COVID-19 Update 8/12: Immunity Training, Ventilation, T-Cells, and More

Dr. Steven Bishop was back on Facebook Live on Wednesday talking COVID-19. He discussed the latest information relating to immunity training from previous vaccines, best practices for ventilation, the roll of T-cells, seasonality, and more. We had a brief technical glitch during this session, so there are two parts, each available via video below. Our complete Q&A recap begins after the videos. 

PART I (30:01)

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PART II (5:42)

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• I saw another report that one possible explanation for the dramatic variation in the severity of the disease in different people could be “immunity training,” driven by prior vaccinations. Do you think that there is any support for that? Is there any value to getting an MMR booster?
  
  Great question. This has come up a few times in our discussions here at PartnerMD. There is a trial being organized around the MMR vaccine to see if it helps, as well as a trial around the BCG vaccine, which is the old tuberculosis vaccine that's been around for a long time. The theory is that people who have those vaccines seem to have pretty broad protection from a number of infections, including viral infections.
  
  So the theory is these vaccines may help with COVID-19. We don't know if that's true yet because the trial hasn't been completed, but it stands to reason that the MMR vaccine might do that for us. I don't think there's any harm in getting an MMR booster if you and your doctor feel that would be beneficial to you.
  
  However, I would not go seek it out very earnestly right now because there isn't a lot of data to support it. But it's a safe vaccine, if you want to do it, there isn't any reason not to do it, especially if you are in your 50s and above and it's been quite a long time since you've had an MMR vaccine. I'd put this in the same category as Vitamin D and Vitamin C supplements. May help. Probably won't hurt. Not enough data to say one way or the other. 
  
  
• What are some best practices for ventilating indoor spaces where people gather for extended periods, for example classrooms? Is there any new research on how coronavirus infection is transmitted — large droplets vs aerosolized small droplets vs spread from touching surfaces, etc.? If so, does this new research suggest any new practices for reducing infection?
  
  I don't think there has been any new research in the past few weeks. But it does seem like the order of risk for transmission of the virus is 1) Droplets from coughing, sneezing, talking, etc. 2) Aerosols, or airborne transmission. 3) Fomites, aka touching things and then touching your face. Those are the three main ones.
  
  Fomites are fairly straightforward to avoid. Keeping things as clean as possible negates much of that. The first two, droplets and aerosols, are a little more difficult.
  
  Droplets, that's what social distancing and masks are about. The further away you are from someone, the less likely you are to get an infectious dose from that person. 
  Aerosols is where we get into ventilation systems. For everyday interactions at church, grocery stores, restaurants, etc., the ventilation systems are important. There are a few principles that are helpful. First, continuing to distance and wear a mask is critical to reduce the burden of the particles in the air.
  
  The second thing is just general space. The bigger the building and the more air per person, so to speak, the better off you are in terms of your risk level relating to aerosol viral particle density. The fewer people you have in the space is also important. If you go to a small building, that isn't well ventilated, and there is a lot of people, that's a much higher risk than going to say, a very large church with just 100 people in it and lots of open air. 
  Mask wearing. Spacing. And finally, we get into optimizing ventilation systems. Make sure there are at least 4-5 air changes per hour. Air changes refers to the number of times a ventilation system completely recycles the air in a given space. We've installed some air filters in some of our rooms where people spend extended time and set the fan speeds so we are getting 4-5 air changes per hour. Use hepa filters, which collect the viral particles.
  
  And then, one more step, and you start to get into diminishing returns with each of these, but the next level is to use some sort of UV light, UV destruction device with the ventilation system will provide a little bit of extra help and protection. 
  And of course, the more things you can do outside instead of inside the better. 
• I have read more about T-cells and their protective role which makes COVID-19 less than "novel" - can you expand on that and how infections seem to drop at a certain point of prevalence which is much lower than initial "herd immunity" expectations? 
  For those unaware, this question relates to the T-cell immunity going around with COVID-19. And this is true of all viruses, but it seems to be more important than we initially thought with coronavirus. In the immune system, there are two main actors. There is the innate immune system, which is a whole branch of the immune system, and natural killer cells and a whole lot of other things that interact with most pathogens and also act to kill cancer cells and other stuff. 
  
  Then there is the acquired, or adaptive, immune system that changes frequently throughout life and becomes very specified for each pathogen you are exposed to. That includes both antibodies and T-cell responses. Antibodies are what we've been talking about for months. They bind up and inhibit the virus. They identify the virus so other cells can come behind and destroy the viral particles.
  
  T-cell dependent immunity is a whole other part of the acquired immune system. This is the part of the immune system that is affected most by HIV. T-cells are infected and destroyed and ultimately depleted, which leads to infections that result in death in HIV and AIDS, so T-cells are very important to the immune system in dealing with pathogens. One of their main roles is to go around and destroy cells that are infected with a virus. They identify, say an airway cell that is infected with virus, and it helps destroy that cell, which prevents further replication and spread of the virus. 
  
