新的結核疫苗可能會是遊戲改變者

資料來源：BBC news/ 2019年10月31日/ 財團法人台灣紅絲帶基金會編譯/ （譯註：TB與HIV時常共病故應一併重視）

儘管一種新的結核病疫苗在未來幾年內可能不會上市，但研究人員仍非常樂觀，它可能對全球結核病的治療上有巨大幫助。

研究人員最近宣布了一種「革命性」的新結核病治療方法，該方法可能會對結核病（TB）的傳播產生驚人的影響。該疫苗將為這種疾病提供長期保護，該疾病每年殺死150萬人。

儘管現在存有治療方法和疫苗，但事實證明它們並不十分有效。全世界每年看到成千上萬的新病例，其中許多在治療上是多重抗藥性的個案。一段時間以來，這個疾病是危險的，並且正在蔓延。

該疫苗的研究人員團隊來自世界各地，他們看到該疫苗具有巨大的潛力，可以幫助全球各地的社區，尤其是那些高發病的地區。上週在印度南部城市海得拉巴舉行的全球肺健康峰會上宣布了這種新疫苗，該疫苗由觸發免疫反應的細菌蛋白質所組成。

為什麼這個疫苗較特別？

這種新疫苗已被證明對治療結核病患者有效，但它也顯示出具保護性元素的跡象，並有助於建立自然的保護。

結核病專家David Lewinsohn告訴英國廣播公司，潛在的疫苗是「真正的遊戲改變者」。

他說：「真正引人注目的是，它對已經被結核病的病原體結核分枝桿菌感染的成年人有效。」

他繼續解釋為什麼大多數感染結核分枝桿菌的人不會發展為結核病，研究人員認為感染可以提供某種程度上的保護。令人興奮的是，新疫苗「已被證明可以改善這種自然免疫力。」

前方的路

該疫苗已經通過了一系列的臨床測試，但是在正式獲得許可之前，還有少量的測試和更大的試驗需要進行。研究人員說，已經在南非，肯亞和尚比亞等結核病的流行地區針對3,500多名成年人進行了測試。

Lewinsohn說：「假設在其餘試驗中這些數據成立，這似乎很有可能，這種疫苗有可能徹底改變結核病的治療方法。」

Lewinsohn博士估計，如果一切順利，到2028年，該疫苗應能滿足最需要的人。但是，這種疫苗已經存在了很長一段時間。製藥公司葛蘭素史克（GSK）從事結核病疫苗研究已有20年了。

英國廣播公司的一篇文章說，結核病治療測試並不像其他疫苗那麼容易。研究人員說，該疫苗必須在動物（如小鼠，天竺鼠和非人類靈長類動物）中顯示功效才能發展。但是大多數時候，「動物模型實驗卻通常無法反映出我們希望在有效的疫苗中所看到的東西。」

例如，在小鼠中，結核病往往是一種「惰性疾病」，而研究人員可能將成功定義為肺中細菌數量減少約10倍。儘管這結果令人鼓舞，但是針對人類的兒童而言，十分之一的細菌濃度仍然是患有結核病。

目前的情況

根據世界衛生組織（WHO）的數據，僅在去年，全世界就有1,000萬人患有結核病。結核病有多種形式–潛伏性，活躍性，耐藥性和其他形式。

世界近四分之一的人口患有潛伏性結核感染。這意味著它們以非活性形式攜帶細菌，沒有病，不會將疾病傳播給其他人。但潛在結核病患者在一生中轉變為活動性結核病的風險為5％至10％。

但是，這種疾病非常嚴重，如果不及時治療，可能會致命。由於其致死性和全球的盛行，WHO的目標是在2015年至2035年之間將新的結核病病例數減少90％，將結核病死亡人數減少95％。新疫苗有望對此有所幫助。

在以下八個國家中，結核病的盛行率最高，佔全球結核病病例的三分之二：印度（27％），中國（9％），印度尼西亞（8％），菲律賓（6％），巴基斯坦（6％），奈及利亞（4％），孟加拉國（4％）和南非（3％）。

該病是印度最重的負擔，每年有300萬新病例。據世界衛生組織稱，這些病例中約有100,000個是多重抗藥的。這種疾病每年造成40萬印度人死亡，每年政府為此花費約240億美元。

