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Can COVID-19 affect a person a second time?

Can COVID-19 affect a person a second time?


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I keep hearing people are recovering from COVID-19 virus. Is there any chance that same person can become infected with COVID-19 for a second time?


Short answer: Although there are some reports on this, it is pretty unlikely. It is more likely that patients where released too early from hospital, developed further symptoms later on and got worse, was re-hospitalized, tested again for SARS-CoV2, which was positive and counted as re-infected.

Another possibility is that a false negative test happened, when people got re-tested later the test was positive again and the patient was counted as re-infected. Given the rising number of cases worldwide this should become evident pretty soon, if this is a real problem and not an artefact. For the moment, I don't think there is enough evidence for the re-infection of the same patient in such a short time period. If this holds, future will tell.

Long answer: There is now an experimental paper, which infected rhesus macaques with SARS-CoV2, tested if the infection was similar to humans happening in the upper airways (which it was), and re-infected the animals after 28 days with a really high dose of virus (which is much higher than what comes around in our environment), with none of the macaques getting re-infected or showing pathological signs of the infection. See reference 1 for details. This article has its limitations with small sample size and the general questions if the chosen animal model is really comparable with human.

Additionally it looks very much like that patients who are recovering don't shed infectious virus anymore. The PCR test however does not discriminate between infectious virus and plain virus RNA, so it is most like much longer positive than people are infectious. They also show the rapid appearance of specific antibodies, which would at least temporarily protect against a re-infection. See reference 2 for a nice summary and reference 3 for the original article.

References

  1. Reinfection could notoccur in SARS-CoV-2 infected rhesus macaques
  2. People 'shed' high levels of coronavirus, study finds, but most are likely not infectious after recovery begins
  3. Clinical presentation and virological assessment of hospitalized cases of coronavirus disease 2019 in a travel-associated transmission cluster

The impact of COVID-19 on older adults

Before becoming a professor, Sarah Szanton made house calls to older adults as a nurse practitioner. On her visits, she saw how an older person's home environment can contribute to health outcomes. Now, as the Endowed Professor for Health Equity and Social Justice at the Johns Hopkins School of Nursing and the director of the Center for Innovative Care in Aging, Szanton works to identify solutions to narrow racial and socioeconomic disparities for older people.

Szanton joined one of her PhD student mentees, Sarah LaFave, to discuss the challenges that COVID-19 poses for older adults. This conversation has been edited for length and clarity.

How is the COVID-19 pandemic affecting older people differently than younger generations?

Older adults are more likely to have dire outcomes from the virus. It can also be a challenge to prevent older people from being exposed to the virus because they may not be be fully independent. For example, a mother might rely on her adult daughter to come and help her with groceries or take a shower. As another example, some older people depend on help from a family member or friend with sorting mail and sending in checks to pay bills. At this point, people may not have had someone come into the home to help with those kinds of things for many weeks. What happens if one of those unpaid bills is for an essential resource or accrues a lot of interest during this time?

Johns Hopkins responds to COVID-19

Coverage of how the COVID-19 pandemic is affecting operations at JHU and how Hopkins experts and scientists are responding to the outbreak

We also have to think about all of the ways that the pandemic affects older people's lives beyond morbidity and mortality from the virus itself. I am concerned about people experiencing social isolation as a result of not being able to have visitors and not being able to go out and do things with other people. The effects are compounded for any older person who doesn't have access to technology platforms like Skype and FaceTime or who has limited access to phone calls. Many lower-income older people have pay-per-minute phone plans, for example, and may have to choose between using their limited minutes for a phone visit with a doctor or a conversation with a grandchild. So we can't assume that a switch to virtual socialization or virtual access to resources is going to work for all older people.

Also, I think there's a fair amount of ageism—of people thinking right now, even if they aren't saying it out loud, "Well, older people are going to die anyway." But who are we to say that an 80-year-old wouldn't have otherwise lived to be 100 and done a lot of wonderful things in those 20 years? We would never think that the first 20 years of someone's life don't matter we should recognize that the last 20 years are just as valuable.

Has the pandemic exacerbated health disparities for older adults?

