Topic Review: COVID-19

INTRODUCTION

Discovered in the 1930s, coronaviruses are a large family of viruses that mostly infect animals. Seven different types of coronavirus have been able to infect humans but none has had more global impact than SARS-2-CoV (Severe Acute Respiratory Syndrome – 2- CoronaVirus): a respiratory virus first identified on January 7, 2020 in China causing flu like symptoms.

Viruses, and the diseases they cause, often have different names. For example, HIV is the virus that causes AIDS. COVID-19 is the disease caused by this new strain of coronavirus (COVID stands for COronaVIrus Diseases – 2019). On March 11, 2020 the World Health Organisation declared it to be a pandemic -an epidemic occurring worldwide. By June 28, 2020 there have been nearly 10 million people with COVID-19, causing nearly 500,000 deaths.

Why is this virus different?

Infectious disease’s can cause uncontrollable outbreaks via their ability to be transmitted between people. Although not the most lethal coronavirus, COVID-19 spreads far easier than other lethal respiratory viruses (like the flu, SARS or MERS). This ability to spread makes it different than previous virus outbreaks. And since humans have no immunity against this new virus, without any intervention, an explosion of cases is inevitable once introduced into a community. To contain the spread, societies have imposed varying degrees of lockdowns and social distancing which has caused massive economic impact.

Combating the other virus: Misinformation

Just a few days after the COVID-19 outbreak began in Iran, unfounded rumors circulated on social media that drinking or gargling alcohol could prevent or cure COVID-19. Over the coming weeks this false belief caused 3000 hospitalizations and 700 deaths as ingesting Denatured alcohol (methylated spirits) is toxic. This is one of many examples on how misinformation can kill.

With such impact, fear and uncertainty – people naturally look for information. The internet and social media has given rise to hundreds of fringe theories and claims. COVID-19 has been coined an ‘infodemic’: an overabundance of information – some accurate and some not – that makes it hard for people to find trustworthy sources and reliable guidance when they need it. By asking verified independent experts, our goal at Metafact is to help combat this ‘infodemic’.

A different kind of Review

Typically our reviews cover topics that have had decades of evidence behind them like Sleep, Alzheimer’s or Probiotics. COVID-19 is only months old, so knowledge is evolving daily. It’s therefore important to not just find out what scientists know but it’s even more important to publish what they don’t. Uncertainty is almost always unreported in the media – but it’s critical to help people make better decisions.

So far, we’ve asked more than 50 of the worlds top researchers in viruses, infectious disease and public health to share the facts about COVID-19 (all unedited answers can be found here on our Coronavirus page). This is not a complete guide and knowledge is evolving quickly and will change over the coming months. This review summarises what is known and not known so far on some of the big contested questions about COVID-19. Our goal is to help you stay safe and healthy during the pandemic.

Here’s what we found…

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NUMBERS

Meta-Index

 

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WHAT IS KNOWN

The origin and infectious dose of the virus

 

The Origin

Genomic research suggests bats are the closest relative of SARS-2-CoV. Previous coronavirus outbreaks (SARS and MERS) had their origin in bats. Why? Due to evolutionary factors, “bats have evolved to have a benign relationship with their viruses” says Professor Vikram Misra from the University of Saskatchewan. “The viruses don’t cause obvious disease and the bats retain at least some of the viruses for extended periods of time”. So genetics points to bats as the likely origin, with possible transmission via another intermediary host (maybe a pangolin) via a wild animal market in Wuhan China in December 2019 – but there is no direct evidence yet on the origin (Read more from experts here).

The World Health Organisation have launched an investigation. “The WHO investigation should eventually give us some clues, however, WHO is a political animal, and there is no guarantee the truth will come out.” says Professor Adrian Esterman, epidemiologist from the University of South Australia.

