Tetravalent dengue virus vaccine(Instituto Butantan)

New Delhi: Enrolment of about 10,500 participants in the phase III clinical trial of the indigenous one-shot Panacea Biotec developed dengue vaccine, DengiAll, is likely to be completed by October across 20 centres in India, according to ICMR scientists. So far, 8,000 participants in various centres at Pune, Chennai, Kolkata, Delhi and Bhubaneswar among others have received either the vaccine or a placebo as part of the trial sponsored by the Indian Council of Medical Research (ICMR) and Panacea Biotec. The trial is co-led by ICMR-National Institute of Translational Virology and AIDS research in Pune, National Institute of Epidemiology (NIE), Chennai and National Institute of Virology, Pune. Currently, there is no antiviral treatment or licensed vaccine against dengue in India. The results of the Phase-1/2 trial has shown no safety concerns for the one-shot vaccine, NIE Director Dr Manoj Murhekar said. "The participants enrolled in the Phase- III trial will be followed up for two-years. This trial will evaluate the efficacy of this tetravalent dengue vaccine," Dr Murhekar said. The multi-centre, double-blind, randomised, placebo-controlled phase-III trial was launched in August last year to evaluate the jab's efficacy, safety and, long-term immunogenicity. The first participant in this trial was vaccinated at the Pandit Bhagwat Dayal Sharma Post Graduate Institute of Medical Sciences (PGIMS), Rohtak last year. The development of an effective vaccine is complex due to the need to achieve good efficacy for all four serotypes. The dengue virus has four serotypes, 1-4, with low cross-protection against each other, meaning individuals can experience repeated infections, Dr Murhekar said. In India, all four serotypes of dengue virus are known to circulate or co-circulate in many regions. The Union Health Ministry in a statement earlier had said that the tetravalent dengue vaccine strain (TV003/TV005), originally developed by the National Institutes of Health (NIH), USA, has shown promising results in clinical trials in Brazil. Panacea Biotec, one of three Indian companies to receive the strain, is at the most advanced stage of development. The company has worked extensively on these strains to develop a full-fledged vaccine formulation and holds a process patent for this work. Dengue is a major public health concern in India, ranking among the top 30 countries with the highest incidence of the disease. The global incidence of dengue has been steadily increasing over the past two decades, with more than 129 countries reporting dengue viral disease by the end of 2023, according to the World Health Organisation (WHO). In India, approximately 75-80 per cent of infections are asymptomatic, yet these individuals can still transmit the infection through the bite of Aedes mosquitoes. Among the 20-25 per cent of cases where symptoms are clinically apparent, children are at a significantly higher risk of hospitalisation and mortality. In adults, the disease can escalate into severe conditions like dengue hemorrhagic fever and dengue shock syndrome. According to the government data, around 12,043 dengue cases were reported till March this year. In 2024, 2.3 lakh cases and 297 deaths had been recorded.