Every experience in life is influenced by a person's access to resources and, in the United States, a person's race, socioeconomic status, and other characteristics have profound impacts on access to resources. It can be easy to jump to saying, "Oh, well, that person was older and had diabetes, so of course they had a worse outcome from COVID." But you have to take a step back and ask what contributed to the person having diabetes in the first place. Because race is not biological, we know that it's not race itself that causes disparities in co-morbidities and in COVID outcomes—it's the relationship between race and resources. For example, my colleague Laura Samuel has found that the counties that have a high proportion of people who have to spend more than a third of their income on housing have higher COVID mortality rates. If we had a society that was structured so that everyone had the same chance at health, we would not see the disparities we are seeing.

A lot of the potential solutions to health disparities among older adults don't exist in the health care system itself—they occur further upstream. Things like widening access to the federal Supplemental Nutrition Assistance Program, addressing food deserts, and supporting returning citizens in the workforce all relate directly to health, but we don't always think that way.

What challenges has COVID-19 raised for family caregivers of older adults?

First, if family caregivers have jobs that require them to be in regular contact with others, such as bus drivers or nurses, they may have to decide between not providing essential help to an older loved one and risking passing the virus to that person.

Second, direct care workers continue to come in and out of hospitals, nursing homes, and senior living buildings and are being screened upon entrance, but very few family caregivers are allowed into these same facilities right now. In some cases, family caregivers are not being recognized as essential parts of the health care team, and I think they should be. Hospitals and nursing homes have had to place restrictions on visitors for safety reasons, but I think some of those policies may be too limiting. For example, delirium is a very common and very costly issue for older adults who are admitted to hospitals. There is a better chance of preventing and managing delirium if a family member can help attend to the day-night sleep cycle, keep the person oriented, hydrated, and so on. True delirium uses so many health care resources that it can benefit all of us if an older person has a familiar caregiver with them during an inpatient stay. Of course, a major limitation is that there isn't enough personal protective equipment right now, so you have to weigh the risks and benefits of tapping into a finite supply of protective equipment.

What can people do right now to support older adults in their communities during this crisis?

There are many volunteer opportunities. For example, Baltimore Neighbors Network is a coalition of community partners that trains and supports volunteers to provide companionship and resource navigation assistance to older adults in Baltimore, which includes remote options such as phone calls. If people can't volunteer for a program like that right now, maybe they can give blood, or maybe they can take the money they would usually spend eating out each month and instead contribute financially to a food pantry. People can also support their older family members or friends by asking the person what would be most helpful to them—maybe it's dropping off a meal on a front porch, maybe it's mailing a letter. It's really important to remember, even during a crisis, to make time for our elders.


Researchers say that on average, every person who has COVID-19 will pass it on to 2 or 2.5 others. One study says that number is even higher, with one sick person infecting between 4.7 and 6.6 others.

By comparison, someone who has the flu will probably give it to an average of 1.1 to 2.3 others. But one person with measles might spread it to 12 to 18 others.

Research has found that although children tend to get infected with the coronavirus less often and have milder symptoms than adults, they can still catch and spread it. Some have become seriously ill and even died.


Can You Get A Covid-19 Infection Twice? An Infectious Disease Doctor Discusses New Evidence

Dr. Mark Kortepeter, a physician and biodefense expert who formerly worked at the U.S. Army “hot zone” research lab, explore what new cases tell us about the potential for being reinfected with Covid-19.

It's possible that Covid-19 may mutate similarly to the flu.

A frequent question I get when I lecture on Covid-19 is whether someone can get infected a second time. One of the challenges to answering this question has been that the most common test for diagnosing Covid-19 infection, RT-PCR, identifies genetic material from the virus, but doesn’t distinguish between living or dead viruses. This makes figuring out whether someone has lingering symptoms or if someone has been infected a second time harder, because people who are infected can still have a positive test up to several weeks after they are ill.

I previously discussed what we knew about the possibility of reinfection back in early June. At that time, we weren’t sure. Now we have proof that people can be infected a second time. There are now reports coming in from different countries that demonstrate reinfection: the first was a 33-year-old man from Hong Kong returning from Europe who was asymptomatic, but had a swab done upon re-entry at the airport. Other reports have surfaced from Belgium and the Netherlands, and now the United States. A 25-year old man from Reno apparently has also been re-infected. The time frame from the initial illness in these individuals to the time of second infection has ranged from three weeks to 142 days.

