Viruses (like COVID): degree of exposure correlates with degree of severity

We have all heard about factors that can contribute to a bad, even deadly, experience with COVID-19. Factors such as age, gender, and underlying conditions.

But the article linked below, from the NPR website, notes that there is something else going on that can also be an important factor in coming to have a bad experience with COVID-19. Or actually any viral illness for that matter. It involves something called "viral load."

For my part, I had always assumed that when it comes to being exposed to and infected by illness-causing viruses, such as by breathing them in, the number of viruses inhaled didn't matter, as taking in even a small number of them would be sufficient to start the disease-causing process.

But according to the article below this is not true, and the larger the "viral load" of germs taken in during an exposure, the greater the chance of contracting a serious episode of the illness.

From the article:

"Does the size of a viral dose make a difference? That is, if you're exposed to lots of viral particles, will you get sicker? While there is a lot we don't know about SARS-CoV-2, experts believe they can answer this question with confidence: Yes – the amount of virus a person is exposed to makes a difference in whether they get sick and how sick they get."

"Every virus, if you get one particle of virus, you're likely to never know it – you're also likely to really never get sick and never develop an immune response. And for most acute viruses, there is a gray area where you get some version of sick but not horribly sick — and develop an immune response that is protective against the virus in the future."

"If you have someone working in an intensive care unit and the poor physician or the poor nurse gets a hefty dose, then the severity of the disease really is much worse than if one just gets a single particle."

Well, I didn't know that.

And the obvious implication from all this is that minimizing intake of massive quantities of viruses helps to increase one's odds of avoiding a bad case of disease.

Hence, avoidance measures such as wearing masks ("dose-reducing agents," the article calls them), hand-washing, and staying clear of areas with likely high virus-per-unit-area counts will pay off.

Apparently, then, if our bodies are exposed to just a handful of even serious viruses, our immune systems can fight them off. But if it's a massive number, it seems to be as if our systems get overwhelmed by the sheer number of them, and disease follows.

Interesting.

https://www.npr.org/sections/goatsandsoda/2020/04/24/844325330/coronavirus-faqs-does-a-bigger-dose-make-you-sicker-can-you-go-to-the-dentist

I believe this is true and may explain why some have no symptoms and others die awful deaths. If the viral load is low, than our immune function can handle it but if high is overwhelmed and all hell breaks lose. I do not know why many are fighting the recommendation to wear masks. However if everyone did, I think it would make a very large difference in reducing the exposure to the virus. As said, masks do not eliminate all viruses from reaching the respiratory tract but can impact the total number viral particles that infect us.

Paul

The amount of viral load makes sense to my non-medical brain. Might also explain anecdotal incidents of youngish health care workers dying that I've read.

As to the masks, aren't they the way that we're going to end this shutdown? I don't like wearing one, but if wearing a mask is the price we pay for ending the lockdown, that's a very small price to pay.

I have read several such reports regarding the number of viral particles in a given amount of time that it takes to get infected to the point of significant symptoms. Think of it like we do radiation exposure....a small amount over a long period of time is easily dispensed by our body’s mechanism. A very large amount all at once will be overwhelming.

Also many reports show that fomite transmission is rather difficult and insignificant compared to the particles in a sneeze, cough or spittle when talking or singing. More than half the transmissions are within a family unit. Most of the rest are between people in very close quarters like nursing homes, crowded subways, church choirs early in the cycle, and crowded workplaces. The transmission requires time, expression of the disease and proximity. One doctor I heard gave the 6/10 rule. Stay more than six feet away and spend less than 10 minutes together at a time. That is his definition of social distancing and it makes sense. He says passing quickly by someone in the aisle of a big box store is not a significant risk factor

Addendum. On this morning’s Dr. Radio Covid Update Show on SiriusXM from NYU-Langone, one of the virulogists stated that it takes at least 1,000 viral particles together to successfully enter cells to begin the infection. He did not say what that meant in terms of what may be contained in a cough or sneeze or breath. But he reiterated that transmission is not casual, that there needs to be significant time and proximity for enough virus to be transmitted and successfully infect to the point of significant symptoms.

Can anyone offer good links to data on hat is and what is not a big risk in getting infected? So much info AND MISinformation out here it’s sometimes hard to know what to believe.

All of this points to what I'm calling the reopening dilemma. I've heard it put this way: it's easy to shut down, close the doors. It's really, really hard to reopen. I've been in a number of zoom meetings over the last couple of weeks wrestling with the question, "How do we reopen a church?". Facts: we have a significant number of elderly members. We have a number of fairly constricted public spaces within the building. How do we do many of the things we've always done safely? Everything from having a 'coffee hour' after worship to safely seating everyone who shows up? Do we say that we'll only allow a certain number of people into the building--and send everyone else who shows up home? And on and on.

There are no good answers. The fact is, any gathering of random people is going to be difficult to manage for a long time--whether it's a restaurant, a shop on the boardwalk, a church/synagogue/mosque/temple, a hair salon, or anything similar. Those spaces were built for a purpose and designed to accomplish that purpose. To change the basic premise of how that purpose is accomplished requires a total rethinking of how it is designed to be used.

JNF said...
Ken, this one I find helpful, I just don’t know how to activate the link

https://www.erinbromage.com/post/the-risks-know-them-avoid-them

Scientific and he provides links to his professional and educational bona fides.

Edited to activate link.

Thanks Jack. I’ve seen this one but forgot about it. It’s worth re-reading which I will do.