Influenza vaccines historically have been multivalent, whole virus inactivated products. The first bivalent, intranasal, live attenuated influenza vaccine (LAIV; Ingelvac Provenza), with H1N1 and H3N2 subtypes, has been approved for use in swine. We investigated the LAIV hemagglutinin (HA) sequences in diagnostic cases submitted to the Iowa State University Veterinary Diagnostic Laboratory and potential vaccine virus reassortment with endemic influenza A virus (IAV) in swine. From January 3 to October 11, 2018, IAV HA sequences demonstrating 99.5-99.9% nucleotide homology to the H1 HA or 99.4-100% nucleotide homology to the H3 HA parental strains in the LAIV were detected in 58 of 1,116 (5.2%) porcine respiratory cases (H1 HA A/swine/Minnesota/37866/1999[H1N1; MN99]; H3 HA A/swine/Texas/4199-2/1998[H3N2; TX98]). Nine cases had co-detection of HA genes from LAIV and wild-type IAV in the same specimen. Thirty-five cases had associated epidemiologic information that indicated they were submitted from 11 states representing 31 individual sites and 17 production systems in the United States. Whole genome sequences from 11 cases and another subset of 2 plaque-purified IAV were included in our study. Ten whole genome sequences, including 1 plaque-purified IAV, contained at least one internal gene from endemic IAV detected within the past 3 y. Phylogenetic analysis of whole genome sequences indicated that reassortment occurred between vaccine virus and endemic field strains circulating in U.S. swine. Our data highlight the need and importance of continued IAV surveillance to detect emerging IAV with LAIV genes in the swine population.

中文翻译：

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在美国猪种群中检测到减毒活流感疫苗病毒并重新分类的证据。

流感疫苗历来是多价全病毒灭活产品。第一种具有H1N1和H3N2亚型的二价鼻内减毒活流感疫苗（LAIV; Ingelvac Provenza）已获准用于猪。我们调查了提交爱荷华州立大学兽医诊断实验室的诊断病例​​中的LAIV血凝素（HA）序列，以及在猪中与地方性甲型流感病毒（IAV）进行的潜在疫苗病毒重配。从2018年1月3日至10月11日，在1,116（5.2％）猪中的58头猪中检测到IAV HA序列，表明与LAIV的H1 HA亲本菌株具有99.5-99.9％的核苷酸同源性或与H3 HA亲本菌株具有99.4-100％的核苷酸同源性呼吸系统疾病（H1 HA A /猪/明尼苏达州/ 37866/1999 [H1N1; MN99]； H3 HA A /猪/德克萨斯州/得克萨斯州4199-2 / 1998 [H3N2; TX98]）。在同一样本中，有9例患者同时检测了来自LAIV和野生型IAV的HA基因。35例具有相关的流行病学信息，表明它们是从11个州（分别代表美国31个单独站点和17个生产系统）提交的。我们的研究包括11个病例的全基因组序列和2个噬菌斑纯化的IAV的另一个子集。十个完整基因组序列，包括1个噬菌斑纯化的IAV，包含至少一个在过去3年内检测到的地方性IAV内部基因。全基因组序列的系统进化分析表明，疫苗病毒与美国猪中传播的地方性田间毒株之间发生了重配。我们的数据强调了持续进行IAV监测的必要性和重要性，以检测猪群中带有LAIV基因的IAV。