COVID booster

High school student shows barriers are better

A US high school student has published a paper in PLOS ONE, suggesting that physical barriers are more effective than distancing to limit coronavirus spread.

Atreyus A. Bhavsar, from Blake High School in Minneapolis, US, set up a series of experiments with mannequins, using balloons filled with fluorescent paint to mimic coughs and sneezes. When a balloon burst inside a mannequin’s mouth, droplets of paint flew out and patterned the mannequin’s surroundings.

Some of the experiments had mannequins wearing masks, while others were set up to simulate Bhavsar’s high school cafeteria, where students have to take their masks off to eat.

Without masks, six feet of distance did not appear to protect mannequins from paint splatter. But physical barriers did make a difference.

Bhavsar concludes that barriers are a better idea than physical distancing, if masks are impossible.

“Clear barriers would seem prudent so that students would be less likely to lean back to see or to talk to other students,” Bhavsar adds in the paper. Wise words from someone who is (presumably) very familiar with the behaviour of school students during a pandemic.

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Bhavsar’s experimental setup, showing mannequins and barrier. Credit: Atreyus A. Bhavsar, 2021, PLOS ONE

Strategies for limited supplies of vaccines

A paper published in the journal Vaccine outlines potential scenarios for vaccination in the event of a large Australian outbreak.

Using computer models, researchers from the University of New South Wales’ Kirby Institute simulated a series of outbreaks in NSW. They found that if 66% of the population had a 70% effective vaccine, the state would be able to achieve herd immunity. But, as we’re well aware, there aren’t enough vaccines to go around just yet.

“A limited supply requires a targeted strategy where particular populations are prioritised,” explains Raina MacIntyre, a professor at UNSW who led the study. “We show that for a population of 7.5 million people, if faced with an epidemic and an initial restriction in vaccine supply, sustained epidemic control cannot be achieved by this smaller, targeted vaccination strategy. Other non-pharmaceutical interventions, such a face mask use, physical distancing, and limits on the movement of people through travel, will need to continue to mitigate any outbreaks.”

MacIntyre adds: “While our model shows that a targeted vaccine strategy can still reduce illness and death from COVID-19 – it is clear that a mass vaccination strategy would be far more effective at controlling disease. Encouragingly, our model suggests that herd immunity can be achieved in states like NSW by vaccinating two-thirds of the population with a high efficacy vaccine.”

Age informs lockdown learning

A survey of over one million students has found that age has a large effect on the best strategies to teach online. While this is unlikely to surprise any teachers or parents, the sample size is certainly impressive.

The study, which is described in the British Journal of Educational Technology, surveyed 1,170,769 students from Guangdong Province in China.

“Utilising data from a large sample, we identify that student requirements of online learning are not homogeneous. For young children, there is a need for guidance from teachers and parents. In contrast, older students require opportunities to collaborate,” says lead author Lixiang Yan, of the Centre for Learning Analytics at Monash University.

“Our study also showed an overwhelming use of smartphones over other devices by all age groups. This finding has direct implications for the design of online courses in K12 education; however, this can potentially pose a significant limitation for an effective learning experience.”

Novavax 51% effective against South African variant

A randomised controlled trial in South Africa has found the Novavax COVID-19 vaccine to be 51% effective against the B.1.351 variant of SARS-CoV-2.

The study, which is published in The New England Journal of Medicine, gave either the vaccine or a placebo to 2684 adults. A total of 15 participants in the vaccine group developed COVID-19 (with mostly mild to moderate symptoms), while 29 participants in the control group became infected. Most of the COVID-positive people had the B.1.351 variant.

Some of the trial participants were HIV-positive, which increases vulnerability to COVID-19 infection. When the HIV-positive participants were excluded from the study, the effectiveness of the vaccine became 60.1%.

Experts were better at predicting the pandemic, but still underestimated it

Sometimes, when we’re in new territory, the guesses of a layperson are as reliable as those of an expert. Not so for the COVID-19 pandemic – although a study by the University of Cambridge suggests that epidemiologists and statisticians still weren’t great at predicting the course of the virus.

The researchers surveyed 140 UK experts and 2086 non-experts in April 2020, asking them to make quantitative predictions about the pandemic – such as total number of infections and number of deaths in the UK. Participants were asked to give a confidence interval on their guesses, stating the upper and lower numbers that they were 75% confident the answer would fall in.

Only 12% of non-experts’ predictions were correct, while 44% of experts’ predictions were.

“Experts perhaps didn’t predict as accurately as we hoped they might, but the fact that they were far more accurate than the non-expert group reminds us that they have expertise that’s worth listening to,” says Gabriel Recchia, a researcher at the Winton Centre for Risk and Evidence Communication, and lead author on a paper describing the study, published in PLOS ONE.

“Predicting the course of a brand-new disease like COVID-19 just a few months after it had first been identified is incredibly difficult, but the important thing is for experts to be able to acknowledge uncertainty and adapt their predictions as more data become available.”

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