Tens of thousands of people in France demonstrated against a proposed security law. In Paris clashes erupted between police and protesters. Part of the bill would ban publication of images of police. Some civil rights groups say it should be scrapped.
THE SIZE OF THIS MASS GRAVE IS ENORMOUS
Between 1941 and 1943, Nazi forces shot almost 34,000 Jews in the ravine at Babyn Yar on what was then the edge of the Ukrainian capital, Kyiv. But where exactly did the victims lose their lives? The precise location of the Holocaust's biggest massacre was unclear for decades.
New COVID-19 test uses a smartphone microscope to quickly analyze saliva samples
Researchers at the University of Arizona are developing a COVID-19 testing method that uses a smartphone microscope to analyze saliva samples and deliver results in about 10 minutes.
The UArizona research team, led by biomedical engineering professor Jeong-Yeol Yoon, aims to combine the speed of existing nasal swab antigen tests with the high accuracy of nasal swab PCR, or polymerase chain reaction, tests. The researchers are adapting an inexpensive method that they originally created to detect norovirus - the microbe famous for spreading on cruise ships - using a smartphone microscope.
They plan to use the method in conjunction with a saline swish-gargle test developed by Michael Worobey, head of the UArizona Department of Ecology and Evolutionary Biology and associate director of the University of Arizona BIO5 Institute.
The team's latest research using water samples - done in collaboration with Kelly A. Reynolds, chair of the Department of Community, Environment and Policy in the UArizona Mel and Enid Zuckerman College of Public Health - is published today in Nature Protocols.
Yoon - a BIO5 Institute member who is also a professor of biosystems engineering, animal and comparative biomedical sciences, and chemistry and biochemistry - is working with a large group of undergraduate and graduate students to develop the smartphone-based COVID-19 detection method.
"I have a couple of friends who had COVID-19 that were super frustrated, because their PCR results were taking six or seven days or they were getting false negatives from rapid antigen tests. But when they got the final PCR tests, they found out they had been sick, like they'd suspected," said Katie Sosnowski, a biomedical engineering doctoral student who works in Yoon's lab. "It's really cool to be working on a detection platform that can get fast results that are also accurate."
Traditional methods for detection of norovirus or other pathogens are often expensive, involve a large suite of laboratory equipment or require scientific expertise. The smartphone-based norovirus test developed at UArizona consists of a smartphone, a simple microscope and a piece of microfluidic paper - a wax-coated paper that guides the liquid sample to flow through specific channels. It is smaller and cheaper than other tests, with the components costing about $45.
The basis of the technology, described in a 2019 paper published in the journal ACS Omega, is relatively simple. Users introduce antibodies with fluorescent beads to a potentially contaminated water sample. If enough particles of the pathogen are present in the sample, several antibodies attach to each pathogen particle. Under a microscope, the pathogen particles show up as little clumps of fluorescent beads, which the user can then count. The process - adding beads to the sample, soaking a piece of paper in the sample, then taking a smartphone photograph of it under a microscope and counting the beads - takes about 10 to 15 minutes. It's so simple that Yoon says a nonscientist could learn how to do it by watching a brief video.
The version of the technology described in the Nature Protocols paper makes further improvements, such as creating a 3D-printed housing for the microscope attachment and microfluidic paper chip. The paper also introduces a method called adaptive thresholding. Previously, researchers set a fixed value for what quantity of pathogen constituted a danger, which limited precision levels. The new version uses artificial intelligence to set the danger threshold and account for environmental differences, such as the type of smartphone and the quality of the paper.
The researchers plan to partner with testing facilities at the University of Arizona to fine-tune their method as they adapt it for COVID-19 detection. Pending approval of the university's institutional review board, students who are already being tested on campus through other methods will have the option to provide written consent for their sample to be run through the smartphone-based testing device as well. Ultimately, the researchers envision distributing the device to campus hubs so that the average person - such as a resident assistant in a dorm - could test saliva samples from groups of people.
"Adapting a method designed to detect the norovirus - another highly contagious pathogen - is an outstanding example of our researchers pivoting in the face of the pandemic," said University of Arizona President Robert C. Robbins. "This promising technology could allow us to provide fast, accurate, affordable tests to the campus community frequently and easily. We hope to make it a regular part of our 'Test, Trace, Treat' strategy, and that it will have a broader impact in mitigating the spread of the disease."
Yoon and his team are also working on another idea, based on a 2018 paper they published in Chemistry--A European Journal, which is even simpler but leaves slightly more room for error. It involves the same technology, but instead of a smartphone microscope and specially designed enclosure, users would only need to download a smartphone app and use a microfluidic chip stamped with a QR code.
"Unlike the fluorescent microscope technique, where you get the chip into just the right position, you just take a snapshot of the chip," said biomedical engineering master's student Pat Akarapipad. "No matter the angle or distance the photo is taken from, the smartphone app can use AI and the QR code to account for variances and run calculations accordingly."
The method requires no training, so, if perfected, it could potentially allow students to pick up microfluidic chips from a campus location and test their own samples. The team is also working with other members of the university's COVID-19 testing group, including Deepta Bhattacharya, an associate professor in the Department of Immunobiology.
Chung, S., et al. (2021) Norovirus detection in water samples at the level of single virus copies per microliter using a smartphone-based fluorescence microscope. Nature Protocols. doi.org/10.1038/s41596-020-00460-7.
Two new Covid vaccines have less efficacy against South African strain
Early trial data shows Novavax and Johnson & Johnson vaccines have much less efficacy against new variant
Early data from two new coronavirus vaccine trials has indicated that they have less efficacy at protecting from the South African variant of coronavirus.
Clinical trial data showed that the vaccines from Novavax and Johnson & Johnson had significantly less efficacy at preventing coronavirus in trial participants in South Africa, where the new variant is widespread, compared with countries where the variant is less common.
Novavax reported that results from mid-stage trials on Thursday showed its vaccine had 50% efficacy overall in preventing Covid-19 among people in South Africa. In late-stage results from the UK, the vaccine had up to 89.3% efficacy
On Friday, Johnson & Johnson said a single shot of its vaccine had 66% efficacy, judging by a large-scale trial which spanned three continents. In the US, which recorded its first cases of the South African variant this week, the vaccine’s efficacy reached 72%, but it was just 57% in South Africa, where the new variants constituted 95% of the coronavirus cases in the trial.
The trial results also raise questions over the efficacy of the vaccines currently in circulation, such as the Pfizer/BioNTech which has been distributed in the UK. While the vaccines showed high efficacy, the trials were largely undertaken before the South African variant had spread widely.
Dr Dan Barouch, a researcher at Harvard University medical school’s Beth Israel Deaconess medical centre in Boston who helped develop the Johnson & Johnson vaccine, said the new variant meant this was a “different pandemic now”.
Speaking at the World Economic Forum, Pfizer’s chief executive, Albert Bourla, said there was “a high possibility” that the new strains could eventually mean the firm’s vaccine was redundant.
“This is not the case yet … but I think it’s a very high likelihood that one day that will happen,” Bourla said. Pfizer is considering whether its vaccine needs to be altered to protect against the South African variant.
Despite the new variant, experts said that existing vaccines were still valuable in the fight against coronavirus, and Johnson & Johnson’s vaccine was 89% effective at preventing severe disease in South Africa.
“The end game is to stop death, to stop hospitals from going into crisis and all of these vaccines, even including against the South African variant, seem to do that substantially,” said Dr Amesh Adalja, an infectious disease expert at the Johns Hopkins Center for Health Security.