How much virus you need to get COVID-19

To be infected with COVID-19, you need to expose yourself to something called an ‘Infective Dose’, which is the number of virus particles (the ‘dose’) needed to get COVID-19. The actual minimum number varies between different viruses and we don’t yet know what that ‘minimum infectious dose’ is for COVID-19. “We might presume it’s around a hundred virus particles” writes Professor Mike Skinner, virologist from the University College London. “We must be more concerned about situations where somebody receives a massive dose of the virus (we have no data on how large that might be but bodily fluids from those infected with other viruses can contain a million, and up to a hundred million viruses per ml), particularly through inhalation.” This high dose would give the virus a jumpstart where our immune system will struggle to control the virus he says.

Scientists do know COVID-19 spreads much easier than the flu (based on higher Reproduction numbers). This could be because the infectious dose is lower than the flu, or because infected people release a lot more of the virus in their environment. “We do not yet know what the infectious dose is for SARS-CoV-2/COVID-19” writes Professor Paul Digard, virologist from the University of Edinburgh. “Extrapolating from influenza virus, where we know a lot more, the infectious dose by breathing it in (a direct journey from one person to another through droplets released in a cough) might be quite small. However, infection via a contaminated surface – where the virus has to survive a period of drying out, then a journey from surface to hand to face, is likely to require a lot more”. (Read more on this topic from the experts here)

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WHAT IS KNOWN

The role of airborne transmission

“The virus can be released into the air through coughing, sneezing, talking, and breathing. Some people release more than others.” writes Dr Lindsey Marr, virus transmission expert from the Virginia Tech University. “The virus is in droplets that range in size from smaller than we can see to large ones that fall to the floor quickly. There is no hard cutoff between “aerosols” and “droplets” she says.

It’s useful to think about airborne particles and transmission like a puff of smoke from a cigarette. “At close range (imagine a cigarette smoke puff), the concentration of airborne virus will be quite high. As you get farther from the source, the concentration falls off rapidly. If you are close, you are much more likely to inhale the virus. You are also more likely to be sprayed by large droplets that land on your face, which doesn’t happen if you’re farther away.”

That’s why it’s important to maintain the 1.5-2m social distance rule. The further away the safer you are, but some viruses can float around for many hours she says.

“Viruses in small droplets can float around in air for many hours, but they will likely be quite diluted unless you’re in a small confined space. You could inhale these, but it’s much less likely than if you’re close to the person. Airborne viruses will eventually settle on surfaces, like the floor and tables, and could be picked up if someone touches them. However, their ability to survive varies with temperature, humidity, and surface material. They decay gradually over hours or days. It’s not like they all stick around for 9 days and then, poof, suddenly disappear. Think of them as fading away.” (Read more on this topic from the experts here)

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WHAT IS KNOWN

Treatments and preventions

There have been a huge number of claims from people, bloggers and politicians on promising treatments for COVID-19. So far we have asked a number of experts to verify 5 different claims:

Hydroxycholoroquine: President Trump gave this drug a lot of hype early in the pandemic. Dr Rebecca Burton from Oxford University reviewed the evidence for us writing that the hype didn’t match the science. On June 20, the NIH and WHO cancelled studies into the drug as it’s ‘unlikely’ to help COVID-19 patients.

Remdesivir: “Remdesivir may decrease length of hospitalization among very sick patients” writes emergency physician Dr Megan Ranney. More research needed.

Dexamethasone: A research team at Oxford University via a large study of 2000 patients has found that cheap and widely available drug called dexamethasone can be effective in very severe forms of the COVID-19. Dr David Gaze, clinical researcher from the University of Westminster shares a detailed perspective that it’s important to recognise that “The results of the trial have not yet been published in a peer-reviewed journal, [but if confirmed], show the biggest benefit was in those patients on ventilators, where dexamethasone reduced the risk of death by 30%. For those requiring oxygen, there was a 20% reduction.” Good news, but still more work needs to be done to verify these results.

Vitamin D: Recent headlines have suggested vitamin D deficiency could increase the risk of dying from COVID-19, and in turn, that we should consider taking vitamin D supplements to protect ourselves. At least in theory, there may be something to these claims, writes Professor Elina Hyppönen from the University of South Australia. However she along with other experts who wrote detailed reviews on Metafact say there is a lot of conflicting evidence.

