For Minnesota readers, just want to point out again that there are very few active cases, i.e., infectious people, in the state. Your odds of running into one are pretty small. I also again will remind you that in a low prevalence population, high levels of testing, even with supposedly accurate tests, crank out lots of false positives. And an increasing number of positive tests are antigen tests, which may have greater accuracy problems. These issues are almost certainly happening in Minnesota. But has the state even one time done a study to check up on this? No, because it is more important to keep terrifying people and keep schools closed to continue teacher contributions flowing to the IB.
The dynamics and circumstances of transmission are still poorly understood. This study examined clusters of cases in Switzerland. (Medrxiv Paper) The researchers studied clusters of cases. They found that some of the most significant clusters had a member with an extremely high viral load (a billion virions or more). Clusters with the lowest average age tended to have the highest viral loads, suggesting either it took more to infect those younger people or they can tolerate higher doses. And the clusters with the highest average ages had low to middle viral loads, which again would suggest that older persons may be more easily infected.
This paper attempted to explore cycle threshold values in regard to epidemic dynamics. (Medrxiv Paper) Daily median cycle numbers were compared with epidemic measures in El Paso from the middle of September to the middle of January. Remember that higher cycle numbers mean less viral load, and vice versa. As cycle number medians rose during this time period, test positivity rates dropped, as did rates of transmission. Hospitalization also dropped but with a lag, as you would expect. Just one more reason to publish cycle numbers and the distribution of cycle numbers. It gives you relevant information about the likely infectiousness of cases and seriousness of disease.
Another piece of research looked at viral shedding across disease severity and age. (Medrxiv Paper) This was a meta-review and analysis. Near symptom onset, the viral load in the upper respiratory tract was substantially higher for severe as opposed to mild illness. Duration and amount of shedding was highly variable. Adults with severe illness tended to have more lower respiratory tract shedding, and therefore were more likely to be infectious.
The testing nuts think that every person should have test kits in their home and test themselves several times a day. Sounds crazy to me and it is. This paper also finds that there can be issues with relying on people to properly test themselves. (Medrxiv Paper) The study compared self-collected swabs and saliva to professional nasal swabbing. The patient collected specimens were less accurate, particularly in asymptomatic persons.
Okay, can we now assume that being infected causes a lasting adaptive immune response, with study after study finding at least 6 months of antibody/T cell protection. The latest is from Austria and covered over 150 people with varying disease severity. Almost every person, around 99%, had some persistent immune response. There was some correlation of response with disease severity. (Medrxiv Paper)
Another study that examined frequency of patients actually getting CV-19 in a health care setting, this study again from England. (Medrxiv Paper) Somewhere between 15% and 20% of all cases in a hospital appeared to be infections acquired in the hospital.