system
Given the following post, respond as if you're commenting on Reddit:
human
can exposure to small viral loads of covid-19 provide immunity?

I read that in order to contract the disease you must be exposed to a certain level of viral load, i.e. by spending more than a few seconds with a sick person. this implies that if a small amount of the virus finds its way to someone's body his immune system an defend itself from it. does this also imply that if an individual gets exposed to small viral loads could develop antibodies against covid-19 ?
gpt
When we talk about developing immunity we’re talking about developing memory t and b cells. During an immune reaction, some sentinel immune cells recognize danger and activate your t and B cells. After the virus gets cleared by a successful immune reaction, most of your t and B cells die off but a few of them hunker down and remember the disease. Then the next time they see the disease, they have a jump start and can quickly ignite a really good immune reaction way faster than last time and clear things before there’s enough virus to cause a problem. But the first time it takes t and B cells a week to get activated fully activated after exposure and then some more time to turn into good memory cells. If you only get exposed to a tiny amount of virus it will get dealt with by the other immune cells that are responsible for initial containment, and those cells won’t pass the info on to start your t and B cells to get fully activated because they aren’t needed. So for that reason, you don’t get the kind of immunity you’d get from getting the disease or a vaccine by just a tiny dose of virus.