More clinical trials are needed before this link can be verified but “we do know being vitamin D deficient won’t help” Prof Hyppönen writes. “It’s difficult to get enough vitamin D from food alone. A generous portion of oily fish can cover much of our need, but it’s neither healthy nor palatable to eat this every day”. Getting a good dose of sun will help – but make sure it’s not too much. If you don’t think you’re getting enough vitamin D, speak to your doctor. They may recommend incorporating daily supplements into your routine if you are heading into winter.

Vitamin C: There is no evidence so far on the effectiveness of Vitamin C to treat COVID-19 and “We really have no idea whether having more vitamin C will prevent anyone contracting the coronavirus” writes Prof Margreet Vissers from Otago University.

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WHAT IS KNOWN

Immunity, a vaccine and antibodies effectiveness

Without community-wide immunity, this new virus will continue to spread without imposing strict social distance measures. With most societies opening up and more unwilling to reimpose social lockdowns, a vaccine is critical for COVID-19. “A vaccine gives our body a harmless flavour of the virus, alerting the immune response to generate antibodies and/or cellular immunity (T cells) ready to fight the infection. The idea is that we can then deploy a ready-made defence system next time we encounter the virus, and this spares us from severe symptoms” writes Dr Zania Stamataki, a virologist from the University of Birmingham.

Although there are many unknowns, most experts are optimistic about the chance of a vaccine coming for COVID-19. “In all but a tiny percent of cases – maybe 1 in 100 – the immune system naturally eliminates SARS-CoV-2 from the body” writes Professor William Petri, immunologist from the University of Virginia. “This is very encouraging for vaccine development” he says “as making an effective vaccine should be much easier than for HIV or hepatitis C virus, for example, where the immune system often (for hepatitis C) or almost always (for HIV) fails. SARS-CoV-2 differs from these two viruses because it has a so-called proofreader gene that prevents mutations from being introduced during viral replication”.

Dr Stamataki goes into more details about this and the 3 reasons why we should be ‘more upbeat’ about the chance of developing a vaccine:

1) This virus can be cured. Unlike some viruses such as HIV that embed their genome in our own and make fresh copies of themselves after immune elimination, we know that SARS-CoV-2 is unable to persist in this way.

2) Most infected patients develop antibodies and there is evidence of virus-specific T cell responses. Although we don’t know if these responses are protective yet, these are precisely the responses that can lead to immunological memory, the cornerstone of vaccination. Vaccine products will be refined and enriched to induce more potent immune responses than natural infection.

3) Coronaviruses mutate slower than viruses such as influenza, and we know from SARS and MERS that antibodies can persist for at least one to two years following recovery. This is good news for an effective vaccine that may not require updating for quite some time.

Despite the theoretical optimism by experts, it wont be until well into 2021 that the vaccine potentially becomes widely available. It’s also important to recognise there are still some big important unknowns. Although most people who have recovered from COVID-19 have detectable antibodies in their blood, experts don’t yet know how effective these antibodies are and how long immunity lasts. Once you get it once, will you be immune for a month? A year? A lifetime?

A vaccine is likely to be developed, but its effectiveness is unknown. Time will tell.

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WHAT IS KNOWN

The End of COVID-19

 

Is a 2nd wave inevitable?

Read the full answers to this question here. Many countries across the world have successfully ‘flattened the curve’ by adopting social distancing policies and lockdowns that have saved millions of peoples lives. These countries are beginning to open-up their policies, resulting in the debate about whether a resurgence in infections will occur. A second wave discussion is premature for many countries who are still experiencing the first wave (eg India, Brazil, Indonesia). Other countries like the United States started to flatten the curve have reported new record surges in June. So the 2nd wave debate is highly dependent on the city, state and country.

