28/08/19

How close are we to a ‘workable’ HIV vaccine?

援助s Vaccine research1 - Main
专家认为,有效的疫苗对于结束流行病至关重要。版权:图像Ulrike LeonePixabay

速度阅读

  • HIV treatment has vastly improved, but no workable vaccine has yet been developed
  • 专家认为有效的疫苗对于结束流行病至关重要
  • New large-scale clinical trials raise cautious hope within scientific community

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[墨西哥城]尽管在治疗和预防方面取得了巨大进步HIV爱滋病in recent decades, an effective vaccine remains elusive – and is desperately needed to end the global pandemic that kills more than 700,000 people each year.

AIDS is caused by the human immunodeficiency virus (HIV), and is one of thebig diseases affecting people in developing countries, along with tuberculosis and malaria.

根据世界卫生组织的说法,全球有3790万人患有这种疾病,其中2330万人可以使用抗逆转录病毒疗法(ART),这是目前可用的最佳治疗方法。

根据2018年UNAIDS的数据,这是自2016年以来收到艺术的230万人的增长全局更新。但是它警告说:“不应将获得治疗的规模提升为理所当然”。

“控制或消除疾病的唯一方法是使用疫苗。疫苗将比其他任何干预措施便宜,我们需要一种疫苗,因为我们仍然不接近控制艾滋病毒,”

南非医学研究委员会主席格伦达·格雷(Glenda Gray)

The problem is, new infections emerge all the time: at least 1.7 million more every year, of which 160,000 are children under 15.

南非医学研究委员会主席格伦达·格雷(Glenda Gray)(SAMRC), tellsSciDev.Net:“控制或消除疾病的唯一方法是使用疫苗。疫苗将比其他任何干预措施便宜,我们需要一种疫苗,因为我们仍然不接近控制艾滋病毒。我们缺少全球和地方一级的所有里程碑。”

HIV疫苗试验网络的首席研究员Larry Corey(Larry Corey(HVTN),突出显示全球流行病的大小。“艾滋病毒仍然是我们这个时代的大流行;每天有5,000人被感染。”他说。

Researchers such as Corey have worked on developing a vaccine against HIV since the 1980s, and although significant advancements have been made, there is still no workable protection able to be scaled up around the world.

Why is it so hard to find a vaccine that works?

Most effective vaccines use antibodies to neutralise viral infections. But scientists have seen that this doesn’t work for HIV, since the virus reproduces and mutates too fast for antibodies to be effective. Also, research has shown that there are different subtypes of HIV spread around the world: while subtype B is common in North America and Europe, subtype C prevails in southern and eastern Africa.

该病毒也已经进化,因此它能够在显然没有感染的细胞内“隐藏”,从而在疾病的早期抑制免疫反应。另外,Gray补充说,其遗传多样性比迄今已知的任何其他病原体都要大。

“HIV has been a very difficult virus,” says Corey, a virology expert. “It masks itself in ways we have never seen a virus do so well. It is very clever, and it uses different mechanisms to evade the immune system and persist. It’s more effective than any other virus.”

尽管动物模型已被广泛用于研究疫苗功效,但它们通常很昂贵,并且不能保证药物在人类中会起作用。由于其遗传多样性,HIV病毒能够激发我们的免疫系统无法战斗的持续感染,因此疫苗必须比身体更好。

Research has focused on understanding what types of immune responses have to be produced in order to win the battle against the disease.

这个想法是使用能够在广泛感染身体之前能够识别和攻击病毒的抗体。换句话说,疫苗可以有效的病毒最弱的方面。

没有人类的模型显示治愈艾滋病,which constitutes a further barrier. “One of the reasons why we haven’t got a vaccine is that no humans have ever cured themselves of HIV,” Corey explains. “Zero out of 72 million. For every infectious disease there are at least a few people who cure themselves, but that’s not the case in HIV.”

