Tag archive

health

The UK Coronavirus Strain May Be Dominant in The US by March, CDC Says

in Science News by


The fast-spreading “UK variant” of the coronavirus could become the predominant strain in the United States by March, according to a new report from the Centers for Disease Control and Prevention (CDC).

 

About 76 cases of the new variant, known as B.1.1.7, have been detected in 10 US states so far, but its ability to spread more easily than other variants means it could take off rapidly here, according to a new computer model of the spread, detailed in a report Friday (Jan. 15) in the CDC journal Morbidity and Mortality Weekly Report



Source link

Iceland Genetically Sequences Every COVID-19 Case in World-Leading Strategy

in Science News by


Iceland has genetically sequenced all its positive COVID-19 cases since the start of the pandemic, an increasingly vital practice as worrying new strains emerge from Britain and South Africa.

 

The World Health Organization on Friday urged all countries to ramp up genome sequencing to help combat the emerging variants.

Scientists at the Icelandic biopharma group deCODE Genetics’ laboratory in Reykjavik have worked relentlessly for the past 10 months, analysing each positive coronavirus test in Iceland at the request of the country’s health authorities.

The aim is to trace every case in order to prevent problematic ones from slipping through the net.

“It takes us relatively short time to do the actual sequencing,” explains the head of the lab, Olafur Thor Magnusson, adding that “about three hours” is all that is needed to determine the virus strain.

The entire process, from isolating the DNA to sequencing it, can take up to a day and a half, and has enabled Iceland to identify 463 separate variants – which scientists call haplotypes.

Prior to sequencing, the DNA of each sample is first isolated, then purified using magnetic beads.

The samples are then taken to a massive, bright room full of equipment, where a deafening sound emanates from small machines resembling scanners.

The machines are gene sequencers which map the novel coronavirus genome.

 

World leader

Inside each machine is a black box called a “flow cell”, a glass slide that contains the DNA molecules.

This technology has played a large role in Iceland since the start of the pandemic.

“The sequencing of samples is key to helping us follow the state and development of the epidemic,” Health Minister Svandis Svavarsdottir told AFP.

Authorities have used the sequencing information to decide on precise, targeted measures to curb the spread of the virus, she said.

While the South African variant has not been detected in Iceland, 41 people have been identified as carriers of the British variant.

All of them were stopped at the border – where PCR tests are conducted on travellers – effectively preventing the variant’s transmission on the subarctic island. 

DNA identification also made it possible to establish a clear link between visitors of a pub in central Reykjavik and the majority of infections in a new wave in mid-September – leading authorities to close bars and nightclubs in the capital.

Sequencing also identified a separate strain from two French tourists who tested positive on arrival in Iceland, and who were initially accused – mistakenly – of being the cause of the September surge.

 

All of the around 6,000 COVID-19 cases reported in Iceland have been sequenced, making it the world leader in COVID sequencing.

While several countries, such as Britain, Denmark, Australia and New Zealand, carry out high levels of sequencing, none of them come anywhere near Iceland’s levels, although global statistics are incomplete.

Child’s play

So why is Iceland so far ahead of the game?

Gene mapping is deCODE’s speciality.

Founded in 1996, the company has carried out the largest ever genetic study of a population.

For a 2015 study on cancer risk factors, it sequenced the entire genome of 2,500 Icelanders and studied the genetic profile of a third of the then-population of 330,000.

Compared to that, sequencing COVID-19 samples is child’s play.

“It’s very easy to sequence this viral genome: it’s only 30,000 nucleotides, it’s nothing,” quips Kari Stefansson, the 71-year-old founder and chief executive of the company.

By comparison, the human genome normally analysed in his labs consists of 3.4 billion pairs of nucleotides, or organic molecules, he adds.

While Iceland’s rigorous sequencing has been useful for tracking the spread of the virus, it has yet to lead to any major scientific discoveries for deCODE.

“If there are differences between viruses with the various pattern mutations, they aren’t very obvious. Not sufficiently obvious for us to pick it up,” says Stefansson.

© Agence France-Presse

 



Source link

The Pandemic Could Be Harming Kids’ Eyesight, But It Isn’t The Virus to Blame

in Science News by


School closures are among the more controversial options for controlling the COVID-19 pandemic, with authorities debating whether the preventative measure is worth the potential educational, social, and emotional costs.

