2022-01-11 General


This preprint says that Omicron is less virulent than Delta:

  • ~50% less likely to get admitted to hospital from the emergency room;
  • ~75% less likely to go to the ICU;
  • ~70% shorter hospital stay.

Note that something I’m seeing is people not seeing a shorter hospital stay in the UK, e.g. in this tweet. There’s some speculation that it’s being countered by hospital-acquired infections (HAIs).


This preprint says that SARS-CoV-2 virions in aerosols die off pretty quickly: 90% within 20 minutes. Note, though, that I see skepticism on Twitter (e.g. this thread); more people are saying, “wait for the peer review!” than I am used to.

This preprint says (if I understand correctly) that PCR scores don’t always correlate well with true infectiousness (as measured by how well you can grow the virus in test tubes of human cells). They found:

  • Higher PCR scores but lower infectious cultures in COVID Classic than in Delta.
  • With Delta, breakthrough patients had similar PCR scores as unvaxxed patients, but the vaccinated patients had lower infectious cultures and cleared faster.
  • Omicron and Delta grew about equally well in test tubes, meaning it’s something else which makes Omicron more transmissible than Delta.


Cancer patients frequently report “chemo brain” — a type of brain fog which is very similar to the Long COVID brain fog. Previously, a team found that certain cytokines and chemokines (types of signaling protein) were elevated in the central nervous system, causing microgilal cells (central nervous system macrophages which eat defective cells) to go out of control, causing inflammation. This preprint says that they found the same inflammation and same cytokines/chemokines elevated in mice that they’d infected with COVID-19, and in humans with brain fog (but not with Long COVID symptoms without brain fog).

This is a big deal. It does not give a treatment, but it gives a place to start looking.