The world’s governments are under pressure to increase testing for the new coronavirus, officially named SARS-CoV-2, which has infected more than 2.6 million people worldwide, according to the Johns Hopkins Coronavirus Resource Centre.

To that end, six researchers sought to look into the potential diagnostic value of saliva, by looking closely at existing studies on saliva and Covid-19. They concluded that saliva swabs can be effective and yield quicker results – if done correctly.

Generation and transmission of saliva droplets

Saliva is a common medium for virus transmission. According to the World Health Organization (WHO), the new coronavirus virus spreads primarily through droplets of saliva or discharge from the nose – which can happen when an infected person coughs or sneezes.

Saliva, the authors of the paper note, is made up of 99% water, with the remaining 1% comprising components for, among others, the purpose of tasting and digesting.

Breathing, talking, coughing and sneezing are all ways saliva droplets are generated. The droplets are formed as particles and consist of a mixture of moisture and droplet nuclei of microorganisms.

The authors further explain: “The amount, distance, and size of saliva droplets vary among people, suggesting the infectious strength and transmission path of saliva droplets differ when [the] same pathogen was contracted.”

They further add that one cough can generate 3 000 saliva droplet nuclei, which is close to the amount generated during a five-minute talk. And, one sneeze that reaches several metres in air can contain up to 40 000 saliva droplets.

However, studies have shown that it is the smaller droplets that can “travel like a cloud over longer distance by air flow”, explain the authors. But unlike tuberculosis (TB), to date there is no solid evidence to suggest that the virus in saliva droplets can survive in airflow for any length of time.

Testing for SARS-CoV-2 via saliva

The official pathogen detection, the authors explain, occurs when there is a confirmation of SARS-CoV-2 nucleic acid from throat swabs. However, throat swabs, they note, have certain downfalls, including the fact that they are invasive, induce coughing and can cause bleeding. Should this occur, it can increase the risk of healthcare workers being infected.

With the nature of saliva specimen collection, however, it is more secure. The authors draw on three existing methods used to collect saliva: coughing, saliva swabs, and directly from the salivary gland duct.

Studies analysed by the authors included deep throat saliva, saliva in oral cavity, and salivary gland. Out of these three, they found that deep throat saliva had the highest diagnosis rate of SARS-CoV-2, making it the most reliable form of saliva testing for the virus.

One study they investigated involved twelve positive patients coughing out saliva a few days after hospitalisation, and 11 of their specimens tested positive for the virus. Another study (from the same group) used self-collected saliva from deep throat Covid-19 patients, and among 23 patients, 20 cases of their saliva showed detectable SARS-CoV-2 RNA.

Current evidence based on the second method, involving oral swabs, show that it is more applicable in early detection of the virus, but cannot be used as discharge criteria for patients. Saliva collected directly from the opening of the salivary gland can also detect SARS-CoV-2 nucleic acid, and, according to the authors, could possibly be a predictive and non-invasive test for patients with severe cases.

SA testing

Despite mass testing campaigns, more and smarter testing with faster results is needed. In South Africa, currently, SARS-CoV-2 is detected via a polymerase chain reaction, or PCR molecular test, notes the National Institute for Communicable Diseases (NICD).

The test is done by health workers taking a swab of a person’s throat and/or nose, which gets placed into a fluid, after which it is sent to a laboratory to look for signs of the virus’s genetic material, explains News24. If the test is positive, repeat testing is required – all of which can take up to four days.

CNBC recently reported on a new study by Yale University researchers that found that testing saliva for the new coronavirus yields results that are at least as accurate as nasal swabs. The Food and Drug Administration (FDA) also granted emergency use authorisation for a new saliva test which requires a person with coronavirus symptoms to spit into a cup, the Washington Times reports. Results are returned within 24 to 48 hours after arriving at labs.

Compiled by Zakiyah Ebrahim

Managers say staff face long journeys to test centres, with one reporting a three-hour round trip.

The mobile units will travel to “hard to reach” areas as the government looks to ramp up testing.

WHAT’S HAPPENING IN SA

Cases update: 

The latest number of confirmed cases is 4 361.

According to the latest update, 86 deaths have been recorded in the country.

So far, 161 004 tests have been conducted, with more than 8 600 new tests.