For those countries who have flattened the curve “I do very much hope [a 2nd wave] it can be avoided, but being realistic, I think we are going to see the virus still spreading over the next months, if not years” writes epidemiologist Professor Adam Kleczkowski from the University of Strathclyde. “In an ideal world, we should be able to open shops, factories and care homes to such an extend that no significant increase in the number of cases occurs. Any new cases would be detected quickly and isolated, and all vulnerable people will be protected as needed. But real life does not work this way.”

The most likely scenario is that we will “see a number of relatively small outbreaks, hopefully against a backdrop of a general decrease in the cases.” However, there are two big worries:

“Firstly, that the current changes to the lockdown policies will move us above the R=1 threshold and once we are there, the increase could be very fast and hence difficult to contain.

“Secondly, and more importantly, that once we are in such a situation (with R above 1), it will be very difficult to put the country under the severe lockdown again. In such a situation we will probably need to come up with novel ways of increasing social distancing. Regional, and possibly more importantly, sectoral lockdowns will become important (like protecting care homes in a much better way). But also, that we will have to adapt to live with the virus for a long time.”

The idea of a second wave is misleading, writes virologist Dr Jeremy Rossman from the University of Kent. “The concept of a second wave portrays the pandemic as a force of nature that is beyond our control. But we have evidence from many countries that a strong public health system (consisting of widespread testing, contact tracing, isolation and health support) combined with public participation in safe behaviour (wearing face coverings, keeping physical distance, hand washing) is highly effective at minimising COVID-19 transmission. We are not at the mercy of the virus, now or in the future. This is hopeful news, but it puts the burden of responsibility on all of us. We must keep fighting, but in doing so we should not fear an inevitable second wave.”

“Only a few countries have put in place sufficient testing, tracing and isolating of cases, along with more strict social distancing to enable the control of the virus” writes David Hayman, Professor of Infectious Disease Ecology at Massey University. “Given the under-reporting due to poor testing capabilities globally and the pre-symptomatic transmission this infection is very hard to control. Without sufficient control in every country, the infection is so infectious it will re-surge when social distancing is lifted if it has not been eliminated”.

 

Will COVID-19 become endemic?

Read the full answers to this question here. “There are a number of coronaviruses which are endemic in humans” writes Professor Graham Medley, infectious disease expert from the London School of Hygiene & Tropical Medicine. “This means that there are always people who are infected, who pass infection to somebody else and then recover. Over a long time each person infects on average one other person, so that the number infected remains approximately the same.” For example, there are many parts of the world where Malaria is endemic — it is always present and kills over 400,000 people each year. The seasonal flu is another example of a disease that we have to live with.

“In the UK, endemic coronaviruses are seasonal so that the prevalence (proportion infected) goes up towards the end of the year and comes down during the summer. These endemic infections are usually in children causing mild symptoms. Endemic coronaviruses are not associated with significant disease. By the time children are adults they will have been exposed, and potentially infected, many times, and are immune.

The new coronavirus has only been with us for a few months, so it is impossible to be precise about what will happen. However, there is no reason to believe that it will be different. The infection in children is not substantially different to the endemic coronaviruses, but causes substantial risk of disease to older adults. The simplest explanation is that this disease is caused by not having the immunity from being exposed as children. Otherwise, the expectation is that it will become endemic and will continue to circulate, primarily among children, after this initial epidemic.”

“It all depends on whether people get re-exposed to Cov2’s zoonotic reservoir, and whether the virus becomes adapted as a human coronavirus (like some of the common-cold coronavirus strain types). SARS Cov1 disappeared, probably because people stopped eating civets and the virus didn’t adapt to becoming a human coronavirus. MERS continues because the camel appears to be the reservoir, which is a reservoir that is intimately linked to human occupation and livelihood.” writes Dr. Lee Riley, Infectious Disease expert from UC Berkeley.

