Koret School of Veterinary medicine, the Hebrew University, Jerusalem, Israel.
European Food Safety Authority, Via Carlo Magno 1A, 43126 Parma, Italy.
Prev Vet Med. 2020 Aug;181:104595. doi: 10.1016/j.prevetmed.2018.12.001. Epub 2018 Dec 5.
Despite the wide use of the live attenuated Neethling lumpy skin disease (LSD) vaccine, only limited data existed on its efficacy and effectiveness prior to the large LSD epidemic in the Balkans, which took place during 2016-2017. In addition, analysis of risk factors for the disease was hardly performed with proper control for vaccination effects and potential differences in exposure to the virus. Data from the LSD epidemics in six Balkan countries (Bulgaria, Greece, Serbia, Montenegro, Former Yugoslav Republic of Macedonia (FYROM) and Albania) affected during 2016 were analyzed to determine vaccine effectiveness (VE) and risk factors for LSD infection at the farm level. Vaccination was performed along the occurrence of the epidemics and thus vaccination status of some of the farms changed during the epidemic. To allow for this, left truncated and right censored survival analysis was used in a mixed effects Cox proportional hazard regression model to calculate VE and risk factors for LSD. The results indicated of an average VE of 79.8% (95% CI: 73.2-84.7)) in the six countries, with the lowest VE of 62.5% documented in Albania and up to VE of more than 97% as documented in Bulgaria and Serbia. Analysis of time from vaccination to development of protective immunity showed that VE mostly developed during the first 14 days after vaccination. Data from Greece showed that the vaccination adjusted hazard ratio for LSD was 5.7 higher in grazing farms compared to non-grazing farms. However, due to a difference in geographical location of grazing and non-grazing farms and higher vaccination rate in non-grazing farms, this effect can be at least partly attributed to indirect protection due to herd immunity provided by surrounding vaccinated farms.
尽管活减毒尼氏疱疹病毒（LSD）疫苗得到广泛应用，但在 2016-2017 年巴尔干地区大规模 LSD 疫情爆发之前，关于其效力和效果的数据有限。此外，由于疫苗接种效果和潜在病毒暴露差异的适当控制，对疾病的危险因素分析几乎没有进行。对 2016 年期间受 LSD 疫情影响的六个巴尔干国家（保加利亚、希腊、塞尔维亚、黑山、前南斯拉夫马其顿共和国和阿尔巴尼亚）的数据进行了分析，以确定农场层面 LSD 感染的疫苗效力（VE）和危险因素。由于疫情的发生而进行了疫苗接种，因此一些农场的疫苗接种状况在疫情期间发生了变化。为此，使用左截断和右删失生存分析在混合效应 Cox 比例风险回归模型中计算 VE 和 LSD 的危险因素。结果表明，六个国家的平均 VE 为 79.8%（95%CI：73.2-84.7），其中阿尔巴尼亚的 VE 最低，为 62.5%，保加利亚和塞尔维亚的 VE 高达 97%以上。对从接种疫苗到产生保护性免疫的时间进行分析表明，VE 主要在接种后 14 天内发展。来自希腊的数据表明，与非放牧农场相比，放牧农场 LSD 的疫苗调整危险比（HR）高 5.7 倍。然而，由于放牧和非放牧农场的地理位置不同，以及非放牧农场的疫苗接种率较高，这种效应至少部分归因于周围接种疫苗的农场提供的群体免疫产生的间接保护。