READ MORE |All the confirmed cases of coronavirus in SA

Latest news:

As of 1 May, a national curfew from 20:00 to 05:00 will be in place and it will be applicable to everyone except essential workers traveling to and from work.

The country is expected to move from a Level 5 to a Level 4 lockdown, allowing limited economic activity but keeping most existing measures in place.

On Saturday, Minister of Cooperative Governance and Traditional Affairs Nkosazana Dlamini-Zuma and Minister of Trade and Industry Ebrahim Patel addressed the media on the Level 4 lockdown.

While restaurants will be closed for sit-down meals when the country moves to Level 4 next Friday, the movement of takeaway food will be allowed.

READ MORE | Lockdown curfew from 20:00 to 05:00 starting on 1 May

It is now up to South Africans to ensure that the country doesn’t move back to a Level 5 lockdown, Minister of Cooperative Governance and Traditional Affairs Nkosazana Dlamini-Zuma said on Saturday.

On Thursday, President Cyril Ramaphosa announced that the government would use a five-level phased approach towards easing lockdown restrictions. The country is currently on Level 5 – the most restrictive level – but this will be eased to Level 4 on 1 May.

On Saturday, Dlamini-Zuma unpacked what this meant.

“Level 4 means the lockdown is still in place,” she said.

READ MORE | Up to South Africans to ensure we don’t go back to Level 5

The rate of Covid-19 infections is lower than the global one, according to the acting director-general of the Department of Health, Dr Anban Pillay.

At a press briefing on Saturday with Cooperative Governance and Traditional Affairs Minister Nkosazana Dlamini-Zuma and Trade and Industry Minister Ebrahim Patel, Pillay said currently, the trend suggested about 3% of people, who were tested, were positive.

This has been the trend since testing started.

“That is way lower than the global experience, which has been much higher at around 10%.”

READ MORE | SA’s Covid-19 infection rate ‘lower than the global average’

From 1 May, South Africans will be allowed to buy clothes and cigarettes, and order fast food.

A number of businesses can also re-open, it was announced at a media briefing on Saturday.

South Africa will embark on a staged reopening of the economy, starting with a level 4 on the first of May, to help slow down the spread of coronavirus, and ensure that health authorities are not overwhelmed, cooperative governance and traditional affairs minister Nkosazana Dlamini-Zuma said. 

READ MORE | Lockdown level 4: What will be allowed

The unconditional sale of liquor will only be permitted when South Africa reaches Level 2 of its “risk adjusted strategy” to fight Covid-19. 

Details of the country’s five-level economic reopening were released on Saturday, including when which industries will be allowed to return to work. South Africa will be moving from Level 5 to 4 on May 1st.

Cooperative governance and traditional affairs minister Nkosazana Dlamini-Zuma warned that if there was a sudden surge in infections, South Africa – or the most-affected parts of the country – could move back to a stricter level.

READ MORE | You’ll only be able to buy booze at Level 3 – and only on some weekday mornings

WHAT’S HAPPENING IN THE REST OF THE WORLD 

Cases update:

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

Late on Saturday night, positive cases worldwide were more than 2.88 million, while deaths were more than 200 000.

The United States had the most cases in the world – nearly 930 000, as well as the most deaths – more than 53 000.

READ MORE | All the confirmed cases worldwide

Latest news:

Leading manufacturers of cleaning products have issued statements warning their customers not to attempt to inject themselves with disinfectants after US President Donald Trump incorrectly claimed that doing so might cure COVID-19.

Trump suggested at a White House coronavirus briefing on Thursday that because disinfectant can kill the virus on external surfaces, perhaps it could be used internally to treat coronavirus patients.

“I see the disinfectant where it knocks it out in a minute,” he said. “One minute. And is there a way we can do something like that, by injection inside or almost a cleaning?” he said. “So it’d be interesting to check that.”

He added: “I’m not a doctor. But I’m, like, a person that has a good you-know-what.”

The president also suggested that ultraviolet light, used internally, might help treat Covid-19.

Following his comments, RB, which manufacturers disinfectants for the European market, issued a statement urging the public never to attempt to consume its products.

READ MORE | Bleach manufacturers have warned people not to inject themselves with disinfectant after Trump falsely suggested it might cure the coronavirus

LATEST RESEARCH

Epidemiological terms are fast becoming part of everyday language. Terms like “flattening the curve”, “antibody tests” and “infection control” pepper conversations in supermarket queues and Zoom meetings.