“I am not sure that endemic is quite the right word. Endemic means permanently present in the population. Seasonal is probably a better word to use. There is a chance that even with a vaccine, COVID-19 could become similar to influenza with seasonal outbreaks. This is because SARS-CoV-2 like influenza is an RNA virus. RNA viruses tend to mutate quite easily, so that even if someone has been infected and recovered, their immunity might not work against a new strain. This is also true for vaccinations – this is why we have changing influenza vaccines each year. There is some evidence that although the SARS-CoV-2 virus mutates easily, the mutations so far have only been very minor. If this continues, then immunity will hold and vaccinations are likely to be effective for an extensive period of time.” writes Professor Adrian Esterman

“This is a challenging question and the truth is that we don’t know at present. This really depends on the nature and duration of immunity following infection from COVID19 and the degree to which we pursue elimination attempts.”says Dr James Wood, infectious disease expert from UNSW Sydney. Without coordinated social distancing throughout the world he says, the only way it woudln’t become endemic in the future is from the arrival of an effective vaccine. “Depending on the properties of any successful vaccine, there may be an opportunity to eradicate SARS-CoV-2 through vaccine-derived immunity. But this is speculative and it is quite possible that if vaccination is highly effective at preventing severe disease, that there may be little incentive to push further for eradication. It also seems entirely possible that SARS-CoV-2 will evolve to be less severe and therefore drop down our list of public health matters of concern”

Everything is unknown, “but if I had to put my money on it, I would bet on SARS-CoV-2 becoming endemic” he says.

We asked 6 experts if they think COVID-19 will become endemic and most said it’s entirely uncertain. You can read all the expert answers here.

 

When will it end?

We all want to know if or when this pandemic will end and if COVID-19 can be eradicated like smallpox was. That depends on many factors relating to a vaccine which are unknown (see above). It also can be ended by government policies which may have too great a cost says Dr James Wood, infectious disease expert from UNSW Sydney. “It’s certainly theoretically possible that we might push COVID19 to extinction through coordinated social distancing across the globe” he says. “The difficulty there is that for many countries the benefits of such action will be outweighed by the negatives – and therefore such coordinated action seems unlikely. There would remain the possibility of stochastic extinction, if through connectedness, all countries either reached herd immunity in a similar timeframe or maintained R<1 over the equivalent period. But this also seems somewhat unlikely.”

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COVID-19 SURVIVAL GUIDE

Survival Guide at Home

 

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COVID-19 SURVIVAL GUIDE

Going out: what’s your risk?

With many of us being confined to the safety of our homes, we haven’t needed to think and plan too much about what we should do once social restrictions ease. How should we plan to venture beyond our homes during the pandemic? From visiting friends or family, attending events or starting to do normal activities again, how should we assess the risk?

To help you, Professor William Petri, an immunologist from the University of Virginia shares his owns thoughts here. Your plan will be heavily dependent on where you live – you are the best person to judge the risk. Here’s what he does:

Check the number of new COVID-19 infections locally

When I venture out, I am first going to check the number of new COVID-19 infections in my community. In Virginia, for example, some health districts had 200 new daily cases and others fewer than 10. I am going to be less risk-averse when new cases fall to near zero.

Judge the risk of severe infection of me and the people I visit

Second, I will assess my risk for severe infection and the risk for severe infection for those I will be visiting. The CDC defines these risk factors as being over age 65 or having serious underlying medical conditions, which include chronic lung disease, moderate to severe asthma, serious heart conditions, immunocompromise, severe obesity (body mass index over 40), diabetes, kidney disease requiring dialysis, liver disease or living in a nursing home or long-term care facility. If I have one of these risk factors, or am visiting someone with one of these risk factors, I am going to be extra-cautious.

Use knowledge of how the virus is transmitted and take precautions

Third, I will draw from knowledge about how COVID-19 is transmitted. Airborne transmission and fomites, or contaminated surfaces such as doorknobs, are both means of infection. The SARS-CoV-2 virus that causes COVID-19 is stable in airborne droplets, or aerosols, for hours and on the surface of cardboard for a day and plastics for two days. A study in the New England Journal of Medicine, for example, showed that half of nursing home patients who had COVID-19 were without symptoms at the time of diagnosis, by nasal swab PCR test for the virus, and yet infectious to others. Normal speech generates oral fluid droplets which are potentially infectious but are captured by a cloth face mask, preventing transmission to others.

