Saturday, April 25, 2020

Pandemic 2020: COVID-19 Questions From My Tweeps: Part I

Hey Guys! Nice to see you again. I asked my Twitter followers for their questions on COVID-19 and got a lot of great responses. You guys are the best. This post is part one in addressing your questions.

@LaurenWhitticom asked:
Is it for sure going to become endemic?
          I think it will become endemic. There's no reason to think it will go away. Other coronaviruses that have found their way into humans have become endemic so I see no reason to think this will be different. If we want it gone, we would need a concerted eradication effort in every region. With such a powerful antivax movement in the US that's not going to happen anytime soon.

@MerryMary48 asked:
This is probably basic, but is there going to be a % of people who are just immune to this virus, without having had it?
          Not basic at all. It's a good question. And while we do not have data on this, I am confident in saying, not that there will be those who are naturally immune but that there will be those who are less susceptible to this virus than the general population. By this I mean that through as of yet unknown genetic mutations, there are likely people who can't be infected by this virus as easily. Maybe these are people with more cilia in their airways, or more robust cilia. Maybe someone has less ACE2 on the surface of their lung cells than the rest of us. There could be any number of places along the infection and disease development pathway where a mutation could confer the ability to more easily fight off this virus. I expect there are people like this in the world. Perhaps not many, but some. 

@mtw_ams asked:
I live on the ground floor with windows only to the street side with people passing by. Can the breath they exhale with virus infect me in my home?
          Considering the disparity of information being passed around, and the confusion regarding airborne vs droplets, I understand this is a concern for many people. Let me first say, the risk for you in the situation you describe is extremely low. I would feel comfortable leaving my windows open. Here's why. 
          In order to be infected not only does the virus have to survive in the air long enough under the conditions in the atmosphere to get through your open window from the sidewalk as someone passes by (sunlight, humidity, air currents), there must be enough surviving and infectious virus in the 'breath' that reaches you to actually initiate an infection. A person would have to really hack a huge cloud of virus, and that cloud would have to go immediately in through your window and into your nose/mouth to infect you. If someone is walking by that's unlikely. If someone is standing on the sidewalk facing your window as they cough, it's still unlikely. Distance is really your friend here, as are the air currents and ambient conditions. Unless we do a study outside your apartment to mimic someone coughing aerosols as they walk by, we can't say with 100% certainty that it will not happen, but it's highly unlikely to pose a real risk to you. 
          I would feel comfortable leaving my window open, but you may not and that's okay. Maybe you could put a fan by your window that's facing the sidewalk, so some air gets blown back out or a current is generated reducing the amount of outside air coming inside. Alternatively, you could put a sign next to the sidewalk that says something like - COVID patients inside, must leave window open, please cross sidewalk before passing. That should keep people away from your windows. 😏

@KenVaughanSoc asked:
How is touching my face unsafe, but putting food prepared by others in my mouth isn’t?
          Touching your face with contaminated hands can expose the parts of your face most susceptible to virus you've picked up from contaminated surfaces - doorknob, gas pump, elevator button - by touching your nose or mouth leading to exposure in the lungs. For that to be a risk, someone infectious had to contaminate the surface you touched. When you eat food prepared by someone else, the risk of that is lower. People prepping food should be wearing masks, which will protect the food from contamination, if that person is infected, which they likely are not if they are prepping food. In addition, food being chewed then swallowed is forcing particles in your mouth into your stomach and away from your lungs. This reduces the potential for virus to make it to your lungs in the rare instance it might be on your food. In your stomach this virus can't survive the acid. Before you eat your food, you will have touched the packaging. To be on the safe side, wash your hands before you eat. If you'd like more assurance, ask the business if those prepping and packaging food are wearing masks, if any of their employees are being forced to work while unwell, or if anyone employed there has been sick with COVID-19. 

