The Pirbright Institute, Ash Road, Pirbright, Woking, Surrey GU24 0NF, United Kingdom.
The Pirbright Institute, Ash Road, Pirbright, Woking, Surrey GU24 0NF, United Kingdom.
Vaccine. 2018 Mar 27;36(14):1901-1907. doi: 10.1016/j.vaccine.2018.02.016. Epub 2018 Mar 2.
In 2015, outbreaks of foot-and-mouth disease (FMD) in the Middle East were discovered to be caused by a viral lineage (A/ASIA/G-VII), which has recently emerged from the Indian sub-continent. In vitro vaccine matching data generated by the World Reference Laboratory (WRLFMD) indicated that A/ASIA/G-VII field viruses were poorly matched with vaccines (A-SAU-95, A22 IRQ and A-IRN-05) that are already used in the region. In order to assess the likely performance of one of these commercially available FMD vaccines, sixteen cattle were vaccinated with a polyvalent vaccine which contained two serotype A components (A-SAU-95 and A-IRN-05) with a homologous potency of at least 6PD, and two cattle were left unvaccinated as controls. Twenty-one days later, all 18 cattle were challenged by tongue inoculation with an FMDV field isolate A/IRN/22/2015 from the A/ASIA/G-VII lineage, in line with the European Pharmacopeia PPG test conditions. The two control animals developed generalised FMD, and 7/16 vaccinated animals developed at least one foot lesion, thus only 56.3% were defined as protected. For the vaccine components, there was a significant increase in the probability of protection with increasing serological titres for A-SAU-95 (p = 0.03), but not for A-IRN-05 (p = 0.42). Analysis of FMDV in blood and nasal swabs suggested that vaccination reduced shedding and potential onward spread of FMD virus even if the animal developed foot lesions. In summary, the results from this study suggest that whilst this vaccine would not be appropriate for use in an emergency situation (in previously FMD-free countries), it may be partially effective in the field in endemic countries where repeat prophylactic vaccination is practiced. For emergency reactive vaccination, the findings from this study support the idea that a new vaccine strain should be developed that is tailored to the A/ASIA/G-VII lineage.
2015 年，中东地区爆发的口蹄疫（FMD）被发现是由一种病毒谱系（A/ASIA/G-VII）引起的，该谱系最近从印度次大陆出现。世界参考实验室（WRLFMD）生成的体外疫苗匹配数据表明，A/ASIA/G-VII 田间病毒与该地区已使用的疫苗（A-SAU-95、A22IRQ 和 A-IRN-05）匹配不佳。为了评估其中一种市售 FMD 疫苗的可能性能，将 16 头牛用含有两种 A 型成分（A-SAU-95 和 A-IRN-05）的多价疫苗进行了接种，这些成分的同源效力至少为 6PD，并且将两头牛作为对照不接种疫苗。21 天后，根据欧洲药典 PPG 测试条件，用 A/ASIA/G-VII 谱系的 FMDV 田间分离株 A/IRN/22/2015 通过舌接种对所有 18 头牛进行了攻毒。两只对照动物出现了全身性 FMD，16 只接种疫苗的动物中有 7 只至少出现了一只脚部病变，因此只有 56.3%被定义为受保护。对于疫苗成分，随着 A-SAU-95 的血清学滴度增加，保护的可能性有显著增加（p=0.03），但对于 A-IRN-05 则没有（p=0.42）。对血液和鼻腔拭子中的 FMDV 分析表明，即使动物出现脚部病变，接种疫苗也能减少 FMD 病毒的脱落和潜在传播。综上所述，这项研究的结果表明，尽管该疫苗不适合在无口蹄疫国家的紧急情况下使用，但在经常发生口蹄疫的国家，它在重复预防性接种的情况下可能具有部分效果。对于紧急反应性接种，这项研究的结果支持这样一种观点，即应该开发针对 A/ASIA/G-VII 谱系的新型疫苗。