 

Researchers in China have uncovered yet another health concern faced by children kept in isolation for extended periods; deteriorating eyesight.

Short-sightedness – what is medically referred to as myopia – is already a concerning problem in East Asian countries, prompting China to make it a health priority in recent years.

One of its public programs is an annual eye exam for school children. Based on a diagnostic process called photoscreening, the system captures light-induced reflexes in each eye, giving technicians a snapshot of refractive errors or misalignments in crucial eye anatomy.

Researchers used photoscreening records from children in 10 Shandong elementary schools, all collected at the start of every school year since 2015.

With COVID forcing the closure of schools for the first half of 2020, a new school year was kicked off in June rather than the usual September. But the usual screening took place nonetheless, giving eye specialists and researchers a good look at the eyes of thousands of children aged six to 13.

All up, the five consecutive years of testing provided the scientists with a glimpse into a total of 389,808 eyeballs.

 

An analysis of the frequency of refractive errors found in all of those eyes revealed a relatively stable trend from 2015 to 2019, with perhaps a slight shift towards myopia.

That shift was unmistakable in 2020’s results though, with a substantial jump in errors that qualify as short-sightedness, significantly among six to eight year olds.

In fact, the prevalence of myopia in children aged six was three times more than in those of any previous year.

While we can only speculate over the cause of the widespread change, staring intently at books and screens for long periods while isolated indoors will do the trick just nicely.

“This substantial myopic shift was not seen in any other year-to-year comparison, making the cause possibly due to the unusual occurrence of home confinement in 2020,” the researchers suggest in their report.

It’s possible the fact the screening took place in June rather than September, together with all of the masking and distancing precautions that come with pandemic safety, just might have somehow affected the results.

But the differences weren’t consistent across all ages tested, making it unlikely confounding factors are to blame.

 

Just why some ages were more affected than others is a bit of a mystery. Given younger children were typically assigned fewer tasks to complete under home schooling, variations in screen-time or differences in amounts of near-sighted work probably aren’t enough to explain what’s going on.

 

Spending time outdoors is known to help, but again, it’s hard to argue that there’s any big difference between the amount of time six- and 13-year-olds spend outdoors.

What is looking likely is that six-year-olds are simply going through development that is more sensitive to environmental effects. It’s possible that with a longer window of isolation, even older children would soon face challenges with their sight.

“If that is the case, the period of environmental change may be the main risk factor for myopia development, with the younger children more sensitive to the environmental change than the older children,” the team writes.

“Children aged six to eight years may be experiencing an important period for myopia development.”

It’s a hypothesis that requires further research to confirm one way or another.

 

In any case, the results strongly suggests that spending copious amounts of time indoors during our childhood increases the risk to our vision.

This isn’t to say we need schools to be open for the sake of our children’s eyes. With the pandemic far from over, it’s important we do everything we can to save lives by isolating where necessary.

But knowing how isolation can affect our children’s development means we can take measures to reduce its impact.

Limiting screen time, keeping digital media half a metre away (at least 18 inches or so) from the face and spending time outside each day where possible could be enough to mitigate at least some of the effects isolation indoors has on sight.

COVID-19 has taken enough of a toll on humanity’s health. Our eyesight doesn’t need to be another cost.

This research was published in JAMA Ophthalmology.

 



Source link

6 Months After Infection, 76% of COVID-19 Patients Are Still Suffering Symptoms

in Science News by


More than three quarters of people hospitalised with COVID-19 still suffered from at least one symptom after six months, according to a study published Saturday that scientists said shows the need for further investigation into lingering coronavirus effects.

 

The research, which was published in the Lancet medical journal and involved hundreds of patients in the Chinese city of Wuhan, is among the few to trace the long-term symptoms of COVID-19 infection.

It found that fatigue or muscle weakness were the most common symptoms, while people also reported sleeping difficulties.

“Because COVID-19 is such a new disease, we are only beginning to understand some of its long-term effects on patients’ health,” said senior author Bin Cao, of the National Center for Respiratory Medicine.

The professor said the research highlighted the need for ongoing care for patients after they have been discharged from hospital, particularly those who have had severe infections.

“Our work also underscores the importance of conducting longer follow-up studies in larger populations in order to understand the full spectrum of effects that COVID-19 can have on people,” he added.

The World Health Organization has said the virus poses a risk for some people of serious ongoing effects – even among young, otherwise healthy people who were not hospitalised.