In the cases reported to date in the medical literature, scientists were able to compare a sample of virus taken from the patients at the time of their initial infection with a new sample using genetic sequencing. This means, they had a line-by-line comparison of the virus genes. What they found was that the viruses were slightly different.

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Normally, shortly after we are infected with a virus, our bodies will recognize the virus and knock it out quickly if we are re-exposed. Unfortunately, RNA viruses, like influenza and SARS-CoV-2 (which causes Covid-19 illness), make errors as they make copies of themselves. When they reproduce millions of times, those errors can add up and ultimately alter some of the proteins that the virus makes. If enough changes occur, then we may not be able to fight off the slightly modified new virus if we’re exposed. This leads to a new infection.

This is what happens with influenza. The whole reason you need to be vaccinated every year against influenza is due to a constant genetic “drift” by the virus that alters the proteins ever so slightly over the course of a year.

All that said, there’s still a lot we don’t know, so here’s a few things you should keep in mind when thinking about reinfection.

These cases may be the exception, not the rule. Despite having over 28 million cases of Covid-19 reported worldwide, we haven’t seen a lot of proven reinfections. That could be due to the limitations of our routine testing methods. Only time will tell whether this is the tip of the iceberg as we develop better testing and viral surveillance, but no doubt we will see more of these. The good news, at least, is that in most of these reports, the individuals had milder (or no) illness on the second round however, the man from Nevada was hospitalized for more severe illness. With so few reported cases, it is hard to draw conclusions on what to expect.

The reinfections appear to be related to different viral strains. When someone gets infected and recovers, they have shown that they can mount an effective response to the virus. We don’t know how long that response lasts. The antibodies that we can measure decline within a couple months, but we also have certain types of cells (memory T-cells) that can retain the ability to surge quickly to attack the virus. Clearly, if the virus is changing ever so slightly, this may make it easier to re-infect – just like influenza viruses.

Reinfections may impact vaccine development and protection. If the virus does change a lot, it is possible that over time, vaccines created for current circulating strains may gradually lose their effectiveness. It is too early to tell, but we may eventually face a situation similar to influenza, where we need boosters on a periodic basis. This may also depend on how much virus remains in circulation around the world. We will have to watch this closely over the next year.

We still need to protect ourselves. This is a moving target. Our understanding of Covid-19 will continue to evolve, especially now that reinfection is on our radar. Until we know more about the longevity of immunity, it is safer to assume we are still vulnerable after infection, especially if we encounter a different strain of the virus. Even if someone has already been infected, it is still useful to remain cautious and follow public health guidelines to minimize the chance of reinfection. This includes the things you’ve heard about repeatedly: wearing masks, social distancing, and hand washing.


UF Health chief epidemiologist debunks common COVID-19 vaccine myths

As the new vaccines developed to combat COVID-19 begin to flow into communities around the country, myths and misinformation are coursing through the general population as well.

In an effort to blunt some of these misperceptions, Nicole M. Iovine, M.D., Ph.D., chief epidemiology officer at University of Florida Health Shands Hospital, addresses some of the more common myths that are percolating on social media and other places.

Myth: The COVID-19 vaccines will make a person more susceptible to other diseases.

Answer: Our immune systems are wonderfully robust, and are actually responding to potential disease-causing organisms all the time. So, our immune systems are more than capable of responding to this vaccine while continuing to protect us from all the other potential infections we constantly encounter.

Myth: Mass vaccinations will promptly end the COVID-19 pandemic.

Answer: The vaccine is our best tool yet for controlling the COVID-19 pandemic. However, it is important to remember that the vaccine will not end the pandemic on its own. That is because, like all vaccines, it cannot prevent 100% of all infections in vaccinated persons. Although the studies indicate efficacy rates of 90% or more, a small percentage of people will still develop COVID. Also, at this point we do not know if vaccinated people can still transmit the infection to others. We anticipate that we will learn more about this as time passes. Lastly, the vaccine is currently authorized only for people ages 16 and over, so the younger population cannot be vaccinated at this time. As studies in younger populations continue, we hope that more children will be able to be vaccinated.

Myth: The technology that makes the vaccines work will interfere with a person’s DNA.

