Thread by @yoongkhean

Been seeing few folks promoting or doing C19 antibody testing, presumably to ‘check’ whether they received the vaccine in light of the empty syringes reports. Not gonna go into that, but thought I’d elaborate on how our immune response work, in a simplest way possible. /continue

1st of all, the immune response post vax is not just generating antibodies (Ab) & they standby forever waiting for the virus to come.

While the presence of neutralising Ab is a direct response to the antigen introduced by the vax, it’s not the measure of long term immunity.

The level of neutralising Ab will fall in time, body cant continuously produce Ab forever, if not your lymph nodes will also be forever enlarged & your blood will be like peanut butter.

The immune response is mostly a 2 phased curve; primary & secondary Ab response.

Primary response is right after your jab, naive B cells will go thru some changes & make neutralising Abs. After some time the level will drop, since there is no need for Abs to be hang around.

But the work continues, your memory B cells remember how to make the Ab if needed.

So if u get the same infection, memory B cells will get activated, go thru some changes & produce the same Abs needed to fight the infection. But see the 2nd curve, time taken to produce Abs is shorter & level of Abs is higher. This is the ‘strength’ of secondary response.

So in short, there’s a whole lot more than just initial level of nAbs to see if u are protected. Even then, measuring levels of nAb is not necessarily accurate, depends on the lab, person etc.

Just thought I’ll highlight how the immune response works in general. /end