Yuan L
Department of Preventive Medicine and Biostatistics, University of Toronto, Ont.
CMAJ. 1994 Apr 1;150(7):1093-8.
To examine the risk factors for measles vaccine failure and to evaluate the effectiveness of a selective revaccination strategy during a measles outbreak.
Matched case-control study.
Thirty-one schools in Mississauga, Ont.
Eighty-seven previously vaccinated school-aged children with measles that met the Advisory Committee on Epidemiology's clinical case definition for measles. Two previously vaccinated control subjects were randomly selected for each case subject from the same homeroom class.
All susceptible contacts were vaccinated, and contacts who had been vaccinated before Jan. 1, 1980, were revaccinated. When two or more cases occurred in a school all children vaccinated before 1980 were revaccinated.
Risk of measles associated with age at vaccination, time since vaccination, vaccination before 1980 and revaccination.
Subjects vaccinated before 12 months of age were at greater risk of measles than those vaccinated later (adjusted odds ratio [OR] 7.7, 95% confidence interval [CI] 1.6 to 38.3; p = 0.01). Those vaccinated between 12 and 14 months of age were at no greater risk than those vaccinated at 15 months or over. Subjects vaccinated before 1980 were at greater risk than those vaccinated after 1980 (adjusted OR 14.5, 95% CI 1.5 to 135.6). Time since vaccination was not a risk factor. Revaccination was effective in reducing the risk of measles in both subjects vaccinated before 1980 and those vaccinated after 1980 (adjusted OR reduced to 0.6 [95% CI 0.1 to 5.3] and 0.3 [95% CI 0.13 to 2.6] respectively). However, only 18 cases were estimated to have been prevented by this strategy.
Adherence to routine measles vaccination for all eligible children is important in ensuring appropriate coverage with a single dose. The selective revaccination strategy's high labour intensiveness and low measles prevention rate during the outbreak bring into question the effectiveness of such a strategy.
研究麻疹疫苗接种失败的风险因素，并评估麻疹暴发期间选择性再接种策略的有效性。
配对病例对照研究。
安大略省密西沙加市的31所学校。
87名曾接种过疫苗、符合流行病学咨询委员会麻疹临床病例定义的学龄期麻疹患儿。从同一班级中为每名病例随机选取两名曾接种过疫苗的对照。
所有易感接触者均接种疫苗，1980年1月1日前接种过疫苗的接触者进行再接种。当一所学校出现两例或更多病例时，对1980年前接种过疫苗的所有儿童进行再接种。
与接种年龄、接种后时间、1980年前接种以及再接种相关的麻疹风险。
12月龄前接种疫苗的儿童患麻疹的风险高于之后接种的儿童（调整优势比[OR]7.7，95%置信区间[CI]1.6至38.3；p = 0.01）。12至14月龄接种疫苗的儿童与15月龄及以上接种的儿童相比，风险并无增加。1980年前接种疫苗的儿童比1980年后接种的儿童风险更高（调整OR 14.5，95%CI 1.5至135.6）。接种后时间不是风险因素。再接种对降低1980年前和1980年后接种疫苗儿童的麻疹风险均有效（调整OR分别降至0.6[95%CI 0.1至5.3]和0.3[95%CI 0.13至2.6]）。然而，据估计该策略仅预防了18例病例。
确保所有符合条件的儿童坚持常规麻疹疫苗接种对于单剂疫苗的适当覆盖率很重要。选择性再接种策略在暴发期间劳动强度大且预防麻疹率低，这让人质疑该策略的有效性。