The new study included 1,733 COVID-19 patients discharged from Jinyintan Hospital in Wuhan between January and May last year.

 

Patients, who had an average age of 57, were visited between June and September and answered questions on their symptoms and health-related quality of life.

Researchers also conducted physical examinations and lab tests.

The study found that 76 percent of patients who participated in the follow-up (1,265 of 1,655) said they still had symptoms.

Fatigue or muscle weakness was reported by 63 percent, while 26 percent had sleep problems.

The study also looked at 94 patients whose blood antibody levels were recorded at the height of the infection as part of another trial.

When these patients were retested after six month, their levels of neutralising antibodies were 52.5 percent lower.

The authors said this raises concerns about the possibility of COVID-19 re-infection, although they said larger samples would be needed to clarify how immunity to the virus changes over time.

In a comment article also published in The Lancet, Monica Cortinovis, Norberto Perico, and Giuseppe Remuzzi, from Italy’s Istituto di Ricerche Farmacologiche Mario Negri IRCCS, said there was uncertainty over the long-term health consequences of the pandemic.

“Unfortunately, there are few reports on the clinical picture of the aftermath of COVID-19,” they said, adding the latest study was therefore “relevant and timely”.

They said longer term multidisciplinary research being conducted in the United States and Britain would help improve understanding and help develop therapies to “mitigate the long-term consequences of COVID-19 on multiple organs and tissues”.

© Agence France-Presse

 



Source link

Endometriosis May Actually Have a Genetic Link to 2 Common Health Conditions

in Science News by


Those of us who live free of the chronic pain caused by endometriosis can only imagine what a life of constant discomfort is like. Depression can feel like an inevitable consequence, risking assumptions that distract us from searching for further causes.

 

Now, research led by geneticists from the Queensland University of Technology in Australia has uncovered a number of risk factors that raise the chances of developing both endometriosis and depression, as well as a variety of gastrointestinal conditions.

While it doesn’t rule out an environmental influence, the discovery makes it clear that gut health, endometriosis, and chronic mood disorders often coincide thanks to genes common to all three.

Endometriosis is the presence of endometrial tissue – the thick layers of cells lining the uterus – where it has no business growing.

Just like the endometrium, this tissue is also affected by cyclic fluctuations of hormones, giving rise to internal bleeding, scar tissue, and inflammation. In its most aggressive form it pushes deeply into surrounding organs and tissues, such as the bladder, colon, and ligaments holding muscles in place around said organs.

While endometriosis is thought to affect roughly one in ten women, adding up to around 200 million worldwide, the consequences of this rogue lining vary from being completely asymptomatic to living with chronic, debilitating pelvic pain.

Most commonly the condition makes itself known through a litany of symptoms and conditions, including excessive bleeding, pain during intercourse and during menstruation, nausea, and indigestion.

 

On top of all that, it’s not unusual for people diagnosed with endometriosis to also experience bouts of anxiety and depression. Research backs this up, finding they’re the most common disorders found in association with endometriosis.

It’s no great leap to presume this relationship is causal. Studies carried out on mice also imply the pain of endometriosis could directly affect the brain, promoting pain sensitisation and mood disorders.

What’s more, having higher levels of pelvic pain makes depression even more likely, making it look as if it’s the pain that’s causing depression, and not endometriosis itself.

Without necessarily contradicting the role of pain in affecting our moods, researchers are becoming increasingly aware of the sheer complexity of depression, finding it’s more than a psychological state, but rather a whole physiological system affected by a rich variety of genes.

Twin studies have also hinted strongly at a genetic basis for endometriosis. To see if any of the genes involved might also predispose individuals to depression, researchers made use of data from a genome-wide association study (GWAS) conducted by the International Endogene Consortium.  

 

The sample of more than 208,000 individuals included around 17,000 cases of endometriosis, with just under 192,000 serving as controls, all from a diversity of nations around the globe.

This was compared with a similar GWAS database used previously to find genes linked to depression, with a couple of alternative databases used to see if their findings could be reproduced.

After carrying out an assessment on overlapping mutations common to both, the researchers identified 20 independent locations on the genome which could be considered significant to both conditions, eight of which are completely new.

All up, 22 genes were implied, many with roles in pathways governing adhesion between cells, signalling that regulates cell movements and proliferation, and gastric health.

In fact, additional digging uncovered further causative links between endometriosis and depression and at least one abnormal gut condition, such as peptic ulcers or gastroesophageal reflux disease.

