Thread by @ImmunoEthan

Just a thought: When we discuss #COVID19 severity varying in response to the dose of viral exposure, that likely also has a temporal component. 1/?

As in, clearing a virus from the body requires a coordinated response from multiple arms of the immune system, each of which takes different amounts of time to ramp up. Early innate response is quick, but largely incapable of responding to exponential growth. 2/?

So being exposed to a large dose of virus at once could lead to a hyperreactive innate response that causes exaggerated adaptive immune responses down the line. 3/?

Contrast that with a small infectious dose; innate immune system able to keep early viral replication in check while effectively priming antiviral adaptive response, which then never needs to go systemic (IE fever) and viral infection is maybe controlled asymptomatically. 4/?

Also, #Bcells require #Tcell help to effectively establish humoral #immunity. Some studies implicating early T-cell responses in viral control, leading to minimal Ab response. Confusing, but makes sense when thinking of sequence of events of viral infection and Ab production. 5/5

So I guess I'm on #ScienceTwitter now.