Evaluation the Efficacy and Immunity of Influenza Vaccination in Adult and Elderly People

• Main Authors: Chien-Ren, 陳建壬
• Other Authors: 陳志豪
• Format: Others
• Language: zh-TW
• Published: 2008
• Online Access: http://ndltd.ncl.edu.tw/handle/65943411621308426919

碩士 === 中山醫學大學 === 醫學研究所 === 96 === Influenza is one of the important respiratory diseases that infects globally and possibly causes significant morbidity and mortality in human beings. Three influenza pandemics took place during the 20th century. Despite of the improvement in the antiviral therapies during the past decades, vaccination is still the most effective method of prophylaxis. In this study, we used hemagglutination inhibition (HAI) test to assess antibody responses against current influenza viruses in 2006-2007 and 2007-2008 between the adults and the elderly who were vaccinated with influenza vaccine (GlaxoSmithKline) at the end of 2006. Besides, the phylogenetic analysis of the hemagglutinin (HA) gene among these current strains was also performed. We would like to know the efficacy of the influenza vaccine and the evolutionary relationship among these virus strains. Totally 120 serum samples (including pre-vaccination and post-vaccination paired sera collected at an interval of three weeks) were collected from 30 adults (mean age: 35.2±6.6years old) and 30 geriatric volunteers (mean age: 67.7±4.2years old) . Then, HAI test was performed against local circulating strains during two consecutive influenza seasons. The antibody titers of both groups were analyzed by geometry mean titers (GMTs), seroconversion rates, seroconversion factors and seroprotection rates. The results revealed that the GMTs of both groups were significantly increased after vaccination (p<0.05). The seroconversion factors indicated that the antibody response of both groups fitted the criteria of guidelines of the European CPMP (Committee for Proprietary Medicinal Products), except that against A/Taiwan/0586/2006(H1N1) in adults in 2006-2007. However, only the antibody response against A/Taiwan/80175/2008(H3N2) fitted the criteria in 2007-2008. The seroconversion rates of elderly were greater than 30% while the rates of adults were greater than 40%, except that against the B/Taiwan/0050/2006 in 2006-2007. Similarly, only the antibody response against A/Taiwan/80175/2008(H3N2) fitted the criteria in 2007-2008. Besides, the seroprotection rates reached the threshold of 70% for all virus strains in both groups after vaccination in 2006-2007 while the rates were all below the threshold of the criteria next year, except that against A/Taiwan/80175/2008(H3N2) in elderly.The phylogenetic analysis also showed the A/Taiwan/80175/2008(H3N2) was located most nearby the vaccine strain while the B/Taiwan/80141/2008 was located in an independent lineage and distinct from the vaccine strain. In conclusion, our results suggested that the annual influenza vaccination program is appropriate and could provide a protective immunity in the adult and the elderly. In addition, there is a higher efficacy if a good match between vaccine and circulating virus strains.