登革热是全球影响范围最广的节肢动物媒介疾病，主要通过埃及伊蚊或白纹伊蚊传播，全球有近一半的人口面临感染的风险。目前，还没有通用的抗登革病毒药物。登革热的流行病学特征复杂，临床表现多样，从无症状感染到危及生命的登革出血热，任何一种DENV血清型（DENV-1、DENV-2、DENV-3、DENV-4）都可能导致不同程度的疾病。感染一种血清型可对相同血清型产生长期免疫力，对其他血清型仅有短暂免疫力，连续感染不同血清型会使重症登革热的风险增加。登革热病例通常无症状或导致轻度发热性疾病。然而，有些病例会发展为重症登革热，可能会出现休克、严重出血或严重器官损伤。这一阶段通常在退烧后开始，之前有一些警告信号，如剧烈腹痛、持续呕吐、牙龈出血、积液、嗜睡或烦躁以及肝脏肿大[1]。据估计，全球每年有超过1亿至4亿例登革热病例，38亿人生活在登革热流行国家，其中大部分位于非洲、美洲和亚洲。2023年报告的登革热病例数最多，世卫组织美洲区域报告了450万例病例和2300例死亡。由于气候变化和城市化，登革热病例可能还会上升并在地理上出现扩大[2]。我国2019—2023年共报告病例43095例，平均报告发病率为0.61/10万，年报告发病率波动显著（AAPC=-3.16%，95% CI：-54.16%~91.47%），主要集中在2019年和2023年，约占近5年总报告病例数的96.83%。各年龄组人群均可发病，30~<40岁年龄组病例占22.6%。全年均有病例发生，6月份开始快速上升，高峰期集中在8—10月份，为34 780例（RR=12.44，LLR=29 262.52，P<0.05）。疫情特征以输入引发本地传播为主，输入病例主要来源于东南亚地区（占86.56%），其中柬埔寨3284例（占46.11%）、缅甸1851例（占25.99%）为病例主要来源国家。不同年份有显著不同，西南地区、华南地区、华东地区发生本地传播疫情风险高，高发地区主要分布在云南和广东[3]。近几十年来，持续的登革热疫情对维护全球公共卫生安全带来了艰巨的挑战，公众迫切需要一种安全有效的登革热疫苗。对于DENV，有效的疫苗必须对4种DENV血清型都产生免疫保护，又要尽可能避免异源血清型继发感染导致ADE效应。目前，进入临床试验阶段的登革热疫苗主要有减毒活疫苗、灭活病毒疫苗、DNA疫苗、重组亚单位疫苗等。详细情况见下表：赛诺菲巴斯德公司研发的四价减毒活疫苗CYD-TDV是首个上市的登革热疫苗，该疫苗以黄热减毒活疫苗（YFV17D）为骨架，用DENV的前体膜蛋白（prM）和包膜蛋白（E）基因取代YFV 17D相应的结构蛋白基因构建而成[4]。TAK-003是由武田制药开发的一种四价登革热减毒活疫苗，最近已获准在欧盟和印度尼西亚用于6~45岁人群预防接种，且无论其血清阳性或阴性都可接种[5]-[6]。目前，TAK-003正在亚洲、拉丁美洲及其他登革热流行国家接受监管审查[7]。武田制药正在开展一项新的临床试验（NCT03999996），以评估第1次接种15个月和24个月后加强接种的效用。结果表明，TAK-003中来自DENV-2骨架的NS被证明可以引发NS特异性T细胞免疫，所以该疫苗对DENV-2（病毒骨架的起源株）的保护效果最高，这表明未来DENV疫苗研发要同时考虑特异性抗体和T细胞表位产生的免疫影响[8]。TV003/TV005是由美国国家过敏与传染病研究所（NIAID）研制的一种处于临床试验阶段的减毒活疫苗。其研发策略主要分为两种：第一种是在3′非翻译区引入30个核苷酸缺失来设计疫苗（rDEN1Δ30、rDEN3Δ30、rDEN4Δ30）[9]；第二种是用DENV-2的prM和E蛋白替代rDEN4Δ30中的prM和E蛋白[10]。TV003 （103 PFU）和TV005（104 PFU的主要差异在于rDEN2/4Δ30组分用量不同。当不同血清型DENV继发感染宿主时，体内预存的DENV抗体会促进第2种DENV进入单核细胞和巨噬细胞。DENV首先与抗体的Fc片段结合，然后在宿主细胞FcγRs（特别是FcγR Ⅱa和FcγR Ⅲa）的介导下进行吸附和侵袭，并抑制Ⅰ型干扰素的产生，从而增强宿主细胞内病毒的复制[11]。交叉免疫应答抗体可以介导同属病毒的ADE效应。几乎所有抗DENV抗体都可以诱导寨卡病毒（ZIKV）感染的ADE效应[12]。交叉免疫应答的非中和抗体识别两种主要的抗原表位，分别是prM蛋白表位和E蛋白上的融合环表位（FLE）。Dai等[13]通过改变FLE构象但保留其中和表位，重新设计了ZIKV亚单位疫苗免疫原。研究发现，免疫诱导的抗体不会与DENV发生交叉反应，这是消除ZIKV感染导致ADE效应的重大突破。与基于野生型毒株的疫苗相比，该疫苗产生的抗体反应具有更好的免疫优势。野生型毒株疫苗引发的抗体反应主要集中在特定的抗体基因上，而此抗体反应更为多样和分散。这意味着此二聚体疫苗能够改变对ZIKV的免疫优势，在免疫应答中减少了与ADE效应相关的抗体反应。晶体结构表明，免疫原二聚体的E蛋白片段在形成过程中被改变，抑制了ADE效应，为避免产生ADE效应的DENV疫苗研发提供了一种思路[14]。参考文献：[1]世界卫生组织.登革热-全球形势[EB/OL].(2023-12-21) [2025-04-08].https://www-who-int.libproxy1.nus.edu.sg/zh/emergencies/disease-outbreak-news/item/2023-DON498.[2] 世界卫生组织.世卫组织预认证新型登革热疫苗[EB/OL].(2024-05-15) [2025-04-08].https://www-who-int.libproxy1.nus.edu.sg/zh/news/item/15-05-2024-who-prequalifies-new-dengue-vaccine.[3] 李卓威, 黄晓霞, 田婷婷, 等. 我国2019—2023年登革热报告病例流行病学特征. 中国热带医学. 2024, 24(8): 925-930 https://doi-org.libproxy1.nus.edu.sg/10.13604/j.cnki.46-1064/r.2024.08.07.[4] Guy B, Saville M, Lang J. Development of Sanofi Pasteur tetravalent dengue vaccine[J]. Hum Vaccin, 2010, 6(9).[5]Takeda’s QDENGA®▼ (Dengue Tetravalent Vaccine [Live, Attenuated]) Approved for Use in European Union [EB/OL]. (2022-08-22) [2025-04-15]. https://www.takeda.com/newsroom/newsreleases/2022/takedas-qdenga-dengue-tetravalent-vaccine-live-attenuated-approved-for-use-in-european-union/.[6]Takeda’s QDENGA®▼ (Dengue Tetravalent Vaccine [Live, Attenuated]) Approved for Use in European Union [EB/OL]. (2022-12-08) [2025-04-15]. https://www.takeda.com/newsroom/newsreleases/2022/takedas-qdenga-dengue-tetravalent-vaccine-live-attenuated-approved-for-use-in-european-union/.[7]Takeda comienza con las presentaciones regulatorias para la vacuna candidata contra el dengue en la UE y los países endémicos[EB/OL]. (2021-04-01) [2025-04-15]. https://www.takeda.com/es-ar/prensa/2021/takeda-comienza-con-las-presentaciones-regulatorias-para-la-vacuna-candidata-contra-el-dengue-en-la-ue-y-los-paises-endemicos/.[8] Tricou V, Gottardo R, Egan MA, et al. Characterization of the cell-mediated immune response to Takeda′s live-attenuated tetravalent dengue vaccine in adolescents participating in a phase 2 randomized controlled trial conducted in a dengue-endemic setting[J]. Vaccine, 2022, 40 (8): 1143-1151.[9] Durbin AP, Kirkpatrick BD, Pierce KK, et al. Development and clinical evaluation of multiple investigational monovalent DENV vaccines to identify components for inclusion in a live attenuated tetravalent DENV vaccine[J]. Vaccine, 2011, 29(42): 7242-7250.[10] Whitehead SS, Hanley KA, Blaney JE Jr, et al. Substitution of the stru识别微信二维码，可添加药时空小编请注明：姓名+研究方向！