Where are we now? Trials and their promises

大型临床试验测试针对HIV的疫苗功效的大型临床试验在2003年开始产生结果,尽管疫苗尚未准备就绪,但已经取得了重大进展。

Out of more than 100 vaccines that have been tested in humans, the biggest achievement so far has been the RV144 trial, also known as the “泰国研究”。这项研究表明,实验性疫苗的第一个有希望的结果,但成功是部分的:在接种疫苗后的几个月中,参与者被感染的可能性降低了60%,但三分之一和A-的参与者下降到50%半年。

国际艾滋病学会前主席琳达·盖尔·贝克(Linda-Gail Bekker)告诉scidev.net:“Importantly, we know [vaccination] can be achieved… the Thai vaccine taught us that. We have also now found ways to secure and create antibodies which very effectively bind and neutralise the virus.”

A modified version of the Thai vaccine is being tested in a large-scale phase 3 study in southern Africa. It is hoped it will reduce the risk of infection by at least 50 per cent and extend its protection period. The results will be public by 2021.

7月在10月10日宣布了最近的另一个有前途的进步th国际的艾滋病会议in Mexico City: the “Mosaico” vaccine, so-called because it is composed of different strains of the virus. This vaccine has proven to beeffective在涉及非洲妇女的测试中,将在美国,阿根廷,巴西,意大利,墨西哥,秘鲁,波兰和西班牙发生与​​男性(MSM)和跨性别人群发生性关系的男性中进行进一步评估。

“ Mosaico是我们在保护动物方面看到的最好的疫苗。现在,我们实际上必须看看它在人类中是否有效。”科里说。

贝克(Bekker),他是副主任Desmond Tutu HIV中心, thinks this vaccine should have a global impact if it works. While Mosaico’s researchers are cautiously optimistic about this new “global” vaccine, others havesaid期望应缓解,因为该病毒已被证明是高度动态的,能够快速改变,从而避免所有免疫反应。

Corey认为,如果Mosaico不起作用,则另一种路径是使用相同的单克隆抗体,以查看这是否比Mosaico方法更好。“我们将查看数据,看看它是一个还是另一个,或者可能两者都有。因此,我们确实有另一种方法。”他补充说。

A recent社论Nature总结说:“最终,只有疗效研究才能确定这些有前途的概念中的任何一个能够降低感染率或现有感染的水平。但是,早期临床研究和加速诊所的加速速度的管道非常令人鼓舞。”

艾滋病毒未来

Finding at least a partially effective vaccine remains of critical importance for the HIV response.

According to global sexual health charity避免,通过口服预防前预防(PREP),已经患有HIV的患者的普遍抗逆转录病毒治疗和疫苗的结合,新感染的最大降低将实现。该组织在其网站上说:“艾滋病毒疫苗比十年前更现实,对艾滋病毒疫苗的可用性的乐观预测是,到2030年可能会提供一种。”

尽管HIV研究历史上比任何其他传染病都获得了更多的融资,但不同的专家警告说,持续投资受到威胁。“几乎所有疫苗创新都在公共部门;药物和生物技术公司坐在场上。”格雷说。

Corey补充说:“这是一家非常高风险的业务,因此企业已经回避了它。”An exception has been the Mosaico study, a public-private partnership sponsored mainly by Janssen Vaccines & Prevention, with funding from the US National Institutes of Health’s National Institute of Allergy and Infectious Diseases (NIAID) and supported by the HVTN, headquartered at the Fred Hutchinson Cancer Research Center in Seattle, which facilitates its implementation.

根据科里(Corey)的估计,最大的投资者在美国的疫苗研究投资每年从政府获得7亿美元,而比尔·梅琳达·盖茨基金会(Bill&Melinda Gates Foundation)获得了2.5亿美元。他说:“实际上,美国政府和慈善事业使我们的重视使我们至少有一种乐观感,我们可以开发艾滋病毒疫苗。”

Unaids表示,迫切需要进行艾滋病毒疫苗研究的扩展。“在过去的十年中,投资一直保持稳定,每年约为9亿美元,不到艾滋病响应所需的总资源的5%。”陈述in 2018.

“通过扩大对艾滋病毒疫苗研究的投资,使资金多样化并吸引来自世界各地的最佳科学家,艾滋病毒的疫苗可能成为现实。”