新型コロナの大規模検査、実施のネックはリソース不足

【パリＡＦＰ＝時事】新型コロナウイルスのパンデミック（世界的な大流行）抑制に成功するための処方箋として世界保健機関（WHO）が呼び掛けているのは、「一にも二にも、とにかく検査」だ。単純なことのようにみえるが、実際に従うことができる国が多くはないのはなぜだろうか？（写真は資料写真）
　ウイルス感染拡大を抑えるために大規模な検査を実施し、称賛を受けている韓国などの国がある一方で、多くの国々はこの方法に追随できずにいると専門家らは指摘している。
　ＷＨＯのテドロス・アダノム・ゲブレイェスス事務局長は２３日、「一部の国は、こうした攻めの手を使う能力がなく悪戦苦闘している」と認めた。
　だが同氏のメッセージは一貫している。「勝利のためには、われわれは積極果敢かつ狙いを定めた戦術でウイルスと闘わなければならない。疑わしいケースはすべて検査し、感染が確認された人は全員隔離の上で治療し、濃厚接触者もすべて突き止めて検疫するということだ」
　従来のリアルタイムＰＣＲ検査は、呼吸器系ウイルスの検出を目的としたものだ。だが、検査レベルは国によってばらつきがある。スイス・ジュネーブ大学の公衆衛生・伝染病学専門家、アントワーヌ・フラオー教授は「それはすべて国の発展水準に左右される」とＡＦＰの取材に語った。
　韓国は約３０万件に及ぶ大規模な検査を実施した。感染者を隔離し、それと組み合わせて野心的な追跡プログラムを展開。ビデオ監視や銀行のカード利用、スマートフォンのデータ収集などで感染者が接触した人々を突き止めた。こうした努力が実り、１日当たりの新規感染者は１００人未満に減った。このような積極的な検査戦略はシンガポールでも奏功している。

■血清検査
　欧州諸国の検査は韓国ほどの規模ではなく、重症で入院した患者に集中している。これについてフラオー氏は、検査をする意志がないのではなく、必要なリソースが不足しているのが問題だという。
　韓国やシンガポールがそうした困難に直面していないのはなぜか。フランスのウイルス学者アン・ゴファール氏は、両国は過去の重症急性呼吸器症候群（ＳＡＲＳ）や中東呼吸器症候群（ＭＥＲＳ）の流行で学んだ教訓を生かしていると説明する。
　欧州諸国の中では１週間に１６万件の検査をする能力があるドイツが、他国と比較して「自律的」かもしれないとフラオー氏はいう。
　初動で大がかりな検査を行わなかったフランスでは現在、ウイルスの感染拡大を阻止するために厳格な外出禁止措置を講じているが、その終了時に大規模な検査を実施する計画を立てている。これには血清学的スクリーニングと呼ばれる新たな検査を導入する可能性がある。
　これは血液サンプルを用いて特定のウイルスやバクテリアに関連する抗体の存在を検査するもので、個人の免疫システムがウイルスに反応し、免疫がついたかどうかを調べる。
　世界各地で複数のチームが、新型コロナウイルス感染症（ＣＯＶＩＤ-１９）を引き起こすウイルスの血清検査を開発中だ。フランスのオリビエ・ベラン保健相は、数週間内にこの検査が実施可能となることを期待していると語った。【翻訳編集ＡＦＰＢＢＮｅｗｓ】
〔ＡＦＰ＝時事〕（2020/03/27-13:20）

Test, test, test. The World Health Organisation's prescription for success in wrestling the new coronavirus pandemic under control may seem simple. So why are so few countries able to follow it?
While nations like South Korea have been praised for their decisive efforts to control the spread of the virus with mass screening, experts say many other countries have been unable to emulate their approach.
WHO chief Tedros Adhanom Ghebreyesus acknowledged this on Monday, saying that the organisation recognised that some countries are struggling with the capacity to carry out these offensive measures.
But his message remains the same: To win, we need to attack the virus with aggressive and targeted tactics -- testing every suspected case, isolating and caring for every confirmed case, and tracing and quarantining every close contact.
Existing tests, called RT-PCR, are designed to detect the virus in respiratory specimens from nasal or oral swabs, based on genetic analysis.
The results can be ready within hours.
But testing levels have diverged widely across the world.
It all depends on the level of development of the countries, Antoine Flahault, a specialist in public health and epidemiology at the University of Geneva, told AFP.
South Korea at one point was the country hardest-hit by the virus outside China.
It responded with a massive screening campaign, carrying out around 300,000 tests.
Authorities quarantined infected people and combined that with an ambitious tracing programme that tracked down people they had been in contact with using video surveillance, bank card usage and via smartphone.
As a result of these efforts, new cases have fallen below 100 a day.
This aggressive testing strategy has also paid off in Singapore, although the city-state this week announced a month-long shutdown of bars and banned mass gatherings.
Both countries have largely avoided the large-scale lockdown measures currently in place in many other countries, with related concerns over economic and social consequences.
- Shortages -
European countries have not tested to the same extent as South Korea, often focussing on people admitted to hospital with severe symptoms.
Flahault said the issue was less a lack of will to test, and more a shortage of the materials needed.
For countries like France and Switzerland, the problem in recent days has been more that of the availability of reagents (substances used in chemical testing process) than machines or human resources, he said.
Why haven't South Korea and Singapore encountered the same difficulties?
French virologist Anne Goffard said they had drawn on their experience facing other epidemics caused by different coronaviruses -- namely SARS, which emerged in 2002, and MERS a decade later.
This has enabled them to be better prepared and equipped, she told AFP, adding that many European countries would have to assess their manufacturing capacity in the future.
Germany, which has the capacity to carry out some 160,000 tests per week appears to be more autonomous, she added.
In poorer nations, the barrier to testing is even higher.
In the Philippines, infectious disease specialist Edsel Salvana has said testing potentially diverts scant resources away from other vital expenditure, like personal protective equipment (PPE) for health workers.
In comments on Twitter on Tuesday, he was scathing about the focus on testing -- WHO this is CRIMINAL -- and urged a more nuanced approach for resource-stretched nations.
I admire what South Korea did and I would do that if we had as much money and resources. But we don't, and my colleagues are wearing trash bags for PPE, he said.
- Must 'vastly expand' testing -
After it failed to test extensively at the beginning of its outbreak, France now plans to carry out mass screening at the end of the tough confinement measures it has implemented to try and halt the spread of the virus.
This could be facilitated by new kinds of tests, known as serological screening.
This process tests blood samples for the presence of antibodies associated with certain viruses or bacteria. It is used to find out if a person's immune system has reacted to a virus and has potentially built up immunity.
Several teams around the world are developing serology tests for the coronavirus that causes COVID-19 and French health minister Olivier Veran has said he hopes they will be available within weeks.
So which approach is the best?
In an analysis published by the Washington Post, US epidemiologist Marc Lipsitch said: The best strategy depends critically on which stage of the outbreak you are in and how much testing is available.
He added that countries like the US had passed the point of being able to trace individual cases.
But he said even when tough lockdown measures would be needed to wrestle the epidemic under control, we must vastly expand our testing capacity.