國際抗癆聯盟駐德里辦公室主任Jamhoih Tonsing說：「除非能在印度消除結核，否則我們無法在全球範圍內消除結核病。」

有關結核病的其他事實

BBC的文章提供了有關該疾病及其對個人和社區的影響之以下事實：

•結核病是一種細菌感染，透過吸入由被感染者於咳嗽或打噴嚏中所飛濺的微小飛沫而傳播。

•它主要影響肺部，但也可以影響其他身體部位，例如腹部腺體，骨骼和神經系統。

•最常見的結核病症狀是持續咳嗽超過三週，無法解釋的體重減輕，發燒和盜汗。

•結核病並不是那麼容易感染，通常您需要花較長的時間與感染者密切接觸才能感染它。

•如果不進行治療，結核病可能致命，但如果用正確的抗生素持續治療六個月，則可以治癒。

•當前的刺戳式的卡介苗可提供抗結核的保護，推薦給35歲以下的嬰兒、兒童和成人，他們有染上結核病的風險。

•高危人群包括生活在結核病高發地區的兒童以及有來自結核病高發國家的家庭近親。

幾個世代以來結核病一直是公共衛生關注的問題，儘管現在比一個世紀前有更多的治療方法和疫苗，但每年該疾病仍然有數以千計的人們喪生。隨著疫苗的到來，研究人員希望全球結核病盛行率能夠永遠下降。

New Tuberculosis Vaccine Could be a Game Changer

While a new vaccine for TB might not see the market for another couple years, researchers are very optimistic it could be hugely helpful in treating TB worldwide. Oct 31, 2019

Researchers recently announced a “revolutionary” new tuberculosis treatment that could have amazing effects on the spread of tuberculosis (TB). The vaccine would provide long-term protection against the disease that kills 1.5 million people every year.

While there are existing treatments and vaccines, they have proven not very effective. The world sees thousands of new cases each year, and many of these are multi-treatment resistant. It has been clear for some time that this disease is dangerous, and spreading.

The team of researchers for the vaccine come from all over the world, and they see the vaccine having incredible potential to help communities around the globe—especially those with high rates of the disease. The new vaccine, which is made up of proteins from bacteria that triggers an immune response, was announced at a global summit on lung health in the southern Indian city of Hyderabad last week.

Why is this One Special?

This new vaccine has already proven to be effective in treating people with TB, but it is showing signs of a protective element too and helping build natural protection.

David Lewinsohn, a TB expert, told the BBC the potential vaccine was a “real game changer.”

“What is really remarkable is that it was effective in adults who were already infected with Mycobacterium tuberculosis that is the causative agent of TB,” he said.

He goes on to explain that while most people with Mycobaterium tuberculosis do not develop TB, researchers believe that infection confers a degree of protection. This is exciting, as the new vaccine “has been shown to improve on this natural immunity.”

The Road Ahead

The vaccine has already passed a series of clinical tests, but there are still a handful more tests and bigger trials to go before it can be officially lisenced released. It has been tested on more than 3,500 adults in TB endemic regions of South African, Kenya and Zambia, researchers said.

“Assuming the data holds up in the remaining trials, which seems likely, this vaccine has the potential to revolutionise TB treatment,” said Lewinsohn.

Dr. Lewinsohn estimates that if all goes well, the vaccine should reach people who need it most by 2028. However, this vaccine has already been a long time coming; drug firm GlaxoSmithKline (GSK) has been working on the TB vaccine for nearly 20 years.

Tuberculosis treatment testing is not as easy as some other vaccines, according to one BBC article. Researchers say that the vaccine must show efficacy in animals (like mice, guinea pigs, and non-human primates) to progress. But most of the time, “animal models often do not reflect what we would like to see in an effective vaccine.”

For example, in the mouse, TB tends to be an “indolent disease” and researchers might define success as a roughly 10-fold reduction in the number of bacteria in the lung.

While this is encouraging, but for a human child, one tenth of that bacteria concentration still has TB.

The Current Situation

In last year alone, the world saw 10 million people ill with TB, according to the World Health Organization (WHO). And TB takes many forms—latent, active, drug-resistant, and others.

Nearly a quarter of the world’s entire population has a latent TB infection. This means that they carry the bacteria in an inactive form, are not ill, and do not transmit the disease to others. Those with latent TB have a five to ten percent risk of developing active TB in their lifetime.

However, the disease is very serious, and if untreated, can be fatal. Because of its deathly mark and its global prevalence, the WHO aims to reduce the number of new TB cases by 90 percent and the number of TB deaths by 95 percent between 2015 and 2035. The new vaccine will hopefully help with this.

The prevalence of TB is highest in the following eight countries, and they account for two thirds of the global TB cases: India (27 percent), China (nine percent), Indonesia (eight percent), the Philippines (six percent), Pakistan (six percent), Nigeria (four percent), Bangladesh (four percent), and South Africa (three percent).

India is most burdened by the disease with more than three million new cases annually. About 100,000 of these cases are multi-drug resistant, according to the WHO. The disease kills 400,000 Indians annually, and it costs the government about $24bn annually.

“We cannot eliminate TB globally unless we end it in India,” said Jamhoih Tonsing, director of the International Union Against Tuberculosis and Lung Disease’s office in Delhi.