The Risks - Know Them - Avoid Them
 

https://erinbromage.wixsite.com/covi...hem-avoid-them

Where are people getting sick?

We know most people get infected in their own home. A household member contracts the virus in the community and brings it into the house where sustained contact between household members leads to infection.

But where are people contracting the infection in the community? I regularly hear people worrying about grocery stores, bike rides, inconsiderate runners who are not wearing masks.... are these places of concern? Well, not really. Let me explain.

In order to get infected you need to get exposed to an infectious dose of the virus; the estimate is that you need about ~1000 SARS-CoV2 viral particles for an infection to take hold, but this still needs to be determined experimentally. That could be 1000 viral particles you receive in one breath or from one eye-rub, or 100 viral particles inhaled with each breath over 10 breaths, or 10 viral particles with 100 breaths. Each of these situations can lead to an infection.

Remember the formulae: Successful Infection = Exposure to Virus x Time

...

Commonality of outbreaks

The reason to highlight these different outbreaks is to show you the commonality of outbreaks of COVID-19. All these infection events were indoors, with people closely-spaced, with lots of talking, singing, or yelling. The main sources for infection are home, workplace, public transport, social gatherings, and restaurants. This accounts for 90% of all transmission events. In contrast, infections while shopping appear to be responsible for 3-5% of infections.

Importantly, of the countries performing contact tracing properly, only a single outbreak has been reported from an outdoor environment (less than 0.3% of traced infections).

So back to the original thought of my post.

Indoor spaces, with limited air exchange or recycled air and lots of people, are concerning from a transmission standpoint. We know that 60 people in a volleyball court-sized room (choir) results in massive infections. Same situation with the restaurant and the call center. Social distancing guidelines don't hold in indoor spaces where you spend a lot of time, as people on the opposite side of the room were infected.

The principle is viral exposure over an extended period of time. In all these cases, people were exposed to the virus in the air for a prolonged period (hours). Even if they were 50 feet away (choir or call center), even a low dose of the virus in the air reaching them, over a sustained period, was enough to cause infection and in some cases, death.

Social distancing rules are really to protect you with brief exposures or outdoor exposures. In these situations there is not enough time to achieve the infectious viral load when you are standing 6 feet apart or where wind and the infinite outdoor space for viral dilution reduces viral load. The effects of sunlight, heat, and humidity on viral survival, all serve to minimize the risk to everyone when outside.

When assessing the risk of infection (via respiration) at the grocery store or mall, you need to consider the volume of the air space (very large), the number of people (restricted), how long people are spending in the store (workers - all day; customers - an hour). Taken together, for a person shopping: the low density, high air volume of the store, along with the restricted time you spend in the store, means that the opportunity to receive an infectious dose is low. But, for the store worker, the extended time they spend in the store provides a greater opportunity to receive the infectious dose and therefore the job becomes more risky.

Basically, as the work closures are loosened, and we start to venture out more, possibly even resuming in-office activities, you need to look at your environment and make judgments. How many people are here, how much airflow is there around me, and how long will I be in this environment. If you are in an open floorplan office, you really need critically assess the risk (volume, people, and airflow). If you are in a job that requires face-to-face talking or even worse, yelling, you need to assess the risk.

If you are sitting in a well ventilated space, with few people, the risk is low.

If I am outside, and I walk past someone, remember it is “dose and time” needed for infection. You would have to be in their airstream for 5+ minutes for a chance of infection. While joggers may be releasing more virus due to deep breathing, remember the exposure time is also less due to their speed.

While I have focused on respiratory exposure here, please don't forget surfaces. Those infected respiratory droplets land somewhere. Wash your hands often and stop touching your face!

Addressing the opening sentence above........as measured and concluded by.........???

Excellent post. Just to add to it, your synopsis gives you a clearer understanding of why so many healthcare workers that contract Covid19 end up with a terrible case or worse yet, die. Their viral load is huge because they work 12-16 hour shifts with constant exposure, with or without all of their PPEs.

Yes, very key observation, severity seems linked to total viral load as discussed by the author here:

https://erinbromage.wixsite.com/covi...ere-we-are-now

Makes me wonder if the asymptomatic people are those who encountered a viral load too small to infect them?

Also clear to me it's essential to establish a minimum air exchange rate for closed interior spaces such as Rec Centers, restaurants, theaters, etc. OSHA has minimum air exchange guidelines for "sick building syndrome" that would be a good place to start.

Read the article, links and related posts by the author...

Is the viral load cumulative? You go to the grocery store, get some of the virus on you. You then go for a walk, someone rides their bike close to you, you get some more viral load etc etc. How long is the virus active on your body? You may have many exposures to small amounts at a time.

Excellent-Thanks for the article too.
 

I hope all read your information and link. Knowledge is power.

The Risks - Know Them - Avoid Them

Thank you for sharing this.

That is the difficulty right there. We don't have many conclusive facts at all. AND we don't know where to get facts we can trust.

We are still reading new symptoms very POSSIBLY linked to Covid-19 like Kawasaki Syndrome, but only half of the children affected in NYC tested positive for the virus.

We have some entities that are trustworthy, like the website from Johns Hopkins Hospital in Baltimore that has been Newsweeks number one hospital. Or was that Time? And wasn't Time the one who...…………….

