Thursday, May 28, 2020

COVID-19 and Photography: Part 1, Understanding how the virus spreads

COVID-19 Virus (Image Courtesy of the CDC)In the U.S., COVID-19 has killed more than 100,000 people. It's done it in less than five months. COVID-19 is a serious, highly infectious coronavirus. Photographers, amateurs and professionals alike, need to determine how to safely make photographs in the COVID-19 pandemic world. We need to not only stay safe and healthy ourselves, but ensure, as much as possible, that we don't spread the disease to others while making photographs.

While much about COVID-19 is still unknown, scientists have learned a great deal about how the virus spreads in the last several months. Here's what we know at this time.

COVID-19 transmission is primarily person-to-person.
The Centers for Disease Control and Prevention (CDC) has said for months that the primary way that COVID-19 spreads is person-to-person. It's spread mainly between people who are near to each other, six feet or closer, via respiratory droplets expelled from an infected person when they cough, sneeze, or merely talk. The droplets are inhaled by those nearby, infecting them. The CDC therefore recommends that during the pandemic, everyone “socially distances” by staying six feet or further from those around us.

Two aspects about person-to-person transmission of the virus are particularly important. First, according to public health experts, the COVID-19 virus can be spread by people who are infected, whether or not they're symptomatic. Second, you can be further than six feet from an infected person and still become infected from them, but as you get further away, the likelihood of infection decreases.

Deviations from the “6 foot rule” to social distance.
Scientists are beginning to uncover deviations from the “6 foot rule.” For example, during exercise people expel more air, more forcefully, than people standing, sitting or walking at a leisurely pace. As a result, the respiratory droplets in their breath will be driven further from their mouth than in normal conversation and will be more numerous. According to a simulation study published by scientists at the Eindhoven University of Technology in the Netherlands, it appears likely that the air behind runners and bicyclists could be contaminated over a significant distance. Studies infer that it's likely prudent to stay twelve feet or more from someone exercising while stationary and as far as 30 feet behind a runner or 60 feet behind a bicyclist, in case they are infectious with COVID-19.

COVID-19 infection can occur by touching contaminated surfaces.
COVID-19 infection can occur by touching contaminated surfaces, then touching your nose, mouth, and possibly your eyes. The CDC states,
“It may be possible that a person can get COVID-19 by touching a surface or object that has the virus on it and then touching their own mouth, nose, or possibly their eyes. This is not thought to be the main way the virus spreads, but we are still learning more about this virus.”
Too many interpret that statement to mean that we shouldn't worry about contaminated surfaces. What the CDC is saying is that we need to worry about person-to-person contact more than any other manner of becoming infected. Therefore, we need to “mask up” and wash our hands. In addition, the CDC directs us to “routinely clean and disinfect frequently touched surfaces.”

To understand about potential COVID-19 transmission from various surfaces, such as we find on camera gear, we need to understand how the virus behaves on the materials used to make the gear.

COVID-19 (SARS-CoV-2) studies to determine its viability on surfaces have been completed by scientists from the National Institute of Allergy and Infectious Diseases, Princeton University, UCLA and the CDC. They published their findings in the prestigious New England Journal of Medicine.

They found that COVID-19 was viable on plastic surfaces for up to 72 hours (half-life < 7 hrs.), on stainless steel surfaces for up to 48 hours (half-life < 6 hrs.), on copper for 4 hours (half-life = ~1 hr.), and on cardboard for up to 24 hours (half-life < 4 hrs.).

No studies of the viability of COVID-19 on fabrics are complete, but since the studies on other surfaces show that COVID-19 and SARS are similar, infectious disease experts such as Dr. Amesh A. Adalja of the Johns Hopkins Center for Health Security believe that COVID-19's viability on fabrics is from “several hours to maybe a day.”

Time is a critical COVID-19 infection factor.
Time is a critical factor in COVID-19 transmission and spread. For example, if we come in contact with an infected person for a very short time, such as if they pass us on the street, or if they're behind a checkout counter, we don't have a high likelihood that they will transmit the disease to us. On the other hand, we would have a higher likelihood of becoming infected in a restaurant, regardless of sitting inside or outside, if our server is infected with COVID-19. That's because over the course of 45 minutes to several hours, the server would often be physically close and handling much of what we touch. In a hair salon type setting, with an infected stylist, the likelihood of becoming infected is higher yet. That's because for a half hour to 45 minutes, the stylist works just inches from us most of the time.

Of course, in each case, if the infected person was wearing a mask, and we washed our hands before touching our mouth, nose and eyes, that would reduce the likelihood that we would become infected.

If we touch an COVID-19 contaminated surface within an hour of its contamination, then touch our face, particularly our nose, mouth and eyes, as the virus is most viable at that point, transmission of the virus to us has a reasonable likelihood, particularly with multiple touches. On the other hand, if we touch the contaminated surface hours later, we're less likely to become infected than shortly after its contamination.

That's because COVID-19 degrades exponentially. Scientists found that while COVID-19 can remain viable on surfaces like polycarbonate camera gear cases for up to 72 hours, it initially degrades rapidly soon after contamination, then more slowly degrades until it's no longer viable. The virus half-life is less than 7 hours. So, in less the 10 percent of the time the virus could remain viable, its viability is already cut in half.

Of course, if we refrain from touching our face, particularly our mouth, nose and eyes after coming into contact with a contaminated surface, until we wash our hands as recommended by the CDC, we're unlikely to become infected by the virus.

By taking into account what we know about COVID-19 transmission, we can devise a reasonable and effective strategy to keep us and those around us as safe as possible, while we're photographing the people and scene before us. Next, in Part 2, A strategy to protect photographers and subjects, I'll discuss what safety measures photographers can use for COVID-19 protection.


Herb-San Antonio said...

Wow. This is the most comprehensive guide to COVID transmission I've seen for business people of all types. Waiting for your strategy tomorrow.

Bob-Tempe said...

Thanks for the great guide. I'm looking forward to part 2.

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