To avoid sickness we're all taught to wash our hands, cover our mouths when we cough or sneeze, and avoid touching our face. However, for most of my life I viewed the prospect of getting sick as a binary state: either I caught something or I didn't. As I got older I considered that I might get less sick if I reduce my exposure to infected fluids, even if I couldn't avoid getting sick entirely. I read about attenuated vaccines that contained live viruses but didn't make their recipients sick (usually). As I investigated further, I finally came across a description of viral load and the puzzle pieces fell into place. Why hadn't anyone told me about this concept as a kid? Maybe most people don't know that infections aren't binary! So what is viral load?
Viral load, also known as viral burden, viral titre or viral titer, is a measure of the severity of an active viral infection, and can be calculated by estimating the live amount of virus in an involved body fluid.
Basically, it's how many copies of a virus you've got in your body: your infection (and immune response) is worse if you've got more of the virus. Your kid gives you a lot of virus copies when she sneezes into your open eyes, and you're likely to get sick more severely and more quickly. This is significant especially as a parent because it's impossible to avoid contamination from a sick kid completely, but you can reduce the severity of your eventual sickness if you work to minimize your viral load.
Viral load is also an important factor when it comes to Ebola infections:
The relatively swift recoveries of Vinson and Pham might also be attributed to their personal protective equipment (PPE) they were wearing when they treated Duncan.
While some nurses at the Texas hospital reportedly complained about PPE that left their necks exposed, at least Vinson was suited up.
"She was wearing personal protective equipment during the care of her patient in Dallas, and therefore it is quite likely that the amount of virus she was exposed to was substantially less than what we see in patients who get infected in less developed countries," Ribner said.
"And we also know that the higher the viral load that you get infected with, the more severe your disease is likely to be."
"Infection" is a continuum. Even when you can't avoid exposure entirely, you can minimize the severity of your illness by minimizing your viral load.