Knowing links can be genetic is one thing. Mapping out the complicated mess of pathways from genes to health and back again, is a whole other story.

We’re still a long way off a cure, and even finding suitable treatments is an ongoing challenge. Given we’ve known about the condition for nearly a century, it’s shocking that endometriosis is still so regularly overlooked.

Knowing more about the underlying genetics and how they might play out in other health conditions is beyond worthwhile.

This research was published in Human Genetics

 



Source link

What Are The Health Risks of Space? Scientists Just Unveiled The Biggest Study Yet

in Science News by


Space is a hostile place. We may have developed the technology to launch astronauts into orbit and get them home safely, but scientists are still figuring out how space travel affects human health, especially over the long haul. 

 

That’s essential before any planned missions to Mars go ahead, to assure the health and safety of the astronauts aboard those momentous flights.

We already know from astronaut studies – perhaps most famously, NASA’s Twins Study co-starring identical twins Scott and Mark Kelly – that extended space time affects blood flow to the brain, alters the gut microbiome, increases inflammation and causes blurred vision, brittle bones, and muscle wasting

Mouse studies simulating spaceflight have also suggested that heading into space ages the immune system and damages the brain.

Now, in a huge collective effort, scientists have published a giant trove of almost 30 papers investigating the health risks associated with space travel.

The collection amounts to the largest set of space biology data ever produced, and features some hefty analyses of observations from space-going flies, worms, mice, and of course, astronauts.  

Some of the results reaffirm what we knew about space-related health problems, while other studies provide new insights, clarify previous results, or have found ways to improve future experiments.

“Although significant advances have been made in the past decade to understand [the] health risks [of space travel], additional research is required to enable safer human space exploration beyond [low Earth orbit], including lunar, Mars, and deep-space missions,” the researchers write in an over-arching review paper that fronts the collection.

 

The health perils of space travel start with the G forces felt by astronauts on lift-off, and continue with the exposure to hazardous space radiation and microgravity while in space.

On the treacherous journey to Mars, for example, astronauts will go far beyond Earth’s protective magnetosphere and be exposed to cosmic radiation during the significant stretch of time it will take for them to venture out to our nearest planetary neighbour and return. 

For astronauts hovering in low gravity aboard the International Space Station (ISS), the longest stay of any astronaut is currently sitting at 437 days. Clearly, we still have a long way to go to truly appreciate what the health risks of long-distance space flights might be, and scientists just have to work with the data we’ve got.

Many of the studies published in this collection have pooled or re-analysed data from previous experiments made available to researchers through open-access data portals such NASA’s GeneLab platform.

Combining data like this is a way to strengthen the resulting analyses (often researchers look to see if what was found in one dataset holds true in another), and maximise the data collected from costly spaceflights.

 

“A collective analysis across multiple models and human studies can lead to a more comprehensive understanding of physiological and human health-related impacts of the space environment,” the researchers write, explaining their approach.

One study, for example, analysed data from close to 60 astronauts and hundreds of GeneLab samples to look for a universal mechanism linking the widespread health changes that have been observed in different genes, cells, tissues, body systems, organs, and muscles.

Across the board, the study showed “systemic shifts” in the function of mitochondria – which are the power packs inside our cells, converting oxygen and nutrients into energy. 

“What we found over and over was that something is happening with the mitochondria regulation that throws everything out of whack,” said Afshin Beheshti, a bioinformatician at NASA’s Ames Research Center.

This might explain the disruptions observed in astronauts’ immune systems and circadian rhythms, the authors write.

Another study compared data from the Kelly twins with 11 unrelated astronauts who spent around six months on the ISS, looking specifically at their telomeres. These are the protective caps on the ends of our chromosomes, which typically erode with age.

 

Unexpectedly, the researchers found that some of the astronauts’ telomeres got longer during their spaceflight, but the group generally had shorter telomeres after returning than they did before they took flight. 

“Going forward, our goal is to get a better idea of underlying mechanisms, of what’s going on during long-duration space flight in the human body, and how it varies between people,” said Susan Bailey, an expert in telomere biology at Colorado State University. “Not everybody responds the same way.”

There were also some interesting findings from a study that re-analysed data from NASA’s Twins Study. It suggested that the spike in inflammatory molecules observed in Scott Kelly’s blood when he returned to Earth (after 340 days on the ISS) could be a marker of muscle regeneration rather than an immune response.

