[nomadking]

Originally Posted by jfman

There's no solid evidence for this, merely optimistic speculation. A few of you do have a lot of immediate buy-in to anything that tells you what you want to hear - that the virus isn't serious/will go away by itself/we can go back to normal with little/no restrictions.

Hundreds are now testing positive every day in the 'at risk' age groups. Hospitalisations are creeping up. Test, trace, isolate is falling apart at the seams and the Government are preparing for telling 4.6 million people (customers?) to shield for an almost indefinite period of time.

The way the immune system works is that antibodies disappear after a few months, so no antibodies doesn't meant you're not immune. It would be wasteful of the immune system to be constantly churning out antibodies for every single thing you've come across in your lifetime without the antigen(virus etc) being present.
Differences between Primary and Secondary Immune Response

The primary immune response occurs when an antigen comes in contact to the immune system for the first time. During this time the immune system has to learn to recognize antigen and how to make antibody against it and eventually produce memory lymphocytes.
The secondary immune response occurs when the second time (3rd, 4th, etc.) the person is exposed to the same antigen. At this point immunological memory has been established and the immune system can start making antibodies immediately.

Link

• Declining phase

Antibody levels slowly decrease, due to existing plasma cells dying off, with no new plasma cells generated to replace them. The immunogen has probably been eliminated from the body, so no further antibody production is needed

Secondary Immune Response

For second and subsequent encounters with similar antigens, secondary (anamnestic) immune responses occur. Here, the lag phase is shorter, and high and steady levels of antibodies are generated within a few days. This is due to antigen-specific memory T and B cells, originally produced during the primary response.
Due to the rapidness of the secondary immune response, the antigen can be eliminated from the body fairly soon after it has entered, and before it causes disease. The antibodies produced remain in circulation longer to ensure the infection has disappeared.