First a couple of points on why not to panic in Minnesota or any state right now. According to the state there have been 160923 cases. 136457 have recovered or are cleared from isolation, meaning they aren’t infectious. (Again, the state calculates this no longer needing isolation by just waiting 14 days from when the case was identified. Most stop being infectious long before that.) 2530 have died. So our current active case total is 21,936. If everyone of those has infected or will infect an average of one other person, that would be about 22,000 more cases, which either are already in the case total or will be in the next week or so. We are regularly reporting over 3000 cases a day on average, so I can’t imagine the current transmission rate or R, is much over one. It would take a week for those new cases to show up at that rate of new daily cases. 3844 cases were reported yesterday, but remember that those are spread over at least the prior ten days. That number is 2.4% of the total, and a 2.44% increase over the prior day’s total. Remember when how long it took for cases to double was the thing to watch, well that number is about 40 days right now. The rate of daily growth in the active case total is between 5% and 10%. That will slow shortly, partly because some of the cases in the early part of the swell will be rolling out. Rates of hospitalization are not up, and many of those are short stays related to remdesivir administration and oxygen management. And deaths are even more concentrated in the combination of the very old and LTC residents. So no reason to panic into new lockdowns, school closures, etc. Have a little patience.
One more Minnesota note; we are at 450 deaths per million. As I noted before, we are gaining on Sweden in that ratio. Might get there by the end of the month. When we are there, would you rather have accomplished that dubious feat by living here, under the regime of futile and damaging mitigation orders or in Sweden?
Here is an important paper in what I would think of as the methods area. (Medrxiv Paper) The authors were examining the accuracy of assessments of various interventions to reduce cases in facilities. Outbreaks tend to cause interventions; there is therefore selection bias in determining the effectiveness of the intervention as applied more widely. In addition, variability in infectiousness and susceptibility, which likely accounts for superspreading events, confounds the analysis of an intervention’s effect in these pre and post intervention effect studies. They found that this use of data from larger outbreaks tended to bias the outcomes of studies in favor of finding greater intervention effectiveness than actually existed. I would think the same issue applies to larger population level evaluation of interventions.
This is another study looking at the comparative epidemic performance in higher and lower quality nursing homes. (NBER Study) Quality was measured by Medicare’s system for rating nursing homes. The authors initially note that the death rate from CV-19 among LTC residents is over 150 times that of the community dwelling population. Think about that. The higher quality nursing homes were not more successful in avoiding having at least one CV-19 in the facility, but they were more successful at preventing spread within the facility. As you might expect, facilities with higher ratings had fewer CV-19 deaths. But, and this is very important, they had higher non-CV-19 death rates. Total deaths across facilities were the same. The why is obvious. In clamping down to prevent infections and deaths, the facilities increased the isolation for these very frail people and those restrictions probably led to missed health care for other needs. As the authors suggest, a “more-nuanced” approach might be appropriate.
Understanding household transmission rates and dynamics has proven challenging and inconsistent results have been presented from various studies. This piece of research examined household transmission in Norway. There were 112 index cases. Antibody testing was used to determine secondary attack rates. (Medrxiv Paper) Some of the most interesting findings, however, were not strictly about transmission. But the secondary attack rate varied by age, lowest in children at 43% and highest in those over 60, at 72%. Index cases which were symptomatic were far more likely to transmit than those that were not, 56% versus 16%. The households were tested for positive antibodies and an astoundingly high number of people had antibodies even though they tested negative by PCR test. This suggest much greater prevalence than believed to exist.
This paper explored the role of innate immunity in protecting against CV-19 infection and disease severity. (Medrxiv Paper) The researchers basically built a model which mimicked the interaction between virus and the body. The model identified early general immune processes, those existing against any pathogen, as key to controlling viral load and disease severity.