Kerfua Susan D, Haydon Daniel T, Wilsden Ginette, Ludi Anna, King Donald P, Okurut Rose Ademun, Atim Stella, Dhikusooka Moses T, Kyakuwa Ivan, Motta Paolo, Paton David J
National Livestock Resources Research Institute, National Agricultural Research Organisation, Uganda.
School of Biodiversity, One Health and Veterinary Medicine, College of Medical Veterinary and Life Sciences, University of Glasgow, United Kingdom.
Vaccine. 2024 Dec 2;42(26):126325. doi: 10.1016/j.vaccine.2024.126325. Epub 2024 Sep 12.
Foot-and-mouth disease virus (FMDV) causes a contagious disease (FMD) in cloven-hoofed animals. For FMD-endemic countries, vaccination is critical for controlling disease but is rarely monitored, despite substantial funds spent on vaccine purchases. We evaluated antibody responses in cattle to two commercial vaccines each containing antigens of four FMDV serotypes. Sampling was done over 360 days, with serology for each serotype performed using commercially available solid phase competition ELISAs (SPCE) and with virus neutralization tests (VNT) employing regionally relevant test viruses. A primary course of each vaccine was administered to 37 calves, some of which received a second dose after 28 days. Using new production batches of vaccines, all calves received a booster vaccination 180 days post vaccination, while 10 additional naïve calves were also vaccinated using the new batches and followed up for ∼180 days. Simple and general linear models were used to compare antibody responses which varied substantially according to vaccine, dose regime, serotype, and test, but were mostly insufficient to ensure a high likelihood of adequate or sustained probable protection. One of the vaccines administered as a two-dose primary course of vaccination was superior to other options, but even then, data trajectories from VNT responses suggested probable protection of 75 % of calves for 6 months for only one virus serotype. Calves administered with the other vaccine and those given a single primary dose developed low levels of antibodies, offering predicted likely protection lasting less than two months. Individual SPCE results were weakly correlated (r = 0.48) to neutralization and associated likelihoods of protection but SPCE and VNT agreed on which vaccine and dose regime performed best. Our findings highlight gaps in immunogenicity of FMD vaccines used in East Africa and reinforce the importance of independent quality control studies to evaluate and improve commercial FMD vaccines and vaccination regimes.
口蹄疫病毒（FMDV）可引起偶蹄类动物的一种传染性疾病（口蹄疫，FMD）。对于口蹄疫流行国家而言，疫苗接种对于控制该病至关重要，但尽管在疫苗采购上投入了大量资金，却很少对其进行监测。我们评估了牛对两种商业疫苗的抗体反应，每种疫苗均含有四种口蹄疫病毒血清型的抗原。采样持续360天，使用市售固相竞争ELISA（SPCE）对每种血清型进行血清学检测，并使用区域相关的试验病毒进行病毒中和试验（VNT）。每种疫苗的一个主要接种程序接种给37头犊牛，其中一些在28天后接受了第二剂。使用新生产批次的疫苗，所有犊牛在接种疫苗180天后接受加强免疫，同时另外10头未接种过疫苗的犊牛也使用新批次疫苗进行接种，并随访约180天。使用简单和一般线性模型比较抗体反应，抗体反应因疫苗、剂量方案、血清型和检测方法而异，差异很大，但大多不足以确保有很高的可能性获得充分或持续的可能保护。作为两剂主要接种程序接种的一种疫苗优于其他选择，但即便如此，VNT反应的数据轨迹表明，仅对于一种病毒血清型，75%的犊牛可能在6个月内得到保护。接种另一种疫苗的犊牛以及接受单次主要剂量接种的犊牛产生的抗体水平较低，预计可能的保护持续时间不到两个月。个体SPCE结果与中和作用及相关保护可能性的相关性较弱（r = 0.48），但SPCE和VNT在哪种疫苗和剂量方案效果最佳方面达成了一致。我们研究结果凸显了东非使用的口蹄疫疫苗在免疫原性方面的差距，并强化了开展独立质量控制研究以评估和改进商业口蹄疫疫苗及接种方案的重要性。