These studies are obviously limited by the very small number of astronauts and animals we can send into space – which is where the worms and flies come in. Using these creatures is an easy way to scale-up spaceflight experiments, so they feature in the papers, too.

A study of roundworms on the ISS found subtle changes in roughly 1,000 genes, particularly those relating to nerve cell function, while another study, this time with flies, suggested that a lengthy stay in microgravity reduces the strength of their beating heart.  

All in all, this collection of papers – the work of some 200 researchers from NASA and other government agencies, universities, and aerospace industry groups – represents a solid contribution to our understanding of the health risks of hanging out in space.

The full list of published papers has been collated in the journal Cell.

 



Source link

Scientists Figured Out How Much Exercise You Need to ‘Offset’ a Day of Sitting

in Science News by


We know that spending hour after hour sitting down isn’t good for us, but just how much exercise is needed to counteract the negative health impact of a day at a desk? A new study suggests about 30-40 minutes per day of building up a sweat should do it.

 

Up to 40 minutes of “moderate to vigorous intensity physical activity” every day is about the right amount to balance out 10 hours of sitting still, the research says – although any amount of exercise or even just standing up helps to some extent.

That’s based on a meta-analysis across nine previous studies, involving a total of 44,370 people in four different countries who were wearing some form of fitness tracker.

The analysis found the risk of death among those with a more sedentary lifestyle went up as time spent engaging in moderate-to-vigorous intensity physical activity went down.

“In active individuals doing about 30-40 minutes of moderate to vigorous intensity physical activity, the association between high sedentary time and risk of death is not significantly different from those with low amounts of sedentary time,” write the researchers in their published paper.

In other words, putting in some reasonably intensive activities – cycling, brisk walking, gardening – can lower your risk of an earlier death right back down to what it would be if you weren’t doing all that sitting around, to the extent that this link can be seen in the amassed data of many thousands of people.

 

While meta-analyses like this one always require some elaborate dot-joining across separate studies with different volunteers, timescales, and conditions, the benefit of this particular piece of research is that it relied on relatively objective data from wearables – not data self-reported by the participants.

The study arrives alongside the publication of the World Health Organization 2020 Global Guidelines on Physical Activity and Sedentary Behaviour, put together by 40 scientists across six continents. The British Journal of Sports Medicine (BHSM) has put out a special edition to carry both the new study and the new guidelines.

“These guidelines are very timely, given that we are in the middle of a global pandemic, which has confined people indoors for long periods and encouraged an increase in sedentary behaviour,” says physical activity and population health researcher Emmanuel Stamatakis from the University of Sydney in Australia.

“People can still protect their health and offset the harmful effects of physical inactivity,” says Stamatakis, who wasn’t involved in the meta-analysis but is the co-editor of the BJSM. “As these guidelines emphasise, all physical activity counts and any amount of it is better than none.”

The research based on fitness trackers is broadly in line with the new WHO guidelines, which recommend 150-300 mins of moderate intensity or 75-150 mins of vigorous intensity physical activity every week to counter sedentary behaviour.

Walking up the stairs instead of taking the lift, playing with children and pets, taking part in yoga or dancing, doing household chores, walking, and cycling are all put forward as ways in which people can be more active – and if you can’t manage the 30-40 minutes right away, the researchers say, start off small.

Making recommendations across all ages and body types is tricky, though the 40 minute time frame for activity fits in with previous research. As more data gets published, we should learn more about how to stay healthy even if we have to spend extended periods of time at a desk.

“Although the new guidelines reflect the best available science, there are still some gaps in our knowledge,” says Stamatakis. “We are still not clear, for example, where exactly the bar for ‘too much sitting’ is. But this is a fast-paced field of research, and we will hopefully have answers in a few years’ time.”

The research has been published here, and the new guidelines here, in the British Journal of Sports Medicine.

 



Source link

The Oxford AstraZeneca Vaccine Is Now a Global Game Changer. Here’s Why

in Science News by


In the long dark tunnel that has been 2020, November stands out as the month that light appeared. Some might see it as a bright light, others as a faint light – but it is unmistakably a light.

 

On November 9, Pfizer announced the interim results of its candidate vaccine, showing it to be “more than 90 percent effective” in preventing symptomatic COVID-19 in late-stage human trials. The news was greeted with joy.

