One last story for @nytimes : a dive into the amazing field of virus physics.
Virology isn't just a life scientist's game. To truly understand viruses, we need to understand how they build themselves — then learn to tear them apart. 1/
Virology isn't just about proteins and genes. It's about forces. It's about chaos and order. It's about the improbability of teeny, tiny structures coming together in ways we can't explain. It's incredible. 2/
I am so grateful to @AlxndriaTH3Gr8 for introducing me to this world and walking me through it. Also to Vinny Manoharan, Juan Perilla, Jodi Hadden-Perilla, Bill Gelbart, Adam Zlotnick, Jasmine Cubuk, @royalzandi@BustamanteLab for sharing their work. 3/
And one more big thank you to my editor @alanburdick for helping this piece come together, along with so many others. 4/4
It's 2021! Time for a crash course in four terms that I often see mixed up when people talk about testing: sensitivity, specificity, positive predictive value, negative predictive value.
These terms help us talk about how accurate a test is, but from different viewpoints. 1/
Viewpoint 1 is about the status of the person taking the test. Are they infected, or not infected? How good is the test at identifying these people? That's sensitivity/specificity. 2/
A test that is very *sensitive* will be very good at accurately identifying people who are infected.
A test that is very *specific* will be very good at accurately ruling out infection in people who are not infected. 3/
Spouse got his first dose of Moderna's vaccine today! His arm's sore and he's a bit tired and not feeling 100%, but that's not a worry at all — it's evidence that his immune system is already hard at work. 1/
Protection takes energy and effort and I'm proud to say his body is rising to the challenge.
He got the vaccine this morning, so right now we can expect that his cells are starting to churn out some spike protein. Spike is not infectious and it can't cause Covid. 2/
But those proteins will teach a cadre of immune cells to recognize one of the coronavirus's most salient features. That way, if the real virus comes around, his body will recognize it and marshal forces to keep him from getting sick.
Tests don't stop when you get your result. Think about the circumstances under which you took that test — they could really influence how you interpret what that test tells you. 1/
For starters: Positive and negative can be useful words, but we should be careful not to overinterpret them. Think instead about "detected" and "not detected." We're describing what a test has found — not a permanent identifier that says anything about who you are as a person. 2/
A "negative" result could be outdated within hours, either because the virus has built up to detectable levels, or because you were exposed anew.
"Positive" in the context of disease can also sound incriminating. 3/
The world has never asked this much of clin micro and public health lab workers.
Tests are not just pushed buttons and sloshing liquids. They make fingers ache. They make eyes water. They require sprinting back and forth, and perfect pipetting precision. 2/
We do not often look inside these labs. And for decades, that's been okay. “We’re accustomed to holding things up in the background," one scientist told me. "We enjoy doing it because we know we’re helping people.” 3/
In the leadup to the holidays, maybe we can start talking about our coronavirus tests in a slightly different way.
If you do not test positive for the coronavirus, consider that is more about the virus being "not detected," rather than you being "negative" for the virus. 1/
Because maybe the virus is there — but it's not yet present at high enough levels to be found on a test. You could still be infected. You could still be contagious. You could test again tomorrow and be positive; you could test again in five hours and be positive. 2/
Or perhaps you're not infected yet. A test is a snapshot in time; it says nothing about your status in the future. Every trip to the grocery store, even masked, could be an exposure. And a test today won't catch tomorrow's infection. Tests are also imperfect. 3/
Researchers working with harmless, noninfectious genetic material from the virus (in the form of DNA) were testing positive, over and over again.
They weren't shoving their science up their noses. They were being careful, and doing great work.
The DNA clung to them anyway. 2/
If that DNA happened to overlap with the target of a coronavirus test, that quickly spelled trouble for some. The test picked up that "contaminating" DNA, and thought hey, this is exactly what I was looking for. Positive. 3/