Answer: All living things make messenger riobonucleic acid, or mRNA, that provides the instructions for our cells to make proteins. mRNA has no ability to integrate or otherwise become part of a person’s DNA. There is nothing special about the mRNA in the COVID-19 vaccine that would allow it to interfere with the DNA in our cells or persist in our bodies.

Myth: If everyone around me is immune due to vaccination or a prior COVID-19 case, I don’t need a vaccine.

Answer: There are several reasons why this is not true. First, we do not know if a vaccinated person can still transmit the virus to another person. Second, this is a two-vaccine series that takes several weeks after the second dose to generate a full immune response. That means a vaccinated person could still be susceptible to infection and possibly transmit COVID-19 while the immune response develops. Third, like all vaccines, it is not able to prevent COVID-19 infection in 100% of vaccinated people. And while we hope that immunity is long-lasting, it isn’t known if or when a vaccinated person may again become susceptible to infection.

Myth: The vaccines were developed so quickly that its safety and efficacy are questionable.

Answer: Tremendous support and resources have been dedicated to the COVID-19 vaccine effort. That is why it has been able to come to fruition so quickly. It is important to remember that all of the necessary efficacy and safety studies have been completed, just as if the vaccines had taken years to produce. All of the regulatory oversight on vaccine production has also remained unchanged.

Media contact: Ken Garcia at [email protected] or 352-273-9799.

Learn more about UF Health's efforts to combat the COVID-19 pandemic at Coronavirus.UFHealth.org.


The impact of COVID-19 on older adults

Credit: CC0 Public Domain

Before becoming a professor, Sarah Szanton made house calls to older adults as a nurse practitioner. On her visits, she saw how an older person's home environment can contribute to health outcomes. Now, as the Endowed Professor for Health Equity and Social Justice at the Johns Hopkins School of Nursing and the director of the Center for Innovative Care in Aging, Szanton works to identify solutions to narrow racial and socioeconomic disparities for older people.

Szanton joined one of her Ph.D. student mentees, Sarah LaFave, to discuss the challenges that COVID-19 poses for older adults. This conversation has been edited for length and clarity.

How is the COVID-19 pandemic affecting older people differently than younger generations?

Older adults are more likely to have dire outcomes from the virus. It can also be a challenge to prevent older people from being exposed to the virus because they may not be be fully independent. For example, a mother might rely on her adult daughter to come and help her with groceries or take a shower. As another example, some older people depend on help from a family member or friend with sorting mail and sending in checks to pay bills. At this point, people may not have had someone come into the home to help with those kinds of things for many weeks. What happens if one of those unpaid bills is for an essential resource or accrues a lot of interest during this time?

We also have to think about all of the ways that the pandemic affects older people's lives beyond morbidity and mortality from the virus itself. I am concerned about people experiencing social isolation as a result of not being able to have visitors and not being able to go out and do things with other people. The effects are compounded for any older person who doesn't have access to technology platforms like Skype and FaceTime or who has limited access to phone calls. Many lower-income older people have pay-per-minute phone plans, for example, and may have to choose between using their limited minutes for a phone visit with a doctor or a conversation with a grandchild. So we can't assume that a switch to virtual socialization or virtual access to resources is going to work for all older people.

Also, I think there's a fair amount of ageism—of people thinking right now, even if they aren't saying it out loud, "Well, older people are going to die anyway." But who are we to say that an 80-year-old wouldn't have otherwise lived to be 100 and done a lot of wonderful things in those 20 years? We would never think that the first 20 years of someone's life don't matter we should recognize that the last 20 years are just as valuable.

Has the pandemic exacerbated health disparities for older adults?

Every experience in life is influenced by a person's access to resources and, in the United States, a person's race, socioeconomic status, and other characteristics have profound impacts on access to resources. It can be easy to jump to saying, "Oh, well, that person was older and had diabetes, so of course they had a worse outcome from COVID." But you have to take a step back and ask what contributed to the person having diabetes in the first place. Because race is not biological, we know that it's not race itself that causes disparities in co-morbidities and in COVID outcomes—it's the relationship between race and resources. For example, my colleague Laura Samuel has found that the counties that have a high proportion of people who have to spend more than a third of their income on housing have higher COVID mortality rates. If we had a society that was structured so that everyone had the same chance at health, we would not see the disparities we are seeing.

