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なぜまだ経口ポリオワクチンなのか(インドの話ですが)

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2012年4月8日のインドのビジネス関連のメディアにのっていた、"インドでの”不活化ポリオワクチン関連のインタビュー記事です。

Injectibles should replace oral polio vaccinations

誰の?ですが、インタビューに答えているのはウイルス学者のT Jacob John博士。バックグラウンドはウイルス学者。WHOのポリオ根絶委員会のメンバーでもあります。
検索をしてみたところ、2000年(2010年や2012年じゃないですよ)のLancetに下記のような記事が掲載されています。
Polio vaccine strategies for the end game
1976年の論文1980年、インドの予防接種プログラムについての論文


英語がOKな人は英語だけ読んでください。
英語パスな人は概要だけでもつかんでください。
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Injectibles should replace oral polio vaccinations: T Jacob John
Interview with Member, WHO Committee on Global Polio Eradication

T Jacob John, virologist from Christian Medical College in Vellore and member of the WHO Committee on Global Polio Eradication, tells Sreelatha Menon that oral polio vaccines lead to 100 to 200 non-infectious polio cases every year, which are not reported or compensated for


経口ポリオワクチンを使用しているインドでは、毎年、VAPP =野生ウイルスではなく、生ワクチンのウイルスでポリオ症例(他人に感染させることはありません)が100-200例発生しています。 データがアバウトなのは、報告システム上の問題です。

According to the health ministry’s website, seven cases of polio were caused due to oral polio doses this year. Is that a correct estimate?
There are two kinds of reactions to oral polio vaccines (OPVs). One is the vaccine-associated paralytic polio, or VAPP, which is a rare adverse event that can occur following a polio vaccine. This occurs in a vaccinated child or by an immediate contact. It is like a side effect. This is not counted in India.


The other possible reaction to OPVs is the vaccine-derived poliovirus or VDPV. In this case, the virus mutates back to wild-like properties. How many VAPP cases are estimated each year?
Between 100 and 200 cases are estimated each year. But these are non-infectious.

Why does the government not report VAPP cases, but reports only VDPV ones?

VAPP is considered an adverse reaction to OPV. It occurs only rarely, but mostly in a vaccinated child, within a month of vaccination. The cause is the vaccine virus itself, which, even if transmitted to another child, is still the vaccine virus and not virulent. VAPP is not epidemiologically relevant to the eradication programme, although the paralysis is just as severe as in natural polio or polio due to VDPV. Unfortunately, for the child and the family, VAPP is clinically indistinguishable from natural polio ― the paralysis is just as severe, and also permanent. VAPP must weigh on our collective conscience ― because such children would not have been paralysed, if OPV was not given. If the government compensates all children with VAPP, which is the moral duty of any government, the overall cost of OPV-based programme will increase.

VDPV, on the other hand, is vaccine poliovirus that has genetically reverted to virulence and can spread widely just like natural (or wild) poliovirus. Therefore, VDPV is epidemiologically very relevant to the polio eradication programme.

As the former chairman of the India Expert Advisory Group for Polio Eradication, why did you not advise the government on the risks of OPV?

I have been consistently advising the government and anybody who would listen that this problem will arise. I have been saying this for the last 25 years. Injectible vaccines are known to have no side effects.

「私は25年もこの問題を政府に言い続けてきたのに」

Then, why did the government go for OPVs rather than injectible vaccines in the first place?
You never asked me this question ten years ago. Back then, the government said 10 doses would be given to every child (below the age of five) every year, without realising that it was stepping on a slippery slope. As for regrets, collectively there is none. Will the United States apologise for Iraq? When powerful organisations make wrong decisions, we all suffer. If your mother burns the house down, will you question her?

「なぜ政府は経口ワクチンから不活化ワクチンにかえないんでしょうね」
「あなたは同じ質問を10年前にしましたか?10年前、政府は、5歳以下のこどもひとりあたりに合計10回投与(ワクチン接種)しようとしました。米国政府はイラクに謝罪をしましたか? 力のある組織が誤った決定をすると人々が被害を受けます」

Is the government doing any introspection on the matter? Does it realise its mistake?
The bureaucracy is not going to tell the health minister that they gave a wrong advice earlier, and they should correct it now. Only the judiciary and the media could have intervened to save the situation. The latter is not united and credible. Investigative journalism could have brought this out long ago.

「政府だけでなく、ジャーナリズムもこの問題をもっと早く扱うべきだった」

When did the western countries switch over to injectible polio vaccinations (IPVs)? How much do these cost?
France and Germany made this transition in late 1980s, the United States in 1997 and the United Kingdom in 2004. Till then, these countries also gave oral vaccinations and suffered from VAPP cases.
Today, some 70 rich countries use only IPVs and do not allow the entry of OPVs.