  So T-cell immunity is very important. It is just as important as the B-cell immunity that generates antibodies. There seems to be a pretty strong response of T-cells. The reason it hasn't gotten much focus is it is very hard to test for this. It involves very complicated molecular analysis of cells that we can't just do as a routine matter. It's not something we can measure quickly.
  
  So, the question has arisen if T-cell immunity we've acquired from other coronaviruses provides some protection to COVID-19. That's certainly possible. That being said, T-cells are just like antibodies in that they tend to be pretty specific to specific illnesses. There will always be some cross-talk between different things. The coronavirus we're dealing with now is fairly similar to the SARS-COV1 virus from more than 10 years ago, so there is a reasonable expectations that there may be some cross-talk between the receptors that might be around for other coronaviruses.
  
  Not that people have been exposed to SARS in general because most people have not, but other coronaviruses that are out in the community and have caused routine colds and infections in years past. There is a reasonable expectation that there may be some cross-talk between those viruses and this virus in terms of the T-cell response and the B-cell response.
  
  I have not seen a lot of data to validate that theory, but it is a very reasonable theory and could explain why the infections seem to drop-off after a much lower threshold of infected individuals than we might otherwise expect. And it would also explain why the elderly are more at risk because they don't have as robust T-cell and B-cell responses in general and might not have as many memory T-cells and B-cells around that are functional as younger people.
  
  
• Can you speak R. Edgar Hope-Simpson's take on seasonality (with both flu & coronaviruses)? Seems to have validity when comparing the death curves, in particular, seen in the NE (NY & NJ specifically) to the lower/flatter curves seen in the south (Florida, Arizona, California, & Texas).
  
  I looked into this and plan to read a very long article about this, because I had not seen this before. The crux of Dr. Simpson's argument is that its related to Vitamin D levels, which makes quite a lot of sense to me. Vitamin D levels tend to naturally decline into the fall and winter and rise again in the spring and summer. And people who are overweight, have diabetes, or are older tend to have lower Vitamin D levels than younger, healthier people. This would explain, in some regard, it's a reasonable theory, that the seasonality of flu is correlated with the rise and fall of Vitamin D levels. 
  
  That being said, I have not seen any studies using Vitamin D as a sort-of prophylactic treatment to minimize the risk of influenza. We have all been recommending that people get enough Vitamin D, get out in the sun at least 20 minutes per day, take a supplement if needed, exercise, and eat healthy, because Vitamin D is an important regulator of the immune system and of the inflammatory cascade in the body. 
  
  So, again, this is a reasonable theory that makes a lot of sense to me and also makes some biological sense based on what we know about the absence of Vitamin D. 
  
  
• War Room Pandemic (Episodes 323 and 324) focused on hydroxychloroquine. Did you see them and do you have any comment. Is it banned in Virginia?
  
  I don't typically watch the War Room Pandemic and hadn't seen it prior to today. I was able to watch episode 323, but could not find 324 on their website. What they talked about was a lot of the stuff we've talked about already over the last several weeks, discussing that not all the information about hydroxychloroquine is getting out into the public the way it should and that we need more trials to be done in a transparent and appropriate way so we can get a better sense of what is going on with hydroxychloroquine. 
  
  I don't think there is any attempt to ban hydroxychloroquine in Virginia for any reason. There was a note sent out to pharmacists asking them to make sure any prescriptions they fill for hydroxychloroquine have a diagnosis consistent with its use and to prioritize people who need it for proven indications, rheumatoid arthritis and things like that, which is fine to do and we should prioritize it for people who need it for many other reasons other than COVID.
  
  I don't think it's important to ban a drug from being prescribed that is generally prescribed by physicians for many purposes. We prescribe off-label things all the time. We always have. We probably will continue to do so. Hydroxychloroquine is not unique in that sense. There are many, many, many drugs that are prescribed off-label for all sorts of things all the time.
  
  Any decision made about a prescription for that should be between the physician and the patient. If it's an approved drug that's on the market and proven to be safe, then the physician should be allowed to prescribe it for whatever indication they feel is appropriate.
  
  That being said, physicians do have a responsibility to not prescribe things in a willy nilly fashion. They do need to look at the evidence. They do need to be cautious. They do need to be thoughtful about the way they prescribe things, especially when they are prescribing things off-label, because the evidence is not as sound.
   
• New Zealand had 4 people in one family test positive after over 100 days with no cases - family had not traveled cause unknown. Hypothesis? Does this suggest we will never be rid of it?
  
  My hypothesis is that they contracted it from someone who had an asymptomatic infection and therefore an infection that was not picked up by testing and had circulated in the community without anyone knowing.
  
  And yes, this goes along with the fact that I don't think the virus is going away, potentially ever. It may be with us for a very, very long time, even if we get an effective vaccine. I don't think the virus will go away. I think it will continue to circulate much like influenza. I wish that weren't the case, but I think that is probably going to be true. I think that's been the case since March when it escaped into the general population. There really is no way to eradicate the virus completely from the population at this point. 
  