A couple of days later, the Russian Direct Investment Fund announced that the candidate vaccine they are funding – dubbed Sputnik V – showed 92 percent efficacy in late-stage trials. Not to be outdone, Moderna then announced that its candidate vaccine showed 94.5 percent efficacy.

The latest COVID-19 vaccine announcement comes from Oxford University. And, as with all of the above announcements, it came via press release. Its vaccine candidate, developed in partnership with AstraZeneca, showed an overall effectiveness of 70.4 percent.

In case that sounds disappointing, bear in mind that these are interim results and the figures might change. Also, the Oxford vaccine was given to one group of volunteers as two standard doses, which showed 62 percent effectiveness, and another group of volunteers as a smaller dose followed by a standard second dose. This raised effectiveness to 90 percent.

It’s not immediately clear why this is the case. Professor Andrew Pollard, one of the lead researchers on the project, described the results as “intriguing”. He also highlighted that the use of lower doses means that there would be more vaccine doses available.

There were no cases of severe COVID-19 in those who received the vaccine. And it seems to generate a protective immune response in older people. Although we’ll have to wait for the final breakdown of results to get clarification on that.

 

Effectiveness is not the only measure

Despite the Oxford vaccine having lower overall effectiveness than the Pfizer or Moderna vaccines – at least at this interim stage – there are other success factors to consider. Safety is one, and the Oxford vaccine is so far reported to have a good safety record with no serious side-effects.

Another crucial factor is storage. The Oxford vaccine can be stored in a domestic fridge. The need for sustained freezing across the whole vaccine journey from factory to clinic at ultra-low temperatures – as seen with the Pfizer vaccine – may be a problem for many countries, but especially poorer countries.

The Oxford vaccine, based on a viral vector, is also cheaper (around US$4) than Pfizer and Moderna’s mRNA vaccines – around US$20 and $33, respectively. AstraZeneca has made a “no profit pledge“.

Equitable distribution

As I have previously discussed, equitable distribution of new vaccines is vital, especially for low- and middle-income countries who don’t have the profile or purchasing power of wealthier countries. GAVI – a global health partnership that aims to increase access to immunisation in poor countries – has worked for years to address this very point. It set up the COVAX initiative in 2020, which has access to 700 million doses of COVID vaccine if clinical trials are successful.

Oxford and AstraZeneca have previously made their own commitments to provide a billion doses of their vaccine for low- and middle-income countries, with a commitment to provide 400 million doses before the end of 2020. Certainly, AstraZeneca has committed to provide more doses to countries outside of Europe and the US than any of its nearest competitors.

 

An excellent start

These commitments will clearly not be enough for immediate global coverage, but it is an excellent start. Around 9 percent of the world’s population live in extreme poverty, and the health systems around them are fragile.

With promises for equitable vaccine distribution, there is hope that the poorer populations around the world will not be forgotten. The global health community must keep its focus on this area.

What does this announcement mean for the world? Potentially a huge amount. But remember that the trials are not yet complete and, at the time of writing, the regulators have yet to approve any of the new vaccine candidates.

Even when those hurdles are cleared, we still need to vaccinate the world, which requires successfully navigating the complex obstacles of distance, terrain, politics, cold-chain logistics and human behaviour.

The global pandemic is not over and won’t be for a long time yet – but the light is getting brighter.The Conversation

Michael Head, Senior Research Fellow in Global Health, University of Southampton.

This article is republished from The Conversation under a Creative Commons license. Read the original article.

 



Source link

Radical Testing Plan Could ‘Drive Epidemic Toward Extinction’ in Weeks, Study Claims

in Science News by


Mass rapid-testing for COVID-19 – especially of those people showing no signs of infection – could bring an end to the pandemic within six weeks, claims a new study by researchers at the Harvard TH Chan School of Public Health and the University of Colorado Boulder.

 

Published November 20 in the peer-reviewed journal Science Advancesthe study suggests that rapid tests, although less reliable, could allow public health authorities to rely on more targeted interventions, rather than economy-wide lockdowns, if deployed on a massive scale.

Rapid tests are low cost and can return results in a matter of minutes, rather than the days associated with the lab variety. If half the US population were tested weekly, with those who test positive isolating from the rest, the impact would be enormous, researchers said.

“Our big picture finding is that, when it comes to public health, it’s better to have a less sensitive test with results today than a more sensitive test with results tomorrow,” Daniel Larremore, a computer science professor at CU Boulder and lead author of the study, said Friday.