A lot of the potential solutions to health disparities among older adults don't exist in the health care system itself—they occur further upstream. Things like widening access to the federal Supplemental Nutrition Assistance Program, addressing food deserts, and supporting returning citizens in the workforce all relate directly to health, but we don't always think that way.

What challenges has COVID-19 raised for family caregivers of older adults?

First, if family caregivers have jobs that require them to be in regular contact with others, such as bus drivers or nurses, they may have to decide between not providing essential help to an older loved one and risking passing the virus to that person.

Second, direct care workers continue to come in and out of hospitals, nursing homes, and senior living buildings and are being screened upon entrance, but very few family caregivers are allowed into these same facilities right now. In some cases, family caregivers are not being recognized as essential parts of the health care team, and I think they should be. Hospitals and nursing homes have had to place restrictions on visitors for safety reasons, but I think some of those policies may be too limiting. For example, delirium is a very common and very costly issue for older adults who are admitted to hospitals. There is a better chance of preventing and managing delirium if a family member can help attend to the day-night sleep cycle, keep the person oriented, hydrated, and so on. True delirium uses so many health care resources that it can benefit all of us if an older person has a familiar caregiver with them during an inpatient stay. Of course, a major limitation is that there isn't enough personal protective equipment right now, so you have to weigh the risks and benefits of tapping into a finite supply of protective equipment.

What can people do right now to support older adults in their communities during this crisis?

There are many volunteer opportunities. For example, Baltimore Neighbors Network is a coalition of community partners that trains and supports volunteers to provide companionship and resource navigation assistance to older adults in Baltimore, which includes remote options such as phone calls. If people can't volunteer for a program like that right now, maybe they can give blood, or maybe they can take the money they would usually spend eating out each month and instead contribute financially to a food pantry. People can also support their older family members or friends by asking the person what would be most helpful to them—maybe it's dropping off a meal on a front porch, maybe it's mailing a letter. It's really important to remember, even during a crisis, to make time for our elders.


How does COVID-19 reinfection affect a potential vaccine?

We won't really know until one or more vaccines are approved and widely distributed, but doctors are hopeful that coronavirus vaccines will give people at least enough immunity to be able to resume normal life once enough people have been vaccinated. That's because in the vast majority of cases, COVID-19 patients have so far not appeared to contract the virus a second time, which gives scientists some hope that a vaccine will work.

In fact, cases of coronavirus reinfection could help researchers better understand how to best distribute and administer a vaccine. For example, it may be necessary to give people regular booster shots, which reinforce immunity, until the virus is completely contained.

Signage seen at Whole Foods in Asheville, North Carolina explains that they now require masks to be worn inside, and they will provide one for customers if need be.


“Towards aerodynamically equivalent COVID‐19 1.5m social distancing for walking and running”

Questions and Answers

Authors: Bert Blocken, ([email protected]), Thierry Marchal

Question 1: What was the objective of the study?

The starting point was the 1.5 m (or in some countries 2.0 m or 6 ft) social distance that is recommended to be kept between two people standing still to avoid respiratory droplets of person A reaching person B. It is common sense that when person A exhales droplets and person B moves forwards, person B can move into the droplet cloud exhaled by person A. So people movement can affect droplet exposure. The objective of this study therefore was to find out to which extent the social distance of 1.5 m is enough or not for two people walking, running, cycling in each other’s vicinity. And if not, how it should be adjusted to yield a similar (non‐)droplet exposure risk as for the case of 1.5 m with two people standing still.

Question 2: What it meant by “aerodynamically equivalent social distance” for walking, running, cycling?

The standard social distance is 1.5 m, 2 m or 6 ft (depending on the country). The aerodynamically equivalent social distance is the social distance that two persons need to maintain when walking/running/cycling to have the same level of (non‐)droplet exposure risk as in the case of 1.5 m, 2 m or 6 ft for two persons standing still and facing each other.

Question 3: What are the main findings of this study?