Scientists must publicly share and explain, more now than ever before, the science behind efforts to stop the Covid-19 virus in its tracks. And, apart from some fake news and bad armchair epidemiology, it generally seems to work. In my experience at least, most people seem to talk about the virus with a decent scientific understanding of the basic mechanisms of transmission and the need to follow protective measures.

The communication of science to the public can however have negative consequences if the science underpinning the conversation is not as robust as it ideally should be. This risk is heightened in an emergency environment where not all the scientific method’s usual checks and balances are in place.

The rate at which scientific knowledge about Sars-CoV-2 (the virus that causes Covid-19) has been acquired is a remarkable collective achievement. Just five months ago no-one knew about the virus’s existence, but today it is the subject of study on an unprecedented scale.

In the face of a public health emergency, academic secrecy appears to have been suspended and scientific collaboration has increased. Leading medical journals have made their Covid-19 articles free-to-read for all. More than 200 clinical trials have been launched, in many cases uniting hospitals and laboratories from different countries. The hunt is on for a vaccine, a number of antiviral drug trials are on the go and new diagnostic tests are rapidly being developed and validated.

READ MORE | Covid-19: The pros and cons of high-speed science

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.

READ MORE: Coronavirus 101 

^{Image credit: Getty Images}

We all have our snack or beverage of choice to keep us sustained and energised when we’re working from home. If you need coffee to deliver your best, the least you can do is to make sure it’s as healthy as possible. 

Research to examine the links between the way you brew your coffee and the risks of heart attacks and death concluded that filtered coffee is your healthiest choice.

This study was published in The European Journal of Preventive Cardiology.

“Our study provides strong and convincing evidence of a link between coffee brewing methods, heart attacks and longevity,” said study author Professor Dag S. Thelle of the University of Gothenburg, Sweden.

“Unfiltered coffee contains substances which increase blood cholesterol. Using a filter removes these and makes heart attacks and premature death less likely,” he stated. 

Coffee and cholesterol?

Like it or loathe it, coffee is a popular beverage worldwide and there have been many debates about its benefits. According to a news report, Professor Thelle discovered nearly three decades ago that drinking coffee was linked with higher cholesterol – specifically the “bad” LDL cholesterol.

But experiments concluded that this side-effect was largely caused by substances that can be removed using a filter. A cup of unfiltered coffee contains almost 30 times the concentration of the substance that is known to raise LDL cholesterol.

Thelle said: “We wondered whether this effect on cholesterol would result in more heart attacks and death from heart disease. But it was unethical to do a trial randomising people to drink coffee or not. So, we set up a large population study, and several decades later we are reporting the results.”

What the study entailed

This study was conducted between 1985 and 2003 and looked at 508 747 healthy men and women between the ages of 20 and 79. They all completed a questionnaire on the type of coffee they consumed, and data on general health factors such as height, weight, blood pressure and cholesterol were collected.

A total of 46 341 participants died over the course of 20 years. Of those, 12 621 deaths were due to cardiovascular disease. Of the cardiovascular deaths, 6 202 were caused by a heart attack.

Compared to no coffee, filtered brew was linked with a 15% reduced risk of death from any cause during follow up, according to the news report. In death from cardiovascular disease, filtered brew was associated with a 12% decreased risk of death in men and a 20% lowered risk of death in women compared to no coffee.

The lowest mortality was among those who drank one to four cups of filtered coffee per day.

Professor Thelle said: “The finding that those drinking the filtered beverage did a little better than those not drinking coffee at all could not be explained by any other variable such as age, gender, or lifestyle habits. So, we think this observation is true.”

Choose the best you can afford

Filtered brew was also less risky than the unfiltered beverage for death from any cause, death due to cardiovascular disease, and deaths from heart attacks. “Our analysis shows that this was partly because of the cholesterol-increasing effect of unfiltered coffee,” said Professor Thelle.

Professor Thelle noted that unfiltered coffee did not necessarily raise the risk of death compared to completely cutting out coffee.

He said: “We believe that some women and younger men drinking unfiltered coffee switched to filtered, thereby reducing the strength of the association with cardiovascular mortality, whereas older men were less inclined to change their habits.”

The outcome? Keep your cholesterol low and your heart healthy by choosing the best filtered coffee you can afford.

