Variants
This preprint looks at the effectiveness of a COVID-19 infection (as opposed to a vaccination) against future COVID unpleasantness:
| Variant | against infection | against hospitalization or death |
| Alpha | 90.2% | 69.4% |
| Beta | 84.8% | 88.0% |
| Delta | 92.0% | 100% |
| Omicron | 56.0% | 87.8% |
This preprint says that most people have a quite good T-cell response to Omicron after a COVID-19 infection or vaccination, but ~20% have a really crappy response. Boosters help, but even after boosting, ~9% still had a crappy response.
Neither age nor sex nor vaccine brand correlated with whether you had a good response or a crappy response. Infection did give a bit higher T-cell response than vaccination.
Transmission
This preprint says you can estimate the reproductive number by looking at a random sample of Ct levels in your population.
Long COVID
This study found that elite soccer players in Germany and Italy’s performance declined 6% after recovering from COVID-19, and was down 5% even a year later. This lay article about the study points out that elite pro athletes are young, fit, and highly able to get world-class medical care; the rest of us are not as lucky.
This meta-analysis of 81 different papers on Long COVID found that:
- About a third of patients have fatigue at 12 weeks, and almost as many still have fatigue after six months.
- Slightly over one fifth of patients have cognitive impairment at 12 weeks, and almost as many still have it after six months.
- In other words, fatigue and cognitive impairment basically doesn’t get better.
- Fatigue and cognitive impairment were not statistically significantly different between hospitalized and non-hospitalized patients.
- Adults had fatigue at about 3x the rate of children.
- Adults had cognitive impairment at about 2.5x the rate of children.
- The studies reported that between ~30% and ~50% (depending on the study) of patients were not able to return to work.
Recommended Reading
This long Twitter thread talks about Long COVID from many angles.