First, is was found that the droplets (range 40 mm — 200 mm) exhaled by a moving person are mainly entrained in the slipstream (wake) behind this person. Second, in absence of strong wind, the equivalent social distance for walking/running/cycling can remain 1.5 m (or 2 m or 6 ft) if the two persons are moving side‐by‐side or in a staggered formation. However, if person B is positioned in the slipstream (or wake) of person A, this person can be exposed to the droplets emitted by person A. Then the equivalent social distances are: 5 m for walking fast (4 km/h), 10 m for running fast (14.4 km/h), 20 m for cycling fast (30 km/h). The social distance to be kept when in the slipstream increases with increasing speed of person B.

Question 4: What are the virological, medical or epidemiological conclusions from your study?

None. This study does not draw any conclusions on the infection risk associated with particular social distances or droplet exposure. We are sharing these results with healthcare authorities and remain at their disposal for further information. It is obvious that no or reduced droplet exposure is better than larger droplet exposure. Therefore, the adjusted and equivalent social distances are to be preferred over the single value of 1.5 m.

Question 5: Why is it important to have these updated and larger social distances in walking, running and cycling?

These distances should not be larger than 1.5 m, except when person B is in the slipstream of person A. Then, the larger social distances are not only common sense but also a matter of consistency. If one now argues that this distance when moving fast (walking, running, cycling) should not be larger than 1.5 m, this logically implies that the 1.5 m when standing still and talking is also too large — which is not the case, as shown by the vast literature since 2002 on travel distance of drops. Note that organizations like CDC (Center for Disease, Control and Prevention) are asking for additional evidence and technology to give better recommendations in the future.

Question 6: What is the value of this study?

The value of this study is not to indicate that person B moving closely behind person A can inhale the droplets emitted by person A. That is common sense for most people with a minimum fluid dynamics background and/or intuition. The value of this study is to indicate where exhaled droplets go (i.e. in the slipstream) and which specific social distances should be used in walking/running/cycling to be equivalent to 1.5 m standing still.

Question 7: Was this study only done by engineers and not by medical experts?

Not really. The study was done by four engineers (2 x civil, mechanical, aeronautical) but one of these, Thierry Marchal, is also seen as a top medical expert in simulation, formally a e‐Health expert to EU authorities, leader of Avicenna Alliance and therefore spokesperson for the discussion with various authorities ( https://youtu.be/Sig5Q7rMFfY ). The medical world is moving towards in silico (computer model) to complement in vitro and in vivo data. These models have been reviewed by other experts such as Marc Horner, co‐author of the V&V 40 standard and presented to the US healthcare authorities before sharing them publicly. The medical world is now moving fast towards computer models. Therefore our study fits in these new developments.

Question 8: Should you not have involved virologists, epidemiologists and medical experts?

Not for the scope of this particular study. This study is an aerodynamics study, not a virology study. The only two facts we adopt from virology are two basic and well‐established facts: (1) Respiratory droplets are an effective way of transferring this type of viruses (well‐established in scientific literature) (2) It is better to not be exposed to other people’s saliva droplets than to be exposed to them (common sense).

Question 9: Does it make sense that mostly engineers performed this study?

The role of civil and mechanical engineers in current and previous SARS epidemics should not be underestimated. Engineers have been heavily involved in SARS since the outbreak in 2002 in Asia because the transfer of droplets in the indoor air in hospitals and houses is a key civil and mechanical engineering expertise. Thousands of papers on this topic have been published by civil and mechanical engineers in the peer reviewed literature. Note that the 1.5 m social distance has been defined in the past decades based on studies by engineers, not medical professionals. Engineering is now an important part of all biomedical and pharmaceutical research as illustrated by the fast and growing success of biomedical engineers.

Question 10: Why did you choose to not follow the standard academic procedure to first get the study peer reviewed and only announce results in the media later?

This is an exceptional situation. Even the extremely careful FDA (Food and Drug Administration) has wisely adjusted some guidance to ensure the rapid approval of any device or treatment / vaccine related to COVID‐19 (e.g. Guidance document for ventilators and accessories) without compromising patient safety. Time matters a lot here. So it is important to temporarily adjust processes to make sure new products are reviewed faster. Similarly here, once the results were properly validated, the priority was to share the results with the public to help reduce the risk of propagation of the COVID‐19 a few days later the scientific publication was shared in open access to allow all other scientists to review and challenge the approach and contribute to its future extension. The peer review publication will follow next. But we are not on the same time line when there is a pandemic storming the world. We thought that the priority was on people’s health.

