That Bloomberg article says they found viral RNA in brains, not whole culturable virus. This is the problem with a lot of these articles about Delta and Omicron. They are measuring RNA fragments that could circulate in the blood after the immune system has deactivated the virus. Just like the studies that said people shed virus more or longer, when all they are doing is finding RNA fragments by PCR. Yes, those RNA fragments could hang around a long time in the body, especially if the person is dead and their body is chilled. There are tests that show the presence of competent virus, but they are more difficult and expensive. For example, to run one of the tests, you need a live culture of a human cell line or Green Monkey cell line, to see if your sample can infect those cells. Not a test a normal clinical lab could run.

The immune system does not react against RNA, be it human or viral, it reacts against proteins made according to the RNA. (Hopefully, it does not react against your own proteins or you get an autoimmune disease.) Vaccines or an infection introduce viral proteins (like spike) that elicit an immune response. Your immune system makes anti-spike antibodies or a lot of other antibodies from an infection. But it also does a bunch of other things, like make cytokines, activate killer T-cells, etc. Some of those kill infected cells, so they are fairly toxic. Continuing production of such things probably contributes to Long Covid. Simple anoxia can actually cause brain damage. That's why drowning victims and people on ventilators are often never quite the same. Anoxia is a common Covid symptom.

You have to parse statements from government and media very carefully. For example:
Quote
“Those who have received three doses of a vaccine and test positive for COVID-19 are more likely to be infected with infections compatible with the Omicron variant compared with those who are unvaccinated.”
Sounds like big bad Omicron is seeking out the vaccinated. But it doesn't mention that those vaccinated people who get infected are a tiny fraction of people who get infected. Or that triple-vaccinated people may be less careful than the unvaccinated. Or that infections among triple-vaxxed people are generally mild or asymptomatic, no matter what variant. While infections among the unvaxxed are more severe, no matter what variant.

It's really difficult to get any reliable data from infection counts, because human behavior is so unpredictable. It's not like we can lock people up in isolation, and give them uniform virus exposures.

Educating anyone benefits everyone.