Bui Y, Sow M, Cambron-Goulet E, Levac E, Milord F
Institut national de santé publique du Québec, Montréal, QC.
Direction de santé publique de la Montérégie, QC.
Can Commun Dis Rep. 2015 Mar 5;41(3):55-62. doi: 10.14745/ccdr.v41i03a03.
Preexposure vaccination against rabies is recommended for some travellers and individuals exposed to the virus through their work. At a cost of at least $150 per intramuscular (IM) dose, few follow this recommendation. In Canada, provided certain conditions are met, the National Advisory Committee on Immunization (NACI) and the Comité d'immunisation du Québec allow a more economical alternative, intradermal vaccine administration (ID) which uses 1/10 the IM dose. The purpose of this study is to assess the feasibility and immunogenicity of intradermal preexposure vaccination.
Students and employees at the Faculty of Veterinary Medicine received three doses of ImovaxRage™ (Sanofi Pasteur) inactivated, human diploid cell rabies vaccine at days 0, 7 and 21 or 28. An IM or ID booster dose was administered after two years when indicated.
Among the 159 participants who received three doses, 139 underwent serological testing in the year following vaccination and all achieved protective antibody levels. The antibody level was higher when measured within five weeks of the third dose. When the serological control was performed two years later, 65% of participants had a <0.5 IU/ml titre. Of the 22/30 participants who chose an ID booster, 100% responded and the average antibody titres were multiplied by 11, indicating a strong anamnestic response.
ID rabies vaccination is immunogenic, economic and could be considered for the booster dose. Protective antibodies decline rapidly after primary immunization by ID, so it would seem prudent to perform a serological control one year later on individuals at high risk of occult occupational exposure. An alternative would be to give these individuals a routine ID booster dose one year after primary vaccination, which would simplify initial treatment and reduce related costs (follow-up, blood sampling, serological tests, etc.). The persistence of protective antibodies after this booster dose should be assessed to determine the need for subsequent serological tests and the ideal interval between tests.
对于一些旅行者以及因工作接触病毒的个体，建议进行狂犬病暴露前疫苗接种。每剂肌内注射（IM）疫苗成本至少为150美元，很少有人遵循这一建议。在加拿大，只要满足某些条件，国家免疫咨询委员会（NACI）和魁北克免疫委员会允许采用一种更经济的替代方法，即皮内疫苗接种（ID），其使用的剂量仅为肌内注射剂量的十分之一。本研究的目的是评估皮内暴露前疫苗接种的可行性和免疫原性。
兽医学院的学生和员工在第0、7和21或28天接种三剂ImovaxRage™（赛诺菲巴斯德公司）灭活人二倍体细胞狂犬病疫苗。如有需要，在两年后给予肌内注射或皮内加强剂量。
在接受三剂疫苗的159名参与者中，139人在接种疫苗后的一年内进行了血清学检测，所有人都达到了保护性抗体水平。在第三剂接种后五周内测量时，抗体水平更高。两年后进行血清学对照时，65%的参与者滴度<0.5 IU/ml。在选择皮内加强剂量的22/30名参与者中，100%有反应，平均抗体滴度增加了11倍，表明有强烈的回忆反应。
皮内狂犬病疫苗接种具有免疫原性且经济，可考虑用于加强剂量。皮内初次免疫后，保护性抗体迅速下降，因此对有隐匿职业暴露高风险的个体在一年后进行血清学对照似乎是谨慎的做法。另一种选择是在初次接种疫苗一年后给这些个体常规皮内加强剂量，这将简化初始治疗并降低相关成本（随访、采血、血清学检测等）。应评估此加强剂量后保护性抗体的持久性，以确定后续血清学检测的必要性以及检测之间的理想间隔。
