Humoral Response to TBE Vaccine in Elderly (50+ Year Olds) After Changed Dosage Intervals/Number of Doses?
试验速览
- 阶段
- 2 期
- 状态
- 已完成
- 发起方
- 入组人数
- 250
- 试验地点
- 3
- 主要终点
- Serum concentration of neutralising antibodies against TBE one month after two or three doses.
研究概览
简要总结
The risk for tick borne encephalitis increases in Sweden. Together with an increased awareness of the possibility to acquire protection by vaccination, this has led to an increase in the number of doses of the vaccine distributed in Sweden each year - now being approximately 400.000. The first year, two doses with an interval of 1 month is recommended for the general population, followed by a third dose approximately one year later and an additional booster dose three years after the third.
Preliminary results from a previous study showed a higher percentage protected (=titer at least 10) after 3 doses than after 2 doses (Rombo et al. EUDRA CT 2011 001348-31, unpublished information). In the same study, there were no differences between those who were vaccinated 0+7+21 compared to 0+30+90. The investigators were surprised to find marked differences between 2 and 3 doses also in the younger control group.
The investigators therefore aim to confirm results in a new study and to add a group with a double dose at day 0 and then a single dose at day 30 and 360
详细描述
The risk for tick borne encephalitis increases in Sweden. Together with an increased awareness of the possibility to acquire protection by vaccination, this has led to an increase in the number of doses of the vaccine distributed in Sweden each year - now being approximately 400.000. The first year, two doses with an interval of 1 month is recommended for the general population, followed by a third dose approximately one year later and an additional booster dose three years after the third.
The manufacturer of Encepur recommended a total of three doses to this age group using the same regimen as with "accelerated vaccination schedule (0+7+21 days). Unfortunately, geometrical mean of titers after 3 doses with the accelerated schedule is not superior to 2 doses given at 0+30 days The manufacturer of FSME-immune instead recommended that serology should be checked one month after the second dose and that a third dose should be given if titers are not sufficient (0+30+60 days). Unfortunately, determinations of titers in a large number of samples put severe strain on logistics and is not feasible in Sweden.
In order to try to improve immunity in the age group 60+ , the Department of Communicable Disease Control and Prevention in Stockholm therefore recommends a third dose two months after the first two doses to the age group 60+ (= 0+30+90 days).
Preliminary results from a previous study showed a higher percentage protected (=titer at least 10) after 3 doses than after 2 doses (Rombo et al. EUDRA CT 2011 001348-31, unpublished information). In the same study, there were no differences between those who were vaccinated 0+7+21 compared to 0+30+90. The investigators were surprised to find marked differences between 2 and 3 doses also in the younger control group
Primary aim: To study whether any differences remain before and one month after an additional dose at the following season Secondary aim: To study whether an additional dose of TBE vaccine 2 months after the second dose will improve protection in an age group 50+.
研究设计
- 研究类型
- Interventional
- 分配方式
- Randomized
- 干预模型
- Parallel
- 主要目的
- Prevention
- 盲法
- None
入排标准
- 年龄范围
- 18 Years 至 —（Adult, Older Adult）
- 性别
- All
- 接受健康志愿者
- 是
入选标准
- •Age 50 years or more (Control group 18 years)
- •generally healthy
- •no immunosuppressive condition
- •fertile women must use contraceptives
排除标准
- •Previous TBE infection
- •Previously immunized with TBE vaccine
- •Anaphylactic reaction to egg protein
- •Any disease or therapy which might suppress the immune response
- •Vaccination should be delayed if a participant has fever
结局指标
主要结局
Serum concentration of neutralising antibodies against TBE one month after two or three doses.
时间窗: 18 months after the first dose
Determination of neutralising antibodies one month after completion of the first years vaccination series
次要结局
- Serum concentration of neutralising antibodies against TBE one month after the dose which will be given a year later(18 months after the first dose has been given)
研究者
Lars Rombo
professor
Sormland County Council, Sweden