What is the consensus on face masks and why was there so much debate amongst scientists early on regarding their use for the general public?
          Ah, face masks. A confusing and never-ending battle. Initially, scientists, including myself, were trying to convey how dangerous it was for an untrained person to wear a respirator that was not fit-tested. For example one they bought online. This is because we knew it would give people a false sense of security. Not only would the mask not truly protect you from exposure to someone coughing near you, but taking off a contaminated mask is a common source of infection for people who are not trained to do so. We were also trying to convey the difference between surgical masks (and folded t-shirts and bandanas) and N95 respirators. Surgical masks are designed to protect people from the wearer. N95s are designed to protect the wearer. So while some people, mostly non-scientists, were yelling at people to wear masks, we were trying to convey the differences between the masks, the differences between when they are needed and how they really would and would not protect you. Here is an image that really illustrates what's happening with masks. I saw it on Twitter shared by Don Jazzy don't know if that's the original source.
          We have reached the point where public health leaders are recommending face masks for everyone going out in public. This is because, in places that did not get ahead of the epidemic through testing and contact tracing early, we have no idea who is sick and infectious. It's important to understand that this recommendation is still to protect people people from the wearer, not to protect the wearer. But the bonus here is that if everyone wears a mask then no one has to understand anything. I'm protecting you from me and you're protecting me from you. Who cares if someone thinks it's the other way around if we're both being protected.
          But don't forget that touching the mask can contaminate your hands, or your chin if it's been contaminated. So drop it straight into the trash or washer, wash your hands immediately, and use a new/clean one the next time you go out.

@The_Twenty_Two asked:
How much are you worried about surface to human transfer?
          Contaminated surfaces, called fomites, are a definite risk with SARS-CoV-2. A research letter documenting apparent fomite transmission in China, I think did a great job evaluating this risk while still recognizing the limits of their work. A more recent and well executed, rigorous study indicates the virus can remain alive and able to infect longer than we would have expected under their conditions. However, every time someone touches a contaminated surface, they wipe some virus off, so the last person to touch that surface won't get as much virus on their hand as the first person. This is why washing hands has been urged from the beginning. It's also why gloves aren't necessarily better than hand washing. I see people in stores wearing gloves and touching everything, as though wearing gloves means they no longer have to be careful. If they get virus on their gloves, they then transfer it to their credit card or wallet or mask, or head or even face. I don't wear gloves at the grocery store just like I never wore gloves when SCUBA diving. Gloves make you feel like you can touch anything. While diving that damages the living things you feel compelled to touch, during a pandemic it increases your risk of infection. Touch only what you absolutely must touch and force yourself to think about not touching anything else, like your face. As soon as possible disinfect/wash your hands thoroughly.
          As for things like packages left at your door, food delivery bags/boxes or grocery bags. If those are prepared by people without symptoms then there is very little risk. Use the same caution: handle the items only as much as needed and discard. Then wash hands thoroughly with soap and water.

@goatbroken asked:
I heard a rumor that the flu shots might interfere with the body's ability to fight other corona viruses... is this credible?
          I have not come across anything credible supporting this. The paper you asked about, "Influenza vaccination and respiratory virus interference among Department of Defense personnel during the 2017–2018 influenza season" by Greg G. Wolff, does not provide evidence for that theory. Some studies describe the phenomen of vaccine-associated virus interference: that vaccinated people may have increased risk for other respiratory viruses. Their logic is that it's because vaccinated people do not get the non-specific immunity associated with natural respiratory infections. 
          There is contradictory evidence regarding this idea in general, and contradictory evidence that the influenza vaccine is associated with it. I haven't seen anything that convinces me that this happens. In the linked paper, the study was rigorous: it's the "first virus interference study conducted among highly vaccinated DoD personnel. The study included a diverse, well dispersed population based on sex, age group, beneficiary category, and vaccination status." the results "showed little to no evidence supporting the association of virus interference and influenza vaccination." In fact they showed that "those receiving the influenza vaccine were more likely to have no pathogen detected and reduced risk of influenza when compared to unvaccinated individuals." This further supports my opinion.
          On a related note, a really interesting study on influenza vaccination came out last year by a group at UT Austin. This was a study on the persistence of antibodies from influenza vaccines over time. They found that the antibodies generated by the yearly vaccine are relatively short-lived and that once they are gone, the remaining antibodies are a group that has persisted over time - a group of antibodies against the parts of the influenza virus that are not usually mutated. So in addition to the antibodies we have from the vaccine, we also carry antibodies we've had for years against various parts of the virus. Previous exposure and vaccination thus work synergistically with the yearly vaccination to protect us. The coolest part of this is that it provides insight into potential vaccination strategies previously thought not worth pursuing.

That's it for Part I. I hope it's been helpful so far. If something wasn't clear enough please let me know so I can improve my answer for you. If your question isn't here, it will be posted ASAP. Thank you for your patience! And thank you for the questions. No doubt they will be helpful for many others.

Stay home and wash your hands,


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