Wear a mask and try to stay outdoors

I am going to wear a mask to help prevent my giving the infection to others, avoid touching surfaces such as handrails, try not to touch my eyes or nose or mouth with my hands and wash my hands frequently.

I am going to try to stay outdoors, where the risk of infection from aerosols is less, and if indoors stay six feet distant from others and limit my time there.

If you have any symptoms, stay at home

I am going to assess my risk for infecting others. If I have a fever, cough or other flu-like symptoms, such as muscle aches or tiredness, I am not going to venture out and risk exposing others to COVID-19. Even if healthy, I am going to wear a mask when out so that I can protect others if I am unknowingly infected but pre-symptomatic.

While it is tempting to resume normal activities, I have to remember – and I hope you will, too – that my individual behavior affects not only my health, but also yours.

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COVID-19 SURVIVAL GUIDE

How to improve your mental health?

While not all of us will get infected, all of us feel the effects of the pandemic (socially and economically). It’s critically important we take steps towards improving our mental health. What can be done?

We asked Dr Michaela Pascoe, an expert in mental health from Victoria University. She shares evidence on six areas for us to invest in to promote or improve our mental health: sleep, nutrition, social connectedness, physical activity/exercise, stress management and avoiding risky substance use.

The American College of Lifestyle Medicine highlights six areas for us to invest in to promote or improve our mental health:

1. Sleep

Lack of sleep, or poor quality sleep, can contribute to poorer mental health. Keeping to your usual sleep routine even when your daily life has been disrupted is helpful. Aim to get seven to nine hours of sleep a night. [During January and February, we asked 50 sleep experts to share some expert tips and methods on how to get better sleep. Our two-part sleep review is available to all Metafact members here.]

2. Nutrition

The food we eat can have a direct impact on our mental health. Try to eat a well-balanced diet rich in vegetables and nutrients. Where possible, avoid processed food, and those high in saturated fat and refined carbohydrates, which have been linked to poorer mental health.

3. Social connectedness

Being connected to others is important for our mental and physical well-being and can protect against anxiety and depression. Despite the physical barriers, it’s important to find alternate ways to maintain your connections with family, friends and the community during this difficult time.

What about reading the news and social media habits?

It is important to pay attention to how you are feeling and reacting. If reading the news or following the news closely is distressing than it might be worth limiting your intake. We are all different in terms of what makes us feel more of less distressed, the key is to be mindfulness and to respond accordingly based on your needs, which can change over time.

4. Exercise

Physical activity decreases anxiety, stress and depression and can be used as part of a treatment plan for people with mental illness. Regular exercise also improves the function of your immune system and decreases inflammation. You might need to find different ways of exercising, such as running, walking or tuning into an online class, but try to make physical activity an enjoyable and rewarding part of your daily routine while at home. Scheduling physical activity at the end of your “work day” can help to separate work from your personal life when working from home.

5. Stress management

It’s important to be able to recognise when you’re stressed. You might have feelings of panic, a racing heart or butterflies in the stomach, for example. And then find ways to reduce this stress. Mindfulness practices such as meditation, for example, can decrease stress and improve mental health. There are a number of breathing exercises that can also help to manage stress. Spending time outdoors has also been shown to reduce stress.

So consider spending time in your backyard, on your balcony or deck, or if possible, take a greener route when accessing essential services. Talking about your experiences and concerns with a trusted person can also protect your mental health.

6. Avoiding risky substance use

While it might be tempting to reach for alcohol or other drugs while you’re self-isolating, keep in mind they can trigger mental health problems, or make them worse. The draft alcohol guidelines recommend Australians drink no more than ten standard drinks a week, and no more than four a day. People who drink more than four standard drinks per day experience more psychological distress than those who do not.

Please remember that we are all in this together, so it’s important to keep a lookout for friends, colleagues, and family at this time – help from your doctor and mental health professionals in your state or country are just a phone call away.

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