Departments of Pediatrics (MacDonald) and Community Health Sciences (Simmonds, Svenson), University of Calgary, Calgary, Alta.; Faculty of Nursing (MacDonald) and School of Public Health (Svenson), University of Alberta, Edmonton, Alta.; and Epidemiology and Surveillance Team (Dover, Simmonds, Svenson), Alberta Ministry of Health, Edmonton, Alta.
CMAJ. 2014 Aug 5;186(11):824-9. doi: 10.1503/cmaj.140078. Epub 2014 Jun 9.
The combination measles-mumps-rubella-varicella (MMRV) vaccine currently used in Canada (Priorix-Tetra) may increase the risk of febrile seizures relative to the separate vaccines (MMR and varicella) previously administered. We determined the risk of febrile seizure after the first dose of MMRV, as well as any additional risk for children at high risk for seizures because of pre-existing medical conditions.
In this retrospective, population-based cohort study, we compared the risk of seizures after the first dose of MMRV with the risk after same-day administration of separate MMR and varicella vaccines (MMR+V) in children 12 to 23 months of age in the province of Alberta. We deterministically linked vaccination data to health service utilization data for seizures. We used Poisson regression, with adjustment for age and calendar year, to determine the risk for the full cohort and for high-risk children.
The risk of seizures 7 to 10 days after vaccination was twice as high with MMRV as with MMR+V (relative risk [RR] 1.99, 95% confidence interval [CI] 1.30-3.05). The excess absolute risk of seizures was 3.52 seizures per 10 000 doses of MMRV relative to MMR+V. In high-risk children, the risk was not differentially higher for MMRV (RR 1.30, 95% CI 0.60-2.79).
Despite an increased risk of febrile seizures following MMRV (compared with MMR+V), the absolute level of risk was small. Policy-makers need to balance these findings with the potential benefits of administering the combination vaccine or determine whether the choice of vaccine rests with clinicians and/or parents.
加拿大目前使用的麻疹-腮腺炎-风疹-水痘（MMRV）联合疫苗（Priorix-Tetra）可能会增加相对于先前使用的单独疫苗（MMR 和水痘）发生热性惊厥的风险。我们确定了 MMRV 第一针后的热性惊厥风险，以及由于先前存在的医疗条件而使癫痫发作风险较高的儿童的任何额外风险。
在这项回顾性基于人群的队列研究中，我们比较了 12 至 23 个月大的艾伯塔省儿童在接种 MMRV 第一针后与同一天接种单独的 MMR 和水痘疫苗（MMR+V）后发生惊厥的风险。我们通过确定性链接将疫苗接种数据与惊厥的卫生服务利用数据进行关联。我们使用泊松回归，根据年龄和日历年份进行调整，确定了整个队列和高危儿童的风险。
接种疫苗后 7 至 10 天发生惊厥的风险，MMRV 是 MMR+V 的两倍（相对风险 [RR] 1.99，95%置信区间 [CI] 1.30-3.05）。与 MMR+V 相比，MMRV 发生惊厥的绝对风险增加了 3.52 例/10000 剂。在高危儿童中，MMRV 的风险并没有更高（RR 1.30，95%CI 0.60-2.79）。
尽管 MMRV 接种后（与 MMR+V 相比）热性惊厥的风险增加，但绝对风险水平较小。政策制定者需要权衡这些发现与接种联合疫苗的潜在益处，或者确定疫苗的选择是否取决于临床医生和/或家长。
