Coronavirus science | Week in review: Life without a vaccine, face shields, and genetics



READ | The race for a Covid-19 vaccine is on - but what if one never emerges?

"Things will get back to normal once we develop a vaccine."

This mantra has been repeated over and over again by governments and individuals – science's golden ticket out of the global pandemic and back to familiarity. But what if we don't find a vaccine soon – or never?

"We invest in 'the vaccine' because we want it all to go away and for life to get back to normal – whatever normal might have been – and that's not going to happen," says Professor Lenore Manderson, an expert in public health and medical anthropology at the University of Witwatersrand, who is stuck in Australia where she's an adjunct professor at Monash University.

"What we are doing now is paying the price for being a highly urbanised, highly developed society with a range of problems in daily life and, in a way, it is a rehearsal for other problems in the future."

Manderson believes the current version of the virus will be around for 18 months without an effective vaccine, after which infection rates will start to decrease, with lower-level strains still circulating among the population.

READ | The role of toilets in the spread of coronavirus - a case study

The coronavirus might have spread through a block of flats in China by means of the sewerage system, according to a new study.

Aerosol transmission of the coronavirus has been well-documented, including through faecal matter. Earlier studies found that coronavirus particles in a person’s stool can be propelled into the air through aerosol droplets when flushing, and could thereby contribute to Covid-19 transmission.

But according to a research analysis published in Environment International, there is evidence that it can even move through a building's sewerage system between different apartments, without contact transmission.

"For many pathogens, transmission is multi-modal, and the contribution of the aerosol route may rely on environmental conditions, proximity of susceptible people, human behaviour, and other factors," write the researchers.

In February, China's Center for Disease Control and Prevention found SARS-CoV-2 on bathroom surfaces in an apartment that had been standing empty for a long time. Situated on the 16th floor of an apartment block, it was right above another apartment where five people who had been infected with Covid-19 lived.

READ | Why some Covid-19 treatments work while others don't - could it be genetics?

As the Covid-19 pandemic progresses, various existing drugs and remedies are being tested to stop the virus in its tracks and reduce mortality.

During the course of the outbreak, there have been glimmers of hope with drugs such as remdesivir and dexamethasone, while other treatments such as hydroxychloroquine proved to be ineffective against Covid-19.

According to researchers at the University of Minnesota College of Pharmacy, various drugs are currently being investigated, often without well-established data on safety or efficacy. But what if our genetics could provide a better understanding of which treatments might work?

Pharmacogenomics is the study of how our genes affect our response to drugs.

Most drugs are manufactured using a one-size-fits-all approach, but pharmacogenomics combines the fields of pharmacology and genetics to develop safe, effective medications that are tailor-made according to a person's exact genetic make-up.

READ | Is a face shield alone sufficient protection?

As the economy slowly reopens, masks have become compulsory to limit the spread of coronavirus droplets. But besides cloth masks, other options such as masks with valves and face shields have become prevalent.

In a previous article, Health24 looked at the effectiveness of valve masks and found that, even though they might protect the user, they do little to protect other people from droplets that escape through the built-in vents.

Now, in an effort to establish the effectiveness of these valve masks and face shields, researchers from Florida Atlantic University's College of Engineering and Computer Science used qualitative visualisations to test how face shields and masks with valves perform in limiting the spread of aerosol-sized droplets, according to a news release.

The study, published in the journal Physics of Fluids, was done by using flow visualisation in a laboratory setting. This was done by setting up a laser light sheet and using a mixture of distilled water and glycerine to create synthetic fog. This was then placed in a cough-jet to simulate droplets expelled from a mannequin’s mouth when coughing.

The results showed that, while the face shield protected the user against droplets being propelled forward, it did little to stop expelled droplets moving out from around the visor.

READ | Latest on children and why infected primary school kids may be hard to spot

Scientists have been trying to make sense of data on the role children play in the transmission of SARS-CoV-2, the virus that causes Covid-19, since the start of the pandemic.

A growing body of evidence suggests that children may play a larger role in transmission than previously thought.

To add to this evidence, a recent study by scientists at Duke University School of Medicine found that infected primary school children could be hard to spot.

Based on their findings, the researchers recommend screening strategies that are in place in schools and daycare centre should focus on age-related differences in symptoms.

The study was published in preprint server medRxiv and has not yet been peer-reviewed.

READ | From a deadly disease in cats, to Covid-19 in humans

With drugs such as remdesivir and the corticosteroid dexamethasone showing promise in trials, researchers are investigating several other options to treat Covid-19.

Now, researchers at the University of Alberta are about to proceed with clinical trials of a drug used to cure another deadly disease caused by a coronavirus. The twist? This disease occurs in cats.

"In just two months, our results have shown that the drug is effective at inhibiting viral replication in cells with SARS-CoV-2," said Joanne Lemieux, a professor of biochemistry in the Faculty of Medicine & Dentistry in a press release.

The drug being investigated is a type of protease inhibitor which slows down the ability of a virus to replicate inside the body, which then stops infection.

Proteases are enzymes which are able to break down proteins and peptides. These enzymes are found throughout the body and are used to treat a wide array of diseases, including high blood pressure, cancer and HIV.


SA cases update: 

The latest number of confirmed cases is 636 884

According to the latest update, 14 779 deaths have been recorded in the country.

There have been 561 204 recoveries.

So far, more than 3 78 million tests have been conducted, with 18 123 new tests reported.

Global cases update:

For the latest global data, follow this interactive map from Johns Hopkins University & Medicine.

Late on Saturday night, positive cases worldwide were 26.7 million, while deaths were more than 876 000.

The United States had the most cases in the world - 6.2 million, as well as the most deaths - more than 188 000.


Latest news:

HEALTH TIPS (as recommended by the NICD and WHO)

• Maintain physical distancing – stay at least one metre away from somebody who is coughing or sneezing

• Practise frequent hand-washing, especially after direct contact with ill people or their environment

• Avoid touching your eyes, nose and mouth, as your hands touch many surfaces and could potentially transfer the virus

• Practise respiratory hygiene – cover your mouth with your bent elbow or tissue when you cough or sneeze. Remember to dispose the tissue immediately after use.

Image credit: Getty Images

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