HALF of positive coronavirus antibody tests could be wrong & give false sense of security – top US health agency
Antibody tests used to confirm whether someone has ever had the coronavirus could be wrong half of the time, driving bad policy decisions, the US Centers for Disease Control and Prevention warns.

The Centers for Disease Control and Prevention (CDC), a top federal health agency, said in a new guidance on Tuesday that during mass screenings in various populations, up to half of the positive results from antibody tests – also known as serologic tests – could be false, warning there are still major obstacles in determining who has been infected or what immunity they might have.

The unreliable tests shouldn’t inform decisions about moving potential patients to “congregate settings” – such as schools, dormitories or jails – nor choices “about returning persons to the workplace,” the CDC said.

But even when a patient is “truly positive” for antibodies, the agency said the result still doesn’t prove that the individual is “protected from future infection” or immune to the virus.

Serologic testing should not be used to determine immune status in individuals until the presence, durability, and duration of immunity is established.

The rate of false positive and negative test results heavily depends on the overall number of infections in a population. If a relatively low proportion of people in a given area have contracted the virus – five percent, for example – the CDC says even a highly sensitive and specific test will still yield a significant number of false positives, up to 51 percent.
偽陽性と偽陰性の結果の割合は、集団内の感染の総数に大きく依存します。 CDCは、特定の地域の比較的低い割合(5%など)でウイルスに感染している場合でも、非常に感度が高く特定のテストを行っても、最大51%のかなりの数の偽陽性が発生することを示しています。

In other words, less than half of those testing positive will truly have antibodies.

Echoing the new guidance, a research team at the University of Minnesota has also warned about antibody tests, issuing a report last week cautioning that they should not be used as a “diagnostic tool” given their inaccuracy.

To get around some of the shortcomings, the CDC recommended that health professionals use only the highest quality tests with the greatest level of specificity, conduct repeat screenings of those who come up positive to verify their result, and to focus testing on patients with a history of Covid-19-like symptoms.

The CDC announcement comes less than a week after the agency admitted that it has been combining data from antibody and RNA tests, conflating two incompatible metrics – one that tallies active infections, and another that looks to see whether someone has ever had the virus. The blending of data, first reported by the Atlantic, could seriously skew figures used by state governments to chart a course to reopening. And given the CDC’s latest announcement about antibody tests, the overall numbers may have been distorted even further by false positives.

In addition to the CDC itself, at least four state-level health agencies – in Texas, Georgia, Pennsylvania, and Vermont – said they are combining figures in the same way, according to the Atlantic.

The health agency also recently made waves when it revised its overall case fatality rate (CFR) estimate, putting the number around 0.4 percent, nearly 10 times lower than the World Health Organization’s initial figure of 3.4.

Despite the questionable data, however, dozens of US states are now moving to lift sweeping containment measures imposed in March to stem the spread of the virus, as some of the nation’s worst hot spots appear to be subsiding, most notably New York City. To date, nearly 1.7 million people have tested positive for the coronavirus in the US throughout the pandemic, with more than 98,000 fatal cases, according to data collected by Johns Hopkins University.
posted by ZUKUNASHI at 22:32| Comment(0) | Covid19

'Stalker Situation': Sweden's Chief Epidemiologist Receives Death Threats

'Stalker Situation': Sweden's Chief Epidemiologist Receives Death Threats
Over the course of the coronavirus crisis, Anders Tegnell, Sweden's state epidemiologist, the man often seen as the architect of the country's no-lockdown strategy, has emerged as a polarising figure, winning both praise and scorn.

Swedish state epidemiologist Anders Tegnell has been exposed to repeated threats, which have prompted an investigation from the police democracy and hate crime group, the newspaper Aftonbladet reported.

As early as 19 March, Tegnell received an email at his job address, which presented a threatening situation.

“It has come to my knowledge that a constellation of extremely dangerous, highly determined individuals has decided to 'neutralise' you”, reads an excerpt from the email.

Subsequently, he received threats at his home address. Threatening messages have also been sent to Tegnell's relatives, Aftonbladet reported.

“Initially, we worked very actively to find one or more perpetrators if possible. Threats, especially (when addressed) to people in a special position, are something the police take a serious look at,” Kristina Forsgren, Group Manager for the Democracy and Hate Crime Group in the Stockholm police Region, said.

However, over the course of the investigation, police have failed to track down any perpetrator. The failure has been attributed to the fact that they used a temporary email service. All the information was deleted within an hour, the police said. No DNA traces were found on the letter sent to Tegnell.

The state epidemiologist was questioned by police and said that he found the threats disquieting.

“I was not so worried myself, but I take it very seriously when it is directed at my family. It doesn't feel good at all. It feels a little like a stalker situation," Tegnell said in a police interview.

Following the repeated threats, Swedish Public Health Agency Director General Johan Carlson emphasised at one of the regular press conferences that although Tegnell plays a significant role in determining Sweden's strategy, the decisions are not his own.

“Never before has there been such a wave of criticism against individual employees,” Carlson stressed.

Remarkably, Tegnell did not show up for Tuesday's press conference, and a last-minute change was arranged. Confronted by the media on whether the excessive focus of Tegnell as a person is a problem, Johan Carlson said “No, the problem is people who threaten others with death.”

In Sweden, state epidemiologist Anders Tegnell, the public face of its no-lockdown strategy, is a polarising figure. While being celebrated as a rock star with memes, t-shirts, tattoos and even a fan club of his own on Facebook, Tegnell has been repeatedly criticised for what is perceived as failure to protect the most vulnerable, including the residents of nurseries and retirement homes, and contradicting messages about herd immunity.

With nearly 34,500 confirmed COVID-19 cases and 4,125 fatalities (the majority of them aged 80 and over), no-lockdown Sweden remains the hardest-hit Scandinavian nation, having more cases that its Nordic peers combined. By contrast, Denmark has witnessed only 11,426 confirmed cases and 563 deaths, whereas Norway has only witnessed 8,383 cases and 236 deaths.

posted by ZUKUNASHI at 17:17| Comment(0) | Covid19






posted by ZUKUNASHI at 16:58| Comment(0) | Covid19

全国人口動態から 3月は大きな変化なし問題は4月以降



東海から中京の指標が悪いのですが、これは東京、関東との交流、移動が活発だからではないかとのご意見をいただきました。確かにありますね。大阪とは少し違うのかもしれません。大阪は、福島第一原発事故直後の汚染野菜が投げ売りされた場所として知られていますが、それが終われば安いのは輸入物ですよね。それがプラスになった? 中京の人たちはまだプライドが高くて関西人とは同じ行動がとれなかった?


札幌市は北海道全体と変わらない。泊原発の影響? 札幌は避難先としては疑問がある。北海道は汚染がある恐れ。






posted by ZUKUNASHI at 16:05| Comment(3) | 福島原発事故