If we follow the normal procedure, we would first write a research proposal. If we are lucky we receive funding to start within a year. Let us say we can produce all results in one day (never happens). Then we write the article in one day (nearly impossible) and submit for peer review. In our field, this can take months, e.g. 6. So 1.5 years from now we have our peer‐reviewed paper. Should we only then communicate to the public, we do not think this would be ethical. We made the choice to do validate our results first, then share the output publicly, before submitting the article for peer review. Not the most comfortable order for us, for multiple reasons, because of no funding, some aggressive and unjustified criticism, more debate on the format than on the study, etc. It appeared more important to us to share this precaution advice to the public.

Note that not following the normal procedure is not so exceptional, it happens frequently in scientific research. Scientists do this all the time, in the form of mass meetings, where often also press is present. These are called scientific conferences and thousands of these events are organized every year world‐ wide. There, often research is presented without publication at all or where no peer review or no decent peer review is performed for the conference publications…

Of course, we will have our study peer reviewed, because we wish to publish it in a journal, but that did not seem most urgent to us now, certainly because the study confirms common sense and adhering to the guidelines of the study cannot have harmful consequences.

Question 11: Don’t you think your advice is dangerous, especially given the study is not yet peer reviewed?

This is not a study related to a treatment. There is no risk in following our guidelines. This is not a situation that can be compared to advising people to take certain medicine that has been insufficiently tested and that can have adverse health effects. There are no adverse effects for you to walk, run or cycle in staggered arrangement instead of inline, except… increased air resistance. We believe that in this exceptional situation increased air resistance should be preferred over potential health risks.

Question 12: One could argue that you are not medical experts and that your guidelines cannot be considered as medical guidance.

The first part is not really correct. Thierry Marchal is not only an engineer but also a top medical expert in simulation, formally a eHealth expert to EU authorities, leader of Avicenna Alliance and therefore spokesperson for the discussion with various authorities (https://youtu.be/Sig5Q7rMFfY).

We do not give medical guidance. We report aerodynamic results and suggest guidance in terms of exposure to droplets. We do not draw conclusions in terms of infection risk. This study did trigger an interest from quite some virologists and epidemiologists, which can lead to future collaboration where experts of different disciplines are joining forces.

Question 13: Did you have sufficient past performance to execute this type of study with high quality?

The main investigator, Bert Blocken, has been studying droplets (of micrometer to millimeter sizes) in airflow for more than 20 years, and airflow around cyclists and runners for more than 15 years.

The other lead investigator, Thierry Marchal, has been leading the healthcare activity of a leading simulation company for 14 years and working closely with US and EU authorities for over 5 years, relying on his vast ecosystem to continuously comment on new results and challenge the hypotheses.

Question 14: Should all people that want to exercise outdoors start wearing masks?

That is not unwise if people want to move very closely behind each other. However, there are serious concerns about the shortage of masks and professional masks should primarily be reserved for the healthcare workers. Assuming that masks are not strictly needed when talking at 1.5 m distance, if people follow our aerodynamic recommendations and the updated equivalent social distances when walking/running/cycling in the slipstream, then also in those cases masks would not be strictly needed.

Question 15: Are there other simple rules that people should consider?

When there is substantial cross‐wind, the suggestion to stay out of the slipstream remains valid. This means that it is advised to not walk/run/cycle directly behind others but offset to the upwind side. When overtaking a person, be kind to this person and only when you have reached a certain distance from this person (5 m when this person is walking, 10 m for running, up to 20 m for cycling), move back on the same straight line as this person.

Question 16: How you do react to some media that have given negative feedback on this study?

It is always advisable to challenge any results, question the hypotheses and consult other experts in the field to collect different opinions. We were however surprised by some personal attacks or judgements on the format of the study rather than discussing the content itself or its conclusions. Not contacting the key researchers for further information and constructively challenging them or when seeking a second opinion on this aerodynamics modeling, asking persons that do not have proper aerodynamics expertise, often leads to embarrassing situations and useless polemics.