We had the statistics from the State Board of Health here in Florida but now the full reporting of whether they traveled and their age and specific area has been ordered changed by Governor DeSantis. I am not sure why. I am not even sure it happened but I did read it in The Tampa Bay Times. But was it political?

I am so sad for the spouses and friends of people who died. Are they afraid to share the information with their neighbors for fear of being treated like a carrier?

I read that we can't be sure of WHY people died and that the hospitals are labeling deaths on Covid-19 that are NOT deaths from Covid-19 and I have never known of hospitals ever mislabeling the cause of death before and WHY would they do that? To get money from relief programs? Everyone has a valid reason (to them) for everything.

Did this bug escape from a lab that was manufacturing it to get back at Trump for the trade embargo? I read that there is evidence of a mutation occurring naturally. But even scientists get their advice wrong sometimes. We have heard conflicting advice from those in control about what to do to avoid getting sick. Then we have read it is patriotic to not follow that advice, that the government is trying to control us.

Then we are told by good decent people, caring people, law abiding people who have never been arrested, always paid their bills, led by calm example, that if we had enough faith in God we would not worry.

But we do worry. We worry about our families, our own life, and the lives of the older friends who we cherish, even though some of them now think we are bat **** crazy.

We worry about the harm to the economy that is going to get worse before it gets better....but when will it get worse? When will it get better?

Oh billethekid. You are right...……..MEASURED and CONCLUDED by who?

A study done in NY
 

This was mentioned by Cuomo during one of his briefings and was a study done in NY on recent infections. Also reiterated on Colbert That evening if you want to go back and find On Demand. They believed Personal factors like washing hands, masks and distancing were the reason, but I have to think population density and higher people count per household had to be a factor too.

Some of the “ I found a doctor on the internet” posts have been garbage conspiracy theories to try to set a “ we made a huge mistake isolating” tone.

I think this one has something to say.

Thank you! This was very helpful!

I see he has a PhD in biology but has no references in his post that refer to actual covid-19 data. He refers to one that is about influenza. Which CDC or Infectious Disease experts have said that the correlation he is making is sound. Even he says these are his “musings.” While he may make some interesting points to ponder, I do not think this is a definitive source regarding covid-19 without the aforementioned experts backing it up.

Great article, thanks. Makes me feel much better about outdoor swimming pools and much worse about indoor activities. I’ll focus on outdoor activities and forgo indoor activities until better treatment drugs are found. Hope the powers to be around here recognize the higher risk with indoor activities too. So far, the powers to be in the villages have done a great job removing dangerous conditions and have not relied on good judgement by villagers. I feel Fortunate to be here!

all good but remember everyone needs to wear a mask . Please don't be the selfish idiot who thinks masks aren't needed.

I go to Publix two or three times a week. I see the same people who work there each time. If the indoors is such a virus haven, how is it that they are still there working and not dying from this pandemic. I think that as infectious as it is, it's really overblown.

Thanks and I agree.

The situation is what it is.

The best we can do is try to learn and understand to mitigate risks as much as possible for the lifestyle we choose to live.

Excellent Robbie! Must read for everybody. Really the first practical article I've read on managing risks.

good information to have...helps to make some sense out of all that is happening....thanks for sharing

until there is a proven vaccine we're not interested in public indoor activities

1721 deaths from this virus in Florida.
Population: 12.48 Million
Stop the fear🇺🇲🌞

Because we are required to take greater precautions. Regular hand-sanitizing, hand-washing, currently we're required to wear masks inside and out if we're on the clock. Our breakroom chairs have been spaced 5 feet apart (that's the best we can do and still have 3 people sitting down). We have shields between the customer and the cashier to prevent droplets from crossing in either direction.

Cart cleaners wear gloves and have their hands (with gloves) CONSTANTLY exposed to industrial strength surface sanitizer, so even if they have to touch their masks to adjust them, it's more likely that they're actually sanitizing their masks in the process rather than infecting them.

Most of us are taking more precautions at the workplace, than most of you do when you come to the supermarket or do anything else for that matter.

That's why most of us aren't sick.

I suspect places that smell clean and fresh are safer than those that do not. Perhaps a question to ask for indoor facities is how many air exchanges per hour are provided.

CDC has guidelines for air in medical facilities shows at least 6 times per hour so that may be a good place to start.

Air | Appendix | Environmental Guidelines | Guidelines Library | Infection Control | CDC

The author agrees.

About the Author - Professor Erin Bromage

"I am not holding myself out as an expert on this virus or epidemiology and I rely on the amazing scientists publishing and discussing their work for the material and data content of my posts. These scientists are the true rock-stars of the response to COVID-19. I just enjoy being able to translate their data and findings into prose that non-scientist lay people can more readily understand as we navigate through this pandemic.
"

Funny! Seems in villages the only way you catch the virus is playing pickleball or tennis 🎾. :popcorn:

Well, if you have an idea to mitigate the risk of a non-symptomatic person multiple times in a game contaminating a ball, the receiver(s) then touching the ball and then their face hence becoming infected, I'm all ears.

I'd love to start playing paddle sports but the risk of contact infection is real.

I was wondering what his source is too.

Most of the world data and experiences would contradict that. If it is overblown there would most likely be a lot of smart people changing the way we are reacting. Seems the smart people are in the other camp.

And where the proof

And softball... 😟

We can take a bag of pickleballs to a local COVID infected correction facility and then and then drop them off for you to test?

They don't play pickleball.