「なぜ西洋諸国はIPVに変更をしたのでしょう?費用はどれくらいかかるのでしょう?」
「フランスとドイツは1980年代に、米国は1997年に、英国は2004年に経口ポリオワクチンから不活化ポリオワクチンに変更をしました。それまではこれらの国にもワクチンによる症例発生がありました。現在、豊かな70数カ国の国では不活化ポリオワクチンを使用しており、経口ポリオワクチンは使用されません」

As only the richer countries are buying IPVs, their manufacturers do not have any incentive to reduce the prices. If India decides to switch over to IPVs, the volume required would be so large that companies would compete and the prices would tumble. Switching to IPV is not only technically unavoidable, it is also an ethical imperative.

「豊かな国が不活化ポリオワクチンを購入するので、製薬会社は価格を下げるインセンティブがありません。不活化ポリオワクチンへの切り替えは技術的な問題だけでなく、倫理的な側面があります」

Is the high cost stopping the government from switching over to injectible vaccination?
The government must continue with OPV for now, as stopping this right away will be the most unwise. But it must introduce injectibles, too, and strengthen the routine immunisation programme till IPVs reach a high coverage level. Then, stop OPVs altogether. This must happen without any further delay.


As far as I know, cost was not the reason for not introducing IPV earlier. In the 1980s, India had access to indigenous and inexpensive injectibles, but health ministry ― for reasons unknown ― insisted on an OPV-only policy, and disallowed the manufacture of injectibles by not licensing these in the country. Only in 2006 was IPV finally licensed.

・・・インドで不活化ポリオワクチンが承認されたのは2006年・・・

Only three doses of injectibles are required. The first two doses can be given in the first year, while the third in the second year or later. So, three doses can be given without any additional health worker-child contact. Today, nationally children under five years are given 15 doses of OPVs ― five in the routine immunisation programme and 10 by campaigns.

Campaigns are quite expensive. Although I have not calculated specifically, the cost of one dose of OPV by campaign might be equal to one dose of IPV given in the routine programme.

There is an additional benefit for the government. For the sake of completing and concluding polio eradication, the routine immunisation programme will have to be strengthened ― in order to achieve high coverage of IPV.


Since the VAPP cases are not reported like the VDPV cases, how would these be compensated for?
This problem is the result of a fundamental flaw in the country’s health management system. Polio eradication is a ‘public health’ programme in which the benefit of the majority could outweigh the risks of a minority. In public health, individual with benefit or risk may not be identified. So, those who are responsible for polio eradication are not interested in specific individuals. Their job is to get rid of wild polioviruses, which has been achieved from 2011.

Diagnosis and treatment of every individual with polio is the responsibility of the health care programme of the country. Had the health care wing of the government’s health management system taken the responsibility to diagnose and treat every child with polio, the problem of VAPP would have been identified and counted nationally. Detection and counting of VAPP was required in every country that opted to use OPV, as strongly recommended by the World Health Organisation in 1982. But, India and many other countries had ignored it.

So, reporting VAPP is the job of the health care department, while removing wild polioviruses is of the polio eradication staff. Countries in which the health management system has public health and health care as organised, separate components, polio eradication is under the public health department and care of children with polio, whether it be due to wild poliovirus, vaccine virus (VAPP) or VDPV is under the health care department. Unfortunately, India has refused to establish a public health department, by policy, and so, a special vehicle had to be created for polio eradication.

So, VAPP falls between the two ― an absent public health system and a weak health care programme. It is the responsibility of the health care programme to diagnose VAPP and treat and recommend to the government for compensation.

「経口ポリオワクチンでポリオを発症してしまう問題は、公衆衛生システムの不在と、ヘルスケアプログラムの弱さの狭間にあります。ワクチン由来の症例を診断すること、政府が健康被害補償をするよう働きかけることはヘルスケアプログラムの責任です」
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ど、どこかで聞いたような・・・。

でも事情はインドが先をいっているのかもしれません。 
Panacea Biotec helps Nigeria battle Polio with new vaccine POLPROTEC 2012年2月24日の記事

"2009年7月から2011年3月までの3年半の間に、世界全体で把握された、経口ポリオワクチンの株でのポリオ症例は434例です。
ナイジェリアがもっとも多く、C-type VDPVが報告されています。
ナイジェリアでは2000年−2009年の10年間の間に、ポリオのアウトブレイクが14回おき、400例以上のポリオワクチンによる症例が発生しています。
Panacea Biotecと Emzorは、 "Polprotec" がグローバルなポリオ根絶計画に貢献すると説明しています。
ナイジェリアの小児科医協会が使用をはじめています。
この組織の代表Dorothy O. Esangbedo医師は、「ナイジェリアでの不活化ポリオワクチンの導入はこれが初めてです。インドは、ポリオが根絶できていない"PAIN"(パキスタン、アフガニスタン、インド、ナイジェリア)から抜けでようとしています。"

ちなみに、、、Panacea Biotecはインドの製薬メーカーです。

5種混合ワクチンEasyfive (DTwP - Hep B - Hib ) 4種混合ワクチン Easyfour (DTwP - Hib) なども扱っています。
より安いワクチンが供給できれば、途上国への拡大なども可能になっていくわけですが、2011年WHOの審査は厳しい結果になったとGAVIの記事にありました。
詳細(WHO)

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