About the study not being complete: no scientific study is ever complete. There is an infinite number of combinations of runner body geometry, wind speed, wind direction, turbulence, droplet size, relative humidity, etc. We chose to start from the most basic choices: two identical runners, no external wind, typical droplet size from literature, etc. as this situation is not only the most common but could also be a worst case scenario. Evidently further work is needed considering different values for these parameters. We expect that various authorities will be monitoring these future studies once this wave of COVID‐19 is over to better understand these phenomena so that we would be ready for a likely future pandemic.

Question 17: Should people not decide to stop exercising outside?

No. The crisis is very large and mental and physical health are important and walking, running and cycling do contribute to both mental and physical health. Our study is intended to indicate how social distancing should be done in those situations. From the beginning, the World Health Organization WHO and the CDC have recommended to keep a distance of at least 1 m or 2 m, acknowledging that this is not always possible especially in public transportation. We are obviously not these prestigious organizations but we are providing recommendations using reliable results to minimize the risk of contamination acknowledging that they cannot always been followed.


Strong link found between abnormal liver tests and poor COVID-19 outcomes

(© stock.adobe.com)

Researchers at the Yale Liver Center found that patients with COVID-19 presented with abnormal liver tests at much higher rates than suggested by earlier studies. They also discovered that higher levels of liver enzymes — proteins released when the liver is damaged — were associated with poorer outcomes for these patients, including ICU admission, mechanical ventilation, and death.

The study appeared online on July 29 in Hepatology.

Previous studies in China found that approximately 15% of patients with COVID-19 had abnormal liver tests. The Yale study, which looked retrospectively at 1,827 COVID-19 patients who were hospitalized in the Yale New Haven Health system between March and April, found that the incidence of abnormal liver tests was much higher — between 41.6% and 83.4% of patients, depending on the specific test.

In all, the Yale researchers examined five liver tests, looking at factors such as elevations in aspartate aminotransferase (AST) and alanine transaminase (ALT), which indicate liver cell inflammation an increase in bilirubin, which indicates liver dysfunction and increased levels of alkaline phosphatase (ALP), which may indicate inflammation of bile ducts.

Although the researchers do not know why the incidence of abnormal liver tests was so much higher than in previous studies from China, senior author Dr. Joseph Lim, professor of medicine and director of the Yale Viral Hepatitis Program, said other health differences between the Chinese and U.S. populations could account for it.

“ We can speculate that U.S. patients may have an increased rate of other risk factors such as alcoholic or non-alcoholic fatty liver disease,” he said.

In the U.S., close to one-third of people have fatty liver disease, and several million people have chronic hepatitis B or C.

Liver disease is widespread in the U.S. population. Dr. Michael Nathanson, the Gladys Phillips Crofoot Professor of Medicine (digestive diseases), professor of cell biology, director of the Yale Liver Center, and a co-author of the study, said: “In the U.S., close to one-third of people have fatty liver disease, and several million people have chronic hepatitis B or C.”

Because the Yale researchers had access to patients’ health records, they were also able to look at their liver tests prior to being diagnosed with COVID-19. Approximately one-quarter of patients in the study had abnormal liver tests prior to being admitted for the virus. But regardless of whether patients came to the hospital with existing liver problems or developed them during their COVID-19-related hospitalization, a strong association was observed between abnormal liver tests and the severity of the COVID-19 cases, the researchers said.

Rather than the liver itself driving poorer outcomes in COVID-19 patients, the organ is more likely “a bystander” affected by the hyperinflammation associated with COVID-19 and by the side effects of related treatments, Nathanson said.

The study noted a relationship between drugs used to treat severe COVID-19 and liver damage, most significantly the drug tocilizumab.

“ We observed a strong association between the use of COVID-19 medications and abnormal liver tests,” said Lim, but added that they could not confidently tease out that the abnormal tests were due to “drug-induced liver injury” as opposed to the disease.

The researchers have additional clinical and lab-based studies underway to further understand COVID-19’s impact on liver pathology. Nathanson noted that as one of only four National Institutes of Health-sponsored liver centers in the country, the Yale Liver Center is uniquely positioned to advance this research.

Additional Yale researchers involved in the study include lead author and internal medicine resident Dr. Melanie Hundt biostatistician Yanhong Deng, co-director of analytics at the Yale Center for Analytical Sciences and Maria Ciarleglio, associate professor at the Yale School of Public Health.