17.1, 52.0%), respectively.
Conclusion: Our study supports the recommendation of annual revaccination against influenza in the elderly, even though the circulating strain of influenza virus was antigenically mismatched with the vaccine strains.
Download full-text PDF |
Source |
|---|---|
| http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7060795 | PMC |
| http://dx.doi.org/10.2147/CIA.S238786 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Rethinking Optimal Immunogens to Face SARS-CoV-2 Evolution Through Vaccination.
Influenza Other Respir Viruses
January 2025
Área de Investigación en Vacunas, Fundación para el Fomento de la Investigación Sanitaria y Biomédica de la Comunitat Valenciana, Valencia, Spain.
SARS-CoV-2, which originated in China in late 2019, quickly fueled the global COVID-19 pandemic, profoundly impacting health and the economy worldwide. A series of vaccines, mostly based on the full SARS-CoV-2 Spike protein, were rapidly developed, showing excellent humoral and cellular responses and high efficacy against both symptomatic infection and severe disease. However, viral evolution and the waning humoral neutralizing responses strongly challenged vaccine long term effectiveness, mainly against symptomatic infection, making necessary a strategy of repeated and updated booster shots.
View Article and Find Full Text PDFObjectives: Patients with chronic lymphocytic leukaemia (CLL) have an increased risk of severe coronavirus disease 2019 (COVID-19) as well as impaired responses to COVID-19 vaccination, which may be overcome by repeated booster vaccinations. Our objective was to explore the uptake of the COVID-19 vaccine in this population since records of this are scarce.
Methods: In this nationwide cohort study, we used multiple population-based health and sociodemographic registries to study COVID-19 vaccine uptake in individuals with CLL in Sweden, from 27 December 2020 to 28 February 2023.
Inequality in COVID-19 vaccine acceptance and uptake: A repeated cross-sectional analysis of COVID vaccine acceptance and uptake in 13 countries.
Health Policy
January 2025
Health Economics Research Centre, Nuffield Department of Population Health, University of Oxford, Oxford OX3 7LF, United Kingdom; National Institute for Health Research Oxford Biomedical Research Centre, John Radcliffe Hospital, Oxford OX3 9DU, United Kingdom; Centre For Health Policy, University of Melbourne, Parkville, VIC 3010, Australia. Electronic address:
Background COVID-19 vaccine hesitancy was a key barrier to ending the pandemic via mass immunisation. Objectives Assess magnitudes and differences in socioeconomic inequality in stated COVID-19 vaccine acceptance (hesitancy) and uptake. Methods Online surveys were conducted in 13 countries, collecting data from 15,337 and 18,189 respondents respectively.
View Article and Find Full Text PDFPersistent Health and Cognitive Impairments up to Four Years Post-COVID-19 in Young Students: The Impact of Virus Variants and Vaccination Timing.
Biomedicines
December 2024
Laboratory of Evolutionary Biology, Department of Philosophy and History of Sciences, Faculty of Science, Charles University, Viničná 7, 128 00 Prague, Czech Republic.
The long-term consequences of COVID-19 infection are becoming increasingly evident in recent studies. This repeated cross-sectional study aimed to explore the long-term health and cognitive effects of COVID-19, focusing on how virus variants, vaccination, illness severity, and time since infection impact post-COVID-19 outcomes. We examined three cohorts of university students ( = 584) and used non-parametric methods to assess correlations of various health and cognitive variables with SARS-CoV-2 infection, COVID-19 severity, vaccination status, time since infection, time since vaccination, and virus variants.
View Article and Find Full Text PDFReflections on COVID-19: A Literature Review of SARS-CoV-2 Testing.
Vaccines (Basel)
December 2024
Department of Laboratory Medicine, Changi General Hospital, 2 Simei Street 3, Singapore 529889, Singapore.
Although the Coronavirus disease 2019 (COVID-19) pandemic has ended, there are still many important lessons we can learn, as the pandemic profoundly affected every area of laboratory practice. During the pandemic, extensive changes to laboratory staffing had to be implemented, as many healthcare institutions required regular screening of all healthcare staff. Several studies examined the effectiveness of different screening regimens and concluded that repeated testing, even with lower sensitivity tests, could rival the performance of gold-standard RT-PCR testing in the detection of new cases.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!