“Rather than telling everyone to stay home so you can be sure that one person who is sick doesn’t spread it, we could give only the contagious people stay-at-home orders so everyone else can go about their lives.”

According to the study, based on mathematical modelling, rapid-testing three-quarters of a city’s population every three days slashed the number of those ultimately infected by 88 percent, “sufficient to drive the epidemic toward extinction within six weeks.”

“These rapid tests are contagiousness tests,” Michael Mina, a professor of epidemiology at Harvard and co-author of the study, said in a news release.

“They are extremely effective in detecting COVID-19 when people are contagious.”

Increasing the availability of “cheap, rapid tests” is one of the key strategies under consideration by President-elect Joe Biden, Politico reported Friday.

This article was originally published by Business Insider.

More from Business Insider:

 



Source link

Can Surgical Masks Be Reused? Scientists Are Asking Some Valid Questions

in Science News by


Health authorities say the most widespread anti-COVID weapon – surgical masks – must be thrown away after a single use, but environmental concerns are pushing some scientists to question this recommendation.

 

As the coronavirus continues to spread, masks have in many places become mandatory on public transport, in shops, and at work.

But cost has become an issue, as has the fact so many disposable plastic masks wind up in waterways and the oceans.

One alternative is reusable cloth masks, but many people prefer single-use surgical masks because they are lighter and individually cheaper.

“Medical masks are for single use only,” the World Health Organization has said. “Discard the mask immediately, preferably into a closed bin.”

But in the context of scarcities during the first wave of the COVID-19 pandemic, the WHO allowed in an April report for the resuse of decontaminated disposable masks when there is a “critical PPE (personal protective equipment) shortage, or lack of PPE.”

The US Food and Drug Administration (FDA) allowed – in emergency circumstances – hydrogen peroxide vapour to decontaminate the N95 masks worn by healthcare workers. 

Other methods to purify single-use masks include exposing them to high temperatures or ultraviolet radiation. 

But these methods are inconvenient for people at home, said French microbiologist and member of Adios Corona, Denis Corpet.

 

Seven-day method

Adios Corona – a group of scientists who provide information on COVID-19 to the public – recommends “placing the mask in a paper envelope with the date clearly marked, and leaving it for seven days”.

“Several scientific studies show that viruses are almost all dead on a mask after seven days,” said Corpet.

A study published in The Lancet found that only 0.1 percent of the virus on the outside surface of the mask was still detectable after one week.

This method, however, is not appropriate for healthcare workers exposed to high viral loads.

Peter Tsai, the inventor of N95 electrostatically charged filter material, agrees with the seven-day method.

But he suggests leaving used masks out in the open for a week before reuse, a cycle he says can be repeated five to 10 times.

Disposable masks can also be placed in the oven, Tsai told AFP, ideally at a temperature between 70 and 75 degrees Celsius (158 and 167 degrees Fahrenheit) – not too high to avoid burning the plastic, but sufficiently hot to kill the virus.

Washing masks in a washing machine, however, is not a good idea.

 

“Washing without detergent may not wash away the virus,” Tsai said. “And washing with detergent will erase the (electrostatic) charges,” diminishing its efficiency.

French consumers’ rights group UFC-Que Choisir washed surgical masks at 60C, put them in the dryer, and ironed them. After 10 such cycles, the masks still filtered at least 90 percent of 3-micron particles.

“Apart from a slight felting, the washed surgical masks were at least as efficient as the best cloth masks,” UFC-Que Choisir reported last week.

‘Like underwear’

Researcher Philippe Vroman from French engineering university Ensait came to the same conclusion.

After five washes, “there are practically no differences (of filtration) for particles of 3 microns,” Vroman said, on the basis of preliminary results not yet published in a peer-reviewed scientific journal.

“And I would rather we swap masks every four hours and wash them, rather than wearing them several days in a row as some people do. It’s a bit like underwear,” he said.

But not all scientists agree.

“Washing the mask at home could potentially cause a secondary contamination and spread the virus if washing is not set appropriately,” said Kaiming Ye, head of the biomedical engineering department at New York’s Binghamton University.

Until more research is published on the matter, official advice from health authorities is not set to change.

“Single-use surgical masks must be thrown into the bin after use,” said France’s health authority DGS, but noted that more studies were underway.

© Agence France-Presse

 



Source link

1 2 3 42
Go to Top