We are now living in a world of testing and antibodies and viruses, and if you don’t have a biology background, some of this information is going to be undecipherable. Here’s quick overview of different stages of our Immune Response and how we get to immunity.
When a new virus infects us, healthy non-immunocompromised bodies react with two timed defenses; Innate, and then Adaptive immunity. How long does this take, and what happens first? (Spoiler: first time around with a new virus, about 2 weeks or 14 days, second time around, much much faster).
When a virus (or unfortunately for those of us with allergies, pollen arghblargh) hits your nose or throat cells, our immune system (I.S.) reacts with a primary innate or general response; “Aigh!! We’re under attack by a new thing! Get it out! Don’t care what it is! Get it out! OUT!!!”
Our I.S. reacts with a non-specific attack on the new viral invader (or pollen which the body stupidly mistakes for a dangerous adversary) starting with mast cells releasing histamines. The result; sneezes (to dislodge and remove the invader), lots of liquid and mucus to wash it out, and inflammatory chemicals called cytokines, which signal for reinforcements of nutrients and other immune cells to the area. Cytokines raise the temperature of the organism to create a hostile environment for invader replication, aka fever. Cytokines also cause inflammation and swelling of the tissues, so in this case the nose and throat constrict, congest and become painful. This all happens after a few days of meeting the virus (days 1-5).
Next on stage are Natural Killer T-cells (NK) which move into action to identify and destroy infected cells, The body also produces proteins called “interferons” (so-called because they interfere with viral replication. I know. Science nomenclature can be a bit unimaginative.)
If all this hasn’t destroyed the invader yet, the fight gets personal. After about 7 days, the Adaptive Immune Response occurs. It’s made up of T- and B- lymphocytes (white blood cells) that have the ability to specifically recognize that particular virus (like a specific key for a lock). The activated white blood cells then clone themselves thousands of times to create armies of specifically-targeted “detect and destroy” T-lymphocytes, or B-lymphocytes that spew out clouds of pathogen-specific antibodies that stick to that particular virus/virally-infected cell and mark it for unavoidable destruction. These adaptive responses customize the response to that particular virus, and a healthy body will fight a regular low-to-medium-virulence virus off in about 2 weeks.
In this way, after you win the fight (you didn’t die, the virus did), you’ll have a positive antibody test for that particular virus because you had an adaptive response, and now have B and T cells and antibodies floating around that will recognize that viral antigen again. The next time your body sees it, the body goes, “Oh no, we’ve seen you before - you are bad news - goodbye!” The Adaptive Immune Response kicks in immediately and kills the virus within a few days, without all the nasty side effects from your innate response the first time around.
These two responses happen every time you encounter a new pathogen - bacterial or viral, so you collect immunity as you age. Kids may seem to be sick all the time, and it’s because they are meeting all the pathogens for the first time and fighting them off messily. This is also the principle behind vaccines: bits of pathogen are injected into you, and your body generates an adaptive immune response to them, so that when the real thing comes along, your body is ready and waiting. Sometimes you need boosters to remind your immune system what to fight off, for example, tetanus boosters are helpful every 10 years or so.
A nasal-swab virus test is a snapshot as to whether there is virus in your nose at the time of the test, but doesn’t tell you anything about your immune status. An antibody blood test lets you know if you successfully fought it off and now have circulating antibodies, which then hopefully confer lasting immunity. The reason for the 2 week Coronavirus quarantine is in part to allow your body to fight the virus and mount an adaptive response, creating identifiable antibodies. If up to 70% of the population can do this, it’s called “herd immunity” and it’s enough to protect the general population from transferring the virus around as quickly.
Some tips: wash your hands, gather and enjoy meeting folks outside where exhaled virus particles can be blown away and diluted, wear masks in close quarters, especially indoors, and up your outdoor gear and indoor ventilation game a LOT.