^{Image credit:}

Compiled by Marelize Wilke

It comes as Prime Minister Boris Johnson is to return to work in Downing Street on Monday morning.

Epidemiological terms are fast becoming part of everyday language. Terms like “flattening the curve”, “antibody tests” and “infection control” pepper conversations in supermarket queues and Zoom meetings.

Scientists must publicly share and explain, more now than ever before, the science behind efforts to stop the Covid-19 virus in its tracks. And, apart from some fake news and bad armchair epidemiology, it generally seems to work. In my experience at least, most people seem to talk about the virus with a decent scientific understanding of the basic mechanisms of transmission and the need to follow protective measures.

The communication of science to the public can however have negative consequences if the science underpinning the conversation is not as robust as it ideally should be. This risk is heightened in an emergency environment where not all the scientific method’s usual checks and balances are in place.

Unprecedented speed

The rate at which scientific knowledge about Sars-CoV-2 (the virus that causes Covid-19) has been acquired is a remarkable collective achievement. Just five months ago no-one knew about the virus’s existence, but today it is the subject of study on an unprecedented scale.

In the face of a public health emergency, academic secrecy appears to have been suspended and scientific collaboration has increased. Leading medical journals have made their Covid-19 articles free-to-read for all. More than 200 clinical trials have been launched, in many cases uniting hospitals and laboratories from different countries. The hunt is on for a vaccine, a number of antiviral drug trials are on the go and new diagnostic tests are rapidly being developed and validated.

At the height of the HIV/AIDS epidemic in the 1990s, researchers and clinicians, spurred on by activists, rallied to combat the disease in what was then an unprecedented effort. But today’s technology and the pace of information-sharing surpasses what was possible 30 years ago.

Professor Tulio de Oliveira, a geneticist at KRISP in KwaZulu-Natal, said in a recent Data@breakfast webinar that “in just 100 days the scientific community has identified the virus, sequenced the genome, understood transmission, understood the proteins, and had an understanding of the receptor that enters the cell”. He said this came about because scientists decided to release their data quickly. “We talk about from sample to scientific results in days,” he said.

“This has completely changed the way we do traditional science.” de Oliveira said in a pre-Covid-19 world it could take up to 100 days from submission of a science paper to it being accepted for publication in a journal. “[Now]in that time we already have thousands of publications.”

Warning bells

Warning bells are ringing however about the poor quality of some scientific research in these pressurised times. The politicisation of science and hype in the media around clinically unproven drug treatments can create public confusion and fuel unrealistic expectations.

The closely related antimalarial drugs chloroquine and hydroxychloroquine recently became household names after US President Donald Trump touted them as proven treatments for Covid-19. This was after early trials suggested they may have some efficacy in the treatment of people with the disease. The public responded by buying up the drugs – in the process putting those who need them for rheumatoid arthritis and other auto immune conditions at risk.

Some scientists have warned against over-interpreting the early studies due to methodological flaws.  Some hydroxychloroquine studies have since been abandoned, and some have suggested the drugs may increase the risk of cardiac arrest in patients with Covid-19 disease. While most scientists seem to consider hydroxychloroquine worth studying further, most also seem to agree that the jury is very much still out.

“The problem is when trial results come out and are presented to the media without important contextualisation, peer review and critique,” says Graeme Meintjes, an infectious diseases physician at the University of Cape Town. “A treatment (drug) needs to be safe and effective and focussed on patient outcomes. We are interested in saving lives, faster recovery and reduced hospitalisation.”

Too many small trials?

The urgency to do research and then to publish one’s findings as quickly as possible is entirely understandable given the severe toll Covid-19 is taking. But might the publication of findings from small, methodologically flawed studies end up doing more harm than good?

There is currently a deluge of small trials being registered which could result in low quality evidence, according to Helen Macdonald, research editor of the British Medical Journal(BMJ). In a recent “BMJ Evidence-based Medicine” podcast she said many of the trials could not be compared and was wasteful research.

“There is a need for less speed and more careful thought and for proper blinded randomised control trials done properly,” she said.

Andy Gray, a pharmacologist at the University of KwaZulu-Natal, has similar concerns. He says the new trend of fast-paced research could be risky in the future. “Speed will be valued over quality, with a weakening of the peer review process. That risks poor-quality research entering the ‘literature’ to a far greater extent than is already the case.”

