by monotreme 1000 4/3/2022

B cells, T cells and the brain

As I’ve said many times, I am not an immunologist, so take the following with a large grain of salt. The following is a gross oversimplification.

Our bodies have two major lines of defense against SARS-CoV-2: B cells and T cells. B cells produce antibodies that bind to and inactivate virus. T-cells destroy cells that are infected with virus. B cells are our first line of defense against infection. T cells are our second line of defense.

B cells work well when a vaccine is well-matched against a specific strain, or the individual has recently been infected with the same strain. They work much less well, or not at all, when vaccines are poorly matched against the infecting strain or when a person has been previously infected by another strain.

The effectiveness of T cells, however, appears to hold up better against new strains of SARS-CoV-2.

When both B cells and T cells are working, SARS-CoV-2 cannot get a foothold in our bodies and is quickly destroyed. Not only do we not get sick, we also don’t spread the virus to others.

If B cells fail but T cells work, the virus does get in and does get a foothold but the cells hosting the virus do get killed by T cells limiting its spread. We may get a little bit sick, and we can spread the virus to others, but our odds of dying are much lower than if we were not vaccinated or previously infected with another strain.

Doesn’t sound so bad, right? Here’s the thing, what is typically killing people is damage to the lungs. So, having effective T cells is apparently enough to prevent so much damage to the lungs that we don’t die.

But what about the brain?

It is also affected by SARS-CoV-2. If the B cells don’t work, then the virus can get to the brain. We know that SARS-CoV-2 can cause brain damage. The exact mechanism is unclear. However, I worry that relying on T cells, only, to protect us, will lead to brain damage for many people. There are reports that each attack of SARS-CoV-2 destroys 1% our cerebral cortex, even in "mild" cases. Many people will probably not even notice this loss although some may complain of “brain fog.” If an individual gets infected multiple times with SARS-CoV-2 and is relying only on their T cells to protect them, what happens to their brains?

I worry that the effects of this virus on the brain, even in “mild”, T cell protected infections, is being grossly underestimated. You can lose quite a bit of your cerebral cortex and not die. But do you want to see your IQ lowered every time you get infected?

This is why I still wear a mask even though I have received 4 vaccinations.

XE strain

There is a new strain of SARS-CoV-2 that appears to more infectious than all previous strains. Its current designation is “XE”.

It is recombinant of BA.1 and BA.2. That means it is chimera with part of its genetic material from BA.1 and part from BA.2.

There are two variables that determine whether a new strain of SARS-CoV-2 will become dominant: does it have a transmissibility advantage and can it overcome immunity in the host? XE has a transmissibility advantage. What remains to be seen is whether it can overcome herd immunity conferred by previous strains and vaccines.

A sister of mine in Australia went to her choir practice 2 weeks ago. They met outside and stood 2 metres apart from each other and sang for 30 minutes. She wore her mask the entire time, no one else did. Two days later she started to feel unwell with a sore throat, by the end of the week 16 out of the 20 people present had tested positive to Covid. And they were outside!!!!!

That's how contagious it is!

At this point, I feel like I have had Covid 3 times. Only tested positive once, but same symptoms as other times.  I have had all 3 shots and not looking forward to getting it again!  Really hoping I have some immunity!!