  
• For those of us that are healthy but in the at-risk age category, what are some wellness suggestions to improve our immune systems?
  
  Here is a link to an infographic I put together about maximizing your resilience to COVID-19 and trying to help you, if you should acquire the infection, minimize your risk of doing poorly. It really is all about lifestyle, diet, and exercise, and trying to minimize your risk factors related to those things. 
  
  
• Would spraying/misting the cloth masks with or without inserts using 80%+ IPA be more effective then machine washing? The “3MD” masks have a permanent felt insert which seems ideal for alcohol decontamination.
  
  Cloth items could certainly be sprayed with a decontaminating solution. The thing I would worry about with that is degrading the fabric over time. A lot of high-dose alcohol sprays can sometimes damage the fabrics. Anything that can be washed, you're probably better off washing in hot water rather than spraying it with something. If there is a removable insert, such as hard plastic, where it's not meant to go in the wash, then I would spray that with a decontaminating solution.
• Is there research that shows full face shields offer more protection from COVID-19?
  
  Below are two resources from an old mentor of mine, Dr. Edmond, who used to be an epidemiologist at VCU and now works at the University of Iowa. He has been a proponent for face shields since April and May. It started out of a concern for the supply chain for masks.
  
  Based on the data I've seen and he's presented, I am willing to say that face shields are at least as effective as masks and perhaps more effective for certain reasons and in certain situations.
  
  If you have people who can't wear face masks for one reason or another, which is true for a lot of people. Some people have claustrophobia. Some people have anxiety issues. We've been talking a lot about kids getting back into school. A lot of special needs children and those with disabilities cannot wear masks. Face shields make a lot of sense there. 
  
  The data indicates face shields reduce the droplet transmission significantly, around 96% compared to no face shield at all. They do work. And they are non-porous, unlike cloth masks, where some particles do escape. It is true that particles escape under the shield, on the sides of the shield, and to the back to some degree, but it's still very good at mitigating the forward exposure of the particles. Especially if two people who are near each other both have face shields, it helps quite a lot. 
  
  The other nice thing is shields can be cleaned. It's actually easier to clean them than face masks. The other thing that is helpful is they reduce the risk of the auto-inoculation problem. If you have a big face shield, and when I've worn mine, you forget it's there because it's transparent and not directly on your face. But if you go up to touch your face, you hit it before you touch your face, so it reduces the risk of touching your face and infecting yourself that way. 
  
  
• Any thoughts on the anti-viral nasal spray (AeroNabs) being developed by UCSF?
  
  Nasal sprays do make sense theoretically, because the primary infection site of the virus is the naval cavity. So, it makes a lot of sense to try and fight the virus there first. There's a thought, and I've seen this since March, that most of the pneumonias caused by COVID are related to the transit of the virus from the nasal cavity down to the lung, and then a resulting inflammatory reaction related to that.
  
  It makes a lot of sense, but we will not really know for sure if that is the mechanism of the pneumonia for some time, but it makes theoretical sense. It jives with the people who are most at-risk for the pneumonias, like the elderly, people with obesity, people with breathing disorders. They are more likely to aspirate things, meaning take in secretions and fluids from the nasal fairings down into the lungs. If you are routinely aspirating COVID from the nasal fairings down to the lungs, it stands to reason that that might be a mechanism for the pneumonia. 
  
  So these nasal sprays would be targeting anti-viral treatment at the nasal fairings. I haven't seen what's in the anti-virals for these nasal sprays or how exactly they are working, but I'll look forward to seeing hopefully some positive data on that in the coming weeks. 
  
  
• Since you are talking about nasal transmission, do allergies and chronic sinus issues increase your risk?
  
  That's a good question. I do not know the answer to that. It does stand to reason that might be an issue, because it involves some inflammation of the sinus cavity and such.
• Did you see dashboard presented at CCPS board meeting yesterday? What did you think of the metrics and levels needed to get kids back to school? Will we meet these metrics anytime soon?
  
  I made some comments to to the school board about this. I think the metrics are not wholly unreasonable in terms of what they have chosen. That being said, I think using the percent positivity metric does not make sense based on what we've learned from the Department of Health and the Chesterfield Health District, because the percent positivity does not really reflect the community prevalence of the virus. It's more of a test of whether there is enough testing capacity.
  
  I can envision a scenario when we have a lot fewer people seeking testing, because the case counts have dropped and the virus isn't spreading as much, but that means that those who are still seeking testing are actually more likely to have the virus because they are ill and looking for tests. There is a possible scenario where the case count drops down into what they are calling the green, but then the positivity rate goes up to the red, so it creates a conundrum of what to do in that scenario. 
  
  And my general concern is that we may never get to green on case count, especially if we don't get an extremely effective vaccine that is rapidly taken up by the population. I think that is a concern, and they need to think out a little further than just the next couple months. 
• Looking for some City of Richmond specific COVID-19 daily data updates. Would like to see "increase" numbers and not only totals. Any references? Also Henrico County. Same question.