Gray says “underpowered clinical trials” (meaning small trials with few participants) with inadequate processes for blinding and randomisation risk results that can be misleading or misinterpreted.

“When inclusion and exclusion criteria for participating in the trials are poorly determined, or applied, and clinician choice to alter allocations or regimens is allowed, the risks of biases are also increased.” This ultimately undermines the research study, he says. Gray adds: “When attempts are then made to synthesise the literature, we are left with only poor quality evidence on which to make decisions.”

Meintjes says there are an unprecedented number of similar hydroxychloroquine studies, addressing similar scientific hypothesis. “We now need larger studies,” he says, that will look at patient related outcomes.

As with HIV networks studies, Gray says, co-ordination and multi-centre studies for Covid-19 are possible, but these trials take time and have to be meticulously conducted and monitored.

Two large Covid-19 studies have been launched that should help avoid some of the pitfalls of doing many smaller trials with varying methodologies. These are both randomised controlled trials that will recruit large numbers of people to a standardised protocol that allows for a meaningful comparison of different Covid-19 treatments.

The United Kingdom’s RECOVERY trial has recruited more than 5 000 patients in over 165 hospitals and the SOLIDARITY trial, coordinated by the World Health Organisation, has four treatment arms and involves over 100 countries. Spotlight previously reported on South Africa’s participation in the SOLIDARITY trial and published an opinion piece on why such large, multi-arm clinical trials are needed for Covid-19. 

Single-arm trials 

One benefit of multi-arm trials such as RECOVERY and SOLIDARITY is that they allow us to compare treatments with each other and with placebo. Single-arm trials (where a treatment is not directly compared to any other treatment), on the other hand, do not allow for direct comparisons and accordingly provide less certain findings. They are however generally easier and quicker to do.

In a recent Covid-19 drug study reported in the New England Journal of Medicine (NEJM) for example, data were presented for “61 patients who received at least one dose of the antiviral drug remdesivir”, but in seven patients there were no post-treatment data and one patient had a dosing error. There was also no control arm (in which one group of participants is not given the drug so they can be compared with the group receiving the drug).

Gray says although a University of Chicago Medicine study recruited more patients (125, of which 113 were described as “severe”) in another trial of remdesivir, there was no control arm either, so no means of comparison.

The trial results, yet to be peer-reviewed and published, were leaked to the media after they were discussed at a university faculty meeting and soon after started making waves on Twitter.

The authors of an article published in the NEJM and which appeared after the remdesivir study, highlighted concerns about how evaluating and approving drugs can go awry during a public health crisis. They said: “It is a false dichotomy to suggest that we must choose between rapid deployment of treatments and adequate scientific scrutiny. For the Covid-19 pandemic and other pressing medical challenges, the health of individual patients and the public at large will be best served by remaining true to our time-tested approach to clinical trial evidence and drug evaluation, rather than cutting corners and resorting to appealing yet risky quick fixes.”

BCG: Correlation is not cause

Another study grabbing media attention in South Africa suggested a correlation between the century-old Bacillus Calmette–Guérin (BCG) vaccine and protection against Covid-19. The BCG vaccine is used in South Africa and various other countries with high TB burdens to prevent severe forms of TB in young children. 

Following the publication of the study, Facebook and other social media platforms quickly ignited with BCG being declared a “game changer”. 

But it is worth considering where the study was published. It was uploaded to the preprint server medRxiv, an online archive that shares academic research before it has been peer-reviewed and published in journals. In normal times, publication of such a study without peer-review would be frowned upon by many.

A number of critiques of the study have since been published (here is a particularly good one). One point some have made is that correlation is not cause and that there are other more plausible explanations for the correlation between BCG and Covid-19. It is also possible that the correlation will vanish as Covid-19 numbers increase in poorer countries with widespread BCG vaccination.

Given the compelling criticisms that have been published of the article, it seems unlikely that the article in its original form would have made it through peer-review at a reputable journal without very significant alterations. As such, the affair both raises questions over the need for scientific peer-review and over the media’s handling of studies that have not been peer-reviewed. 

^{*Adele Baleta is an independent science writer, media consultant and trainer.}

^{This article was produced by SPOTLIGHT – health journalism in the public interest. SIGN UP for our newsletter.} 

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^{Image credit: National Cancer Institute, Unsplash}

Adele Baleta

Millions of key workers and people they live with can apply for a coronavirus test online.