May 4th, 2020


Тесты на антитела к Ковид-19

Пока оставляют желать лучшего.
Потому что дают 10-15% ложнопозитивных  ответов.
Это много.
"Since the FDA issued its initial antibody test policy in mid-March, the agency said it has become aware of “a concerning number” of commercial serology tests being promoted inappropriately, including for diagnostic use, or performing poorly.
The FDA’s policy update comes too late as faulty and inaccurate tests have already flooded the market.
..some of the tests were extremely unreliable and could create a dangerous “false sense of security” for some Americans..

Dr. Scott Gottlieb, the former FDA commissioner, told CNBC that the tests have a high false-positive rate, making it difficult to know whether a single result is credible. He said the likely accuracy of the test increases if the same person gets two positive determinations in a row.
“Quite frankly, if it was me, I would repeat it three times,” said Gottlieb,

Ввиду этого, пока нельзя ориентироваться на пилотные данные о зараженности популяции  коронавирусом САРС2, и гипотетических "уже переболевших"  Ковид-19, исходя из выборочных тестирований на антитела, как на нечто более весомое и показательное, чем текущие тестирования на сам вирус..
Не говоря уж о том, что рано использовать результаты этих тестов как критерий "для выхода из карантина" или "на работу" (возвращение к нормальной жизни)
"It's crucial that the tests work properly. A false positive -- telling someone they have antibodies when they don't -- could have grave consequences, since that person would then think they're immune to Covid-19 when they're not. "Having many inaccurate tests is worse than having no tests at all."
В США ФДА, сначала давшее "зеленый свет" компаниям, производящим киты для тестированияантител в  крови, спохватилось, ввиду  того, что качество (чувствительность, точность, специфичность, воспроизводимость) тестов оказалась никудышней.
"one of the reasons for the high false-positive rates is relaxed requirements from the US Food and Drug Administration.
In mid-March, when it became clear that Covid-19 was starting to whirl out of control, the FDA loosened its approval standards in order to get more antibody tests out on the market quickly.
The agency started to allow companies to sell tests without first providing evidence that they worked. Some 175 test developers have taken advantage of these new rules and can legally market their antibody tests without first having their validation data evaluated by the FDA."

После того, как киты (12, одобренных ФДА без проверок, для срочного применения) "проверили", с использованием  крови образцов 2018 года, задолго до эпидемии Ковид-19, и грустная правда вышла наружу, ФДА срочно затребовала от производителей документацию  об исследованиях, подтверждающую валидность, точность и воспроизводимость их тестов. Кто предоставит в течении 10 дней, тот и получит одобрение на рынок.
Кроме того,  пока еще неясен вопрос и с ложно-негативными резульатами тестов.
"The researchers also checked whether the tests accurately detected positive samples, but are less confident about those results, "

Первый случай Ковид-19 во Франции

Франция, считалось, получила своего первого больного Ковид-19 в конце января 2020.
"France, which has seen almost 25,000 people die from the virus since March 1, confirmed its first three COVID-19 cases on Jan. 24, including two patients in Paris and another in the southwestern city of Bordeaux."
Оказалось, это не так.
Исследователи протестировали в одной из больниц сохранившиеся образцы больных, болевших пневмонией в декабре 2019 и январе 2020, которые показали отрицательные ответы при тестировании на грипп.
Оказалось, что 27 декабряв Париже у них был пациент, болевший 15 дней пневмонией.
Этот мужчина болел пневмонией,  выжил,  жена не болела (вроде бы, хотя могла быть асимптоматичной, или слегка простудной, в декабре, раньше него). Но он заразил своих двоих детей:
"Yves Cohen, head of resuscitation at the Avicenne and Jean Verdier hospitals in the northern suburbs of Paris, told BFM TV that scientists had retested samples from 24 patients treated in December and January who tested negative for the flu.
"Of the 24, we had one who was positive for COVID-19 on Dec. 27," he told the news channel on Sunday.
Each sample was retested several times to ensure there were no errors, he added.
Cohen said the patient had survived and that a first investigation to trace the first contamination has been carried out.
"He was sick for 15 days and infected his two children, but not his wife, who works in a supermarket.
"He was amazed, he didn't understand how he had been infected. We put the puzzle together and he had not made any trips. The only contact that he had was with his wife.
The man's wife worked alongside a Sushi stand, close to colleagues of Chinese origin,..
"We're wondering whether she was asymptomatic," he said.
"He may be the 'patient zero', but perhaps there are others in other regions. All the negative PCRs for pneumonia must be tested again. The virus was probably circulating (then)
Французы размышляют, мог ли он быть "0-вым" пациентом?
Впрочем, если протетсировать все что осталось, не исключено, что вявятся и другие больные (или умершие),   у которых была пневмония в декабре..
""He may be the 'patient zero', but perhaps there are others in other regions. All the negative PCRs for pneumonia must be tested again. The virus was probably circulating (then)," he said."
Я думаю, это имело бы смысл сделать не только во Франции.