A few studies of interest as the holiday weekend winds down. But first, an intriguing change in Minnesota data that a reader brought to my attention and DD is attempting to chase down. Minnesota has always given us deaths by date reported. And when I last intensively looked at the tables every day last summer and fall, there were no changes in the daily data. Now, apparently on July 1, there has been a massive change in the data for almost every day. The state is no longer answering questions on anything, so hard to know what happened–did they change to date of death reporting? Just funny why that would occur now, but I will let you know if we learn any more about this change.
As usual, let’s focus on good news. Here is study from Chicago, that most mis-managed of cities, finding that the lockdowns were associated with greatly increased opioid overdoses, by over 50%. Among young people opioid fatalities far outnumber CV-19 deaths. (JAMA Article)
The most useful study of the day is one studying the kinetics of an infection. (Medrxiv Paper) The paper finds that viral load is correlated with infectiousness, although not linearly. At the low end of supposed infection and viral load, a person is very non-infectious.
This study followed about 3700 vaccinated health care workers for CV-19 infections. Less than 1% developed an infection, all asymptomatic or mild. Two possible cases of transmission were identified. Only about half the positive persons had samples that could be cultured, so once again we see PCR tests calling people positive who don’t actually have viable virus. (Medrxiv Paper)
One way to ascertain for vaccine effectiveness is to compare potential household transmission of or by vaccinated persons, with that for unvaxed people. (Medrxiv Paper) Vaccine effectiveness appeared to be about 80% by this measure, but note that people were considered fully vaccinated by 7 days after the second dose, which is not nearly long enough, so infection rates are likely exaggerated in the vaccinated group. In addition, no information was given about the seriousness of infections.
More on meteorological factors. This study focused on the role of indoor relative humidity in viral spread. (Arxiv Paper) Humidity affects evaporation rates and suspended particle lifetimes and sizes. The work suggested that conditions similar to drier winter conditions are more favorable to spread that those associated with moister summer ones.
People are trying to figure out excess mortality figures from the epidemic. In this study researchers in Germany determined age specific excess mortality, finding some variability by age groups, but almost all the total excess mortality was accounted for by 90 plus year olds. (Arxiv Paper)
Here is the silly study for the day. One lesson from the epidemic should be that PCR testing is worthless. After reports of teen-agers using soda drinks to obtain false positive rapid antigen test readings, the authors tested a number of soft drinks and sparkling water. They indeed found multiple false positives, mostly low levels. There has to be a better diagnostic tool. (Medrxiv Paper)